ref: 02c6058f5d529e41afb0208c69f0cbf694b02b18
dir: /sys/src/cmd/forp/parse.c/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ctype.h>
#include <mp.h>
#include "dat.h"
#include "fns.h"
Biobuf *bin;
Line line;
char lexbuf[512];
int peektok;
enum {
TEOF = -1,
TSYM = -2,
TNUM = -3,
TBIT = -4,
TOBVIOUSLY = -5,
TEQ = -6,
TNEQ = -7,
TLSH = -8,
TRSH = -9,
TLE = -10,
TGE = -11,
TLAND = -12,
TLOR = -13,
TASSUME = -14,
TIMP = -15,
TEQV = -16,
TSIGNED = -17,
};
typedef struct Keyword Keyword;
typedef struct Oper Oper;
struct Keyword {
char *name;
int tok;
};
/* both tables must be sorted */
static Keyword kwtab[] = {
"assume", TASSUME,
"bit", TBIT,
"obviously", TOBVIOUSLY,
"signed", TSIGNED,
};
/* <=> is implemented through a hack below */
static Keyword koptab[] = {
"!=", TNEQ,
"&&", TLAND,
"<<", TLSH,
"<=", TLE,
"==", TEQ,
"=>", TIMP,
">=", TGE,
">>", TRSH,
"||", TLOR,
};
static Keyword *kwjmp[128];
static Keyword *kopjmp[128];
struct Oper {
int tok;
int type;
int pred;
char *str;
};
#define MAXPREC 15
static Oper optab[] = {
'*', OPMUL, 14, "*",
'/', OPDIV, 14, "/",
'%', OPMOD, 14, "%",
'+', OPADD, 13, "+",
'-', OPSUB, 13, "-",
TLSH, OPLSH, 12, "<<",
TRSH, OPRSH, 12, ">>",
'<', OPLT, 11, "<",
TLE, OPLE, 11, "<=",
'>', OPGT, 11, ">",
TGE, OPGE, 11, ">=",
TEQ, OPEQ, 10, "==",
TNEQ, OPNEQ, 10, "!=",
'&', OPAND, 9, "&",
'^', OPXOR, 8, "^",
'|', OPOR, 7, "|",
TLAND, OPLAND, 6, "&&",
TLOR, OPLOR, 5, "||",
TEQV, OPEQV, 4, "<=>",
TIMP, OPIMP, 4, "=>",
/* ?: */
'=', OPASS, 2, "=",
',', OPCOMMA, 1, ",",
-1, OPNOT, MAXPREC, "!",
-1, OPCOM, MAXPREC, "~",
-1, OPNEG, MAXPREC, "-",
};
void
error(Line *l, char *msg, ...)
{
char buf[256];
Fmt f;
va_list va;
if(l == nil) l = &line;
fmtfdinit(&f, 2, buf, sizeof(buf));
fmtprint(&f, "%s:%d: ", l->filen, l->lineno);
va_start(va, msg);
fmtvprint(&f, msg, va);
va_end(va);
fmtrune(&f, '\n');
fmtfdflush(&f);
exits("error");
}
static int
tokfmt(Fmt *f)
{
int t;
Keyword *k;
t = va_arg(f->args, int);
if(t >= ' ' && t < 0x7f) return fmtprint(f, "%c", t);
for(k = kwtab; k < kwtab + nelem(kwtab); k++)
if(k->tok == t)
return fmtprint(f, "%s", k->name);
for(k = koptab; k < koptab + nelem(koptab); k++)
if(k->tok == t)
return fmtprint(f, "%s", k->name);
switch(t){
case TSYM: return fmtprint(f, "TSYM"); break;
case TNUM: return fmtprint(f, "TNUM"); break;
case TEOF: return fmtprint(f, "eof"); break;
default: return fmtprint(f, "%d", t); break;
}
}
static int
exprfmt(Fmt *f)
{
Node *n;
Oper *o;
int w;
n = va_arg(f->args, Node *);
if(n == nil) return fmtprint(f, "nil");
switch(n->type){
case ASTSYM: return fmtprint(f, "%s", n->sym->name);
case ASTBIN:
for(o = optab; o < optab + nelem(optab); o++)
if(o->type == n->op)
break;
if(o == optab + nelem(optab)) return fmtprint(f, "[unknown operation %O]", n->op);
w = f->width;
if(w > o->pred) fmtrune(f, '(');
fmtprint(f, "%*ε %s %*ε", o->pred, n->n1, o->str, o->pred + 1, n->n2);
if(w > o->pred) fmtrune(f, ')');
return 0;
case ASTNUM: return fmtprint(f, "0x%B", n->num);
default: return fmtprint(f, "???(%α)", n->type);
}
}
static int
issymchar(int c)
{
return c >= 0 && (isalnum(c) || c == '_' || c >= 0x80);
}
static int
lex(void)
{
int c, d;
char *p;
Keyword *kw;
if(peektok != 0){
c = peektok;
peektok = 0;
return c;
}
loop:
do{
c = Bgetc(bin);
if(c == '\n') line.lineno++;
}while(c >= 0 && isspace(c));
if(c < 0) return TEOF;
if(c == '/'){
c = Bgetc(bin);
if(c == '/'){
do
c = Bgetc(bin);
while(c >= 0 && c != '\n');
if(c < 0) return TEOF;
line.lineno++;
goto loop;
}else if(c == '*'){
s0:
c = Bgetc(bin);
if(c != '*') goto s0;
s1:
c = Bgetc(bin);
if(c == '*') goto s1;
if(c != '/') goto s0;
goto loop;
}else{
Bungetc(bin);
return '/';
}
}
if(isdigit(c)){
p = lexbuf;
*p++ = c;
while(c = Bgetc(bin), issymchar(c))
if(p < lexbuf + sizeof(lexbuf) - 1)
*p++ = c;
Bungetc(bin);
*p = 0;
strtol(lexbuf, &p, 0);
