ref: bc895417f804bbb78410a365412bcf8ab59a44b4
dir: /sys/src/cmd/hoc/hoc.y/
%{ #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 */ Formal *formals; /* list of formal parameters */ } %token <sym> NUMBER STRING PRINT VAR BLTIN UNDEF WHILE FOR IF ELSE %token <sym> FUNCTION PROCEDURE RETURN FUNC PROC READ %type <formals> formals %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(printtop, 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; } ; 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); } | 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 { $$ = code2(prstr, (Inst)$1); } | prlist ',' expr { code(prexpr); } | prlist ',' STRING { code2(prstr, (Inst)$3); } ; defn: FUNC procname { $2->type=FUNCTION; indef=1; } '(' formals ')' stmt { code(procret); define($2, $5); indef=0; } | PROC procname { $2->type=PROCEDURE; indef=1; } '(' formals ')' stmt { code(procret); define($2, $5); indef=0; } ; formals: { $$ = 0; } | VAR { $$ = formallist($1, 0); } | VAR ',' formals { $$ = formallist($1, $3); } ; procname: VAR | FUNCTION | PROCEDURE ; arglist: /* nothing */ { $$ = 0; } | expr { $$ = 1; } | arglist ',' expr { $$ = $1 + 1; } ; %% /* end of grammar */ #include <u.h> #include <libc.h> #include <bio.h> #include <ctype.h> char *progname; int lineno = 1; jmp_buf begin; int indef; char *infile; /* input file name */ Biobuf *bin; /* input file descriptor */ Biobuf binbuf; char **gargv; /* global argument list */ int gargc; int c = '\n'; /* global for use by warning() */ int backslash(int), follow(int, int, int); void defnonly(char*), run(void); void warning(char*, char*); yylex(void) /* hoc6 */ { while ((c=Bgetc(bin)) == ' ' || c == '\t') ; if (c < 0) return 0; if (c == '\\') { c = Bgetc(bin); if (c == '\n') { lineno++; return yylex(); } } if (c == '#') { /* comment */ while ((c=Bgetc(bin)) != '\n' && c >= 0) ; if (c == '\n') lineno++; return c; } if (c == '.' || isdigit(c)) { /* number */ double d; Bungetc(bin); Bgetd(bin, &d); yylval.sym = install("", NUMBER, d); return NUMBER; } if (isalpha(c) || c == '_' || c >= 0x80) { 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=Bgetc(bin)) >= 0 && (isalnum(c) || c == '_' || c >= 0x80)); Bungetc(bin); *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 == '"') { /* quoted string */ char sbuf[100], *p; for (p = sbuf; (c=Bgetc(bin)) != '"'; p++) { if (c == '\n' || c == Beof) 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((char*)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(int c) /* get next char with \'s interpreted */ { static char transtab[] = "b\bf\fn\nr\rt\t"; if (c != '\\') return c; c = Bgetc(bin); if (islower(c) && strchr(transtab, c)) return strchr(transtab, c)[1]; return c; } follow(int expect, int ifyes, int ifno) /* look ahead for >=, etc. */ { int c = Bgetc(bin); if (c == expect) return ifyes; Bungetc(bin); return ifno; } void yyerror(char* s) /* report compile-time error */ { /*rob warning(s, (char *)0); longjmp(begin, 0); rob*/ execerror(s, (char *)0); } void execerror(char* s, char* t) /* recover from run-time error */ { warning(s, t); Bseek(bin, 0L, 2); /* flush rest of file */ restoreall(); longjmp(begin, 0); } void fpecatch(void) /* catch floating point exceptions */ { execerror("floating point exception", (char *) 0); } void intcatch(void) /* catch interrupts */ { execerror("interrupt", 0); } void run(void) /* execute until EOF */ { setjmp(begin); for (initcode(); yyparse(); initcode()) execute(progbase); } void main(int argc, char* argv[]) /* hoc6 */ { static int first = 1; #ifdef YYDEBUG extern int yydebug; yydebug=3; #endif 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; } Binit(&binbuf, 0, OREAD); bin = &binbuf; while (moreinput()) run(); exits(0); } moreinput(void) { char *expr; static char buf[64]; int fd; static Biobuf b; if (gargc-- <= 0) return 0; if (bin && bin != &binbuf) Bterm(bin); infile = *gargv++; lineno = 1; if (strcmp(infile, "-") == 0) { bin = &binbuf; infile = 0; return 1; } if(strncmp(infile, "-e", 2) == 0) { if(infile[2]==0){ if(gargc == 0){ fprint(2, "%s: no argument for -e\n", progname); return 0; } gargc--; expr = *gargv++; }else expr = infile+2; sprint(buf, "/tmp/hocXXXXXXX"); infile = mktemp(buf); fd = create(infile, ORDWR|ORCLOSE, 0600); if(fd < 0){ fprint(2, "%s: can't create temp. file: %r\n", progname); return 0; } fprint(fd, "%s\n", expr); /* leave fd around; file will be removed on exit */ /* the following looks weird but is required for unix version */ bin = &b; seek(fd, 0, 0); Binit(bin, fd, OREAD); } else { bin=Bopen(infile, OREAD); if (bin == 0) { fprint(2, "%s: can't open %s\n", progname, infile); return moreinput(); } } return 1; } void warning(char* s, char* t) /* print warning message */ { fprint(2, "%s: %s", progname, s); if (t) fprint(2, " %s", t); if (infile) fprint(2, " in %s", infile); fprint(2, " near line %d\n", lineno); while (c != '\n' && c != Beof) if((c = Bgetc(bin)) == '\n') /* flush rest of input line */ lineno++; } void defnonly(char *s) /* warn if illegal definition */ { if (!indef) execerror(s, "used outside definition"); }