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new pattern item ".-";

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empty patterns may be used in gsub.
This commit is contained in:
Roberto Ierusalimschy 1997-02-21 12:21:34 -03:00
parent bc323435ee
commit 8b7f271ea2
1 changed files with 22 additions and 10 deletions
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32
strlib.c
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@ -3,7 +3,7 @@
** String library to LUA ** String library to LUA
*/ */
char *rcs_strlib="$Id: strlib.c,v 1.33 1996/11/20 13:47:59 roberto Exp roberto $"; char *rcs_strlib="$Id: strlib.c,v 1.34 1996/11/22 13:08:02 roberto Exp roberto $";
#include <string.h> #include <string.h>
#include <stdio.h> #include <stdio.h>
@ -195,7 +195,7 @@ static void str_ascii (void)
/* pattern matching */ /* pattern matching */
#define ESC '%' #define ESC '%'
#define SPECIALS "^$*?.([%" #define SPECIALS "^$*?.([%-"
static char *bracket_end (char *p) static char *bracket_end (char *p)
{ {
@ -367,6 +367,17 @@ static char *match (char *s, char *p, int level)
return res; return res;
p=ep+1; goto init; /* else return match(s, ep+1, level); */ p=ep+1; goto init; /* else return match(s, ep+1, level); */
} }
case '-': { /* repetition */
char *res;
if ((res = match(s, ep+1, level)) != 0)
return res;
else if (m) {
s++;
goto init; /* return match(s+1, p, level); */
}
else
return NULL;
}
case '?': { /* optional */ case '?': { /* optional */
char *res; char *res;
if (m && (res = match(s+1, ep+1, level))) if (m && (res = match(s+1, ep+1, level)))
@ -447,20 +458,21 @@ static void str_gsub (void)
char *src = lua_check_string(1, "gsub"); char *src = lua_check_string(1, "gsub");
char *p = lua_check_string(2, "gsub"); char *p = lua_check_string(2, "gsub");
lua_Object newp = lua_getparam(3); lua_Object newp = lua_getparam(3);
int max_s = lua_opt_number(4, strlen(src), "gsub"); int max_s = lua_opt_number(4, strlen(src)+1, "gsub");
int anchor = (*p == '^') ? (p++, 1) : 0; int anchor = (*p == '^') ? (p++, 1) : 0;
int n = 0; int n = 0;
luaI_addchar(0); luaI_addchar(0);
while (*src && n < max_s) { while (n < max_s) {
char *e; char *e = match(src, p, 0);
if ((e=match(src, p, 0)) == NULL) if (e) {
luaI_addchar(*src++);
else {
if (e == src) lua_error("empty pattern in substitution");
add_s(newp); add_s(newp);
src = e;
n++; n++;
} }
if (e && e>src) /* non empty match? */
src = e; /* skip it */
else if (*src)
luaI_addchar(*src++);
else break;
if (anchor) break; if (anchor) break;
} }
addstr(src); addstr(src);