mirror of
https://github.com/lua/lua
synced 2024-12-11 13:35:21 +03:00
410 lines
10 KiB
C
410 lines
10 KiB
C
/*
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** $Id: llex.c,v 2.2 2004/03/12 19:53:56 roberto Exp roberto $
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** Lexical Analyzer
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** See Copyright Notice in lua.h
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*/
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#include <ctype.h>
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#include <string.h>
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#define llex_c
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#define LUA_CORE
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#include "lua.h"
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#include "ldo.h"
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#include "llex.h"
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#include "lobject.h"
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#include "lparser.h"
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#include "lstate.h"
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#include "lstring.h"
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#include "lzio.h"
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#define next(ls) (ls->current = zgetc(ls->z))
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#define save(ls,c) { \
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Mbuffer *b = ls->buff; \
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if (b->n + 1 > b->buffsize) \
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luaZ_resizebuffer(ls->L, b, ((b->buffsize*2) + LUA_MINBUFFER)); \
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b->buffer[b->n++] = cast(char, c); }
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#define currIsNewline(ls) (ls->current == '\n' || ls->current == '\r')
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/* ORDER RESERVED */
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static const char *const token2string [] = {
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"and", "break", "do", "else", "elseif",
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"end", "false", "for", "function", "if",
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"in", "local", "nil", "not", "or", "repeat",
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"return", "then", "true", "until", "while", "*name",
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"..", "...", "==", ">=", "<=", "~=",
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"*number", "*string", "<eof>"
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};
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void luaX_init (lua_State *L) {
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int i;
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for (i=0; i<NUM_RESERVED; i++) {
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TString *ts = luaS_new(L, token2string[i]);
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luaS_fix(ts); /* reserved words are never collected */
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lua_assert(strlen(token2string[i])+1 <= TOKEN_LEN);
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ts->tsv.reserved = cast(lu_byte, i+1); /* reserved word */
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}
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}
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#define MAXSRC 80
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const char *luaX_token2str (LexState *ls, int token) {
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if (token < FIRST_RESERVED) {
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lua_assert(token == (unsigned char)token);
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return (iscntrl(token)) ? luaO_pushfstring(ls->L, "char(%d)", token) :
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luaO_pushfstring(ls->L, "%c", token);
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}
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else
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return token2string[token-FIRST_RESERVED];
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}
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static const char *txtToken (LexState *ls, int token) {
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switch (token) {
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case TK_NAME:
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case TK_STRING:
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case TK_NUMBER:
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save(ls, '\0');
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return luaZ_buffer(ls->buff);
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default:
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return luaX_token2str(ls, token);
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}
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}
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void luaX_lexerror (LexState *ls, const char *msg, int token) {
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char buff[MAXSRC];
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luaO_chunkid(buff, getstr(ls->source), MAXSRC);
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msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
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if (token)
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luaO_pushfstring(ls->L, "%s near `%s'", msg, txtToken(ls, token));
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luaD_throw(ls->L, LUA_ERRSYNTAX);
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}
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void luaX_syntaxerror (LexState *ls, const char *msg) {
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luaX_lexerror(ls, msg, ls->t.token);
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}
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TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
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lua_State *L = ls->L;
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TString *ts = luaS_newlstr(L, str, l);
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TValue *o = luaH_setstr(L, ls->fs->h, ts); /* entry for `str' */
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if (ttisnil(o))
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setbvalue(o, 1); /* make sure `str' will not be collected */
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return ts;
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}
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static void inclinenumber (LexState *ls) {
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int old = ls->current;
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lua_assert(currIsNewline(ls));
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next(ls); /* skip `\n' or `\r' */
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if (currIsNewline(ls) && ls->current != old)
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next(ls); /* skip `\n\r' or `\r\n' */
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if (++ls->linenumber >= MAX_INT)
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luaX_syntaxerror(ls, "chunk has too many lines");
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}
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void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source) {
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ls->L = L;
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ls->lookahead.token = TK_EOS; /* no look-ahead token */
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ls->z = z;
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ls->fs = NULL;
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ls->linenumber = 1;
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ls->lastline = 1;
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ls->source = source;
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next(ls); /* read first char */
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}
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/*
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** =======================================================
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** LEXICAL ANALYZER
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** =======================================================
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*/
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static void save_and_next (LexState *ls) {
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save(ls, ls->current);
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next(ls);
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}
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/* LUA_NUMBER */
