llex.c
上传用户:yisoukefu
上传日期:2020-08-09
资源大小:39506k
文件大小:12k
- /*
- ** $Id: llex.c,v 2.19 2006/02/06 18:28:16 roberto Exp $
- ** Lexical Analyzer
- ** See Copyright Notice in lua.h
- */
- #include <ctype.h>
- #include <locale.h>
- #include <string.h>
- #define llex_c
- #define LUA_CORE
- #include "lua.h"
- #include "ldo.h"
- #include "llex.h"
- #include "lobject.h"
- #include "lparser.h"
- #include "lstate.h"
- #include "lstring.h"
- #include "lzio.h"
- #define next(ls) (ls->current = zgetc(ls->z))
- #define currIsNewline(ls) (ls->current == 'n' || ls->current == 'r')
- /* ORDER RESERVED */
- const char *const luaX_tokens [] = {
- "and", "break", "do", "else", "elseif",
- "end", "false", "for", "function", "if",
- "in", "local", "nil", "not", "or", "repeat",
- "return", "then", "true", "until", "while",
- "..", "...", "==", ">=", "<=", "~=",
- "<number>", "<name>", "<string>", "<eof>",
- NULL
- };
- #define save_and_next(ls) (save(ls, ls->current), next(ls))
- static void save (LexState *ls, int c) {
- Mbuffer *b = ls->buff;
- if (b->n + 1 > b->buffsize) {
- size_t newsize;
- if (b->buffsize >= MAX_SIZET/2)
- luaX_lexerror(ls, "lexical element too long", 0);
- newsize = b->buffsize * 2;
- luaZ_resizebuffer(ls->L, b, newsize);
- }
- b->buffer[b->n++] = cast(char, c);
- }
- void luaX_init (lua_State *L) {
- int i;
- for (i=0; i<NUM_RESERVED; i++) {
- TString *ts = luaS_new(L, luaX_tokens[i]);
- luaS_fix(ts); /* reserved words are never collected */
- lua_assert(strlen(luaX_tokens[i])+1 <= TOKEN_LEN);
- ts->tsv.reserved = cast_byte(i+1); /* reserved word */
- }
- }
- #define MAXSRC 80
- const char *luaX_token2str (LexState *ls, int token) {
- if (token < FIRST_RESERVED) {
- lua_assert(token == cast(unsigned char, token));
- return (iscntrl(token)) ? luaO_pushfstring(ls->L, "char(%d)", token) :
- luaO_pushfstring(ls->L, "%c", token);
- }
- else
- return luaX_tokens[token-FIRST_RESERVED];
- }
- static const char *txtToken (LexState *ls, int token) {
- switch (token) {
- case TK_NAME:
- case TK_STRING:
- case TK_NUMBER:
- save(ls, ' ');
- return luaZ_buffer(ls->buff);
- default:
- return luaX_token2str(ls, token);
- }
- }
- void luaX_lexerror (LexState *ls, const char *msg, int token) {
- char buff[MAXSRC];
- luaO_chunkid(buff, getstr(ls->source), MAXSRC);
- msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
- if (token)
- luaO_pushfstring(ls->L, "%s near " LUA_QS, msg, txtToken(ls, token));
- luaD_throw(ls->L, LUA_ERRSYNTAX);
- }
- void luaX_syntaxerror (LexState *ls, const char *msg) {
- luaX_lexerror(ls, msg, ls->t.token);
- }
- TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
- lua_State *L = ls->L;
- TString *ts = luaS_newlstr(L, str, l);
- TValue *o = luaH_setstr(L, ls->fs->h, ts); /* entry for `str' */
- if (ttisnil(o))
- setbvalue(o, 1); /* make sure `str' will not be collected */
- return ts;
- }
- static void inclinenumber (LexState *ls) {
- int old = ls->current;
- lua_assert(currIsNewline(ls));
- next(ls); /* skip `n' or `r' */
- if (currIsNewline(ls) && ls->current != old)
- next(ls); /* skip `nr' or `rn' */
- if (++ls->linenumber >= MAX_INT)
- luaX_syntaxerror(ls, "chunk has too many lines");
- }
- void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source) {
- ls->decpoint = '.';
- ls->L = L;
- ls->lookahead.token = TK_EOS; /* no look-ahead token */
- ls->z = z;
- ls->fs = NULL;
- ls->linenumber = 1;
- ls->lastline = 1;
- ls->source = source;
- luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER); /* initialize buffer */
- next(ls); /* read first char */
- }
- /*
- ** =======================================================
- ** LEXICAL ANALYZER
