add some utility methods to PtNode to find the defining subroutine/block

codeAst/src/prog8/code/ast/AstBase.kt

@@ -30,6 +30,10 @@ sealed class PtNode(val position: Position) {
         children.add(index, child)
         child.parent = this
     }
+
+    fun definingBlock() = findParentNode<PtBlock>(this)
+    fun definingSub() = findParentNode<PtSub>(this)
+    fun definingAsmSub() = findParentNode<PtAsmSub>(this)
 }
 
 
@@ -116,3 +120,17 @@ class PtNop(position: Position): PtNode(position) {
 class PtScopeVarsDecls(position: Position): PtNode(position) {
     override fun printProperties() {}
 }
+
+
+
+// find the parent node of a specific type or interface
+// (useful to figure out in what namespace/block something is defined, etc.)
+inline fun <reified T> findParentNode(node: PtNode): T? {
+    var candidate = node.parent
+    while(candidate !is T && candidate !is PtProgram)
+        candidate = candidate.parent
+    return if(candidate is PtProgram)
+        null
+    else
+        candidate as T
+}

examples/test.p8

@@ -6,31 +6,24 @@
 
 main {
     sub start() {
-
-        txt.chrout('\x40')
-        txt.chrout('\x41')
-        txt.chrout('\x42')
-        txt.chrout('\n')
-        txt.print("Hello\n\"quotes\"\n")
-
         ; a "pixelshader":
-;        void syscall1(8, 0)      ; enable lo res creen
-;        ubyte shifter
-;
-;        shifter >>= 1
-;
-;        repeat {
-;            uword xx
-;            uword yy = 0
-;            repeat 240 {
-;                xx = 0
-;                repeat 320 {
-;                    syscall3(10, xx, yy, xx*yy + shifter)   ; plot pixel
-;                    xx++
-;                }
-;                yy++
-;            }
-;            shifter+=4
-;        }
+        void syscall1(8, 0)      ; enable lo res creen
+        ubyte shifter
+
+        shifter >>= 1
+
+        repeat {
+            uword xx
+            uword yy = 0
+            repeat 240 {
+                xx = 0
+                repeat 320 {
+                    syscall3(10, xx, yy, xx*yy + shifter)   ; plot pixel
+                    xx++
+                }
+                yy++
+            }
+            shifter+=4
+        }
     }
 }