From dde8db59b846ec59f809b3d885fd1c82a567b67a Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor.andersson@artifex.com>
Date: Sat, 28 Dec 2013 17:39:47 +0100
Subject: [PATCH] Add [no line-terminator here] context handling in lexer.

Return a semicolon if a newline is encountered following the
"break", "continue", "return" and "throw" keywords.

Add special tokens for ++ and -- with preceding line terminators,
so that they can be handled in the postfix expression grammar rules.
---
 js-lex.c   | 24 ++++++++++++++++++++----
 js-parse.h |  2 ++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/js-lex.c b/js-lex.c
index d8f3e01..53e3c4b 100644
--- a/js-lex.c
+++ b/js-lex.c
@@ -283,8 +283,7 @@ static inline int lexstring(js_State *J, const char **sp, int q)
 /* the ugliest language wart ever... */
 static int isregexpcontext(int last)
 {
-	switch (last)
-	{
+	switch (last) {
 	case ']':
 	case ')':
 	case TK_IDENTIFIER:
@@ -344,6 +343,20 @@ static int lexregexp(js_State *J, const char **sp)
 	return TK_REGEXP;
 }
 
+/* simple "return [no Line Terminator here] ..." contexts */
+static inline int isnlthcontext(int last)
+{
+	switch (last) {
+	case TK_BREAK:
+	case TK_CONTINUE:
+	case TK_RETURN:
+	case TK_THROW:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
 static int lex(js_State *J, const char **sp)
 {
 	J->newline = 0;
@@ -360,6 +373,8 @@ static int lex(js_State *J, const char **sp)
 				NEXT();
 			J->yyline++;
 			J->newline = 1;
+			if (isnlthcontext(J->lasttoken))
+				return ';';
 			continue;
 		}
 
@@ -468,14 +483,14 @@ static int lex(js_State *J, const char **sp)
 
 		case '+':
 			if (LOOK('+'))
-				return TK_INC;
+				return J->newline ? TK_INC : TK_NLTH_INC;
 			if (LOOK('='))
 				return TK_ADD_ASS;
 			return '+';
 
 		case '-':
 			if (LOOK('-'))
-				return TK_DEC;
+				return J->newline ? TK_DEC : TK_NLTH_DEC;
 			if (LOOK('='))
 				return TK_SUB_ASS;
 			return '-';
@@ -529,6 +544,7 @@ void jsP_initlex(js_State *J, const char *source)
 int jsP_lex(js_State *J)
 {
 	int t = lex(J, &J->yysource);
+	// TODO: move yytext/yynumber into jsP_lval
 	J->lasttoken = t;
 	return t;
 }
diff --git a/js-parse.h b/js-parse.h
index 82fb17f..91f70a0 100644
--- a/js-parse.h
+++ b/js-parse.h
@@ -33,7 +33,9 @@ enum {
 	TK_OR_ASS,
 	TK_XOR_ASS,
 	TK_INC,
+	TK_NLTH_INC,
 	TK_DEC,
+	TK_NLTH_DEC,
 
 	/* keywords */
 	TK_BREAK,