- ** =======================================================
- */
- static int check_next (LexState *ls, const char *set) {
- if (!strchr(set, ls->current))
- return 0;
- save_and_next(ls);
- return 1;
- }
- static void buffreplace (LexState *ls, char from, char to) {
- size_t n = luaZ_bufflen(ls->buff);
- char *p = luaZ_buffer(ls->buff);
- while (n--)
- if (p[n] == from) p[n] = to;
- }
- static void trydecpoint (LexState *ls, SemInfo *seminfo) {
- /* format error: try to update decimal point separator */
- struct lconv *cv = localeconv();
- char old = ls->decpoint;
- ls->decpoint = (cv ? cv->decimal_point[0] : '.');
- buffreplace(ls, old, ls->decpoint); /* try updated decimal separator */
- if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r)) {
- /* format error with correct decimal point: no more options */
- buffreplace(ls, ls->decpoint, '.'); /* undo change (for error message) */
- luaX_lexerror(ls, "malformed number", TK_NUMBER);
- }
- }
- /* LUA_NUMBER */
- static void read_numeral (LexState *ls, SemInfo *seminfo) {
- lua_assert(isdigit(ls->current));
- do {
- save_and_next(ls);
- } while (isdigit(ls->current) || ls->current == '.');
- if (check_next(ls, "Ee")) /* `E'? */
- check_next(ls, "+-"); /* optional exponent sign */
- while (isalnum(ls->current) || ls->current == '_')
- save_and_next(ls);
- save(ls, ' ');
- buffreplace(ls, '.', ls->decpoint); /* follow locale for decimal point */
- if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r)) /* format error? */
- trydecpoint(ls, seminfo); /* try to update decimal point separator */
- }
- static int skip_sep (LexState *ls) {
- int count = 0;
- int s = ls->current;
- lua_assert(s == '[' || s == ']');
- save_and_next(ls);
- while (ls->current == '=') {
- save_and_next(ls);
- count++;
- }
- return (ls->current == s) ? count : (-count) - 1;
- }
- static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
- int cont = 0;
- (void)(cont); /* avoid warnings when `cont' is not used */
- save_and_next(ls); /* skip 2nd `[' */
- if (currIsNewline(ls)) /* string starts with a newline? */
- inclinenumber(ls); /* skip it */
- for (;;) {
- switch (ls->current) {
- case EOZ:
- luaX_lexerror(ls, (seminfo) ? "unfinished long string" :
- "unfinished long comment", TK_EOS);
- break; /* to avoid warnings */
- #if defined(LUA_COMPAT_LSTR)
- case '[': {
- if (skip_sep(ls) == sep) {
- save_and_next(ls); /* skip 2nd `[' */
- cont++;
- #if LUA_COMPAT_LSTR == 1
- if (sep == 0)
- luaX_lexerror(ls, "nesting of [[...]] is deprecated", '[');
- #endif
- }
- break;
- }
- #endif
- case ']': {
- if (skip_sep(ls) == sep) {
- save_and_next(ls); /* skip 2nd `]' */
- #if defined(LUA_COMPAT_LSTR) && LUA_COMPAT_LSTR == 2
- cont--;
- if (sep == 0 && cont >= 0) break;
- #endif
- goto endloop;
- }
- break;
- }
- case 'n':
- case 'r': {
- save(ls, 'n');
- inclinenumber(ls);
- if (!seminfo) luaZ_resetbuffer(ls->buff); /* avoid wasting space */
- break;
- }
- default: {
- if (seminfo) save_and_next(ls);
- else next(ls);
- }
- }
- } endloop:
- if (seminfo)
- seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep),
- luaZ_bufflen(ls->buff) - 2*(2 + sep));
- }
- static void read_string (LexState *ls, int del, SemInfo *seminfo) {
- save_and_next(ls);
- while (ls->current != del) {
- switch (ls->current) {
- case EOZ:
- luaX_lexerror(ls, "unfinished string", TK_EOS);
- continue; /* to avoid warnings */
- case 'n':
- case 'r':
- luaX_lexerror(ls, "unfinished string", TK_STRING);
- continue; /* to avoid warnings */
- case '\': {
- int c;
- next(ls); /* do not save the `' */
- switch (ls->current) {
- case 'a': c = 'a'; break;
- case 'b': c = 'b'; break;
- case 'f': c = 'f'; break;
- case 'n': c = 'n'; break;
