From 3626828ceb96dedb118a2c4f8ff12a81006327dd Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Mon, 22 Mar 2021 01:45:19 +0100
Subject: [PATCH] decided

---
 .../src/prog8/ast/statements/AstStatements.kt |  5 ++--
 compilerAst/src/prog8/ast/walk/AstWalker.kt   | 15 +++++++++--
 examples/test.p8                              | 27 ++++++++++---------
 3 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/compilerAst/src/prog8/ast/statements/AstStatements.kt b/compilerAst/src/prog8/ast/statements/AstStatements.kt
index 3152acb22..800072f2b 100644
--- a/compilerAst/src/prog8/ast/statements/AstStatements.kt
+++ b/compilerAst/src/prog8/ast/statements/AstStatements.kt
@@ -227,8 +227,9 @@ open class VarDecl(val type: VarDeclType,
     }
 
     override fun replaceChildNode(node: Node, replacement: Node) {
-        // TODO the check that node===value is too strict sometimes, but leaving it out allows for bugs to creep through ... :( Perhaps check when adding the replace if there is already a replace on the same node?
-        require(replacement is Expression)
+        require(replacement is Expression && node===value)
+        // NOTE: ideally you also want to check that node===value but this sometimes crashes the optimizer when queueing multiple node replacements
+        //       just accept the risk of having the wrong node specified in the IAstModification object...
         value = replacement
         replacement.parent = this
     }
diff --git a/compilerAst/src/prog8/ast/walk/AstWalker.kt b/compilerAst/src/prog8/ast/walk/AstWalker.kt
index 09b6c0594..08a7d1ecf 100644
--- a/compilerAst/src/prog8/ast/walk/AstWalker.kt
+++ b/compilerAst/src/prog8/ast/walk/AstWalker.kt
@@ -56,7 +56,7 @@ interface IAstModification {
         }
     }
 
-    class ReplaceNode(private val node: Node, private val replacement: Node, private val parent: Node) :
+    class ReplaceNode(val node: Node, private val replacement: Node, private val parent: Node) :
         IAstModification {
         override fun perform() {
             parent.replaceChildNode(node, replacement)
@@ -158,9 +158,19 @@ abstract class AstWalker {
     open fun after(whileLoop: WhileLoop, parent: Node): Iterable<IAstModification> = emptyList()
 
     private val modifications = mutableListOf<Triple<IAstModification, Node, Node>>()
+    // private val modificationsReplacedNodes = mutableSetOf<Pair<Node, Position>>()
 
     private fun track(mods: Iterable<IAstModification>, node: Node, parent: Node) {
-        for (it in mods) modifications += Triple(it, node, parent)
+        for (it in mods) {
+//            if(it is IAstModification.ReplaceNode) {
+//                val replaceKey = Pair(it.node, it.node.position)
+//                if(replaceKey in modificationsReplacedNodes)
+//                    throw FatalAstException("there already is a node replacement for $replaceKey - optimizer can't deal with multiple replacements for same node yet. Split the ast modification?")
+//                else
+//                    modificationsReplacedNodes.add(replaceKey)
+//            }
+            modifications += Triple(it, node, parent)
+        }
     }
 
     fun applyModifications(): Int {
@@ -169,6 +179,7 @@ abstract class AstWalker {
         }
         val amount = modifications.size
         modifications.clear()
+//        modificationsReplacedNodes.clear()
         return amount
     }
 
diff --git a/examples/test.p8 b/examples/test.p8
index 9a201779b..dbc862141 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -1,23 +1,24 @@
-%target cx16
+;%target cx16
 %import textio
 %zeropage basicsafe
 
 main {
 
     sub start() {
+        txt.print("hello")
 
-        str filename = "titlescreen.bin"
-        ubyte success = cx16.vload(filename, 8, 0, $0000)
-        if success {
-            txt.print("load ok")
-            cx16.VERA_DC_HSCALE = 64
-            cx16.VERA_DC_VSCALE = 64
-            cx16.VERA_L1_CONFIG = %00011111     ; 256c bitmap mode
-            cx16.VERA_L1_MAPBASE = 0
-            cx16.VERA_L1_TILEBASE = 0
-        } else {
-            txt.print("load fail")
-        }
+;        str filename = "titlescreen.bin"
+;        ubyte success = cx16.vload(filename, 8, 0, $0000)
+;        if success {
+;            txt.print("load ok")
+;            cx16.VERA_DC_HSCALE = 64
+;            cx16.VERA_DC_VSCALE = 64
+;            cx16.VERA_L1_CONFIG = %00011111     ; 256c bitmap mode
+;            cx16.VERA_L1_MAPBASE = 0
+;            cx16.VERA_L1_TILEBASE = 0
+;        } else {
+;            txt.print("load fail")
+;        }
     }
 }