source: to-imperative/trunk/compiler/rfp_compile.rf @ 686

// $Source$
// $Revision: 686 $
// $Date: 2003-04-27 14:59:09 +0000 (Sun, 27 Apr 2003) $

$use "rfpc";
$use "rfp_err";
$use "rfp_list";
$use "rfp_helper";
$use "rfp_check";
$use "rfp_as2as";
$use "rfp_format";
$use "rfp_vars";
$use "rfp_const";

$use StdIO;
$use Table;
$use Box;
$use Arithm;
$use Access;
$use Compare;
$use Convert;
$use Class;
$use Apply;
$use Dos;

/*
 * Tables for storing $const'ant values and their lengthes.
 */
$table Const-Len;

/*
 * Table for storing object names.
 */
$table Objects;

/*
 * Table for storing referenced functions.
 */
$table Ref-To-Funcs;

/*
 * Box for storing function out format
 */
$box Out-Format;

/*
 * Box for storing names for function result variables
 */
$box Res-Vars;

/*
 * Following table is used by Gener-Label function for obtaining unical (for
 * certain function) label name.
 * e.Key ::= e.QualifiedName      (parameter given to Gener-Label)
 * e.Val ::= [Int]          (last index used with such e.QualifiedName)
 */
$table Labels;

//$box Var-Stack;
$table Vars-Tab;

$box Last-Re;

$box Greater-Ineqs;
$box Less-Ineqs;

$const New-Clash-Tags = Unknown-length Ties Check-symbols Dereference Compare;

$table Static-Exprs;

$func Compile (e.targets) (e.headers) e.Items = e.Compiled-Items (INTERFACE e.headers);

$func Print-Pragma s.channel t.Pragma = ;

$func AS-To-Ref e.AS-Expr = e.Refal-Expr;

$func Length-of e.Re = e.length;

$func Ref-Len t.name = s.length;

$func? Hard-Exp? e.expr = ;

$func Comp-Func-Stubs = e.asail-funcs;

$func Comp-Func s.tag t.name e.params-and-body = e.compiled-func;

$func Set-Drops (e.declared-exprs) e.comp-func = (e.declared-exprs) e.result-func;

$func Comp-Sentence e.Sentence = e.asail-sentence;

$func Save-Snt-State = ;

$func Recall-Snt-State = ;

$func Pop-Snt-State = ;

$func Extract-Calls e.Re = (e.last-Re) e.calls;

$func Comp-Static-Exprs e.Reult-exprs = e.Result-exprs;

$func Get-Clash-Sequence (e.last-Re) e.Snt = (e.clashes) e.rest-of-the-Sentence;

$func Comp-Pattern t.Pattern e.Snt = e.asail-Snt;

$func? Without-Calls? e.Re = ;

//$func Old-Vars e.expr = e.expr;

//$func Find-Known-Lengths e.clashes = (e.known-len-clashes) e.clashes;

//$func? Known-Vars? e.vars = ;

$func Comp-Clashes (e.clashes) s.tail? (v.fails) e.Sentence = e.asail-sentence;

$func? Find-Var-Length e.clashes = e.cond (e.clashes);

$func Update-Ties t.var e.clashes = e.clashes;

$func Known-Length-of e.expr = e.known-length (e.unknown-vars);

$func? Cyclic-Restrictions e.clashes = e.cond (e.clashes);

$func Cyclic-Min t.var = e.min;

$func? Cyclic-Max t.var = e.max;

$func? Check-Symbols e.clashes = e.cond (e.clashes) s.new?;

$func? Check-Ft t.Ft (e.pos) (e.right-pos) t.name s.dir = e.Ft-cond s.stop?;

$func? Dereference-Subexpr e.clashes = e.cond (e.clashes);

$func Compare-Subexpr e.clashes = e.cond (e.asserts) (e.clashes) s.new?;

$func Compare-Ft t.Ft = e.Ft-cond s;

$func? Get-Source e.clashes = e.cond (e.clashes);

$func Compose-Expr e.expr = e.compose (e.not-instantiated-vars) s.flat?;

$func? Comp-Cyclic e.clashes = e.cond (e.clashes) (e.fail);

$func Get-Subexprs e.vars = e.asail-decls;

$func Unknown-Vars e.expr = e.known-expr (e.unknown-vars);

$func Split-Hard-Left e.expr = e.hard;

$func Split-Hard-Right e.expr = e.hard;

$func Gener-Label e.QualifiedName = t.label;

$func Add-To-Label t.label e.name = t.label;

$func Comp-Calls e.Re = e.calls;

$func Comp-Assigns e.assignments = e.asail-assignments;

$func Comp-Format (e.last-Re) e.He = e.assignments;

$func Get-Static-Exprs e.expr = e.expr (e.decls);

$func Get-Static-Var e.expr = e.var (e.decl);



************ Get AS-Items and targets, and pass it to Compile ************

RFP-Compile e.Items =
  { <Lookup &RFP-Options ITEMS>;; } :: e.targets,
  <Init-Consts>,
  <Compile (e.targets) () e.Items> :: e.Items t.Interface,
  t.Interface (MODULE <Comp-Consts> e.Items);



****************** Choose needed items and compile them ******************

Compile (e.targets) (e.headers) e.Items, {
  e.Items : e t.item e.rest,
    {
      e.targets : v =
        e.targets : e t.name e,
        t.item : (t t t t.name e);;
    }, \{
      t.item : (s.link s.tag t.pragma t.name (e.in) (e.out) e.body) =
//        <WriteLN s.link s.tag t.name>,
        { s.link : EXPORT = (DECL-FUNC t.name);; } :: e.decl,
        {
          e.body : (BRANCH t.p e.branch) =
            <Comp-Func s.tag t.name <Del-Pragmas (e.in) (e.out) e.branch>>;;
        } :: e.comp-func,
        (e.decl) e.comp-func;
      t.item : (s.link CONST t.pragma t.name e.expr) =
        {
          s.link : IMPORT = () (DECL-CONST t.name);
          <Del-Pragmas e.expr> :: e.expr,
            (CONSTEXPR s.link t.name (e.expr) e.expr) :: e.const,
            {
              s.link : EXPORT = (e.const) /*empty*/;
              () e.const;
            };
        };
    } :: (e.decl) e.item =
    e.item <Compile (e.targets) (e.headers e.decl) e.rest>;
  /*<Comp-Func-Stubs>*/ (INTERFACE e.headers);
};

/*
 * For each referenced function generate a stub one with format e = e.
 */
Comp-Func-Stubs =
  <Domain &Ref-To-Funcs> () $iter {
    e.funcs : ((e.QualifiedName)) e.rest,
      (e.QualifiedName 0) :: t.Fname,
//      <Bind &Ref-To-Funcs ((e.QualifiedName)) (t.Fname)>,
//      {
//        <In-Table? &Fun? (e.QualifiedName)> =
//          <Bind &Back-Funcs (t.Fname) ()>;;
//      },
//      <Bind &Fin (t.Fname) ((EVAR))>,
//      <Bind &Fout (t.Fname) ((EVAR))>,
      <Lookup-Func (e.QualifiedName)> :: s.linkage s.tag t.pragma (e.Fin) (e.Fout),
      <Gener-Vars (e.Fin) "stub"> :: e.He,
      <Comp-Func s.tag t.Fname ((EVAR ("arg" 1))) ((EVAR ("res" 1)))
        (LEFT e.He) (RESULT (CALL (e.QualifiedName) e.He))
      > :: e.asail,
      e.rest (e.asail-funcs e.asail);
  } :: e.funcs (e.asail-funcs),
  e.funcs : /*empty*/ =
  // Here is place to define expressions - references to stub functions.
  // Use &Ref-To-Funcs for that.
  e.asail-funcs;

Comp-Func s.tag t.name (e.in) (e.out) e.Sentence =
  <RFP-Clear-Table &Labels>,
  <RFP-Clear-Table &Static-Exprs>,
  <Store &Greater-Ineqs /*empty*/>,
  <Store &Less-Ineqs /*empty*/>,
//!     <RFP-Clear-Table &Vars-Tab>,
  <Init-Vars>,
  <Ref-To-Var e.Sentence> :: e.Sentence,
//!     <Store-Vars <Vars e.out>> :: e.res-vars,
  <Vars <Gener-Vars (e.out) "res">> :: e.res-vars,
  <Vars-Decl e.res-vars> : e,
  <Store &Res-Vars e.res-vars>,
  <Store &Out-Format <Format-Exp e.out>>,
//!     <Norm-Vars (<Vars e.in>) e.Sentence> :: (e.arg-vars) e.Sentence,
//!     <Declare-Vars Expr e.arg-vars> : e,
  <Vars <Gener-Vars (e.in) "arg">> :: e.arg-vars,
  <Vars-Decl e.res-vars> : e,
*       <Instantiate-Vars e.arg-vars>,
  <Store &Last-Re /*empty*/>,
  s.tag : {
    FUNC = FATAL;
    FUNC? = RETFAIL;
  } :: t.retfail,
  (FUNC t.name (<Vars-Print e.arg-vars>) (<Vars-Print e.res-vars>)
    <Comp-Sentence Tail ((t.retfail)) () e.Sentence>
  ) :: e.comp-func,
  <Set-Drops () <Gener-Var-Names e.comp-func>> :: t e.comp-func,
//!     <Post-Comp (e.res-vars) e.comp-func> :: t e.result,
//!     e.result;
  e.comp-func;
//  :: (e.func-decl) e.func-body,
//  () <Domain &Declarations> $iter {
//    e.vars : (t.var) e.rest-vars,
//      (e.var-decls (DECL t.var)) e.rest-vars;
//  } :: (e.var-decls) e.vars,
//  e.vars : /*empty*/,
//  (e.func-decl e.var-decls e.func-body);

Ref-To-Var e.Snt =
  () e.Snt $iter {
    e.Snt : t.Statement e.rest, t.Statement : {
      (REF t.name) = (e.new-Snt /*<New-Vars (VAR REF t.name)>*/) e.rest;

//!                     <Table> :: s.tab,
//!                     <Bind &Vars-Tab (t.name) (s.tab)>,
//!                     <Set-Var t.name (Format) (<Format-Exp (REF t.name)>)>,
//!                     <Set-Var t.name (Declared) (True)>,
//!                     <Set-Var t.name (Instantiated) (True)>,
//!                     <Set-Var t.name (Left-compare) ()>,
//!                     <Set-Var t.name (Right-compare) ()>,
//!                     <Set-Var t.name (Left-checks) ()>,
//!                     <Set-Var t.name (Right-checks) ()>,
//!                     (e.new-Snt (VAR t.name)) e.rest;

      (e.expr) = (e.new-Snt (<Ref-To-Var e.expr>)) e.rest;
      t = (e.new-Snt t.Statement) e.rest;
    };
  } :: (e.new-Snt) e.Snt,
  e.Snt : /*empty*/ =
  e.new-Snt;

Set-Drops (e.declared) e.comp-func =
  e.comp-func () (e.declared) $iter {
    e.comp-func : t.first e.rest, {
      t.first : \{
        (EXPR t.var e) = (DROP t.var) (t.first) t.var Init;
        (DEREF t.var e) = (DROP t.var) (t.first) t.var Init;
        (SUBEXPR t.var e) = (DROP t.var) (t.first) t.var Init;
        (DECL Expr t.var) = (DROP t.var) () t.var Decl;
        (DECL "int" t.var) = /*empty*/ () t.var Decl;
      } :: e.drop (e.constr) t.var s.init,
        {
          e.declared : e1 t.var s.old-init e2, s.old-init : {
            Init, {
              t.var : (VAR ("const" e)) =
                e.rest (e.result-func) (e.declared);
              e.rest (e.result-func e.drop e.constr) (e.declared);
            };
            Decl, s.init : {
              Decl =
                e.rest (e.result-func) (e.declared);
              Init =
                t.first : (s.method t.var e.args),
                e.rest (e.result-func (ASSIGN t.var (s.method e.args)))
                (e1 e2 t.var s.init);
                /*
                 * FIXME: if s.method is EXPR, it shouldn't be written.
                 */
            };
          };
          e.rest (e.result-func t.first) (e.declared t.var s.init);
        };
      t.first : (LABEL t.label e.expr) =
        <Set-Drops (e.declared) e.expr> :: (e.declared) e.expr,
        e.rest (e.result-func (LABEL t.label e.expr)) (e.declared);
      t.first : (e.expr) =
        <Set-Drops (e.declared) e.expr> :: t e.expr,
        e.rest (e.result-func (e.expr)) (e.declared);
      t.first : s.symbol =
        e.rest (e.result-func s.symbol) (e.declared);
    };
  } :: e.comp-func (e.result-func) (e.declared),
  e.comp-func : /*empty*/ =
  (e.declared) e.result-func;


