From a8cd072c76da0a9f11c86d3e44766ecf97a3f402 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Sat, 12 Apr 1997 12:01:49 -0300 Subject: [PATCH] nested "$if's", "$else", and "$if" constants (nil & 1). --- lex.c | 142 ++++++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 103 insertions(+), 39 deletions(-) diff --git a/lex.c b/lex.c index 3c8da4c2..8740f1e2 100644 --- a/lex.c +++ b/lex.c @@ -1,4 +1,4 @@ -char *rcs_lex = "$Id: lex.c,v 2.45 1997/04/01 21:23:20 roberto Exp roberto $"; +char *rcs_lex = "$Id: lex.c,v 2.46 1997/04/07 14:48:53 roberto Exp roberto $"; #include @@ -22,6 +22,18 @@ char *rcs_lex = "$Id: lex.c,v 2.45 1997/04/01 21:23:20 roberto Exp roberto $"; static int current; /* look ahead character */ static Input input; /* input function */ + +#define MAX_IFS 10 + +/* "ifstate" keeps the state of each nested $if the lexical is +** dealing with. The first bit indicates whether the $if condition +** is false or true. The second bit indicates whether the lexical is +** inside the "then" part (0) or the "else" part (2) +*/ +static int ifstate[MAX_IFS]; /* 0 => then part - condition false */ + /* 1 => then part - condition true */ + /* 2 => else part - condition false */ + /* 3 => else part - condition true */ static int iflevel; /* level of nested $if's */ @@ -33,11 +45,15 @@ void lua_setinput (Input fn) input = fn; } -static void luaI_auxsyntaxerror (char *s, char *token) + +static void luaI_auxsyntaxerror (char *s) +{ + luaL_verror("%s;\n> at line %d in file %s", + s, lua_linenumber, lua_parsedfile); +} + +static void luaI_auxsynterrbf (char *s, char *token) { - if (token == NULL) - luaL_verror("%s;\n> at line %d in file %s", - s, lua_linenumber, lua_parsedfile); if (token[0] == 0) token = ""; luaL_verror("%s;\n> last token read: \"%s\" at line %d in file %s", @@ -46,7 +62,7 @@ static void luaI_auxsyntaxerror (char *s, char *token) void luaI_syntaxerror (char *s) { - luaI_auxsyntaxerror(s, luaI_buffer(1)); + luaI_auxsynterrbf(s, luaI_buffer(1)); } @@ -87,27 +103,74 @@ void luaI_addReserved (void) } +/* +** Pragma handling +*/ + +#define PRAGMASIZE 20 + +static void skipspace (void) +{ + while (current == ' ' || current == '\t') next(); +} + + +static int checkcond (char *buff) +{ + if (strcmp(buff, "nil") == 0) + return 0; + else if (strcmp(buff, "1") == 0) + return 1; + else if (isalpha((unsigned char)buff[0])) + return luaI_globaldefined(buff); + else { + luaI_auxsynterrbf("invalid $if condition", buff); + return 0; /* to avoid warnings */ + } +} + + static void readname (char *buff) { int i = 0; - while (current == ' ') next(); + skipspace(); while (isalnum((unsigned char)current)) { - if (i >= MINBUFF) luaI_syntaxerror("pragma too long"); + if (i >= PRAGMASIZE) { + buff[PRAGMASIZE] = 0; + luaI_auxsynterrbf("pragma too long", buff); + } buff[i++] = current; next(); } buff[i] = 0; - if (!isalpha(buff[0]) || (current != 0 && !isspace(current))) - luaI_auxsyntaxerror("invalid pragma format", NULL); } -static int inclinenumber (void) + +static void inclinenumber (void); + + +static void ifskip (int thisiflevel) +{ + while (iflevel > thisiflevel && + (ifstate[thisiflevel] == 0 || ifstate[thisiflevel] == 3)) { + if (current == '\n') + inclinenumber(); + else if (current == 0) + luaI_auxsyntaxerror("input ends inside a $if"); + else next(); + } +} + + +static void inclinenumber (void) { - static char *pragmas [] = {"debug", "nodebug", "endif", "ifnil", "if", NULL}; - int ifnil = 0; + static char *pragmas [] = + {"debug", "nodebug", "end", "ifnot", "if", "else", NULL}; + next(); /* skip '\n' */ ++lua_linenumber; if (current == '$') { /* is a pragma? */ - char buff[MINBUFF+1]; + char buff[PRAGMASIZE+1]; + int ifnot = 0; next(); /* skip $ */ readname(buff); switch (luaI_findstring(buff, pragmas)) { @@ -117,34 +180,35 @@ static int inclinenumber (void) case 1: /* nodebug */ lua_debug = 0; break; - case 2: /* endif */ + case 2: /* end */ if (--iflevel < 0) - luaI_auxsyntaxerror("too many $endif's", NULL); + luaI_auxsyntaxerror("unmatched $endif"); break; - case 3: /* ifnil */ - ifnil = 1; + case 3: /* ifnot */ + ifnot = 1; /* go through */ - case 4: { /* if */ - int thisiflevel = iflevel++; + case 4: /* if */ + if (iflevel == MAX_IFS) + luaI_auxsyntaxerror("too many nested `$ifs'"); readname(buff); - if ((ifnil && luaI_globaldefined(buff)) || - (!ifnil && !luaI_globaldefined(buff))) { /* skip the $if? */ - do { - if (current == '\n') { - next(); - inclinenumber(); - } - else if (current == 0) - luaI_auxsyntaxerror("input ends inside a $if", NULL); - else next(); - } while (iflevel > thisiflevel); - } + ifstate[iflevel++] = checkcond(buff) ? !ifnot : ifnot; break; - } - default: luaI_auxsyntaxerror("invalid pragma", buff); + case 5: /* else */ + if (iflevel <= 0 || (ifstate[iflevel-1] & 2)) + luaI_auxsyntaxerror("unmatched $else"); + ifstate[iflevel-1] = ifstate[iflevel-1] | 2; + break; + default: + luaI_auxsynterrbf("invalid pragma", buff); } + skipspace(); + if (current == '\n') /* pragma must end with a '\n' */ + inclinenumber(); + else if (current != 0) /* or eof */ + luaI_auxsyntaxerror("invalid pragma format"); + if (iflevel > 0) + ifskip(iflevel-1); } - return lua_linenumber; } static int read_long_string (char *yytext, int buffsize) @@ -178,7 +242,7 @@ static int read_long_string (char *yytext, int buffsize) } continue; case '\n': - save_and_next(); + save('\n'); inclinenumber(); continue; default: @@ -209,8 +273,8 @@ int luaY_lex (void) switch (current) { case '\n': - next(); - linelasttoken = inclinenumber(); + inclinenumber(); + linelasttoken = lua_linenumber; continue; case ' ': case '\t': case '\r': /* CR: to avoid problems with DOS */ @@ -274,7 +338,7 @@ int luaY_lex (void) case 'n': save('\n'); next(); break; case 't': save('\t'); next(); break; case 'r': save('\r'); next(); break; - case '\n': save_and_next(); inclinenumber(); break; + case '\n': save('\n'); inclinenumber(); break; default : save_and_next(); break; } break;