Added support for automatic concatenation of adjacent string literals

- [ This commit is part of a larger script engine related update ]
- Adjacent string literals are now automatically concatenated into one
  string upon parsing.
- Adjacent string literals are string literals (i.e. "such as this",
  with only whitespace (including line breaks and/or comments) between
  them. For example, the lines:

mes "this will be concatenated " /* skipping this
              comment */ " into one string"; // at parse time

will produce an output of "this will be concatenated into one string".

- The feature brings parity with other languages (i.e. C), and makes it
  easier to split long strings in multiple lines, without having to
  resort to a, slower, run-time string concatenation operator ('+')
- Special thanks to Trojal for the idea.

Signed-off-by: Haru <haru@dotalux.com>

2 files changed, 35 insertions, 18 deletions

diff --git a/npc/custom/test.txt b/npc/custom/test.txt
index bfd297f5d..0fffecf73 100644
--- a/npc/custom/test.txt
+++ b/npc/custom/test.txt
@@ -19,6 +19,15 @@ OnCheck:
 		//end;
 	}
 	return;
+OnCheckStr:
+	.@msg$ = getarg(0,"Unknown Error");
+	.@val$ = getarg(1,"");
+	.@ref$ = getarg(2,"");
+	if (.@val$ != .@ref$) {
+		debugmes "Error: "+.@msg$+": '"+.@val$+"' != '"+.@ref$+"'";
+		//end;
+	}
+	return;
 OnInit:
 	// Array subscript
 	setarray .@a, 3, 2, 1;
@@ -226,6 +235,11 @@ OnInit:
 	callsub(OnCheck, "Order of <,>,==", .@y);
 
 
+	.@x$ = "string "
+		"concatenation" /* test */ " succeeded";
+	callsub(OnCheckStr, "String concatenation", .@x$, "string concatenation succeeded");
+
+
 	// Bitwise & operator
 	.@x = (7&4); // 0111 & 0100 --> 0100
 	.@y = (4&1); // 0100 & 0001 --> 0000
diff --git a/src/map/script.c b/src/map/script.c
index 73aaafab2..007a3a3d3 100644
--- a/src/map/script.c
+++ b/src/map/script.c
@@ -1070,26 +1070,29 @@ const char* parse_simpleexpr(const char *p) {
 		p=np;
 	} else if(*p=='"') {
 		script->addc(C_STR);
-		p++;
-		while( *p && *p != '"' ) {
-			if( (unsigned char)p[-1] <= 0x7e && *p == '\\' ) {
-				char buf[8];
-				size_t len = sv->skip_escaped_c(p) - p;
-				size_t n = sv->unescape_c(buf, p, len);
-				if( n != 1 )
-					ShowDebug("parse_simpleexpr: unexpected length %d after unescape (\"%.*s\" -> %.*s)\n", (int)n, (int)len, p, (int)n, buf);
-				p += len;
-				script->addb(*buf);
-				continue;
-			} else if( *p == '\n' ) {
-				disp_error_message("parse_simpleexpr: unexpected newline @ string",p);
+		do {
+			p++;
+			while( *p && *p != '"' ) {
+				if( (unsigned char)p[-1] <= 0x7e && *p == '\\' ) {
+					char buf[8];
+					size_t len = sv->skip_escaped_c(p) - p;
+					size_t n = sv->unescape_c(buf, p, len);
+					if( n != 1 )
+						ShowDebug("parse_simpleexpr: unexpected length %d after unescape (\"%.*s\" -> %.*s)\n", (int)n, (int)len, p, (int)n, buf);
+					p += len;
+					script->addb(*buf);
+					continue;
+				} else if( *p == '\n' ) {
+					disp_error_message("parse_simpleexpr: unexpected newline @ string",p);
+				}
+				script->addb(*p++);
 			}
-			script->addb(*p++);
-		}
-		if(!*p)
-			disp_error_message("parse_simpleexpr: unexpected end of file @ string",p);
+			if(!*p)
+				disp_error_message("parse_simpleexpr: unexpected end of file @ string",p);
+			p++;	//'"'
+			p = script->skip_space(p);
+		} while( *p && *p == '"' );
 		script->addb(0);
-		p++;	//'"'
 	} else {
 		int l;
 		const char* pv;