- case 'r': c = 'r'; break;
- case 't': c = 't'; break;
- case 'v': c = 'v'; break;
- case 'n': /* go through */
- case 'r': save(ls, 'n'); inclinenumber(ls); continue;
- case EOZ: continue; /* will raise an error next loop */
- default: {
- if (!isdigit(ls->current))
- save_and_next(ls); /* handles \, ", ', and ? */
- else { /* xxx */
- int i = 0;
- c = 0;
- do {
- c = 10*c + (ls->current-'0');
- next(ls);
- } while (++i<3 && isdigit(ls->current));
- if (c > UCHAR_MAX)
- luaX_lexerror(ls, "escape sequence too large", TK_STRING);
- save(ls, c);
- }
- continue;
- }
- }
- save(ls, c);
- next(ls);
- continue;
- }
- default:
- save_and_next(ls);
- }
- }
- save_and_next(ls); /* skip delimiter */
- seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
- luaZ_bufflen(ls->buff) - 2);
- }
- static int llex (LexState *ls, SemInfo *seminfo) {
- luaZ_resetbuffer(ls->buff);
- for (;;) {
- switch (ls->current) {
- case 'n':
- case 'r': {
- inclinenumber(ls);
- continue;
- }
- case '-': {
- next(ls);
- if (ls->current != '-') return '-';
- /* else is a comment */
- next(ls);
- if (ls->current == '[') {
- int sep = skip_sep(ls);
- luaZ_resetbuffer(ls->buff); /* `skip_sep' may dirty the buffer */
- if (sep >= 0) {
- read_long_string(ls, NULL, sep); /* long comment */
- luaZ_resetbuffer(ls->buff);
- continue;
- }
- }
- /* else short comment */
- while (!currIsNewline(ls) && ls->current != EOZ)
- next(ls);
- continue;
- }
- case '[': {
- int sep = skip_sep(ls);
- if (sep >= 0) {
- read_long_string(ls, seminfo, sep);
- return TK_STRING;
- }
- else if (sep == -1) return '[';
- else luaX_lexerror(ls, "invalid long string delimiter", TK_STRING);
- }
- case '=': {
- next(ls);
- if (ls->current != '=') return '=';
- else { next(ls); return TK_EQ; }
- }
- case '<': {
- next(ls);
- if (ls->current != '=') return '<';
- else { next(ls); return TK_LE; }
- }
- case '>': {
- next(ls);
- if (ls->current != '=') return '>';
- else { next(ls); return TK_GE; }
- }
- case '~': {
- next(ls);
- if (ls->current != '=') return '~';
- else { next(ls); return TK_NE; }
- }
- case '"':
- case ''': {
- read_string(ls, ls->current, seminfo);
- return TK_STRING;
- }
- case '.': {
- save_and_next(ls);
- if (check_next(ls, ".")) {
- if (check_next(ls, "."))
- return TK_DOTS; /* ... */
- else return TK_CONCAT; /* .. */
- }
- else if (!isdigit(ls->current)) return '.';
- else {
- read_numeral(ls, seminfo);
- return TK_NUMBER;
- }
- }
- case EOZ: {
- return TK_EOS;
- }
- default: {
- if (isspace(ls->current)) {
- lua_assert(!currIsNewline(ls));
- next(ls);
- continue;
- }
- else if (isdigit(ls->current)) {
- read_numeral(ls, seminfo);
- return TK_NUMBER;
- }
- else if (isalpha(ls->current) || ls->current == '_') {
- /* identifier or reserved word */
- TString *ts;
- do {
- save_and_next(ls);
- } while (isalnum(ls->current) || ls->current == '_');
- ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
- luaZ_bufflen(ls->buff));
- if (ts->tsv.reserved > 0) /* reserved word? */
- return ts->tsv.reserved - 1 + FIRST_RESERVED;
- else {
- seminfo->ts = ts;
- return TK_NAME;
- }
- }
- else {
- int c = ls->current;
- next(ls);
- return c; /* single-char tokens (+ - / ...) */
- }
- }
- }
- }
- }
- void luaX_next (LexState *ls) {
- ls->lastline = ls->linenumber;
- if (ls->lookahead.token != TK_EOS) { /* is there a look-ahead token? */
- ls->t = ls->lookahead; /* use this one */
- ls->lookahead.token = TK_EOS; /* and discharge it */
- }
- else
- ls->t.token = llex(ls, &ls->t.seminfo); /* read next token */
- }
- void luaX_lookahead (LexState *ls) {
- lua_assert(ls->lookahead.token == TK_EOS);
- ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
- }