ref: 1d9c31d9f5f539c854aea84056d55ad47995ee48
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()) ; }