if(p == lexbuf || *p != 0)
error(nil, "invalid number %q", lexbuf);
return TNUM;
}
if(issymchar(c)){
p = lexbuf;
*p++ = c;
while(c = Bgetc(bin), issymchar(c))
if(p < lexbuf + sizeof(lexbuf) - 1)
*p++ = c;
Bungetc(bin);
*p = 0;
c = lexbuf[0];
if((signed char)c>= 0 && (kw = kwjmp[c], kw != nil))
for(; kw < kwtab + nelem(kwtab) && kw->name[0] == c; kw++)
if(strcmp(lexbuf, kw->name) == 0)
return kw->tok;
return TSYM;
}
if(kw = kopjmp[c], kw != nil){
d = Bgetc(bin);
for(; kw < koptab + nelem(koptab) && kw->name[0] == c; kw++)
if(kw->name[1] == d){
if(kw->tok == TLE){
c = Bgetc(bin);
if(c == '>')
return TEQV;
Bungetc(bin);
}
return kw->tok;
}
Bungetc(bin);
}
return c;
}
static void
superman(int t)
{
assert(peektok == 0);
peektok = t;
}
static int
peek(void)
{
if(peektok != 0) return peektok;
return peektok = lex();
}
static void
expect(int t)
{
int s;
s = lex();
if(t != s)
error(nil, "expected %t, got %t", t, s);
}
static int
got(int t)
{
return peek() == t && (lex(), 1);
}
static Node *
expr(int level)
{
Node *a, *b, *c;
Oper *op;
Symbol *s;
mpint *num;
int t;
if(level == MAXPREC+2){
switch(t = lex()){
case '(':
a = expr(0);
expect(')');
return a;
case TSYM:
s = symget(lexbuf);
switch(s->type){
case SYMNONE:
error(nil, "%#q undefined", s->name);
default:
error(nil, "%#q symbol type error", s->name);
case SYMBITS:
break;
}
return node(ASTSYM, s);
case TNUM:
num = strtomp(lexbuf, nil, 0, nil);
return node(ASTNUM, num);
default:
error(nil, "unexpected %t", t);
}
}else if(level == MAXPREC+1){
a = expr(level + 1);
if(got('[')){
b = expr(0);
if(got(':'))
c = expr(0);
else
c = nil;
expect(']');
a = node(ASTIDX, a, b, c);
}
return a;
}else if(level == MAXPREC){
switch(t = lex()){
case '~': return node(ASTUN, OPCOM, expr(level));
case '!': return node(ASTUN, OPNOT, expr(level));
case '+': return expr(level);
case '-': return node(ASTUN, OPNEG, expr(level));
default: superman(t); return expr(level+1); break;
}
}else if(level == 3){
a = expr(level + 1);
if(got('?')){
b = expr(level);
expect(':');
c = expr(level);
a = node(ASTTERN, a, b, c);
}
return a;
}
a = expr(level+1);
for(;;){
t = peek();
for(op = optab; op < optab + nelem(optab); op++)
if(op->tok == t && op->pred >= level)
break;
if(op == optab+nelem(optab)) return a;
lex();
a = node(ASTBIN, op->type, a, expr(level+1));
}
}
static void
vardecl(void)
{
Symbol *s;
int l, flags;
flags = 0;
for(;;)
switch(l = lex()){
case TBIT: if((flags & 1) != 0) goto err; flags |= 1; break;
case TSIGNED: if((flags & 2) != 0) goto err; flags |= 2; break;
default: superman(l); goto out;
}
out:
do{
expect(TSYM);
s = symget(lexbuf);
if(s->type != SYMNONE) error(nil, "%#q redefined", s->name);
s->type = SYMBITS;
if((flags & 2) != 0)
s->flags |= SYMFSIGNED;
s->size = 1;
if(got('[')){
expect(TNUM);
s->type = SYMBITS;
s->size = strtol(lexbuf, nil, 0);
expect(']');
}
s->vars = emalloc(sizeof(int) * s->size);
}while(got(','));
expect(';');
return;
err: error(nil, "syntax error");
}
static int
statement(void)
{
Node *n;
int t;
switch(t=peek()){
case TEOF:
return 0;
case TBIT:
case TSIGNED:
vardecl();
break;
case TASSUME:
case TOBVIOUSLY:
lex();
n = expr(0);
expect(';');
convert(n, -1);
if(t == TASSUME)
assume(n);
else
obviously(n);
break;
case ';':
lex();
break;
default:
n = expr(0);
convert(n, -1);
expect(';');
}
return 1;
}
void
parsinit(void)
{
Keyword *k;
fmtinstall('t', tokfmt);
fmtinstall(L'ε', exprfmt);
for(k = kwtab; k < kwtab + nelem(kwtab); k++)
if(kwjmp[k->name[0]] == nil)
kwjmp[k->name[0]] = k;
for(k = koptab; k < koptab + nelem(koptab); k++)
if(kopjmp[k->name[0]] == nil)
kopjmp[k->name[0]] = k;
}
void
parse(char *fn)
{
if(fn == nil){
bin = Bfdopen(0, OREAD);
line.filen = "<stdin>";
}else{
bin = Bopen(fn, OREAD);
line.filen = strdup(fn);
}
if(bin == nil) sysfatal("open: %r");
line.lineno = 1;
while(statement())
;
}