fix ptr errors

.gitignore

@@ -7,10 +7,13 @@ build/
 dist/
 output/
 out/
+out-new/
+out-old/
 .*cache/
 *.directory
 *.prg
 *.bin
+*.p8ir
 *.labels.txt
 *.vm.txt
 *.vice-mon-list

codeCore/src/prog8/code/core/Enumerations.kt

@@ -202,6 +202,17 @@ class DataType private constructor(val base: BaseDataType, val sub: BaseDataType
         }
     }
 
+    fun dereference(): DataType {
+        require(isPointer || isUnsignedWord)
+        return when {
+            isUnsignedWord -> forDt(BaseDataType.UBYTE)
+            sub!=null -> forDt(sub)
+            subType!=null -> DataType(BaseDataType.STRUCT_INSTANCE, null, subType)
+            subTypeFromAntlr!=null -> DataType(BaseDataType.STRUCT_INSTANCE, null, null, subTypeFromAntlr)
+            else -> throw IllegalArgumentException("cannot dereference this pointer type")
+        }
+    }
+
     override fun toString(): String = when(base) {
         BaseDataType.ARRAY -> {
             when(sub) {

compiler/src/prog8/compiler/astprocessing/AstIdentifiersChecker.kt

@@ -166,10 +166,6 @@ internal class AstIdentifiersChecker(private val errors: IErrorReporter,
     }
 
     override fun visit(deref: PtrDereference) {
-        val first = deref.identifier.targetStatement()
-        if(first==null)
-            errors.undefined(deref.identifier.nameInSource, deref.identifier.position)
-
         if(deref.field!=null) {
             // check chain and field
             val dt = deref.identifier.inferType(program).getOrUndef()
@@ -191,10 +187,6 @@ internal class AstIdentifiersChecker(private val errors: IErrorReporter,
                 if(fieldDt==null) {
                     errors.err("unknown field '${deref.field}' in struct '${struct.name}'", deref.position)
                 }
-            } else {
-                if (first !is VarDecl || !first.datatype.isStructInstance) {
-                    errors.err("cannot find struct type", deref.identifier.position)
-                }
             }
         }
 

compiler/src/prog8/compiler/astprocessing/CodeDesugarer.kt

@@ -507,6 +507,18 @@ _after:
                 return listOf(IAstModification.ReplaceNode(deref, memread, parent))
             }
         }
+
+        if(deref.chain.isEmpty() && deref.field==null) {
+            val expr = deref.parent as? BinaryExpression
+            if (expr != null && expr.operator == ".") {
+                if (expr.left is IdentifierReference && expr.right === deref) {
+                    // replace  (a) . (b^^)  by (a.b)^^
+                    val identifier = IdentifierReference((expr.left as IdentifierReference).nameInSource + deref.identifier.nameInSource, expr.left.position)
+                    val replacement = PtrDereference(identifier, emptyList(), null, deref.position)
+                    return listOf(IAstModification.ReplaceNode(expr, replacement, expr.parent))
+                }
+            }
+        }
         return noModifications
     }
 

compiler/test/TestPointers.kt

@@ -393,9 +393,9 @@ main {
         val dr1 = (st[3] as Assignment).target.pointerDereference!!
         val dr2 = (st[4] as Assignment).value as PtrDereference
 
-        val dr3 = (st[6] as Assignment).value as PtrDereference
+        val dr3 = (st[7] as Assignment).value as PtrDereference
-        val dr4 = (st[7] as Assignment).value as PtrDereference
+        val dr4 = (st[8] as Assignment).value as PtrDereference
-        val dr5 = (st[8] as Assignment).target.pointerDereference!!
+        val dr5 = (st[9] as Assignment).target.pointerDereference!!
 
         dr0.identifier.nameInSource shouldBe listOf("l1", "s")
         dr0.chain.size shouldBe 0

compilerAst/src/prog8/ast/expressions/AstExpressions.kt

@@ -1631,7 +1631,7 @@ class PtrIndexedDereference(val indexed: ArrayIndexedExpression, override val po
         val vardecl = indexed.arrayvar.targetVarDecl()
         if(vardecl!=null &&vardecl.datatype.isPointer) {
             if(vardecl.datatype.sub!=null)
-                return InferredTypes.knownFor(vardecl.datatype.sub!!)
+                return InferredTypes.knownFor(vardecl.datatype.dereference())
             TODO("cannot determine type of dereferenced indexed pointer(?) that is not a pointer to a basic type")
         }
 
