support nesting

src/pscat.c

@@ -27,8 +27,8 @@ int
 check_arg(char **argv){
 	enum {
 		UNINITIALIZED = 0,
-		INLPAREN = 1,
-		NORMAL = 2
+		NORMAL = 1,
+		INLPAREN = 2
 	} s;
 	int terms;
 
@@ -40,9 +40,12 @@ check_arg(char **argv){
 			else
 				return 0; /* syntax error */
 			break;
-		case INLPAREN:
-			if(scmpflat(*argv, R_PAREN))
-				{ ++s; ++terms; }
+		default: /* >= INLPAREN */
+			if(scmpflat(*argv, R_PAREN)){
+				--s;
+				terms += s == NORMAL;
+			}else if(scmpflat(*argv, L_PAREN)) /* ineligant */
+				++s;
 			break;
 		}
 
@@ -54,6 +57,7 @@ int main(int argc, char *argv[]){
 	char **psstart;
 	int child;
 	int i;
+	int p;
 	int retval;
 	int terms;
 
@@ -70,7 +74,17 @@ int main(int argc, char *argv[]){
 	/* loop starts with *argv -> the next L_PAREN */
 	for(i = 0; i < terms; ++i){
 		psstart = ++argv;
-		while(!scmpflat(*++argv, R_PAREN));
+		p = 1;
+		while(p > 0){
+			++argv;
+			/* branching here potentially saves a comparison.
+			 * this seems like the most optimal way to do this,
+			 * maybe it isn't, i don't care too much */
+			if(scmpflat(*argv, L_PAREN))
+				++p;
+			else if(scmpflat(*argv, R_PAREN))
+				--p;
+		}
 		/* *argv -> the corresponding R_PAREN. turn it into NULL to
 		 * terminate the argument list to send to execvp(3) */
 		*argv = NULL;