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static void read_numeral (LexState *ls, SemInfo *seminfo) {
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while (isdigit(ls->current)) {
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save_and_next(ls);
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}
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if (ls->current == '.') {
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save_and_next(ls);
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if (ls->current == '.') {
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save_and_next(ls);
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luaX_lexerror(ls,
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"ambiguous syntax (decimal point x string concatenation)",
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TK_NUMBER);
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}
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}
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while (isdigit(ls->current)) {
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save_and_next(ls);
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}
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if (ls->current == 'e' || ls->current == 'E') {
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save_and_next(ls); /* read `E' */
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if (ls->current == '+' || ls->current == '-')
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save_and_next(ls); /* optional exponent sign */
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while (isdigit(ls->current)) {
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save_and_next(ls);
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}
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}
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save(ls, '\0');
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if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r))
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luaX_lexerror(ls, "malformed number", TK_NUMBER);
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}
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static int skip_ast (LexState *ls) {
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int count = 0;
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int s = ls->current;
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lua_assert(s == '[' || s == ']');
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save_and_next(ls);
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while (ls->current == '*') {
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save_and_next(ls);
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count++;
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}
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return (ls->current == s) ? count : (-count) - 1;
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}
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static void read_long_string (LexState *ls, SemInfo *seminfo, int ast) {
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int cont = 0;
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save_and_next(ls); /* skip 2nd `[' */
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if (currIsNewline(ls)) /* string starts with a newline? */
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inclinenumber(ls); /* skip it */
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for (;;) {
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switch (ls->current) {
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case EOZ:
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luaX_lexerror(ls, (seminfo) ? "unfinished long string" :
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"unfinished long comment", TK_EOS);
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break; /* to avoid warnings */
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case '[':
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if (skip_ast(ls) == ast) {
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save_and_next(ls); /* skip 2nd `[' */
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cont++;
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}
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continue;
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case ']':
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if (skip_ast(ls) == ast) {
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save_and_next(ls); /* skip 2nd `]' */
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if (cont-- == 0) goto endloop;
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}
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continue;
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case '\n':
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case '\r':
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save(ls, '\n');
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inclinenumber(ls);
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if (!seminfo) luaZ_resetbuffer(ls->buff); /* avoid wasting space */
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continue;
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default:
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if (seminfo) save_and_next(ls);
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else next(ls);
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}
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} endloop:
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if (seminfo)
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seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + ast),
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luaZ_bufflen(ls->buff) - 2*(2 + ast));
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}
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static void read_string (LexState *ls, int del, SemInfo *seminfo) {
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save_and_next(ls);
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while (ls->current != del) {
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switch (ls->current) {
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case EOZ:
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luaX_lexerror(ls, "unfinished string", TK_EOS);
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continue; /* to avoid warnings */
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case '\n':
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case '\r':
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luaX_lexerror(ls, "unfinished string", TK_STRING);
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continue; /* to avoid warnings */
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case '\\': {
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int c;
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next(ls); /* do not save the `\' */
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switch (ls->current) {
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case 'a': c = '\a'; break;
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case 'b': c = '\b'; break;
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case 'f': c = '\f'; break;
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case 'n': c = '\n'; break;
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case 'r': c = '\r'; break;
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case 't': c = '\t'; break;
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case 'v': c = '\v'; break;
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case '\n': /* go through */
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case '\r': save(ls, '\n'); inclinenumber(ls); continue;
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case EOZ: continue; /* will raise an error next loop */
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default: {
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if (!isdigit(ls->current))
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save_and_next(ls); /* handles \\, \", \', and \? */
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else { /* \xxx */
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int i = 0;
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c = 0;
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do {
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c = 10*c + (ls->current-'0');
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next(ls);
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} while (++i<3 && isdigit(ls->current));
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if (c > UCHAR_MAX)
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luaX_lexerror(ls, "escape sequence too large", TK_STRING);
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save(ls, c);
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}
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continue;
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}
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}
