From: Nick Bowler <nbowler@draconx.ca>
Date: Sun, 9 Jul 2023 20:51:29 +0000 (-0400)
Subject: libcdecl: Combine scanner rules for punctuation.
X-Git-Tag: v1.3~120
X-Git-Url: https://git.draconx.ca/gitweb/cdecl99.git/commitdiff_plain/ec4bdd2e748b84924b0b6bae6c37ff6f0ec8cc6c

libcdecl: Combine scanner rules for punctuation.

Use a single rule to match all punctuation, with a lookup table to
return the correct token.  This gives a small size reduction for
the scanner.
---

diff --git a/src/scan.l b/src/scan.l
index 1342e5f..7e3e365 100644
--- a/src/scan.l
+++ b/src/scan.l
@@ -131,14 +131,31 @@ INTEGER 0x[[:xdigit:]]+|0[0-7]+|[[:digit:]]+
 	}
 %}
 
-"..." return T_ELLIPSIS;
-";"   return T_SEMICOLON;
-"*"   return T_ASTERISK;
-"("   return T_LPAREN;
-")"   return T_RPAREN;
-"["   return T_LBRACKET;
-"]"   return T_RBRACKET;
-","   return T_COMMA;
+"..."|[][;*(),] {
+	static const unsigned char tab[2][8] = {
+		"*[](),.;",
+		{
+			T_ASTERISK  & 0xff,
+			T_LBRACKET  & 0xff,
+			T_RBRACKET  & 0xff,
+			T_LPAREN    & 0xff,
+			T_RPAREN    & 0xff,
+			T_COMMA     & 0xff,
+			T_ELLIPSIS  & 0xff,
+			T_SEMICOLON & 0xff
+		}
+	};
+
+	unsigned char *match;
+	int x;
+
+	match = memchr(&tab, yytext[0], sizeof tab[0]);
+	x = match[sizeof tab[0]];
+
+	if (T_VOID >= 256)
+		x += 256;
+	return x;
+}
 
 {INTEGER} {
 	char *end;