Comp-Sentence s.tail? (v.fails) (e.last-Re) e.Sentence, e.Sentence : {

  /*empty*/ = /*empty*/;

  /*
   * In case of Re look if we should do a tailcall.  If not, then compile
   * function calls from the Re and assign results to the out parameters or
   * use them in compilation of the rest of the sentence.
   */
  (RESULT e.Re) e.Snt =
    {
      /*
       * If the Re is the last action in the sentence then we can do
       * tailcall if one of the following is true:
       *  - Re is a call of non-failable function;
       *  - Re is a call of a failable function, current function is
       *  failable, and the failures stack is empty.
       * In both cases out format of the called function should coincide
       * with those of compiled one.
       * FIXME: really we can do tailcall if all the parameters of
       * compiled function that won't get their values from the call can
       * be assigned from other sources.  Some support from runtime is
       * needed though.
       */
      e.Snt : /*empty*/, s.tail? : Tail, e.Re : (CALL t.name e.arg),
        { <In-Table? &Fun? t.name> = v.fails : (RETFAIL);; },
        <Lookup-Func t.name> :: s.linkage s.tag t.pragma (e.Fin) (e.Fout),
        <Subformat? (e.Fout) (<? &Out-Format>)> =
        <Extract-Calls e.arg> :: (e.last-Re) e.calls,
        <Comp-Static-Exprs <Split-Re (e.Fin) e.last-Re>> :: e.splited-Re,
        <Comp-Calls <R 0 v.fails> e.calls>
        (TAILCALL t.name (e.splited-Re) (<? &Res-Vars>));

      <Extract-Calls e.Re> :: (e.last-Re) e.calls,
        <Comp-Calls <R 0 v.fails> e.calls> :: e.comp-calls,
        {
          e.Snt : /*empty*/, s.tail? : Tail =
            <Split-Re (<? &Out-Format>) e.last-Re> :: e.splited-Re,
            <Comp-Static-Exprs e.splited-Re> :: e.splited-Re,
            e.comp-calls <Comp-Assigns <Zip (<? &Res-Vars>) (e.splited-Re)>>;

          e.comp-calls <Comp-Sentence s.tail? (v.fails) (e.last-Re) e.Snt>;
        };
    };

  /*
   * In case of He compile assignments from last Re and then (with new state
   * of variables) proceed with the rest of the sentence.
   */
  (FORMAT e.He) e.Snt =
    <Comp-Format (e.last-Re) e.He>
    <Comp-Sentence s.tail? (v.fails) () e.Snt>;

  /*
   * In case of Pe get from the begining of the sentence a maximum possible
   * sequence of clashes and compile it.  New values of variables from the
   * clashes use in the compilation of the rest of the sentence.
   */
  (s.dir e.Pattern) e.Snt, s.dir : \{ LEFT; RIGHT; } =
    <Get-Clash-Sequence (e.last-Re) e.Sentence> :: (e.clashes) e.Sentence,
//    <WriteLN !!! e.clashes>,
    <Comp-Clashes (e.clashes) s.tail? (v.fails) e.Sentence>;

  (s.block) e, BLOCK BLOCK? : e s.block e = <WriteLN! &StdErr "Empty block?">, $fail;

  /*
   * In case of a block first see if its results are needed for something
   * after the block and determine whether the block is a source.  Then
   * compile each branch in turn.
   */
  (s.block e.branches) e.Snt,
    s.block : \{
      BLOCK = (FATAL);
      BLOCK?;
    } :: e.fatal? =
    /*
     * If the block initializes an $iter then extract from the $iter the He
     * for placing it in the end of each branch.
     * Then look if the block is used by a pattern or format expression.
     * If so, we should declare variables from that expression before
     * entering any branch -- those should be visible after the block.
     * If next after the block is (Comp Error) then block results should be
     * used as values for $error, so place (Comp Error) in the end of each
     * branch.
     */
    {
      e.Snt : (ITER t.body t.format t.cond) e.rest =
        t.format (Comp Iter t.body t.format t.cond) e.rest;
      e.Snt;
    } :: e.Snt,
    e.Snt : {
      t.first e.rest, t.first : \{
        (LEFT e.pattern) = e.pattern;
        (RIGHT e.pattern) = e.pattern;
        (FORMAT e.format) = e.format;
      } :: e.expr =
        <Vars e.expr> :: e.vars,
*                               <New-Vars e.vars>,
        (<Vars-Decl e.vars>) (t.first) ((Comp Source)) e.rest;
      (Comp Error) e.rest =
        () ((Comp Error)) () /*empty*/;
      e = () () () e.Snt;
    } :: (e.decls) (e.next-term) (e.source?) e.Snt,
    /*
     * The block is a source if after it goes pattern or format expression
     * (in that case e.source? isn't empty) or e.Snt isn't empty.
     * Branches in the block are tail sentences if the current sentence is
     * tail and the block isn't a source.
     */
    {
      \{ e.source? : v; e.Snt : v; } = ((Comp Source)) Notail;
      s.tail? : Tail = () Tail;
      () Notail;
    } :: (e.source?) s.tail-branch?,
    /*
     * In case our block is a source we should mark the position in the
     * failures stack, so that we can jump to it after CUTALL.  And if our
     * block isn't failable we should add (FATAL) to the end of the stack.
     */
    v.fails e.source? e.fatal? :: v.branch-fails,
    /*
     * We put all compiled branches in a block, so positive return from a
     * branch is a break from that block.
     * Each branch in its turn is placed in its own block, so for a $fail
     * to the next branch we should just break from that inner block.
     * Each branch is compiled with the current sentence state and the
     * state is recalled after that.  When all branches are compiled the
     * state is popped out from the stack.
     * If last branch fails then the whole block fails, and return from the
     * last branch is return from the block.  So the last branch isn't
     * placed in a block and is processed with the failures stack that was
     * before entering the block.  Note: this trick helps us find more
     * tailcalls.  If the call of a failable function is on the last branch
     * of the block and the failures stack is empty we can do tailcall.
     * When the last branch is compiled with the block's stack, all we
     * should do is to check it.
     */
    <Gener-Label "block"> :: t.label,
    <Save-Snt-State>,
    (e.branches) /*e.comp-branches*/ $iter {
      e.branches : (BRANCH e.branch) e.rest-br =
        <Add-To-Label t.label "branch"> :: t.br-label,
        <Comp-Sentence
          s.tail-branch?
          (v.branch-fails ((BREAK t.br-label)))
          (e.last-Re)
          e.branch e.next-term
        > :: e.comp-br,
        <Recall-Snt-State>,
        (e.rest-br) e.comp-branches (LABEL t.br-label e.comp-br (BREAK t.label));
    } :: (e.branches) e.comp-branches,
    e.branches : (BRANCH e.branch) =
    <Comp-Sentence
      s.tail-branch? (v.branch-fails) (e.last-Re) e.branch e.next-term
    > :: e.last-branch,
    <Pop-Snt-State>,
    e.decls (LABEL t.label e.comp-branches e.last-branch)
    <Comp-Sentence s.tail? (v.fails) () e.Snt>;

  /*
   * In case of $iter first of all compile initial assignment to the hard
   * expression.
   */
  (ITER t.body t.format t.cond) e.Snt =
    <Comp-Sentence s.tail? (v.fails) (e.last-Re)
      t.format (Comp Iter t.body t.format t.cond) e.Snt
    >;

  /*
   * Then compile $iter condition and body both with the current state of the
   * sentence.
   * e.Snt can contain only (Comp Error), so compile it together with the
   * condition.
   * If condition fails we should compute the body, so put the compiled
   * condition in a block and place a break from it to the failures stack.
   */
  (Comp Iter (BRANCH e.body) t.format (BRANCH e.condition)) e.Snt =
    <Gener-Label "iter"> :: t.label,
    <Save-Snt-State>,
    <Comp-Sentence s.tail? (v.fails ((BREAK t.label))) () e.condition e.Snt>
      :: e.comp-condition,
    <Pop-Snt-State>,
    <Comp-Sentence Notail (v.fails) () e.body t.format> :: e.comp-body,
    (FOR () () () (LABEL t.label e.comp-condition) e.comp-body);

  /*
   * In case of $trap/$with at first compile try-sentence.  All $fails from
   * it should become errors.
   * Then recall the state of the sentence and compile catching of an error
   * with a variable err.
   * e.Snt can be only (Comp Error), so compile it together with both
   * sentences -- when either of it comuptes to an object expression it
   * becomes a value of the $error.
   */
  (TRY (BRANCH e.try) e.catch) e.Snt =
    <Save-Snt-State>,
    <Comp-Sentence Notail ((FATAL)) () e.try e.Snt> :: e.comp-try,
    <Pop-Snt-State>,
    <Comp-Sentence s.tail? (v.fails) () (RESULT (EVAR ("err" 0))) e.catch e.Snt>
      :: e.comp-catch,
    (TRY e.comp-try) (CATCH-ERROR e.comp-catch);

  /*
   * In case of \? add Stake to the failures stack.  Add last fail after it
   * for <R 0 v.fails> continue to work.
   */
  (STAKE) e.Snt =
    <Comp-Sentence s.tail? (v.fails (Comp Stake) <R 0 v.fails>) () e.Snt>;

  /*
   * In case of \! forget all failure catchers after last \?.
   * If there is no Stake then we are inside negation or error (we assume the
   * program is correct).  So the right failure catcher is in the bottom of
   * the stack.
   */
  (CUT) e.Snt =
    {
      v.fails : $r v.earlier-fails (Comp Stake) e = v.earlier-fails;
      <L 0 v.fails>;
    } :: v.fails,
    <Comp-Sentence s.tail? (v.fails) () e.Snt>;

  /*
   * In case of = clear the failures stack up to the closest source.
   */
  (CUTALL) e.Snt =
    {
      v.fails : $r v.earlier-fails (Comp Source) e = v.earlier-fails;
      <L 0 v.fails>;
    } :: v.fails,
    <Comp-Sentence s.tail? (v.fails) () e.Snt>;

  /*
   * In case of = in the Refal-6 sense (non-transparent hedge for the fails),
   * $fail(k) should become $error(Fname "Unexpected fail"), so clear the
   * failures stack and put that value in it.
   */
  NOFAIL e.Snt =
    <Comp-Sentence s.tail? ((FATAL)) (e.last-Re) e.Snt>;

  /*
   * In case of $fail return last failure catcher.
   */
  (FAIL) e.Snt =
    v.fails : e (e.last-fail),
    e.last-fail;

  /*
   * In case of # we should proceed with the rest if the source is computed
   * to $fail.
   * We could compile the rest of the sentence and place it in the
   * failures stack.  But then the compiled sentence would be copied as many
   * times as there are $fail's to the upper level in the source.  So we
   * place compiled source in the block and put the break to exit from it in
   * the stack.
   * When compiling the source mark it as Notail as usual.
   * If the source isn't computed to $fail we should proceed with the last
   * failure catcher.
   */
  (NOT (BRANCH e.branch)) e.Snt =
    <Gener-Label "negation"> :: t.label,
    v.fails : e (e.last-fail),
//    <Save-Snt-State>,
    <Comp-Sentence Notail (((BREAK t.label))) () e.branch> e.last-fail
      :: e.comp-negation,
//    <Pop-Snt-State>,
    (LABEL t.label e.comp-negation)     <Comp-Sentence s.tail? (v.fails) () e.Snt>;

//  (Comp Verbatim expr) = expr;

  /*
   * In case of $error all fails become $error(Fname "Unexpected fail").  So
   * place that value in the failures stack and then compile the computation
   * of the rest of the sentence and the last Re which should be the value of
   * $error.
   */
  (ERROR) e.Snt =
    <Comp-Sentence Notail ((FATAL)) e.Snt () (Comp Error)>;

  (Comp Error) e.Snt = (ERROR e.last-Re);

//  (Comp Fatal) = FATAL;

//  (Comp Retfail) = RETFAIL;

};



********** Sentence state stack and functions for work with it. **********

$box Snt-State;

