From 854ae564a34910fe3bd13a83a3d4bfa10cf0d838 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Wed, 30 Apr 2014 10:27:05 +0900
Subject: fix embedded documents

tabs are allowed after `=begin` and `=end`.
raise `SyntaxError` if no =end is found.
---
 src/parse.y | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

(limited to 'src/parse.y')

diff --git a/src/parse.y b/src/parse.y
index 7f1139a07..477305db4 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -3417,15 +3417,15 @@ skip(parser_state *p, char term)
   }
 }
 
-static mrb_bool
-peek_n(parser_state *p, int c, int n)
+static int
+peekc_n(parser_state *p, int n)
 {
   node *list = 0;
   int c0;
 
   do {
     c0 = nextc(p);
-    if (c0 < 0) return FALSE;
+    if (c0 < 0) return c0;
     list = push(list, (node*)(intptr_t)c0);
   } while(n--);
   if (p->pb) {
@@ -3434,8 +3434,13 @@ peek_n(parser_state *p, int c, int n)
   else {
     p->pb = list;
   }
-  if (c0 == c) return TRUE;
-  return FALSE;
+  return c0;
+}
+
+static mrb_bool
+peek_n(parser_state *p, int c, int n)
+{
+  return peekc_n(p, n) == c && c >= 0;
 }
 #define peek(p,c) peek_n((p), (c), 0)
 
@@ -4189,14 +4194,20 @@ parser_yylex(parser_state *p)
 
   case '=':
     if (p->column == 1) {
-      if (peeks(p, "begin ") || peeks(p, "begin\n")) {
-        if (skips(p, "\n=end ")) {
-          goto retry;
-        }
-        if (skips(p, "\n=end\n")) {
+      static const char begin[] = "begin";
+      static const char end[] = "\n=end";
+      if (peeks(p, begin)) {
+        c = peekc_n(p, sizeof(begin)-1);
+        if (c < 0 || isspace(c)) {
+          do {
+            if (!skips(p, end)) {
+              yyerror(p, "embedded document meets end of file");
+              return 0;
+            }
+            c = nextc_n(p, sizeof(end)-1);
+          } while (!(c < 0 || isspace(c)));
           goto retry;
         }
-        goto retry;
       }
     }
     if (p->lstate == EXPR_FNAME || p->lstate == EXPR_DOT) {
-- 
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