From d511864f8ad4094e0a96bbae384ee0913538aa36 Mon Sep 17 00:00:00 2001
From: Peter Wu <lekensteyn@gmail.com>
Date: Sun, 27 Nov 2011 14:08:03 +0000
Subject: Allow for declaration of variables within functions. Warning: local
 variables are not implemented, every variable is global

---
 pp2cc.py | 45 ++++++++++++++++++++++-----------------------
 1 file changed, 22 insertions(+), 23 deletions(-)

diff --git a/pp2cc.py b/pp2cc.py
index d09d792..db1886e 100755
--- a/pp2cc.py
+++ b/pp2cc.py
@@ -251,14 +251,13 @@ class Parse(object):
         """Loops through the nodes in an AST syntax tree and generates ASM"""
         root_node = LinkedNode(self.node)
         for thing in self.node.ext:
-            linked_node = LinkedNode(thing, root_node)
-            self.asm.level = linked_node.level
-            if isinstance(thing, c_ast.Decl):
-                self.defineGlobalVar(linked_node)
-            elif isinstance(thing, c_ast.FuncDef):
-                self.defineFunction(linked_node)
-            else:
-                raise RuntimeError("I don't know a node in the global scope: " + str(thing))
+            if not isinstance(thing, c_ast.Decl) and not isinstance(thing, c_ast.FuncDef):
+                linked_node = LinkedNode(thing, parent=root_node)
+                self.logger.warning("I expected a variable or function"
+                                    " definition or declaration in the root"
+                                    " node, but also found " +
+                                    str(thing), linked_node=linked_node)
+            self.codeSegment += self.parseStatement(thing, root_node)
     def getSource(self):
         """Retrieves the ASM source. You need to compile it first"""
         self.addSource("@DATA")
@@ -274,9 +273,6 @@ class Parse(object):
         self.addSource("@END")
     def addSource(self, line=''):
         print line
-    def defineGlobalVar(self, linked_node):
-        varname = linked_node.node.name
-        self.globalVars.append(varname)
     def nameToVar(self, name):
         """Returns the variable name which will be used in assembly
         
@@ -284,7 +280,7 @@ class Parse(object):
         name -- This name will be returned with the var_ prefix
         """
         return "var_" + name
-    def defineFunction(self, linked_node):
+    def parseFuncDef(self, linked_node):
         node = linked_node.node
         linked_node.incrementLevel()
         self.asm.level = linked_node.level
@@ -300,21 +296,20 @@ class Parse(object):
         self.addLabel(lbl_end)
         linked_node.setFunction(function)
 
-        self.codeSegment.append(self.asm.noop(lbl_func))
+        lines = [self.asm.noop(lbl_func)]
 
-        stmts = self.parseStatement(node.body, linked_node)
+        lines += self.parseStatement(node.body, linked_node)
         self.asm.level = linked_node.level
-        for stmt in stmts:
-            self.codeSegment.append(stmt)
-
+        
         # functions other than main() are subroutines
         #if funcname != "main":
         # since main should never be left, add the instruction anyway.
         # Otherwise, it'd crash anyway because it loops into the stack (if it
         # had not crashed before)
-        self.codeSegment.append(self.asm.format_line("RTS", label=lbl_end))
+        lines.append(self.asm.format_line("RTS", label=lbl_end))
         # add an extra newline
-        self.codeSegment.append("")
+        lines.append("")
+        return lines
     def functionLabel(self, name):
         if name in self.functions:
             function = self.functions[name]
@@ -793,13 +788,17 @@ class Parse(object):
         else:
             raise RuntimeError("Unsupported assignment operator: " + node.op)
         return lines
+    def parseDecl(self, linked_node):
+        varname = linked_node.node.name
+        if varname in self.globalVars:
+            raise RuntimeError("Redefinition of variable '{}'".format(varname))
+        self.globalVars.append(varname)
+        return []
     def parseStatement(self, node, parent_linked_node, level_increment=False):
         linked_node = LinkedNode(node, parent_linked_node, level_increment=level_increment)
         self.asm.level = linked_node.level
         lines = []
-        if isinstance(node, c_ast.Decl):
-            self.defineGlobalVar(linked_node)
-        elif isinstance(node, c_ast.FuncDecl):
+        if isinstance(node, c_ast.FuncDecl):
             raise RuntimeError("Not implemented for type " + repr(node))
         elif isinstance(node, c_ast.PtrDecl):
             raise RuntimeError("Not implemented for type " + repr(node))
@@ -807,7 +806,7 @@ class Parse(object):
             for entry in ("Compound", "BinaryOp", "If", "Constant", "ID",
                           "Return", "FuncCall", "UnaryOp", "Cast",
                           "TernaryOp", "DoWhile", "While", "For", "ExprList",
-                          "Assignment"):
+                          "Assignment", "Decl", "FuncDef"):
                 if isinstance(node, getattr(c_ast, entry)):
                     lines += getattr(self, "parse" + entry)(linked_node)
                     break
-- 
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