/*
 * Put current state in the stack.
 */
Save-Snt-State = <Put &Snt-State <Vars-Copy-State>>;

/*
 * Set current state to that at the top of the stack.
 */
Recall-Snt-State = <Vars-Set-State <R 0 <? &Snt-State>>>;

/*
 * Pop the top from the stack and set current state to it.
 */
Pop-Snt-State =
  <Recall-Snt-State>,
  <Store &Snt-State <Middle 0 1 <? &Snt-State>>>;



********************** Function calls compilation. ***********************

/*
 * $func Extract-Calls e.Re = (e.last-Re) e.calls;
 *
 *
 *
 */
Extract-Calls {
  (CALL t.name e.arg) e.rest =
    <Lookup-Func t.name> :: s.linkage s.tag t.pragma (e.Fin) (e.Fout),
    <Extract-Calls e.arg> :: (e.last-Re) e.calls,
    <Comp-Static-Exprs <Split-Re (e.Fin) e.last-Re>> :: e.splited-Re,
    <RFP-Extract-Qualifiers t.name> :: t e.prefix,
*               <Del-Pragmas <Gener-Vars 0 (e.Fout) e.prefix>> : e.Re s,
//!             <Store-Vars <Vars e.res-Re>> :: e.ress,
//!             <Instantiate-Vars e.ress>,
//!             <Ref-To-Var <Strip-STVE e.res-Re>> :: e.res-Re,
//!             e.decls <Declare-Vars "Expr" e.ress> :: e.decls,
    <Gener-Vars (e.Fout) e.prefix> :: /*(e.vars)*/ e.Re,
    <Vars e.Re> :: e.vars,
*               <Instantiate-Vars e.vars>,
    {
      s.tag : FUNC? =   (Failable (CALL t.name (e.splited-Re) (e.vars)));
      (CALL t.name (e.splited-Re) (e.vars));
    } :: t.call,
    <Extract-Calls e.rest> :: (e.rest-Re) e.rest-calls,
    (e.Re e.rest-Re) e.calls <Vars-Decl e.vars> t.call e.rest-calls;
  (PAREN e.Re) e.rest =
    <Extract-Calls e.Re> :: (e.last-Re) e.calls,
    <Extract-Calls e.rest> :: (e.rest-Re) e.rest-calls,
    ((PAREN e.last-Re) e.rest-Re) e.calls e.rest-calls;
  t.Rt e.Re =
    <Extract-Calls e.Re> :: (e.last-Re) e.calls,
    (t.Rt e.last-Re) e.calls;
  /*empty*/ = () /*empty*/;
};


Comp-Calls (e.fail) e.calls, e.calls : {
  (Failable t.call) e.rest =
    (IF ((NOT t.call)) e.fail) <Comp-Calls (e.fail) e.rest>;
  t.call e.rest =
    t.call <Comp-Calls (e.fail) e.rest>;
  /*empty*/ = /*empty*/;
};



*********** Compilation of static parts of result expressions ************

$func Static-Expr? s.create? e.Re = static? e.Re;

$func Static-Term? t.Rt = static? t.Rt;


/*
 * Extract static parts from each Re.
 */
Comp-Static-Exprs {
  (e.Re) e.rest = <Static-Expr? Create e.Re> :: s e.Re, (e.Re) <Comp-Static-Exprs e.rest>;
  /*empty*/     = /*empty*/;
};


/*
 * Find all the longest static parts in the upper level of Re.  Create STATIC
 * form in place of each one.
 * Return a tag pointing whether the whole expression is static and expression
 * with static parts replaced by STATIC forms.  Dynamic parts are returned
 * unchanged.
 */
Static-Expr? {
  s.create? t.Rt e.Re =
    <Static-Term? t.Rt> : {
      Static t.Rt =
        {
          e.Re : e1 t2 e3, <Static-Term? t2> : Dynamic t.dyn-Rt =
            <Static-Expr? Create e.Re> :: s e.Re,
            Dynamic <Create-Static t.Rt e1> t.dyn-Rt e.Re;
          {
            s.create? : Create = Static <Create-Static t.Rt e.Re>;
            Static t.Rt e.Re;
          };
        };
      Dynamic t.dyn-Rt =
        <Static-Expr? Create e.Re> :: s e.Re,
        Dynamic t.dyn-Rt e.Re;
    };
  s.create? /*empty*/ = Static;
};


/*
 * The same as Static-Expr? but for terms.
 */
Static-Term? {
  symbol       = Static symbol;
  (PAREN e.Re) = <Static-Expr? Not-Create e.Re> :: static? e.Re, static? (PAREN e.Re);
  (REF t.name) = Static (REF t.name);
  t.var        = Dynamic t.var;
};



***************** Compilation of assignment to variables *****************

$func Comp-Assign-to-Var e = e;

Comp-Assign-to-Var (t.var (e.Re)), {
  t.var : e.Re = /*empty*/;
  <Generated-Var? e.Re> = <Gener-Var-Assign t.var e.Re>;
  <Declared? t.var> = (ASSIGN <Vars-Print t.var> e.Re);
  <Vars-Decl t.var> : e, (EXPR <Vars-Print t.var> e.Re);
};

Comp-Assigns e.assigns = <Map &Comp-Assign-to-Var (e.assigns)>;



************************** FORMAT compilation. ***************************

$box Aux-Index;

$func Gener-Aux-Var = t.new-aux-var;

Gener-Aux-Var =
  <? &Aux-Index> : s.n,
  <Store &Aux-Index <"+" s.n 1>>,
  (VAR ("aux" s.n));


$func Create-Aux-Vars (e.vars) e.splited-Re = e.assigns;


Comp-Format (e.last-Re) e.He =
  <Vars e.He> :: e.vars,
  <Comp-Static-Exprs <Split-Re (<Format-Exp e.He>) e.last-Re>> :: e.splited-Re,
  <Store &Aux-Index 1>,
  <Create-Aux-Vars (e.vars) e.splited-Re> :: e.assigns,
  <Comp-Assigns e.assigns>;

/*
 * Итак, e.vars -- все переменные, входящие в форматное выражение.  Каждая
 * переменная может входить в форматное выражение только один раз, поэтому
 * повторяющихся среди них нет.
 * e.splited-Re -- набор результатных выражений.  На каждую переменную из
 * e.vars по выражению, которое должно быть ей присвоено.
 * 
 * Если переменная t.var_i используется в выражении e.Re_j, и i /= j, то
 * переменной t.var_j значение должно быть присвоено раньше, чем перeменной
 * t.var_i.  Если же, по аналогичным соображениям, t.var_i должна получить
 * значение раньше t.var_j, необходимо завести вспомогательную переменную.
 *
 * Пример:
 * 
 * t1 (t1 t2) (t1 t3) :: t2 t1 t3
 *
 * t3 = (t1 + t3)();
 * aux_1 = t1;
 * t1 = (t1 + t2)()
 * t2 = aux_1;
 * 
 * В общем случае вспомогательная переменная требуется, если двум переменным
 * необходимы старые значения друг друга (возможно, не напрямую, а через
 * промежуточные переменные).
 *
 * Вместо того, чтобы искать и анализировать такие циклы, будем действовать по
 * методу "наибольшей пользы".  А именно:
 * 
 *   - Для каждой переменной выпишем все другие переменные, которым требуется
 *     её старое значение, а также отдельно те, старые значения которых
 *     требуются ей.
 *
 *   - Всем переменным, от старых значений которых ничего не зависит, можно
 *     смело присвоить новые значения.  При этом они исчезают из списков
 *     зависимостей оставшихся переменных.
 *
 *   - Все переменные, новые значения которых ни от чего не зависят, можно
 *     отложить, чтобы присвоить им значения тогда, когда будет удобно.  Т.е.
 *     тогда, когда списки зависящих от них переменных опустеют.
 *
 *   - Чтобы означить оставшиеся, нужны вспомогательные переменные.  Выберем
 *     одну из переменных, с максимальным списком тех, от которых она зависит,
 *     и положим её значение во вспомогательную переменную.  Так как мы сразу
 *     уменьшили кол-во зависимостей у максимального кол-ва переменных,
 *     локально мы добились наибольшей пользы, хотя не исключено, что глобально
 *     такой метод и не даст наименьшего кол-ва вспомогательных переменных.
 *     Кроме того, мы не пытаемся выбрать наилучшую переменную из нескольких с
 *     максимальным списком зависимостей.
 *
 *   - Повторяем всё это до тех пор, пока у каждой переменной не опустеет
 *     список зависящих от неё.
 *
 *
 * Для нашего примера:
 * 
 * t1 (t1 t2) (t1 t3) :: t2 t1 t3
 *
 * t1 -- (t2 t3) (t2)
 * t2 -- (t1)    (t1)
 * t3 -- ()      (t1)
 *
 *
 * Для каждой переменной var_i найдём все j /= i, такие что в Re_j встречается
 * var_i -- provide[i], и а также все j /= i, такие что var_j нужна для
 * подсчёта var_i, т.е. встречается в Re_i.
 *
 * Res-vars <- <Map &Vars (Res)>
 * for var_i in vars
 *     provide[i] <-
 *     for vars-Re_j in Res-vars, j /= i
 *         vars-Re_j : e var_i e = j
 *     require[i] <- <Res-vars[i] `*` vars[^i]> : e var_j e, j
 *
 * Res-vars = map Vars Res
 * provide, require =
 *   {   [ j | vars-Re_j <- Res-vars, j /= i, var_i `in` vars-Re_j ]
 *     , [ j | var_j <- Res-vars[i] `*` vars, i /= j]
 *     | var_i <- vars
 *   }
 *
 */

$func CAV e.vars (e.assigns) (e.delayed) = e.assigns;

$func Get-Vars e = e;
Get-Vars (e.Re) = (<Vars e.Re>);

Create-Aux-Vars (e.vars) e.splited-Re =
  <Zip (<Map &Get-Vars (e.splited-Re)>) (e.vars)> :: e.list,
  <Box> :: s.box,
  <Box> :: s.provide-i,
  <Box> :: s.require-i,
  {
    e.vars : e1 t.var-i e2,
      {
        e.list : e ((e.vars-Re) t.var-j) e,
          \{
            t.var-i : t.var-j = <Put s.require-i <And (e1 e2) e.vars-Re>>;
            e.vars-Re : e t.var-i e = <Put s.provide-i t.var-j>;
          },
          $fail;
        <L <Length e1> e.splited-Re> :: t.Re-i,
        <Put s.box (t.var-i t.Re-i (<? s.provide-i>) (<? s.require-i>))>,
          <Store s.provide-i /*empty*/>,
          <Store s.require-i /*empty*/>;
      },
      $fail;;
  },
  <CAV <? s.box> (/*assigns*/) (/*delayed*/)>;


/*
 * Если есть переменная, у которой список provide пуст, её можно посчитать.
 * Это выражается в том, что она (вместе с присваиваемым значением) добавляется
 * в список assigns, убирается из списка vars, а также из всех списков provide
 * и delayed.  В списках require её не было.
 *
 * CAV Res vars provide require assigns delayed =
 *   { i | var_i <- vars, provide_i == [] } ->     // Здесь неверно!  На переменные
 *                                                    из delayed тоже надо смотреть.
 *       vars    = vars - var_i
 *       provide = [ provide_j - i | provide_j <- provide ]
 *       assigns = assigns++[(var_i, Res[i])]
 *       delayed = [ (var_j, provide_j - i) | (var_j, provide_j) <- delayed ]
 *       CAV Res vars provide require assigns delayed
 */

$func Assign-Empty-Provides e.vars  = e.assigns (e.vars);

Assign-Empty-Provides {
  e1 (t.var-i t.Re-i (/*empty provide_i*/) (e.require-i)) e2 =
    <Box> :: s.vars,
    {
      e1 e2 : e (t.var-j t.Re-j (e.provide-j) (e.require-j)) e,
        <Put s.vars (t.var-j t.Re-j (<Sub (e.provide-j) t.var-i>) (e.require-j))>,
        $fail;;
    },
    (t.var-i t.Re-i) <Assign-Empty-Provides <? s.vars>>;
  e.vars = /*empty*/ (e.vars);
};


/*
 * Если есть переменная, у которой список require пуст, кладём её в delayed.
 * Она будет посчитана, когда у неё опустеет список provide, т.е. когда не
 * останется переменных, у которых она в списке require.
 */
$func Delay-Empty-Requires e.vars  = e.delayed (e.vars);

