diff options
Diffstat (limited to 'lua/llex.c')
| -rw-r--r-- | lua/llex.c | 417 |
1 files changed, 417 insertions, 0 deletions
diff --git a/lua/llex.c b/lua/llex.c new file mode 100644 index 000000000..87ca2aed0 --- /dev/null +++ b/lua/llex.c @@ -0,0 +1,417 @@ +/* +** $Id: llex.c,v 1.1 2004/03/16 21:58:30 niemeyer Exp $ +** Lexical Analyzer +** See Copyright Notice in lua.h +*/ + + +#include <ctype.h> +#include <string.h> + +#define llex_c + +#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)) + + + +/* ORDER RESERVED */ +static const char *const token2string [] = { + "and", "break", "do", "else", "elseif", + "end", "false", "for", "function", "if", + "in", "local", "nil", "not", "or", "repeat", + "return", "then", "true", "until", "while", "*name", + "..", "...", "==", ">=", "<=", "~=", + "*number", "*string", "<eof>" +}; + + +void luaX_init (lua_State *L) { + int i; + for (i=0; i<NUM_RESERVED; i++) { + TString *ts = luaS_new(L, token2string[i]); + luaS_fix(ts); /* reserved words are never collected */ + lua_assert(strlen(token2string[i])+1 <= TOKEN_LEN); + ts->tsv.reserved = cast(lu_byte, i+1); /* reserved word */ + } +} + + +#define MAXSRC 80 + + +void luaX_checklimit (LexState *ls, int val, int limit, const char *msg) { + if (val > limit) { + msg = luaO_pushfstring(ls->L, "too many %s (limit=%d)", msg, limit); + luaX_syntaxerror(ls, msg); + } +} + + +void luaX_errorline (LexState *ls, const char *s, const char *token, int line) { + lua_State *L = ls->L; + char buff[MAXSRC]; + luaO_chunkid(buff, getstr(ls->source), MAXSRC); + luaO_pushfstring(L, "%s:%d: %s near `%s'", buff, line, s, token); + luaD_throw(L, LUA_ERRSYNTAX); +} + + +static void luaX_error (LexState *ls, const char *s, const char *token) { + luaX_errorline(ls, s, token, ls->linenumber); +} + + +void luaX_syntaxerror (LexState *ls, const char *msg) { + const char *lasttoken; + switch (ls->t.token) { + case TK_NAME: + lasttoken = getstr(ls->t.seminfo.ts); + break; + case TK_STRING: + case TK_NUMBER: + lasttoken = luaZ_buffer(ls->buff); + break; + default: + lasttoken = luaX_token2str(ls, ls->t.token); + break; + } + luaX_error(ls, msg, lasttoken); +} + + +const char *luaX_token2str (LexState *ls, int token) { + if (token < FIRST_RESERVED) { + lua_assert(token == (unsigned char)token); + return luaO_pushfstring(ls->L, "%c", token); + } + else + return token2string[token-FIRST_RESERVED]; +} + + +static void luaX_lexerror (LexState *ls, const char *s, int token) { + if (token == TK_EOS) + luaX_error(ls, s, luaX_token2str(ls, token)); + else + luaX_error(ls, s, luaZ_buffer(ls->buff)); +} + + +static void inclinenumber (LexState *LS) { + next(LS); /* skip `\n' */ + ++LS->linenumber; + luaX_checklimit(LS, LS->linenumber, MAX_INT, "lines in a chunk"); +} + + +void luaX_setinput (lua_State *L, LexState *LS, ZIO *z, TString *source) { + 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; + next(LS); /* read first char */ + if (LS->current == '#') { + do { /* skip first line */ + next(LS); + } while (LS->current != '\n' && LS->current != EOZ); + } +} + + + +/* +** ======================================================= +** LEXICAL ANALYZER +** ======================================================= +*/ + + +/* use buffer to store names, literal strings and numbers */ + +/* extra space to allocate when growing buffer */ +#define EXTRABUFF 32 + +/* maximum number of chars that can be read without checking buffer size */ +#define MAXNOCHECK 5 + +#define checkbuffer(LS, len) \ + if (((len)+MAXNOCHECK)*sizeof(char) > luaZ_sizebuffer((LS)->buff)) \ + luaZ_openspace((LS)->L, (LS)->buff, (len)+EXTRABUFF) + +#define save(LS, c, l) \ + (luaZ_buffer((LS)->buff)[l++] = cast(char, c)) +#define save_and_next(LS, l) (save(LS, LS->current, l), next(LS)) + + +static size_t readname (LexState *LS) { + size_t l = 0; + checkbuffer(LS, l); + do { + checkbuffer(LS, l); + save_and_next(LS, l); + } while (isalnum(LS->current) || LS->current == '_'); + save(LS, '\0', l); + return l-1; +} + + +/* LUA_NUMBER */ +static void read_numeral (LexState *LS, int comma, SemInfo *seminfo) { + size_t l = 0; + checkbuffer(LS, l); + if (comma) save(LS, '.', l); + while (isdigit(LS->current)) { + checkbuffer(LS, l); + save_and_next(LS, l); + } + if (LS->current == '.') { + save_and_next(LS, l); + if (LS->current == '.') { + save_and_next(LS, l); + save(LS, '\0', l); + luaX_lexerror(LS, + "ambiguous syntax (decimal point x string concatenation)", + TK_NUMBER); + } + } + while (isdigit(LS->current)) { + checkbuffer(LS, l); + save_and_next(LS, l); + } + if (LS->current == 'e' || LS->current == 'E') { + save_and_next(LS, l); /* read `E' */ + if (LS->current == '+' || LS->current == '-') + save_and_next(LS, l); /* optional exponent sign */ + while (isdigit(LS->current)) { + checkbuffer(LS, l); + save_and_next(LS, l); + } + } + save(LS, '\0', l); + if (!luaO_str2d(luaZ_buffer(LS->buff), &seminfo->r)) + luaX_lexerror(LS, "malformed number", TK_NUMBER); +} + + +static void read_long_string (LexState *LS, SemInfo *seminfo) { + int cont = 0; + size_t l = 0; + checkbuffer(LS, l); + save(LS, '[', l); /* save first `[' */ + save_and_next(LS, l); /* pass the second `[' */ + if (LS->current == '\n') /* string starts with a newline? */ + inclinenumber(LS); /* skip it */ + for (;;) { + checkbuffer(LS, l); + switch (LS->current) { + case EOZ: + save(LS, '\0', l); + luaX_lexerror(LS, (seminfo) ? "unfinished long string" : + "unfinished long comment", TK_EOS); + break; /* to avoid warnings */ + case '[': + save_and_next(LS, l); + if (LS->current == '[') { + cont++; + save_and_next(LS, l); + } + continue; + case ']': + save_and_next(LS, l); + if (LS->current == ']') { + if (cont == 0) goto endloop; + cont--; + save_and_next(LS, l); + } + continue; + case '\n': + save(LS, '\n', l); + inclinenumber(LS); + if (!seminfo) l = 0; /* reset buffer to avoid wasting space */ + continue; + default: + save_and_next(LS, l); + } + } endloop: + save_and_next(LS, l); /* skip the second `]' */ + save(LS, '\0', l); + if (seminfo) + seminfo->ts = luaS_newlstr(LS->L, luaZ_buffer(LS->buff) + 2, l - 5); +} + + +static void read_string (LexState *LS, int del, SemInfo *seminfo) { + size_t l = 0; + checkbuffer(LS, l); + save_and_next(LS, l); + while (LS->current != del) { + checkbuffer(LS, l); + switch (LS->current) { + case EOZ: + save(LS, '\0', l); + luaX_lexerror(LS, "unfinished string", TK_EOS); + break; /* to avoid warnings */ + case '\n': + save(LS, '\0', l); + luaX_lexerror(LS, "unfinished string", TK_STRING); + break; /* to avoid warnings */ + case '\\': + next(LS); /* do not save the `\' */ + switch (LS->current) { + case 'a': save(LS, '\a', l); next(LS); break; + case 'b': save(LS, '\b', l); next(LS); break; + case 'f': save(LS, '\f', l); next(LS); break; + case 'n': save(LS, '\n', l); next(LS); break; + case 'r': save(LS, '\r', l); next(LS); break; + case 't': save(LS, '\t', l); next(LS); break; + case 'v': save(LS, '\v', l); next(LS); break; + case '\n': save(LS, '\n', l); inclinenumber(LS); break; + case EOZ: break; /* will raise an error next loop */ + default: { + if (!isdigit(LS->current)) + save_and_next(LS, l); /* handles \\, \", \', and \? */ + else { /* \xxx */ + int c = 0; + int i = 0; + do { + c = 10*c + (LS->current-'0'); + next(LS); + } while (++i<3 && isdigit(LS->current)); + if (c > UCHAR_MAX) { + save(LS, '\0', l); + luaX_lexerror(LS, "escape sequence too large", TK_STRING); + } + save(LS, c, l); + } + } + } + break; + default: + save_and_next(LS, l); + } + } + save_and_next(LS, l); /* skip delimiter */ + save(LS, '\0', l); + seminfo->ts = luaS_newlstr(LS->L, luaZ_buffer(LS->buff) + 1, l - 3); +} + + +int luaX_lex (LexState *LS, SemInfo *seminfo) { + for (;;) { + switch (LS->current) { + + case '\n': { + inclinenumber(LS); + continue; + } + case '-': { + next(LS); + if (LS->current != '-') return '-'; + /* else is a comment */ + next(LS); + if (LS->current == '[' && (next(LS), LS->current == '[')) + read_long_string(LS, NULL); /* long comment */ + else /* short comment */ + while (LS->current != '\n' && LS->current != EOZ) + next(LS); + continue; + } + case '[': { + next(LS); + if (LS->current != '[') return '['; + else { + read_long_string(LS, seminfo); + return 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 '.': { + next(LS); + if (LS->current == '.') { + next(LS); + if (LS->current == '.') { + next(LS); + return TK_DOTS; /* ... */ + } + else return TK_CONCAT; /* .. */ + } + else if (!isdigit(LS->current)) return '.'; + else { + read_numeral(LS, 1, seminfo); + return TK_NUMBER; + } + } + case EOZ: { + return TK_EOS; + } + default: { + if (isspace(LS->current)) { + next(LS); + continue; + } + else if (isdigit(LS->current)) { + read_numeral(LS, 0, seminfo); + return TK_NUMBER; + } + else if (isalpha(LS->current) || LS->current == '_') { + /* identifier or reserved word */ + size_t l = readname(LS); + TString *ts = luaS_newlstr(LS->L, luaZ_buffer(LS->buff), l); + if (ts->tsv.reserved > 0) /* reserved word? */ + return ts->tsv.reserved - 1 + FIRST_RESERVED; + seminfo->ts = ts; + return TK_NAME; + } + else { + int c = LS->current; + if (iscntrl(c)) + luaX_error(LS, "invalid control char", + luaO_pushfstring(LS->L, "char(%d)", c)); + next(LS); + return c; /* single-char tokens (+ - / ...) */ + } + } + } + } +} + +#undef next |