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save(ls, c);
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next(ls);
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continue;
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}
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default:
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save_and_next(ls);
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}
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}
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save_and_next(ls); /* skip delimiter */
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seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
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luaZ_bufflen(ls->buff) - 2);
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}
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int luaX_lex (LexState *ls, SemInfo *seminfo) {
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luaZ_resetbuffer(ls->buff);
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for (;;) {
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switch (ls->current) {
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case '\n':
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case '\r': {
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inclinenumber(ls);
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continue;
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}
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case '-': {
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next(ls);
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if (ls->current != '-') return '-';
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/* else is a comment */
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next(ls);
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if (ls->current == '[') {
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int ast = skip_ast(ls);
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luaZ_resetbuffer(ls->buff); /* `skip_ast' may dirty the buffer */
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if (ast >= 0) {
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read_long_string(ls, NULL, ast); /* long comment */
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luaZ_resetbuffer(ls->buff);
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continue;
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}
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}
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/* else short comment */
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while (!currIsNewline(ls) && ls->current != EOZ)
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next(ls);
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continue;
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}
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case '[': {
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int ast = skip_ast(ls);
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if (ast >= 0) {
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read_long_string(ls, seminfo, ast);
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return TK_STRING;
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}
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else if (ast == -1) return '[';
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else luaX_lexerror(ls, "invalid long string delimiter", TK_STRING);
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}
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case '=': {
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next(ls);
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if (ls->current != '=') return '=';
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else { next(ls); return TK_EQ; }
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}
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case '<': {
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next(ls);
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if (ls->current != '=') return '<';
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else { next(ls); return TK_LE; }
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}
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case '>': {
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next(ls);
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if (ls->current != '=') return '>';
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else { next(ls); return TK_GE; }
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}
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case '~': {
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next(ls);
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if (ls->current != '=') return '~';
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else { next(ls); return TK_NE; }
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}
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case '"':
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case '\'': {
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read_string(ls, ls->current, seminfo);
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return TK_STRING;
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}
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case '.': {
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save_and_next(ls);
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if (ls->current == '.') {
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next(ls);
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if (ls->current == '.') {
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next(ls);
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return TK_DOTS; /* ... */
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}
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else return TK_CONCAT; /* .. */
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}
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else if (!isdigit(ls->current)) return '.';
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else {
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read_numeral(ls, seminfo);
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return TK_NUMBER;
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}
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}
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case EOZ: {
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return TK_EOS;
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}
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default: {
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if (isspace(ls->current)) {
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lua_assert(!currIsNewline(ls));
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next(ls);
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continue;
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}
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else if (isdigit(ls->current)) {
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read_numeral(ls, seminfo);
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return TK_NUMBER;
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}
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else if (isalpha(ls->current) || ls->current == '_') {
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/* identifier or reserved word */
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TString *ts;
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do {
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save_and_next(ls);
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} while (isalnum(ls->current) || ls->current == '_');
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ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
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luaZ_bufflen(ls->buff));
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if (ts->tsv.reserved > 0) /* reserved word? */
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return ts->tsv.reserved - 1 + FIRST_RESERVED;
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else {
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seminfo->ts = ts;
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return TK_NAME;
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}
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}
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else {
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int c = ls->current;
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next(ls);
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return c; /* single-char tokens (+ - / ...) */
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}
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}
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}
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}
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}
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#undef next
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