Delay-Empty-Requires {
  e1 t.var e2, t.var : (t.var-i t.Re-i (e.provide-i) (/*empty require_i*/)) =
    <Delay-Empty-Requires e2> :: e.delayed (e.vars),
    t.var e.delayed (e1 e.vars);
  e.vars = /*empty*/ (e.vars);
};


/*
 * Выбор переменной (из двух) с более длинным списком требуемых ей значений.
 */
$func Max-Require e = e;

Max-Require t.arg1 t.arg2 =
  t.arg1 : (t.var1 t.Re1 t.provide1 (e.require1)),
  t.arg2 : (t.var2 t.Re2 t.provide2 (e.require2)),
  {
    <"<" (<Length e.require1>) (<Length e.require2>)> = t.arg2;
    t.arg1;
  };


/*
 * Подставить вспомогательную переменную вместо исходной во всех результатных выражениях.
 * Присваивание к исходной переменной убрать (оно к этому моменту уже выполнено).
 * Убрать переменную из списков зависимостей.
 */
$func Subst-Aux-Var e = e;

Subst-Aux-Var t.var t.aux (t.v t.Re (e.provide) (e.require)), {
  t.var : t.v = /*empty*/;
  (
    t.v
    <Subst (t.var) ((t.aux)) t.Re>
    (<Sub (e.provide) t.var>)
    (<Sub (e.require) t.var>)
  );
};


/*
 * Извлечь присваивание из всей информации о переменной.
 */
$func Extract-Assigns e = e;
Extract-Assigns (t.var t.Re e) = (t.var t.Re);


/*
 * Основной цикл обработки присваиваний.
 *
 * 1) Из всех переменных (в том числе и отложенных), от которых больше ничего
 *    не зависит, сделать присваивания.
 * 2) Все переменные, которые больше ни от чего не зависят, отложить.
 * 3) Если осталось хотя бы две неотложенных переменных, выбирать из них ту,
 *    которая зависит от наибольшего числа переменных, подставить везде вместо
 *    неё вспомогательную, перейти к пункту 1.
 */
CAV e.vars (e.assigns) (e.delayed) =
  <Assign-Empty-Provides e.vars> :: e.new-assigns (e.vars),
  e.assigns e.new-assigns <Assign-Empty-Provides e.delayed> :: e.assigns (e.delayed),
  e.delayed <Delay-Empty-Requires e.vars> :: e.delayed (e.vars),
  {
    e.vars : t t e =
      <Foldr1 &Max-Require (e.vars)> : (t.var t.Re e),
      <Gener-Aux-Var> :: t.aux,
      e.assigns (t.aux (t.var)) (t.var t.Re) :: e.assigns,
      <Map &Subst-Aux-Var t.var t.aux (e.vars)> :: e.vars,
      <Map &Subst-Aux-Var t.var t.aux (e.delayed)> :: e.delayed,
      <CAV e.vars (e.assigns) (e.delayed)>;
    e.assigns <Map &Extract-Assigns (e.vars e.delayed)>;
  };




Get-Clash-Sequence (e.last-Re) t.Pattern e.Snt =
  ((e.last-Re) t.Pattern) e.Snt $iter {
    e.Snt : (RESULT e.Re) t.Pt e.rest =
      (e.clashes (e.Re) t.Pt) e.rest;
  } :: (e.clashes) e.Snt,
  # \{
    e.Snt : \{
      (RESULT e.Re) (LEFT e) e = e.Re;
      (RESULT e.Re) (RIGHT e) e = e.Re;
    } :: e.Re,
      <Without-Calls? e.Re>;
  } =
  (e.clashes) e.Snt;


Comp-Pattern (s.dir e.PatternExp) e.Sentence =
  <Norm-Vars (<Vars e.PatternExp>) (s.dir e.PatternExp) e.Sentence>
    : t t.Pattern e.Snt,
//  (Unwatched (<? &Last-Re>) t.Pattern) e.Snt $iter {
  /*
   * Uncomment previous line and delete next one to activate Split-Clashes
   * function
   */
  ((<? &Last-Re>) t.Pattern) e.Snt $iter {
    e.Snt : (RESULT e.Re) (s.d e.Pe) e =
//      <WriteLN Matching (RESULT e.Re) (s.d e.Pe)>,
      <Norm-Vars (<Vars e.Pe>) e.Snt> : t t.R t.P e.rest,
//      (e.clashes Unwatched (e.Re) t.P) e.rest;
      /*
       * Uncomment previous line and delete next one to activate
       * Split-Clashes function
       */
      (e.clashes (e.Re) t.P) e.rest;
  } :: (e.clashes) e.Snt,
  # \{
    e.Snt : \{
      (RESULT e.Re) (LEFT e) e = e.Re;
      (RESULT e.Re) (RIGHT e) e = e.Re;
    } :: e.Re,
      <Without-Calls? e.Re>;
  } =
  e.Snt : e.Current-Snt (Comp Sentence) e.Other-Snts =
  <Comp-Sentence () e.Other-Snts> :: e.asail-Others,
  {
//    <Split-Clashes (e.clashes) e.Current-Snt>
//    :: (e.greater) (e.less) (e.hards) (e.clashes) e.Current-Snt =
//      <WriteLN "Hards: " e.hards>,
//      <WriteLN "Less: " e.less>,
//      <WriteLN "Greater: " e.greater>,
//      <WriteLN "Current-Snt: " e.Current-Snt>,
//!                     <Comp-Clashes (e.clashes)
//!                             (e.Current-Snt (Comp Sentence)) e.Other-Snts> :: e.asail-Clashes,
//      e.asail-Clashes (e.greater) $iter {
//        e.greater : (e.vars s.num) e.rest,
//          <Old-Vars e.vars> :: e.vars,  // temporary step
//          (IF ((INFIX ">=" ((LENGTH e.vars)) (s.num)))
//            e.asail-Clashes
//          ) (e.rest);
//      } :: e.asail-Clashes (e.greater),
//      e.greater : /*empty*/ =
//      e.asail-Clashes (e.less) $iter {
//        e.less : (e.vars s.num) e.rest,
//          <Old-Vars e.vars> :: e.vars,  // temporary step
//          (IF ((INFIX "<=" ((LENGTH e.vars)) (s.num)))
//            e.asail-Clashes
//          ) (e.rest);
//      } :: e.asail-Clashes (e.less),
//      e.less : /*empty*/ =
//      e.asail-Clashes (e.hards) $iter {
//        e.hards : (e.Re) (e.Pe) e.rest,
//          <Old-Vars e.Re> :: e.Re,    // temporary step
//          <Old-Vars e.Pe> :: e.Pe,    // temporary step
//          (IF ((INFIX "==" (e.Re) (e.Pe))) e.asail-Clashes) (e.rest);
//      } :: e.asail-Clashes (e.hards),
//      e.hards : /*empty*/ =
//!                     e.asail-Clashes
      e.asail-Others;
    e.asail-Others;
//    <Comp-Sentence () e.Other-Snts>;
  };

Without-Calls? e.Re =
  e.Re $iter {
    e.Re : t.Rt e.rest =
      t.Rt : {
        (CALL e) = $fail;
        (BLOCK e) = $fail;
        (PAREN e.Re1) = <Without-Calls? e.Re1>;
        t.symbol-or-var = /*empty*/;
      },
      e.rest;
  } :: e.Re,
  e.Re : /*empty*/;

//Comp-Clashes (e.clashes) (e.Current-Snt) e.Other-Snts =
//  <WriteLN Clashes e.clashes>,
////  /*
////   * Collect in e.vars all varibles from all clashes.
////   */
////  () e.clashes $iter {
////    e.not-watched : (e.expr) e.rest = (e.vars <Vars e.expr>) e.rest;
////  } :: (e.vars) e.not-watched,
////  e.not-watched : /*empty*/ =
////  /*
////   * Rename all collected variables in all clashes. Never mind multiple
////   * occurences.
////   */
////  (e.clashes) e.vars $iter {
////    e.vars : (s.var-tag s.m (e.n) e.var-id) e.rest, {
////      <Known-Vars? (s.var-tag e.var-id)> =
////        e.var-id : e.NEW (e.QualifiedName),
////        <Subst ((s.var-tag s.m (e.n) e.var-id))
////          (((s.var-tag (s.var-tag NEW ("len" e.QualifiedName))
////          s.m (e.n) e.var-id))) e.clashes>;
////      s.m : e.n =
////        <Subst ((s.var-tag s.m (e.n) e.var-id))
////          (((s.var-tag (s.m) s.m (e.n) e.var-id))) e.clashes>;
////    } :: e.clashes,
////    (e.clashes) e.rest;
////  } :: (e.clashes) e.vars,
////  e.vars : /*empty*/ =
////  /*
////   * Now all variables with known length have ref. term after s.var-tag.
////   * Well, lets see if there are closed variables and compute their lengthes
////   * too.
////   */
////  e.clashes (e.clashes) () $iter {
////    e.not-watched : (e.Re) (s.dir e.Pe) e.rest, {
////      <Find-Closed-Var e.Pe> :: t.old-var t.new-var e.new-cond,
////        <Subst (t.old-var) ((t.new-var)) e.clashes> :: e.clashes,
////        e.clashes (e.clashes) (e.cond e.new-cond);
////      e.rest (e.clashes) (e.cond);
////    };
////  } :: e.not-watched (e.clashes) (e.cond),
////  e.not-watched : /*empty*/ =
//
//  /*
//   * Parenthesize each clash, so from now on they can be seen as a sequence
//   * of such terms: (e.temp-tags (e.Re) t.P)
//   */
//  e.clashes () $iter {
//    e.old-clashes : t.R t.P e.rest =
//      e.rest (e.clashes (t.R t.P));
//  } :: e.old-clashes e.clashes,
//  e.old-clashes : /*empty*/ =
//  
//  <Find-Known-Lengths e.clashes> :: (e.known-len-clashes) e.clashes,
//  {
//    e.known-len-clashes : /*empty*/ =
//      <Find-Symbol-Checks e.clashes> :: (e.sym-check-clashes) e.clashes,
//      {
//        e.sym-check-clashes : /*empty*/ =
//          e.clashes : {
//            (e.Re) (s.dir e.Pe) e.rest =
//              <Gener-Label L> :: t.label,
//              <Comp-Clashes (e.rest) (e.Current-Snt)
//                (Comp Continue t.label) e.Other-Snts>
//              :: e.asail-Snt,
//              (FOR t.label () () ()
//                e.asail-Snt
//              )
//              <Comp-Sentence () e.Other-Snts>;
//            /*empty*/ =
//              <Comp-Sentence () e.Current-Snt e.Other-Snts>;
//          };
//        <Comp-Clashes (e.clashes) (e.Current-Snt) e.Other-Snts> :: e.asail-Snt,
//          (e.sym-check-clashes) e.asail-Snt $iter {
//            e.sym-check-clashes : e.something (e (e.Re) (s.dir e.Pe)),
//              
//    <Comp-Clashes (e.clashes) (e.Current-Snt) e.Other-Snts> :: e.asail-Snt,
//      (e.known-len-clashes) e.asail-Snt $iter {
//        e.known-len-clashes : e.something (e.tags (e.Re) (s.dir e.Pe)),
//          (e.something)
//          (IF ((INFIX "==" (<Length-of e.Re>) (<Length-of e.Pe>)))
//            e.asail-Snt
//          );
//      } :: (e.known-len-clashes) e.asail-Snt,
//      e.known-len-clashes : /*empty*/ =
//      e.asail-Snt
//      <Comp-Sentence () e.Other-Snts>;
//  };
//
//Find-Known-Lengths e.clashes =
//  e.clashes () () $iter {
//    e.old-clashes : t.first e.rest, t.first : {
//      (e1 Known-length e2) =
//        e.rest (e.known) (e.clashes t.first);
//      (e.tags (e.Re) (s.dir e.Pe)) =
////        Known <Vars e.Re> <Vars e.Pe> $iter {
////          e.vars : (VAR t.name) e.rest-vars, {
////            <?? t.name Length> : e = Known;
////            <?? t.name Instantiated> : True = Known;
////            Unknown;
////          } :: s.known? =
////            s.known? e.rest-vars;
////        } :: s.known? e.vars,
////        \{
////          s.known? : Unknown =
////            e.rest (e.known) (e.clashes t.first);
////          e.vars : /*empty*/ =
////            e.rest (e.known t.first)
////            (e.clashes (e.tags Known-length (e.Re) (s.dir e.Pe)));
////        };
//        {
//          <Hard-Exp? <Vars e.Re> <Vars e.Pe>> =
//            e.rest (e.known t.first)
//            (e.clashes (e.tags Known-length (e.Re) (s.dir e.Pe)));
//          e.rest (e.known) (e.clashes t.first);
//        };
//    };
//  } :: e.old-clashes (e.known) (e.clashes),
//  e.old-clashes : /*empty*/ =
//  (e.known) e.clashes;
//
//Known-Vars? e.vars =
//  <? &Var-Stack> :: e.known-vars,
//  e.vars $iter {
//    e.vars : t.var e.rest =
//      e.known-vars : e t.var e,
//      e.rest;
//  } :: e.vars,
//  e.vars : /*empty*/;

