ref: f4f19cdf1a8f0d2aa5f9fce10c896201528b5347
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");
}