%{ #include "hoc.h" #define code2(c1,c2) code(c1); code(c2) #define code3(c1,c2,c3) code(c1); code(c2); code(c3) %} %union { Symbol *sym; /* symbol table pointer */ Inst *inst; /* machine instruction */ int narg; /* number of arguments */ } %token <sym> NUMBER STRING PRINT VAR BLTIN UNDEF WHILE FOR IF ELSE %token <sym> FUNCTION PROCEDURE RETURN FUNC PROC READ %token <narg> ARG %type <inst> expr stmt asgn prlist stmtlist %type <inst> cond while for if begin end %type <sym> procname %type <narg> arglist %right '=' ADDEQ SUBEQ MULEQ DIVEQ MODEQ %left OR %left AND %left GT GE LT LE EQ NE %left '+' '-' %left '*' '/' '%' %left UNARYMINUS NOT INC DEC %right '^' %% list: /* nothing */ | list '\n' | list defn '\n' | list asgn '\n' { code2(xpop, STOP); return 1; } | list stmt '\n' { code(STOP); return 1; } | list expr '\n' { code2(print, STOP); return 1; } | list error '\n' { yyerrok; } ; asgn: VAR '=' expr { code3(varpush,(Inst)$1,assign); $$=$3; } | VAR ADDEQ expr { code3(varpush,(Inst)$1,addeq); $$=$3; } | VAR SUBEQ expr { code3(varpush,(Inst)$1,subeq); $$=$3; } | VAR MULEQ expr { code3(varpush,(Inst)$1,muleq); $$=$3; } | VAR DIVEQ expr { code3(varpush,(Inst)$1,diveq); $$=$3; } | VAR MODEQ expr { code3(varpush,(Inst)$1,modeq); $$=$3; } | ARG '=' expr { defnonly("$"); code2(argassign,(Inst)$1); $$=$3;} | ARG ADDEQ expr { defnonly("$"); code2(argaddeq,(Inst)$1); $$=$3;} | ARG SUBEQ expr { defnonly("$"); code2(argsubeq,(Inst)$1); $$=$3;} | ARG MULEQ expr { defnonly("$"); code2(argmuleq,(Inst)$1); $$=$3;} | ARG DIVEQ expr { defnonly("$"); code2(argdiveq,(Inst)$1); $$=$3;} | ARG MODEQ expr { defnonly("$"); code2(argmodeq,(Inst)$1); $$=$3;} ; stmt: expr { code(xpop); } | RETURN { defnonly("return"); code(procret); } | RETURN expr { defnonly("return"); $$=$2; code(funcret); } | PROCEDURE begin '(' arglist ')' { $$ = $2; code3(call, (Inst)$1, (Inst)$4); } | PRINT prlist { $$ = $2; } | while '(' cond ')' stmt end { ($1)[1] = (Inst)$5; /* body of loop */ ($1)[2] = (Inst)$6; } /* end, if cond fails */ | for '(' cond ';' cond ';' cond ')' stmt end { ($1)[1] = (Inst)$5; /* condition */ ($1)[2] = (Inst)$7; /* post loop */ ($1)[3] = (Inst)$9; /* body of loop */ ($1)[4] = (Inst)$10; } /* end, if cond fails */ | if '(' cond ')' stmt end { /* else-less if */ ($1)[1] = (Inst)$5; /* thenpart */ ($1)[3] = (Inst)$6; } /* end, if cond fails */ | if '(' cond ')' stmt end ELSE stmt end { /* if with else */ ($1)[1] = (Inst)$5; /* thenpart */ ($1)[2] = (Inst)$8; /* elsepart */ ($1)[3] = (Inst)$9; } /* end, if cond fails */ | '{' stmtlist '}' { $$ = $2; } ; cond: expr { code(STOP); } ; while: WHILE { $$ = code3(whilecode,STOP,STOP); } ; for: FOR { $$ = code(forcode); code3(STOP,STOP,STOP); code(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 ')' { $$ = $2; } | expr '+' expr { code(add); } | expr '-' expr { code(sub); } | expr '*' expr { code(mul); } | expr '/' expr { code(div); } | expr '%' expr { code(mod); } | expr '^' expr { code (power); } | '-' expr %prec UNARYMINUS { $$=$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 { $$ = $2; code(not); } | INC VAR { $$ = code2(preinc,(Inst)$2); } | DEC VAR { $$ = code2(predec,(Inst)$2); } | VAR INC { $$ = code2(postinc,(Inst)$1); } | VAR DEC { $$ = code2(postdec,(Inst)$1); } ; prlist: expr { code(prexpr); } | STRING { $$ = 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 { $$ = $1 + 1; } ; %% /* end of grammar */ #include <stdio.h> #include <ctype.h> char *progname; int lineno = 1; #include <signal.h> #include <setjmp.h> #include <errno.h> jmp_buf begin; int indef; char *infile; /* input file name */ FILE *fin; /* input file pointer */ char **gargv; /* global argument list */ extern errno; int gargc; int c = '\n'; /* global for use by warning() */ yylex() /* hoc6 */ { while ((c=getc(fin)) == ' ' || c == '\t') ; if (c == EOF) return 0; if (c == '\\') { c = getc(fin); if (c == '\n') { lineno++; return yylex(); } } if (c == '#') { /* comment */ while ((c=getc(fin)) != '\n' && c != EOF) ; if (c == '\n') lineno++; return c; } if (c == '.' || isdigit(c)) { /* number */ double d; ungetc(c, fin); fscanf(fin, "%lf", &d); yylval.sym = install("", NUMBER, d); return NUMBER; } if (isalpha(c) || c == '_') { Symbol *s; char sbuf[100], *p = sbuf; do { if (p >= sbuf + sizeof(sbuf) - 1) { *p = '\0'; execerror("name too long", sbuf); } *p++ = c; } while ((c=getc(fin)) != EOF && (isalnum(c) || c == '_')); ungetc(c, fin); *p = '\0'; if ((s=lookup(sbuf)) == 0) s = install(sbuf, UNDEF, 0.0); yylval.sym = s; return s->type == UNDEF ? VAR : s->type; } if (c == '$') { /* argument? */ int n = 0; while (isdigit(c=getc(fin))) n = 10 * n + c - '0'; ungetc(c, fin); if (n == 0) execerror("strange $...", (char *)0); yylval.narg = n; return ARG; } if (c == '"') { /* quoted string */ char sbuf[100], *p, *emalloc(); for (p = sbuf; (c=getc(fin)) != '"'; p++) { if (c == '\n' || c == EOF) execerror("missing quote", ""); if (p >= sbuf + sizeof(sbuf) - 1) { *p = '\0'; execerror("string too long", sbuf); } *p = backslash(c); } *p = 0; yylval.sym = (Symbol *)emalloc(strlen(sbuf)+1); strcpy(yylval.sym, sbuf); return STRING; } switch (c) { case '+': return follow('+', INC, follow('=', ADDEQ, '+')); case '-': return follow('-', DEC, follow('=', SUBEQ, '-')); case '*': return follow('=', MULEQ, '*'); case '/': return follow('=', DIVEQ, '/'); case '%': return follow('=', MODEQ, '%'); case '>': return follow('=', GE, GT); case '<': return follow('=', LE, LT); case '=': return follow('=', EQ, '='); case '!': return follow('=', NE, NOT); case '|': return follow('|', OR, '|'); case '&': return follow('&', AND, '&'); case '\n': lineno++; return '\n'; default: return c; } } backslash(c) /* get next char with \'s interpreted */ int c; { char *strchr(); /* `index()' in some systems */ static char transtab[] = "b\bf\fn\nr\rt\t"; if (c != '\\') return c; c = getc(fin); if (islower(c) && strchr(transtab, c)) return strchr(transtab, c)[1]; return c; } follow(expect, ifyes, ifno) /* look ahead for >=, etc. */ { int c = getc(fin); if (c == expect) return ifyes; ungetc(c, fin); return ifno; } defnonly(s) /* warn if illegal definition */ char *s; { if (!indef) execerror(s, "used outside definition"); } yyerror(s) /* report compile-time error */ char *s; { /*rob warning(s, (char *)0); longjmp(begin, 0); rob*/ execerror(s, (char *)0); } execerror(s, t) /* recover from run-time error */ char *s, *t; { warning(s, t); fseek(fin, 0L, 2); /* flush rest of file */ longjmp(begin, 0); } fpecatch() /* catch floating point exceptions */ { execerror("floating point exception", (char *) 0); } intcatch() /* catch interrupts */ { execerror("interrupt", (char *) 0); } main(argc, argv) /* hoc6 */ char *argv[]; { int i, fpecatch(); static int first = 1; progname = argv[0]; init(); if (argc == 1) { /* fake an argument list */ static char *stdinonly[] = { "-" }; gargv = stdinonly; gargc = 1; } else if (first) { /* for interrupts */ first = 0; gargv = argv+1; gargc = argc-1; } while (moreinput()) run(); signal(SIGINT, SIG_IGN); return 0; } moreinput() { if (gargc-- <= 0) return 0; if (fin && fin != stdin) fclose(fin); infile = *gargv++; lineno = 1; if (strcmp(infile, "-") == 0) { fin = stdin; infile = 0; } else if ((fin=fopen(infile, "r")) == NULL) { fprintf(stderr, "%s: can't open %s\n", progname, infile); return moreinput(); } return 1; } run() /* execute until EOF */ { setjmp(begin); signal(SIGINT, intcatch); signal(SIGFPE, fpecatch); for (initcode(); yyparse(); initcode()) execute(progbase); } warning(s, t) /* print warning message */ char *s, *t; { fprintf(stderr, "%s: %s", progname, s); if (t) fprintf(stderr, " %s", t); if (infile) fprintf(stderr, " in %s", infile); fprintf(stderr, " near line %d\n", lineno); while (c != '\n' && c != EOF) if((c = getc(fin)) == '\n') /* flush rest of input line */ lineno++; else if (c == EOF && errno == EINTR) { clearerr(stdin); /* ick! */ errno = 0; } }