Comp-Clashes (e.clashes) s.tail? (v.fails) e.Sentence =
//  <WriteLN Clashes e.clashes>,
  /*
   * Parenthesize each clash, so from now on they can be seen as a sequence
   * of such terms: (e.temp-tags (e.Re) t.P)
   */
  e.clashes () $iter {
    e.old-clashes : t.R t.P e.rest =
      e.rest (e.clashes (<Gener-Label "clash"> &New-Clash-Tags t.R t.P));
  } :: e.old-clashes (e.clashes),
  e.old-clashes : /*empty*/ =
  
  /*empty*/ (/*!e.clashes!*/) () $iter {
    /*
     * First of all see if we have a clash with all variables of known length
     * and without length conditions written out.
     */
    e.clashes : e1 (e.t1 Known-length e.t2 (e.Re) (s.dir e.Pe)) e2,
      <Hard-Exp? e.Re e.Pe> =
      e.cond
      (Cond IF ((INFIX "==" (<Length-of e.Re>) (<Length-of e.Pe>))))
      (e1 (e.t1 Checked-length e.t2 (e.Re) (s.dir e.Pe)) e2) (e.fail);
    /*
     * Next see if we can compute length of some variable.
     */
    e.cond <Find-Var-Length e.clashes> (e.fail);
    /*
     * Write out restrictions for the cyclic variables.
     */
    e.cond <Cyclic-Restrictions e.clashes> (e.fail);
//    <Cyclic-Restrictions e.clashes> :: e.new-cond (e.clashes),
//      {
//        e.fail : v = e.cond e.new-cond (Clear-Restricted) (e.clashes) (e.fail); 
//        e.cond e.new-cond (e.clashes) (e.fail);
//      };
    /*
     * After checking all possible lengthes at the upper level change
     * <<current_label_if_fail>>.
     */
    e.fail : v =
      (Contin e.fail) e.cond (Fail e.fail) (Clear-Restricted) (e.clashes) ();
    /*
     * For all clashes with known left part check unwatched terms whether they
     * are symbols or reference terms or not any.
     */
    \?
    {
      <Check-Symbols e.clashes> : {
        v.new-cond (e.new-clashes) s =
          e.cond (Cond IF (v.new-cond)) (e.new-clashes) ();
        (e.new-clashes) New = e.cond (e.new-clashes) ();
        e \! $fail;
      };
      <PrintLN "Check-Symbols: don't know what to do... ;-)">, $fail;
    };
    /*
     * And then try to compose new clash by dereferencing a part of some one.
     */
    e.cond <Dereference-Subexpr e.clashes> ();
    /*
     * If previous doesn't work then compare recursively all known
     * subexpressions and all unknown repeated subexpressions with
     * corresponding parts of source.
     */
    <Compare-Subexpr e.clashes> :: e.new-cond (e.asserts) (e.new-clashes) s.new?,
      \{
        e.new-cond : v, {
          e.asserts : v =
            e.cond (Assert e.asserts) (Cond IF (e.new-cond)) (e.new-clashes) ();
          e.cond (Cond IF (e.new-cond)) (e.new-clashes) ();
        };
        e.asserts : v = e.cond (Assert e.asserts) (e.new-clashes) ();
        s.new? : New = e.cond (e.new-clashes) ();
      };
    /*
     * Then get first uncatenated source and bring it to the normal
     * form, i.e. concatenate and parenthesize until it became single
     * known expression.
     */
    e.cond <Get-Source e.clashes> ();
    /*
     * Now it's time to deal with cycles.
     */
    e.cond <Comp-Cyclic e.clashes>;
    /*
     * At last initialize all new subexpressions from all clashes.
     */
    e.clashes () $iter {
      e.clashes : (e t.Re (s.dir e.Pe)) e.rest,
        e.rest (e.new-cond <Get-Subexprs <Vars e.Pe>>);
    } :: e.clashes (e.new-cond),
      e.clashes : /*empty*/ =
      {
        e.new-cond : /*empty*/ = e.cond () ();
        e.cond (Assert e.new-cond) () ();
      };
  } :: e.cond (e.clashes) (e.fail),
//  <WriteLN CC-Clashes e.clashes>,
//  <WriteLN CC-Cond e.cond>,
  e.clashes : /*empty*/ =

  e.cond () 0 $iter {
    e.cond : (Contin (CONTINUE t.label)) e.rest =
      e.rest (e.contin (Comp Continue t.label)) 0;
    e.cond (e.contin) 1;
  } :: e.cond (e.contin) s.stop?,
  s.stop? : 1 =
//!     <Comp-Sentence () e.Current-Snt e.contin e.Other-Snts> :: e.asail-Snt,
  <Comp-Sentence s.tail? (v.fails) () e.Sentence> :: e.asail-Snt,
  e.cond (e.asail-Snt) () $iter {
    e.cond : e.some (e.last),
      e.last : {
        Cond e.condition =
          e.some ((e.condition e.asail-Snt)) (e.vars);
        Assert e.assertion =
          e.some (e.assertion e.asail-Snt) (e.vars);
        Fail e.fail1 =
          e.some (e.asail-Snt e.fail1) (e.vars);
        Restricted t.var =
          e.some (e.asail-Snt) (e.vars t.var);
        If-not-restricted t.var e.restr-cond, {
          e.vars : e t.var e = e.some (e.asail-Snt) (e.vars);
          e.some e.restr-cond (e.asail-Snt) (e.vars);
        };
        Clear-Restricted = e.some (e.asail-Snt) ();
      };
  } :: e.cond (e.asail-Snt) (e.vars),
  e.cond : /*empty*/ =
  e.asail-Snt/* <Comp-Sentence () e.Other-Snts>*/;

Find-Var-Length e.clashes =
//  <WriteLN Find-Var-Length e.clashes>,
  e.clashes : e1 (e.t1 Unknown-length e.t2 (e.Re) (s.dir e.Pe)) e2 \?
  <Unknown-Vars e.Pe> :: e.new-Pe (e.Pe-unknown),
  <Unknown-Vars e.Re> :: e.new-Re (e.Re-unknown),
//  <Write Unknown>, <Write (e.Re-unknown)>, <WriteLN (e.Pe-unknown)>,
  e.Re-unknown e.Pe-unknown : {
    /*empty*/ =
      (e1 (e.t1 Known-length e.t2 (e.Re) (s.dir e.Pe)) e2);
    (VAR t.name) e.rest,
      e.rest $iter \{
        e.unknown : (VAR t.name) e.rest1 = e.rest1;
      } :: e.unknown,
      e.unknown : /*empty*/,
      <"-" <Length e.Re-unknown> <Length e.Pe-unknown>> : {
        0 \! $fail;
        s.diff, {
          <"<" (s.diff) (0)> =
            <"*" s.diff -1>
            (INFIX "-" (<Length-of e.new-Re>) (<Length-of e.new-Pe>));
          <">" (s.diff) (0)> =
            s.diff
            (INFIX "-" (<Length-of e.new-Pe>) (<Length-of e.new-Re>));
        } :: s.mult e.diff,
          t.name : (e.QualifiedName),
          (VAR ("len" e.QualifiedName)) :: t.len-var,
          {
            <?? t.name Max> :: e.max =
              (INFIX "<=" 
                (t.len-var)
                ((INFIX "*" (s.mult) (e.max)))
              );
            /*empty*/;
          } :: e.cond,
          e.cond
          (INFIX ">=" 
            (t.len-var)
            ((INFIX "*" (s.mult) (<?? t.name Min>)))
          )
          (NOT (INFIX "%"
            (t.len-var)
            (s.mult)
          )) :: e.cond,
          <Set-Var t.name (Max) (//(LENGTH (VAR t.name))
            (INFIX "/" (t.len-var) (s.mult))
          )>,
          <Set-Var t.name (Min) (<?? t.name Max>)>,
          <Set-Var t.name (Length) (<?? t.name Max>)>,
//          <WriteLN Unknown-Num s.mult> =
          (Restricted (VAR t.name))
          (Assert
            <Declare-Vars "int" t.len-var>
            (ASSIGN t.len-var e.diff)
          )
          (Cond IF (e.cond))
          (<Update-Ties (VAR t.name) e1>
            (e.t1 Checked-length e.t2 (e.Re) (s.dir e.Pe))
          <Update-Ties (VAR t.name) e2>);
      };
    e.unknown \!
      e.t1 Unknown-length e.t2 : e.t3 Ties e.t4 =
      e.t1 : t.id e,
      e.unknown () $iter {
        e.unknown : (VAR t.name) e.rest, {
          e.tied : e (VAR t.name) e = e.rest (e.tied);
          <Entries (VAR t.name) (e.Re)> :: s.Re-ent e.new-Re,
            <Entries (VAR t.name) (e.Pe)> :: s.Pe-ent e.new-Pe,
            <"-" s.Re-ent s.Pe-ent> :: s.diff,
            {
              s.diff : 0 = e.rest (e.tied (VAR t.name));
              {
                <"<" (s.diff) (0)> =
                  <"*" s.diff -1> (e.new-Re) (e.new-Pe);
                s.diff (e.new-Pe) (e.new-Re);
              } :: s.diff (e.plus) (e.minus),
                (
                  t.id
                  (<Known-Length-of e.plus>)
                  (<Known-Length-of e.minus>)
                  s.diff
                ) :: t.tie,
                {
                  <?? t.name Ties> : {
                    e.c1 (t.id e) e.c2 = e.c1 e.c2;
                    e.ties = e.ties;
                  };
                  /*empty*/;
                } :: e.ties,
                {
                  e.ties : e t.tie e;
                  <Set-Var t.name (Ties) (e.ties t.tie)>;
                },
                e.rest (e.tied (VAR t.name));
            };
        };
      } :: e.unknown (e.tied),
      e.unknown : /*empty*/ =
      {
        e.t3 e.t4 : e Cyclic e = e.t3 e.t4;
        e.t3 e.t4 Cyclic;
      } :: e.tags,
      (e1 (e.tags (e.Re) (s.dir e.Pe)) e2);
  };

Known-Length-of e.expr =
  <Unknown-Vars e.expr> :: e.expr (e.vars),
  <Length-of e.expr> (e.vars);

Update-Ties t.var e.clashes =
  e.clashes () $iter {
    e.clashes : t.clash e.rest,
      t.clash : (e.tags (e.Re) (s.dir e.Pe)),
      {
        e.tags : e Ties e = e.rest (e.new-clashes t.clash);
        e.Re e.Pe : e t.var e =
          e.rest (e.new-clashes (e.tags Ties (e.Re) (s.dir e.Pe)));
        e.rest (e.new-clashes t.clash);
      };
  } :: e.clashes (e.new-clashes),
  e.clashes : /*empty*/ =
  e.new-clashes;

Cyclic-Restrictions e.clashes =
  e.clashes : e1 (e.t1 Cyclic e.t2 (e.Re) (s.dir e.Pe)) e2 =
  <Unknown-Vars e.Re e.Pe> :: e (e.unknown),
  e.unknown () $iter {
    e.unknown : t.var e.rest,
      t.var : (VAR (e.QualifiedName)),
      (VAR ("min" e.QualifiedName)) :: t.min-var,
      <Cyclic-Min t.var> :: e.min,
      {
        <Cyclic-Max t.var> :: e.max =
          e.rest (e.cond (Restricted t.var) (If-not-restricted t.var
            (Assert 
              <Declare-Vars "int" t.min-var> (ASSIGN t.min-var e.min)
            )
            (Cond IF ((INFIX "<=" (t.min-var) (e.max))))
        ));
        e.rest (e.cond);
      };
  } :: e.unknown (e.cond),
  e.unknown : /*empty*/ =
  e.cond (e1 (e.t1 e.t2 (e.Re) (s.dir e.Pe)) e2);

