From 13e11b2fafe60cad7d04d80c602adc12d6080036 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@gmail.com>
Date: Fri, 22 Apr 2011 18:24:59 -0400
Subject: Handle symbol aliases in dmnsn_find_symbol() directly.

Fixes infinite loops when macro arguments have the same name as existing
symbols.
---
 dimension/common.rules         |  8 +-------
 dimension/parse.c              |  9 +++++++--
 tests/dimension/directives.pov | 12 ++++++++++++
 tests/dimension/directives.sh  | 16 ++++++++++++++++
 4 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/dimension/common.rules b/dimension/common.rules
index 9383d4b..a987c69 100644
--- a/dimension/common.rules
+++ b/dimension/common.rules
@@ -22,14 +22,8 @@
 /* Fundamental language elements */
 
 IDENTIFIER: "identifier" {
-            const char *id = $1;
-            dmnsn_astnode *symbol = dmnsn_find_symbol(symtable, id);
-            while (symbol && symbol->type == DMNSN_AST_IDENTIFIER) {
-              id = symbol->ptr;
-              symbol = dmnsn_find_symbol(symtable, id);
-            }
             $$ = dmnsn_new_astleaf(DMNSN_AST_IDENTIFIER, @$);
-            $$.ptr = dmnsn_strdup(id);
+            $$.ptr = dmnsn_strdup($1);
             dmnsn_free($1);
           }
 ;
diff --git a/dimension/parse.c b/dimension/parse.c
index 74075a7..6651d41 100644
--- a/dimension/parse.c
+++ b/dimension/parse.c
@@ -131,8 +131,13 @@ dmnsn_find_symbol(dmnsn_symbol_table *symtable, const char *id)
 
   DMNSN_ARRAY_FOREACH_REVERSE (dmnsn_dictionary **, dict, symtable) {
     symbol = dmnsn_dictionary_at(*dict, id);
-    if (symbol)
-      break;
+    if (symbol) {
+      if (symbol->type == DMNSN_AST_IDENTIFIER) {
+        id = symbol->ptr;
+      } else {
+        break;
+      }
+    }
   }
 
   return symbol;
diff --git a/tests/dimension/directives.pov b/tests/dimension/directives.pov
index 089622c..5c3cfa3 100644
--- a/tests/dimension/directives.pov
+++ b/tests/dimension/directives.pov
@@ -64,6 +64,18 @@
   Inc(Counter)
 #end
 
+// Test macro parameters with the same name as existing variables
+#declare Test1 = 0;
+#declare Test2 = 1;
+#declare Test3 = 2;
+#macro ScopeTest(Test1, Test2, Test3)
+  #declare Test1 = Test2 - Test3;
+#end
+ScopeTest(Test1, Test3, Test2)
+sphere {
+  0, Test1
+}
+
 #declare Box =
   box {
     <-1, -1, -1>, <1, 1, 1>
diff --git a/tests/dimension/directives.sh b/tests/dimension/directives.sh
index 7c66263..9e3974a 100755
--- a/tests/dimension/directives.sh
+++ b/tests/dimension/directives.sh
@@ -56,6 +56,17 @@ directives_exp="$(echo -n \
     (identifier "Inc") \( (identifier "Counter") \)
   #end
 
+  #declare (identifier "Test1") = (integer "0") ;
+  #declare (identifier "Test2") = (integer "1") ;
+  #declare (identifier "Test3") = (integer "2") ;
+  #macro (identifier "ScopeTest") \( (identifier "Test1") , (identifier "Test2") , (identifier "Test3") \)
+    #declare (identifier "Test1") = (identifier "Test2") - (identifier "Test3") ;
+  #end
+  (identifier "ScopeTest") \( (identifier "Test1") , (identifier "Test3") , (identifier "Test2") \)
+  sphere {
+    (integer "0") , (identifier "Test1")
+  }
+
   #declare (identifier "Box") =
     box {
       < - (integer "1") , - (integer "1") , - (integer "1") > ,
@@ -89,6 +100,11 @@ $(echo -n \
       (pigment
         (vector (integer 1) (integer 1) (integer 1) (integer 0) (integer 0))
          pigment-modifiers)))
+  (object
+    (sphere
+      (vector (integer 0) (integer 0) (integer 0) (integer 0) (integer 0))
+      (integer 1))
+    object-modifiers)
   (object
     (box
       (vector (integer -1) (integer -1) (integer -1) (integer 0) (integer 0))
-- 
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