UNIX — универсальная среда программирования

  | ARG '=' expr
  { defnonly("$"); code2(argassign,(Inst)$1); $$=$3;}
  ;
 stmt: expr { code(pop); }
  | RETURN { defnonly("return"); code(procret); }
  | RETURN expr
  { defnonly("return"); $$=$2; code(funcret); }
  | PROCEDURE begin '(' arglist ')'
  { $$ = $2; code3(call, (Inst)$1, (Inst)$4); }
  | PRINT prlist { $$ = $2; }
  | while cond stmt end {
  ($1)UID = (Inst)$3; /* body of loop */
  ($1)[2] = (Inst)$4;
  } /* end, if cond fails */
  | if cond stmt end { /* else-less if */
  ($1)[1] = (Inst)$3; /* thenpart */
  ($1)[3] = (Inst)$4;
  } /* end, if cond fails */
  | if cond stmt end ELSE stmt end { /* if with else */
  ($1)[1] = (Inst)$3; /* thenpart */
  ($1)[2] = (Inst)$6; /* elsepart */
  ($1)[3] = (Inst)$7;
  } /* end, if cond fails */
  | '{' stmtlist '}' { $$ = $2; }
  ;
 cond: '(' expr ')' { code(STOP); $$ = $2; }
  ;
 while: WHILE { $$ = code3(whilecode,STOP,STOP); }
  ;
 if: IF { $$ = code(ifcode); code3(STOP,STOP,STOP); }
  ;
 begin: /* nothing */ { $$ = progp; }
  ;
 end: /* nothing */ { code(STOP); $$ = progp; }
  ;
 stmtlist: /* nothing */ { $$ = progp; }
  | stmtlist '\n'
  | stmtlist stmt
  ;
 expr: NUMBER { $$ = code2(constpush, (Inst)$1); }
  | VAR { $$ = code3(varpush, (Inst)$1, eval); }
  | ARG { defnonly("$"); $$ = code2(arg, (Inst)$1); }
  | asgn
  | FUNCTION begin '(' arglist ');
  { $$ = $2; code3(call,(Inst)$1,(Inst)$4); }
  | READ '(' VAR ')'{$$ = code2(varread, (Inst)$3); }
  | BLTIN '(' expr ')' { $$=$3; code2(bltin, (Inst)$1->u.ptr); }
  | '(' expr ')' { $$ = $2; }
  | expr '+' expr { code(add); }
  | expr '-' expr { code(sub); }
  | expr '*' expr { code(mul); }
  | expr '/' expr { code(div); }
  | expr '^' expr { code(power); }
  | '-' expr %prec UNARYMINUS { $$=$2; code(negate); }
  | expr GT expr { code(gt); }
  | expr GE expr { code(ge); }
  | expr LT expr { code(lt); }
  | expr LE expr { code(le); }
  | expr EQ expr { code(eq); }
  | expr NE expr { code(ne); }
  | expr AND expr { code(and); }
  | expr OR expr { code(or); }
  | NOT expr { $$ = $2; code(not); }
  ;
 prlist: expr { code(prexpr); }
  | STRING { $$ = code2(prstr, (Inst)$1); }
  | prlist expr { code(prexpr); }
  | prlist STRING { code2(prstr, (Inst)$3); }
  ;
 defn: FUNC procname { $2->type=FUNCTION; indef=1; }
  '(' ')' stmt { code(procret); define($2); indef=0; }
  | PROC procname { $2->type=PROCEDURE; indef=1; }
  '(' ')' stmt { code(procret); define($2); indef=0; }
  ;
 procname: VAR
  | FUNCTION
  | PROCEDURE
  ;
 arglist: /* nothing */ { $$ = 0; }
  | expr { $$ = 1; }
  | arglist expr { $$ = $1 + 1; }
  ;
 %%
 /* end of grammar */
 #include <stdio.h>
 #include <ctype.h>
 char *progname;
 int lineno = 1;
 #include <signal.h>
 #include <setjmp.h>

 jmp_buf begin;
 int indef;
 char *infile; /* input file name */
 FILE *fin; /* input file pointer */
 char **gargv; /* global argument list */
 int gargc;

 int c; /* global for use by warning */

 yylex /* hoc6 */
 {
  while ((c=getc(fin)) == ' ' || c == '\t')
  ;
  if (c == EOF)
  return 0;
  if (c == '.' || isdigit(c)) { /* number */
  double d;
  ungetc(c, fin);
  fscanf(fin, "%lf", &d);
  yylval.sym = install("", NUMBER, d);
  return NUMBER;
  }
  if (isalpha(c)) {
  Symbol *s;
  char sbuf[100], *p = sbuf;
  do {
  if (p >= sbuf + sizeof(sbuf) - 1) {
  *p = '\0';
  execerror("name too long", sbuf);