Cyclic-Min (VAR t.name) =
  <?? t.name Ties> () $iter {
    e.ties : (t (e.plus (e.plus-vars)) (e.minus (e.minus-vars)) s.mult) e.rest, {
      e.minus-vars () $iter \{
        e.minus-vars : t.var e.vars-rest,
          e.vars-rest (e.minus-maxes <Cyclic-Max t.var>);
      } :: e.minus-vars (e.minus-maxes),
        e.minus-vars : /*empty*/ =
        e.plus-vars () $iter {
          e.plus-vars : (VAR t.var-name) e.vars-rest =
            e.vars-rest (e.plus-mins <?? t.var-name Min>);
        } :: e.plus-vars (e.plus-mins),
        e.plus-vars : /*empty*/ =
        e.rest (e.mins ((INFIX "/"
          ((INFIX "-" (e.plus e.plus-mins) (e.minus e.minus-maxes))) (s.mult)
        )));
      e.rest (e.mins);
    };
  } :: e.ties (e.mins),
  e.ties : /*empty*/ =
  (<?? t.name Min>) e.mins :: e.mins,
  {
    e.mins : (e.min) = e.min;
    (MAX e.mins);
  };

Cyclic-Max (VAR t.name) =
  <?? t.name Ties> () $iter {
    e.ties : (t (e.plus (e.plus-vars)) (e.minus (e.minus-vars)) s.mult) e.rest, {
      e.plus-vars () $iter \{
        e.plus-vars : (VAR t.var-name) e.vars-rest,
          e.vars-rest (e.plus-maxes <?? t.var-name Max>);
      } :: e.plus-vars (e.plus-maxes),
        e.plus-vars : /*empty*/ =
        e.minus-vars () $iter {
          e.minus-vars : (VAR t.var-name) e.vars-rest =
            e.vars-rest (e.minus-mins <?? t.var-name Min>);
        } :: e.minus-vars (e.minus-mins),
        e.minus-vars : /*empty*/ =
        e.rest (e.maxes ((INFIX "/"
          ((INFIX "-" (e.plus e.plus-maxes) (e.minus e.minus-mins))) (s.mult)
        )));
      e.rest (e.maxes);
    };
  } :: e.ties (e.maxes),
  e.ties : /*empty*/ =
  {
    (<?? t.name Max>) e.maxes;
    e.maxes;
  } :: e.maxes,
  {
    e.maxes : /*empty*/ = $fail;
    e.maxes : (e.max) = e.max;
    (MIN e.maxes);
  };

Check-Symbols e.clashes =
  e.clashes () () Old $iter {
    e.clashes : t.clash e.rest, {
      t.clash : (e.t1 Check-symbols e.t2 (e.Re) (s.dir e.Pe)),
        e.Re : (VAR t.name),
        <?? t.name Instantiated> : True =
//        <Format e.Pe> () () Continue $iter {
        e.Pe () () Continue $iter {
          e.format : t.Ft e.Fe =
            <Length-of e.left> :: e.pos,
            <Check-Ft t.Ft (e.pos) (1 <Length-of e.Fe>) t.name Left-checks> : {
              /*empty*/ s.stop??? = /*empty*/ s.stop???;
              Sym s.stop??? =
                (Used e.Re) (SYMBOL? e.Re (e.pos)) s.stop???;
              Ref s.stop??? =
                (Used e.Re) (NOT (SYMBOL? e.Re (e.pos))) s.stop???;
              Flat e.len s.stop??? =
                (Used e.Re) (FLAT-SUBEXPR? e.Re (e.pos) (e.len)) s.stop???;
            } :: e.Ft-cond s.stop? =
            e.Fe (e.left t.Ft) (e.new-cond e.Ft-cond) s.stop?;
        } :: e.format (e.left) (e.new-cond) s.stop?,
        \{
          e.format : /*empty*/ =
            e.rest (e.cond e.new-cond)
            (e.new-clashes (e.t1 e.t2 (e.Re) (s.dir e.Pe))) New;
          s.stop? : Stop =
            e.format () (e.new-cond) Continue $iter {
              e.format : e.Fe t.Ft =
                1 <Length-of e.right> :: e.pos,
                <Check-Ft t.Ft (e.pos) () t.name Right-checks>
                  :: e.Ft-cond s.stop?,
                e.Ft-cond : {
                  /*empty*/ = /*empty*/;
                  Sym =
                    (Used e.Re)
                    (SYMBOL? e.Re (
                      (INFIX "-" (<Length-of e.Re>) (e.pos))
                    ));
                  Ref =
                    (Used e.Re)
                    (NOT (SYMBOL? e.Re (
                      (INFIX "-" (<Length-of e.Re>) (e.pos))
                    )));
                  Flat e.len s.stop??? =
                    (Used e.Re)
                    (FLAT-SUBEXPR? e.Re (
                      (INFIX "-" (<Length-of e.Re>) (e.pos))
                    ) e.len) s.stop???;
                } :: e.Ft-cond,
                e.Fe (t.Ft e.right) (e.new-cond e.Ft-cond) s.stop?;
            } :: e.format (e.right) (e.new-cond) s.stop?,
            s.stop? : Stop =
            e.rest (e.cond e.new-cond) (e.new-clashes t.clash) s.new?;
        };
      e.rest (e.cond) (e.new-clashes t.clash) s.new?;
    };
  } :: e.clashes (e.cond) (e.new-clashes) s.new?,
//  <WriteLN Check-Symbols e.clashes (e.cond) (e.new-clashes) s.new?>,
  e.clashes : /*empty*/ =
  e.cond (e.new-clashes) s.new?;

Check-Ft t.Ft (e.pos) (e.right-pos) t.name s.dir, t.Ft : {
  s.ObjectSymbol, {
    <?? t.name s.dir> : \{
      e (e.pos Sym) e = /*empty*/ Continue;
      e (e.pos (Ref e)) e = $fail;
    };
    s.dir : Left-checks,
      <?? t.name Right-checks> : \{
        e (e.right-pos Sym) e = /*empty*/ Continue;
        e (e.right-pos (Ref e)) e = $fail;
      };
    <Set-Var t.name (s.dir) (<?? t.name s.dir> (e.pos Sym))> = Sym Continue;
  };
  (PAREN e.expr), {
    <?? t.name s.dir> : \{
      e (e.pos (Ref e)) e = /*empty*/ Continue;
      e (e.pos Sym) e = $fail;
    };
    s.dir : Left-checks,
      <?? t.name Right-checks> : \{
        e (e.right-pos (Ref e)) e = /*empty*/ Continue;
        e (e.right-pos Sym) e = $fail;
      };
    s.dir : {
      Left-checks = "lderef";
      Right-checks = "rderef";
    } :: s.name-dir,
      t.name : (e.QualifiedName),
      <Gener-Label s.name-dir e.QualifiedName> :: t.ref-name,
//      <Declare-Vars "Expr" (VAR t.ref-name)> : e,
      <Set-Var t.name (s.dir) (<?? t.name s.dir> (e.pos (Ref t.ref-name)))> =
      Ref Continue;
  };
//!     (VAR t.Ft-name), {
  (s t.Ft-name), { // STUB!
    <Hard-Exp? t.Ft>, {
      <?? t.Ft-name Flat> : True, {
        <?? t.Ft-name Length> : 1, {
          <?? t.name s.dir> : \{
            e (e.pos Sym) e = /*empty*/ Continue;
            e (e.pos (Ref e)) e = $fail;
          };
          s.dir : Left-checks,
            <?? t.name Right-checks> : \{
              e (e.right-pos Sym) e = /*empty*/ Continue;
              e (e.right-pos (Ref e)) e = $fail;
            };
//          <?? t.Ft-name Instantiated> : True =
//            /*empty*/ Continue;
          <Set-Var t.name (s.dir) (<?? t.name s.dir> (e.pos Sym))> =
            Sym Continue;
        };
        <Set-Var t.name (s.dir) (<?? t.name s.dir> (e.pos Flat))> =
          Flat <Length-of t.Ft> Continue;
      };
      /*empty*/ Continue;
    };
    /*empty*/ Stop;
  };
};

Dereference-Subexpr e.clashes =
  e.clashes : e1 (e.t1 Dereference e.t2 (e.Re) (s.dir e.Pe)) e2 \?
  e.Re : (VAR t.name),
  <?? t.name Instantiated> : True,
//  <WriteLN Dereference!!! t.name <?? t.name Right-checks>>,
//  <Format e.Pe> : e.f1 t.Ft e.f2 \?
  e.Pe : e.f1 t.Ft e.f2 \?
  \{
    t.Ft : (PAREN e.expr),
      <Length-of e.f1> :: e.pos,
      {
        <?? t.name Left-checks> : e (e.pos (Ref t.ref-name)) e \!
          # \{ <?? t.ref-name Instantiated> : True; } =
          <Declare-Vars "Expr" (VAR t.ref-name)> : e,
          <Instantiate-Vars (VAR t.ref-name)>,
          (Assert (DEREF (VAR t.ref-name) e.Re (e.pos))) :: e.cond,
          (e.t1 Dereference e.t2 (e.Re) (s.dir e.Pe)) :: t.old-clash,
          {
            e.t1 e.t2 : e Without-object-symbols e = Without-object-symbols;
            /*empty*/;
          } :: e.wos,
          (<Gener-Label "clash"> &New-Clash-Tags e.wos
            ((VAR t.ref-name)) (s.dir e.expr)
          ) :: t.new-clash,
          s.dir : {
            LEFT =
              e.cond (e1 t.new-clash t.old-clash e2);
            RIGHT =
              e.cond (e1 t.old-clash t.new-clash e2);
          };
        t.Ft e.f2 : $r e.f3 (PAREN e.expr1) e.f4 \?
          1 <Length-of e.f4> :: e.pos,
          {
            <?? t.name Right-checks> : e (e.pos (Ref t.ref-name)) e \!
              # \{ <?? t.ref-name Instantiated> : True; } =
              <Declare-Vars "Expr" (VAR t.ref-name)> : e,
              <Instantiate-Vars (VAR t.ref-name)>,
              (Assert 
                (DEREF (VAR t.ref-name) e.Re (
                  (INFIX "-" (<Length-of e.Re>) (e.pos))
                ))
              ) :: e.cond,
              (e.t1 Dereference e.t2 (e.Re) (s.dir e.Pe)) :: t.old-clash,
              {
                e.t1 e.t2 : e Without-object-symbols e =
                  Without-object-symbols;
                /*empty*/;
              } :: e.wos,
              (<Gener-Label "clash"> &New-Clash-Tags e.wos
                ((VAR t.ref-name)) (s.dir e.expr1)
              ) :: t.new-clash,
              s.dir : {
                RIGHT =
                  e.cond (e1 t.new-clash t.old-clash e2);
                LEFT =
                  e.cond (e1 t.old-clash t.new-clash e2);
              };
            \!\!\! $fail;
          };
        \!\! $fail;
      };
    e.f2 : /*empty*/ =
      (e1 (e.t1 e.t2 (e.Re) (s.dir e.Pe)) e2);
  };

