From 8442968f9c478fd547a583e25d9811386927e8d5 Mon Sep 17 00:00:00 2001
From: "hyunghwan.chung" <hyunghwan.chung@c9d47f8d-4fed-4a2f-8cad-691f5fbe3904>
Date: Sun, 19 Feb 2017 15:45:51 +0000
Subject: [PATCH] fixed a tokenization bug in getting a empty string literal.
 allowed a zero-length symbol to be created

---
 moo/lib/comp.c | 52 ++++++++++++++++++++++++++++++--------------------
 moo/lib/sym.c  |  9 +--------
 2 files changed, 32 insertions(+), 29 deletions(-)

diff --git a/moo/lib/comp.c b/moo/lib/comp.c
index d4d6cf2..f468287 100644
--- a/moo/lib/comp.c
+++ b/moo/lib/comp.c
@@ -1238,30 +1238,42 @@ static int get_strlit (moo_t* moo)
 	 * normal-character := character-except-single-quote
 	 */
 
-	moo_ooci_t c = moo->c->lxc.c;
-	SET_TOKEN_TYPE (moo, MOO_IOTOK_STRLIT);
+	moo_ooci_t oc, c;
 
-	do 
+	oc = moo->c->lxc.c; /* opening quote */
+
+	SET_TOKEN_TYPE (moo, MOO_IOTOK_STRLIT);
+	GET_CHAR_TO (moo, c);
+
+	if (c != oc)
 	{
 		do 
 		{
-			ADD_TOKEN_CHAR (moo, c);
-			GET_CHAR_TO (moo, c);
-
-			if (c == MOO_UCI_EOF) 
+			do 
 			{
-				/* string not closed */
-				set_syntax_error (moo, MOO_SYNERR_STRNC, TOKEN_LOC(moo) /*&moo->c->lxc.l*/, MOO_NULL);
-				return -1;
-			}
-		} 
-		while (c != '\'');
+			in_strlit:
+				ADD_TOKEN_CHAR (moo, c);
+				GET_CHAR_TO (moo, c);
 
-		/* 'c' must be a single quote at this point*/
+				if (c == MOO_UCI_EOF) 
+				{
+					/* string not closed */
+					set_syntax_error (moo, MOO_SYNERR_STRNC, TOKEN_LOC(moo) /*&moo->c->lxc.l*/, MOO_NULL);
+					return -1;
+				}
+			} 
+			while (c != oc);
+
+			/* 'c' must be a single quote at this point*/
+			GET_CHAR_TO (moo, c);
+		} 
+		while (c == oc); /* if the next character is a single quote, it becomes a literal single quote character. */
+	}
+	else
+	{
 		GET_CHAR_TO (moo, c);
-	} 
-	while (c == '\''); /* if the next character is a single quote,
-	                      it becomes a literal single quote character. */
+		if (c == oc) goto in_strlit;
+	}
 
 	unget_char (moo, &moo->c->lxc);
 	return 0;
@@ -1509,7 +1521,6 @@ retry:
 			break;
 
 		case '\'': /* string literal */
-			GET_CHAR (moo);
 			if (get_strlit(moo) <= -1) return -1;
 			break;
 
@@ -1612,9 +1623,8 @@ retry:
 
 				case '\'':
 					/* quoted symbol literal */
-					GET_CHAR (moo);
-					if (get_strlit(moo) <= -1) return -1;
-					SET_TOKEN_TYPE (moo, MOO_IOTOK_SYMLIT);
+					if (get_strlit(moo) <= -1) return -1; /* reuse the string literal tokenizer */
+					SET_TOKEN_TYPE (moo, MOO_IOTOK_SYMLIT); /* change the symbol type to symbol */
 					break;
 
 				default:
diff --git a/moo/lib/sym.c b/moo/lib/sym.c
index b9316f1..ad8bdf6 100644
--- a/moo/lib/sym.c
+++ b/moo/lib/sym.c
@@ -88,14 +88,6 @@ static moo_oop_t find_or_make_symbol (moo_t* moo, const moo_ooch_t* ptr, moo_oow
 	moo_oow_t index;
 	moo_oop_char_t symbol;
 
-	MOO_ASSERT (moo, len > 0);
-	if (len <= 0) 
-	{
-		/* i don't allow an empty symbol name */
-		moo->errnum = MOO_EINVAL;
-		return MOO_NULL;
-	}
-
 	MOO_ASSERT (moo, MOO_CLASSOF(moo,moo->symtab->bucket) == moo->_array);
 	index = moo_hashoochars(ptr, len) % MOO_OBJ_GET_SIZE(moo->symtab->bucket);
 
@@ -175,6 +167,7 @@ moo_oop_t moo_makesymbol (moo_t* moo, const moo_ooch_t* ptr, moo_oow_t len)
 {
 	return find_or_make_symbol (moo, ptr, len, 1);
 }
+
 moo_oop_t moo_findsymbol (moo_t* moo, const moo_ooch_t* ptr, moo_oow_t len)
 {
 	return find_or_make_symbol (moo, ptr, len, 0);