Compare-Subexpr e.clashes =
  e.clashes () () () Old $iter e.clashes : {
    (e.t1 Compare e.t2 (e.Re) (s.dir e.Pe)) e.rest,
      e.Re : (VAR t.name),
      <?? t.name Instantiated> : True =
      {
        e.t1 e.t2 : e Without-object-symbols e =
          /*empty*/ (e.t2) (e.Re) (e.Pe);
        <Get-Static-Exprs e.Re> :: e.Re (e.Re-decls),
          <Get-Static-Exprs e.Pe> :: e.Pe (e.Pe-decls) =
          e.Re-decls e.Pe-decls (e.t2 Without-object-symbols) (e.Re) (e.Pe);
      } :: e.new-asserts (e.t2) (e.Re) (e.Pe),
      e.Pe () () Continue $iter {
        e.format : t.Ft e.Fe,
          <Length-of e.left> :: e.pos,
          <Length-of t.Ft> :: e.len,
          <Length-of e.Fe> :: e.right-pos,
          {
            \{
              <?? t.name Left-compare> :
                e (t.Ft Left (0) (e.pos) e.len) e;
              <?? t.name Right-compare> :
                e (t.Ft Left (0) (e.right-pos) e.len) e;
            } =
               /*empty*/ Continue;
            <Compare-Ft t.Ft> : {
              /*empty*/ s.stop??? = /*empty*/ s.stop???;
              e.compare s.eq =
//                <WriteLN Compare e.compare s.eq>,
                t.Ft : (VAR t.Ft-name),
                <Set-Var t.name (Left-compare) (<?? t.name Left-compare>
                  (t.Ft Left (0) (e.pos) e.len))>,
                <Set-Var t.Ft-name (Left-compare)
                  (<?? t.Ft-name Left-compare>
                  (e.Re Left (e.pos) (0) e.len))>,
                e.compare : {
                  Empty = /*empty*/ Continue;
                  Instantiated =
                    (t.Ft) (0) (e.len) :: e.sub1,
                    (e.Re) (e.pos) (e.len) :: e.sub2,
                    { s.eq : EQ = 0; 1; } :: s.R,
                    (Used t.Ft e.Re)
                    (s.eq <Middle 0 s.R e.sub1> e.sub2) Continue;
//                    (s.eq ((FIRST t.Ft)) ((LAST t.Ft))
//                      ((FIRST e.Re) e.pos) ((FIRST e.Re) e.pos e.len)
//                    ) Continue;
                  (t.var s.dir1 (e.pos1) (0) e.len), s.dir1 : {
                    Left =
                      (t.var) (e.pos1) (e.len) :: e.sub1,
                      (e.Re) (e.pos) (e.len) :: e.sub2,
                      { s.eq : EQ = 0; 1; } :: s.R,
                      (Used t.var e.Re)
                      (s.eq <Middle 0 s.R e.sub1> e.sub2) Continue;
//                      (s.eq ((FIRST t.var) e.pos1)
//                        ((FIRST t.var) e.pos1 e.len)
//                        ((FIRST e.Re) e.pos)
//                        ((FIRST e.Re) e.pos e.len)
//                      ) Continue;
                    Right =
                      (t.var)
                      ((INFIX "-" ((LENGTH t.var)) (e.pos1) (e.len)))
                      (e.len) :: e.sub1,
                      (e.Re) (e.pos) (e.len) :: e.sub2,
                      { s.eq : EQ = 0; 1; } :: s.R,
                      (Used t.var e.Re)
                      (s.eq <Middle 0 s.R e.sub1> e.sub2) Continue;
//                      (s.eq
//                        ((INFIX "-"
//                          ((LAST t.var)) (e.pos1) (e.len))
//                        )
//                        ((INFIX "-" ((LAST t.var)) (e.pos1)))
//                        ((FIRST e.Re) e.pos)
//                        ((FIRST e.Re) e.pos e.len)
//                      ) Continue;
//                    <Set-Var t.name Left-compare
//                      <?? t.name Left-compare>
//                      (t.name1 s.dir (e.pos1) (e.pos) e.len)
                  };
                };
            };
          } :: e.Ft-cond s.stop? =
          e.Fe (e.left t.Ft) (e.new-cond e.Ft-cond) s.stop?;
      } :: e.format (e.left) (e.new-cond) s.stop?,
      \{
        e.format : /*empty*/ =
          e.rest (e.cond e.new-cond) (e.new-asserts)
          (e.new-clashes (e.t1 e.t2 (e.Re) (s.dir e.Pe))) New;
        s.stop? : Stop = e.format () (e.new-cond) Continue $iter {
          e.format : e.Fe t.Ft,
            <Length-of e.right> :: e.pos,
            <Length-of t.Ft> :: e.len,
            {
              <?? t.name Right-compare> : e (t.Ft Left (0) (e.pos) e.len) e =
                /*empty*/ Continue;
              <Compare-Ft t.Ft> : {
                /*empty*/ s.stop??? = /*empty*/ s.stop???;
                e.compare s.eq =
                  t.Ft : (VAR t.Ft-name),
                  <Set-Var t.name (Right-compare)
                    (<?? t.name Right-compare>
                    (t.Ft Left (0) (e.pos) e.len))>,
                  <Set-Var t.Ft-name (Left-compare)
                    (<?? t.Ft-name Left-compare>
                    (e.Re Right (e.pos) (0) e.len))>,
                  e.compare : {
                    Empty = /*empty*/ Continue;
                    Instantiated =
                      (t.Ft) (0) (e.len) :: e.sub1,
                      (e.Re)
                      ((INFIX "-" ((LENGTH e.Re)) (e.pos) (e.len)))
                      (e.len) :: e.sub2,
                      { s.eq : EQ = 0; 1; } :: s.R,
                      (Used t.Ft e.Re)
                      (s.eq <Middle 0 s.R e.sub1> e.sub2) Continue;
//                      (s.eq ((FIRST t.Ft)) ((LAST t.Ft))
//                        ((INFIX "-" ((LAST e.Re)) (e.pos) (e.len)))
//                        ((INFIX "-" ((LAST e.Re)) (e.pos)))
//                      ) Continue;
                    (t.var s.dir1 (e.pos1) (0) e.len), s.dir1 : {
                      Left =
                        (t.var) (e.pos1) (e.len) :: e.sub1,
                        (e.Re)
                        ((INFIX "-" 
                          ((LENGTH e.Re)) (e.pos) (e.len)
                        )) (e.len) :: e.sub2,
                        { s.eq : EQ = 0; 1; } :: s.R,
                        (Used t.var e.Re)
                        (s.eq <Middle 0 s.R e.sub1> e.sub2)
                        Continue;
//                        (s.eq ((FIRST t.var) e.pos1)
//                          ((FIRST t.var) e.pos1 e.len)
//                          ((INFIX "-"
//                            ((LAST e.Re)) (e.pos) (e.len)
//                          ))
//                          ((INFIX "-" ((LAST e.Re)) (e.pos)))
//                        ) Continue;
                      Right =
                        (t.var)
                        ((INFIX "-"
                          ((LENGTH t.var)) (e.pos1) (e.len)
                        )) (e.len) :: e.sub1,
                        (e.Re)
                        ((INFIX "-" 
                          ((LENGTH e.Re)) (e.pos) (e.len)
                        )) (e.len) :: e.sub2,
                        { s.eq : EQ = 0; 1; } :: s.R,
                        (Used t.var e.Re)
                        (s.eq <Middle 0 s.R e.sub1> e.sub2)
                        Continue;
//                        (s.eq
//                          ((INFIX "-"
//                            ((LAST t.var)) (e.pos1) (e.len)
//                          ))
//                          ((INFIX "-" ((LAST t.var)) (e.pos1)))
//                          ((INFIX "-"
//                            ((LAST e.Re)) (e.pos) (e.len)
//                          ))
//                          ((INFIX "-" ((LAST e.Re)) (e.pos)))
//                        ) Continue;
                    };
                  };
              };
            } :: e.Ft-cond s.stop? =
            e.Fe (t.Ft e.right) (e.new-cond e.Ft-cond) s.stop?;
        } :: e.format (e.right) (e.new-cond) s.stop?,
          s.stop? : Stop =
          e.rest (e.cond e.new-cond) (e.new-asserts)
          (e.new-clashes (e.t1 Compare e.t2 (e.Re) (s.dir e.Pe))) s.new?;
      };
    t.clash e.rest = e.rest (e.cond) (e.asserts) (e.new-clashes t.clash) s.new?;
  } :: e.clashes (e.cond) (e.asserts) (e.new-clashes) s.new?,
//  <WriteLN Compare-Subexpr e.clashes (e.cond) (e.asserts) (e.new-clashes) s.new?>,
  e.clashes : /*empty*/ =
  e.cond (e.asserts) (e.new-clashes) s.new?;

Compare-Ft {
  s.ObjectSymbol =
    <PrintLN "Compare-Ft: can't compare object symbols!">, $fail;
  (PAREN e.expr) =
    /*empty*/ Continue;
//!     (VAR t.name), {
  (s t.name), { // STUB!
    <Hard-Exp? (VAR t.name)>, {
      <?? t.name Instantiated> : True = Instantiated;
      <?? t.name Left-compare> : {
        t.compare e = t.compare;
        /*empty*/ = Empty;
      };
    } :: e.compare,
      {
        <?? t.name Flat> : True,
          <?? t.name Length> : 1 = FLAT-EQ;
        EQ;
      } :: s.eq =
      e.compare s.eq;
    /*empty*/ Stop;
  };
};

Get-Source e.clashes =
  e.clashes : e1 (e.tags (e.Re) (s.dir e.Pe)) e2,
  \{ 
    /*
     * If source is an instantiated variable then go to the next clash.
     */
    e.Re : (VAR t.name),
      <?? t.name Instantiated> : True = $fail;
    /*
     * If in source there is unknown variable then we can't compute it, so
     * go to the next clash.
     */
    e.Re $iter e.Re : {               
      (VAR t.name) e.rest =           
        \{                    
          <?? t.name Instantiated> : True;  
          <?? t.name Left-compare> : v;   
        }, e.rest;                
      t e.rest = e.rest;              
    } :: e.Re,                    
      e.Re : /*empty*/;             
  } =
//  <WriteLN Get-Source (e.tags (e.Re) (s.dir e.Pe))>,
  {
    e.Re : /*empty*/ =
      <Store-Vars (EVAR ("empty" 0))> : t.empty,
      <Set-Var ("empty") (Instantiated) (True)>,
      () () (e.tags (t.empty) (s.dir e.Pe));
    e.Re : (VAR t.name) =
      (e.Re) () (e.tags (e.Re) (s.dir e.Pe));
    {
      e.tags : e Without-object-symbols e =
        /*empty*/ (e.tags (e.Re) (s.dir e.Pe));
      <Get-Static-Exprs e.Re> :: e.Re (e.Re-decls),
        <Get-Static-Exprs e.Pe> :: e.Pe (e.Pe-decls) =
        e.Re-decls e.Pe-decls (e.tags Without-object-symbols (e.Re) (s.dir e.Pe));
    } :: e.asserts (e.tags (e.Re) (s.dir e.Pe)), {
      e.Re : (VAR t.name) =
        () (e.asserts) (e.tags (e.Re) (s.dir e.Pe));
      <Compose-Expr e.Re> :: e.compose (e.not-inst) s.flat?,
        <Gener-Label "compose"> :: t.name,
        <Declare-Vars "Expr" (VAR t.name)> :: e.decl,
        <Instantiate-Vars (VAR t.name)>,
        {
          s.flat? : 0 = <Set-Var t.name (Flat) (True)>;;
        },
        <Set-Var t.name (Length) (<Length-of e.Re>)>,
        <Set-Var t.name (Format) (<Format-Exp e.Re>)> =
        (e.not-inst) (e.asserts e.decl (ASSIGN (VAR t.name) e.compose))
        (e.tags ((VAR t.name)) (s.dir e.Pe));
    };
  } :: (e.not-inst) (e.decl) t.clash,
  (Assert <Get-Subexprs e.not-inst> e.decl) (e1 t.clash e2);

Compose-Expr e.Re =
  e.Re () () 0 $iter {
    e.Re : t.Rt e.rest, t.Rt : {
      s.ObjectSymbol =
        <PrintLN "Compose-Expr: can't deal with object symbols!">, $fail;
      (PAREN e.expr) =
        <Compose-Expr e.expr> :: e.expr (e.new-not-inst) s,
        (PAREN e.expr) (e.new-not-inst) 1;
      (VAR t.name) =
        {
          <?? t.name Instantiated> : True = /*empty*/;
          t.Rt;
        } :: e.new-not-inst,
        {
          <?? t.name Flat> : True = 0;
          1;
        } :: s.new-flat?,
        (Used t.Rt) t.Rt (e.new-not-inst) s.new-flat?;
      t = t.Rt () 0; // STUB!
    } :: e.new-compose (e.new-not-inst) s.new-flat? =
      e.rest (e.compose e.new-compose) (e.not-inst e.new-not-inst)
      <"+" s.flat? s.new-flat?>;
  } :: e.Re (e.compose) (e.not-inst) s.flat?,
  e.Re : /*empty*/ =
  e.compose (e.not-inst) s.flat?;

Comp-Cyclic e.clashes =
  <WriteLN ??? e.clashes>,
  e.clashes : e1 (e.t1 Unknown-length e.t2 (e.Re) (s.dir e.Pe)) e2 =
  e.Re : (VAR (e.QualifiedName)),
  <Split-Hard-Left e.Pe> :: e.left-hard,
  <Split-Hard-Right e.Pe> :: e.right-hard,
  e.Pe : e.left-hard e.Cycle e.right-hard,
  {
    e.left-hard e.right-hard : /*empty*/ = /*empty*/ (e.QualifiedName) ();
    <Gener-Label "ref" e.QualifiedName> :: t.name,
      t.name : (e.CycleName),
      <Declare-Vars "Expr" (VAR t.name)> : e,
      <Instantiate-Vars (VAR t.name)>,
      <Set-Var t.name (Format) (<Format-Exp e.Cycle>)>,
      (INFIX "-" (<Length-of e.Re>) (<Length-of e.right-hard>)) :: e.len,
      (Used e.Re)
      (SUBEXPR (VAR t.name) e.Re (<Length-of e.left-hard>) (e.len)) :: e.decl,
      <Set-Var t.name (Left-compare)
        ((e.Re Left (<Length-of e.left-hard>) (0) <Length-of (VAR t.name)>))>,
      <Set-Var (e.QualifiedName) (Left-compare) ((
        (VAR t.name) Left (0) (<Length-of e.left-hard>) <Length-of (VAR t.name)>
      ))> =
      (e.t1 Checked-length e.t2 (e.Re) (s.dir e.left-hard (VAR t.name) e.right-hard))
      (e.CycleName) (e.decl);
  } :: e.old-clash (e.CycleName) (e.decl),
  (VAR (e.CycleName)) :: t.var,
  <Gener-Label L "For" "Break"> :: t.break-label,
  <Gener-Label L "For" "Cont"> :: t.cont-label,
  s.dir : {
    LEFT =
      <WriteLN XXXXX e.Cycle>,
      e.Cycle : t.var-e1 e.rest,
//!                     t.var-e1 : (VAR (e.SplitName)),
      t.var-e1 : (s (e.SplitName)), //STUB!
      {
//        e.rest : t.var-e2 = t.var-e2;
        (VAR <Gener-Label "lsplit" e.CycleName>);
      } :: t.var-e2,
      <Declare-Vars "Expr" t.var-e2> : e,
//!                     <Instantiate-Vars t.var-e1 t.var-e2>
      (Assert 
        e.decl
        (LSPLIT t.var ((VAR ("min" e.SplitName))) t.var-e1 t.var-e2)
      )
      (Cond LABEL t.break-label)
      (Cond FOR (t.cont-label) () ((INC-ITER t.var)))
      (Fail (BREAK t.break-label))
      (Clear-Restricted)
      (<Update-Ties t.var-e2 <Update-Ties t.var-e1 e1>>
        e.old-clash
        (<Gener-Label "clash"> &New-Clash-Tags (t.var-e2) (s.dir e.rest))
      <Update-Ties t.var-e2 <Update-Ties t.var-e1 e2>>)
      ((CONTINUE t.cont-label));
    RIGHT =
      e.Cycle : e.rest t.var-e2,
      t.var-e2 : (VAR (e.SplitName)),
      {
//        e.rest : t.var-e2 = t.var-e2;
        (VAR <Gener-Label "lsplit" e.CycleName>);
      } :: t.var-e1,
      <Declare-Vars "Expr" t.var-e1> : e,
      <Instantiate-Vars t.var-e1 t.var-e2>
      (Assert 
        e.decl
        (RSPLIT t.var ((VAR ("min" e.SplitName))) t.var-e1 t.var-e2)
      )
      (Cond LABEL t.break-label)
      (Cond FOR (t.cont-label) () ((INC-ITER t.var)))
      (Fail (BREAK t.break-label))
      (Clear-Restricted)
      (<Update-Ties t.var-e2 <Update-Ties t.var-e1 e1>>
        e.old-clash
        (<Gener-Label "clash"> &New-Clash-Tags (t.var-e1) (s.dir e.rest))
      <Update-Ties t.var-e2 <Update-Ties t.var-e1 e2>>)
      ((CONTINUE t.cont-label));
  };

Get-Subexprs e.vars =
//  <WriteLN Get-Subexprs e.vars>,
  e.vars () $iter {
    e.vars : (VAR t.name) e.rest,
      # \{ <?? t.name Instantiated> : True; },
      <?? t.name Left-compare> : (t.var s.dir (e.pos) (0) e.len) e =
      <Instantiate-Vars (VAR t.name)>,
      <Declare-Vars "Expr" (VAR t.name)> : e,
      {
        s.dir : Right =
          (INFIX "-" (<Length-of t.var>) (e.pos e.len));
        e.pos;
      } :: e.pos,
      e.rest (e.decls (Used t.var) (SUBEXPR (VAR t.name) t.var (e.pos) (e.len)));
    // STUB:
    e.vars : t e.rest = e.rest (e.decls);
  } :: e.vars (e.decls),
  e.vars : /*empty*/ =
  e.decls;

/*
 * Returns those parts of e.expr which lengthes are known. Also returns a list
 * of variables with unknown lengthes.
 */
Unknown-Vars e.expr =
  e.expr () () $iter {
    e.expr : t.first e.rest, {
      t.first : (VAR t.name), {
        <?? t.name Instantiated> : True =
          e.new-expr t.first (e.unknown);
        <?? t.name Max> :: e.max, <?? t.name Min> : e.max =
          e.new-expr t.first (e.unknown);
        e.new-expr (e.unknown t.first);
      };
      e.new-expr t.first (e.unknown);
    } :: e.new-expr (e.unknown) =
      e.rest (e.new-expr) (e.unknown);
  } :: e.expr (e.new-expr) (e.unknown),
  e.expr : /*empty*/ =
  e.new-expr (e.unknown);
  
Split-Hard-Left e.expr =
  e.expr () $iter {
    e.expr : t.Pt e.rest, {
      <Hard-Exp? t.Pt> = e.rest (e.hard t.Pt);
      (e.hard);
    };
  } :: e.expr (e.hard),
  e.expr : /*empty*/ =
  e.hard;

Split-Hard-Right e.expr =
  e.expr () $iter {
    e.expr : e.some t.Pt, {
      <Hard-Exp? t.Pt> = e.some (t.Pt e.hard);
      (e.hard);
    };
  } :: e.expr (e.hard),
  e.expr : /*empty*/ =
  e.hard;

Gener-Label e.QualifiedName =
  {
    <Lookup &Labels e.QualifiedName> : s.num,
      <"+" s.num 1>;
    1;
  } :: s.num,
  <Bind &Labels (e.QualifiedName) (s.num)>,
  (e.QualifiedName s.num);

Add-To-Label (e.label) e.name = <Gener-Label e.label "_" e.name>;

Get-Static-Exprs e.Re =
  e.Re () () () $iter {
    e.Re : t.Rt e.rest, t.Rt : {
      s.ObjectSymbol, {
        <Char? t.Rt> =
          e.rest (e.new-Re) (e.decls) (e.expr t.Rt);
        <Get-Static-Var "chars" e.expr> :: e.expr-var (e.expr-decl),
          {
            <Int? t.Rt> = "int";
            <Word? t.Rt> = "word";
          } :: s.prefix,
          <Get-Static-Var s.prefix t.Rt> :: e.Rt-var (e.Rt-decl) =
          e.rest (e.new-Re e.expr-var e.Rt-var)
          (e.decls e.expr-decl e.Rt-decl) ();
      };
      (PAREN e.paren-Re) =
        <Get-Static-Exprs e.paren-Re> :: e.new-paren-Re (e.paren-decls),
        <Get-Static-Var "chars" e.expr> :: e.expr-var (e.expr-decl),
        e.rest (e.new-Re e.expr-var (PAREN e.new-paren-Re))
        (e.decls e.expr-decl e.paren-decls) ();
      t.var =
        <Get-Static-Var "chars" e.expr> :: e.expr-var (e.expr-decl),
        e.rest (e.new-Re e.expr-var t.var) (e.decls e.expr-decl) ();
    };
  } :: e.Re (e.new-Re) (e.decls) (e.expr),
//  <WriteLN Get-Static-Exprs e.Re>,
  e.Re : /*empty*/ =
  <Get-Static-Var "chars" e.expr> :: e.expr-var (e.expr-decl),
  e.new-Re e.expr-var (e.decls e.expr-decl);

Get-Static-Var s.prefix e.expr, {
  e.expr : /*empty*/ = /*empty*/ ();
  {
    <Lookup &Static-Exprs s.prefix e.expr> : t.var = t.var ();
    ("const" s.prefix e.expr) :: t.name,
      <Bind &Static-Exprs (s.prefix e.expr) ((VAR t.name))>,
      <Declare-Vars "Expr" (VAR t.name)> : e,
      <Instantiate-Vars (VAR t.name)>,
      <Set-Var t.name (Flat) (True)>,
      <Length e.expr> :: s.len,
      <Set-Var t.name (Length) (s.len)>,
      <Set-Var t.name (Min) (s.len)>,
      <Set-Var t.name (Max) (s.len)>,
      <Set-Var t.name (Format) (e.expr)> =
      (VAR t.name) ((EXPR (VAR t.name) e.expr));
  };
};

Length-of {
  /*empty*/ = 0;
  e.Re =
    e.Re () $iter {
      e.Re : t.Rt e.rest, t.Rt : {
        s.ObjectSymbol = 1;
        (PAREN e) = 1;
        (REF t.name) = <Ref-Len t.name>;
        (VAR t.name), {
          <?? t.name Length>;
          (Used t.Rt) (LENGTH t.Rt);
        };
        t = (LENGTH t.Rt); // STUB!
      } :: e.new-len,
      e.rest (e.Length e.new-len);
    } :: e.Re (e.Length),
    e.Re : /*empty*/ =
//    (INFIX "+" e.Length);
//    <WriteLN Length e.Length>,
    e.Length;
};

Ref-Len t.name = {
  <To-Int <Lookup &Const-Len t.name>>;
  <Length <Length-of <Lookup &Const t.name>>> :: s.len =
    <Bind &Const-Len (t.name) (s.len)>,
    s.len;
};

/*
 * Ends good if lengths of all variables in e.expr can be calculated.
 */
Hard-Exp? e.expr =
  e.expr $iter {
    e.expr : t.first e.rest =
    {
      t.first : (VAR t.name), {
        <?? t.name Instantiated> : True;
        <?? t.name Max> :: e.max, <?? t.name Min> : e.max;
        = $fail;
      };;
    },
      e.rest;
  } :: e.expr,
  e.expr : /*empty*/,
  = $fail; // STUB!

Print-Error s.WE e.Descrip t.Pragma =
  <? &Error-Counter> : s.n,
  <Store &Error-Counter <"+" s.n 1>>,
  <Print-Pragma &StdErr t.Pragma>,
  <Print! &StdErr " " s.WE " ">,
  s.WE e.Descrip : {
    Error! Re = <PrintLN! &StdErr "Wrong format of result expression">;
    Error! Call = <PrintLN! &StdErr "Wrong argument format in function call">;
    Error! Pattern = <PrintLN! &StdErr "Wrong format of pattern expression">;
    Warning! Pattern = <PrintLN! &StdErr "Clash can't be solved">;
    Error! Var-Re t.var =
      <PrintLN! &StdErr "Unknown variable '"
                <AS-To-Ref t.var> "' in result expression">;
    Error! Var-Hard t.var =
      <PrintLN! &StdErr "Repeated occurence of the variable '"
                <AS-To-Ref t.var> "' in hard expression">;
    Error! Var-Type t.var s.type =
      <PrintLN! &StdErr "Incorrect type '" <AS-To-Ref s.type>
                "' of the variable '" <AS-To-Ref t.var> "'">;
    Error! Cut = <PrintLN! &StdErr "'\\\\!' without corresponding '\\\\?'">;
  };

Print-Pragma s.channel (PRAGMA e.pragmas),
  e.pragmas : {
    e (FILE e.file-name) e, <Print! s.channel e.file-name>, $fail;
    e (LINE s.line s.col) e, <Print! s.channel (s.line ", " s.col)>, $fail;
    e = <Print! s.channel ":">;
  };

AS-To-Ref {
  SVAR = 's';
  TVAR = 't';
  VVAR = 'v';
  EVAR = 'e';
  (s.tag t (e.name)) = <AS-To-Ref s.tag> '.' <To-Chars e.name>;
};

Lookup-Func t.Fname, \{
  <Lookup &Fun t.Fname>;
  <Lookup &Fun? t.Fname>;
} : s.linkage s.tag t.pragma (e.Fin) (e.Fout) =
  s.linkage s.tag t.pragma (e.Fin) (e.Fout);