@@ -1641,7 +1641,7 @@ class PtrIndexedDereference(val indexed: ArrayIndexedExpression, override val po
                 dt.isUndefined -> InferredTypes.unknown()
                 dt.isUnsignedWord -> InferredTypes.knownFor(BaseDataType.UBYTE)
                 dt.isPointer -> {
-                    return if(dt.sub!=null) InferredTypes.knownFor(dt.sub!!)
+                    return if(dt.sub!=null) InferredTypes.knownFor(dt.dereference())
                     else InferredTypes.unknown()
                 }
                 else -> InferredTypes.unknown()
@@ -1657,6 +1657,8 @@ class PtrIndexedDereference(val indexed: ArrayIndexedExpression, override val po
 }
 
 class PtrDereference(val identifier: IdentifierReference, val chain: List<String>, val field: String?, override val position: Position) : Expression() {
+    // TODO why both identifier and chain?
+
     override lateinit var parent: Node
 
     override fun linkParents(parent: Node) {
@@ -1674,7 +1676,7 @@ class PtrDereference(val identifier: IdentifierReference, val chain: List<String
         if(first==null)
             return InferredTypes.unknown()
         if(first is StructFieldRef) {
-            return InferredTypes.knownFor(first.type)
+            return InferredTypes.knownFor(first.type.dereference())
         }
         val vardecl = identifier.targetVarDecl()
         if(vardecl==null || vardecl.datatype.isUndefined || (!vardecl.datatype.isPointer && !vardecl.datatype.isStructInstance) )
@@ -1683,7 +1685,7 @@ class PtrDereference(val identifier: IdentifierReference, val chain: List<String
         if(chain.isEmpty()) {
             return if(field==null) {
                 require(vardecl.datatype.sub!=null) { "can only dereference a pointer to a simple datatype " }
-                InferredTypes.knownFor(vardecl.datatype.sub!!)
+                InferredTypes.knownFor(vardecl.datatype.dereference())
             } else {
                 // lookup struct field type
                 val struct = vardecl.datatype.subType as StructDecl
@@ -1691,7 +1693,7 @@ class PtrDereference(val identifier: IdentifierReference, val chain: List<String
                 if (fieldDt == null)
                     InferredTypes.unknown()
                 else
-                    InferredTypes.knownFor(fieldDt)
+                    InferredTypes.knownFor(fieldDt.dereference())
             }
         } else {
             // lookup type of field at the end of a dereference chain
@@ -1705,13 +1707,13 @@ class PtrDereference(val identifier: IdentifierReference, val chain: List<String
                 struct = fieldDt.subType as StructDecl
             }
             if(field==null) {
-                return InferredTypes.knownFor(DataType.pointer(struct))
+                return InferredTypes.knownFor(DataType.structInstance(struct))
             }
             val fieldDt = struct.getFieldType(field)
             return if(fieldDt==null)
                 InferredTypes.unknown()
             else
-                InferredTypes.knownFor(fieldDt)
+                InferredTypes.knownFor(fieldDt.dereference())
         }
     }
 

docs/source/todo.rst

@@ -53,8 +53,9 @@ STRUCTS and TYPED POINTERS
 - DONE: fix _msb/_lsb storage of the split-words pointer-arrays
 - DONE: what about static initialization of an array of struct pointers? -> impossible right now because the pointer values are not constants.
 - DONE: make typeForAddressOf() be even more specific about the typed pointers it returns for the address-of operator.
-- fix ptr indexed problems (see todo.p8)
+- fix ptr problems in re.p8
 - Can we now get rid of PtPointerIndexedDeref ?  Both for expression (value) as assigntarget? All code for translate(idxderef: PtPointerIndexedDeref)  in ExpressionGen?
+- why does PtrDereference have both identifier and chain property? what goes where? is the distinction needed?
 - add unit tests for all changes (pointers and structs)
 - 6502 codegen: remove checks in checkForPointerTypesOn6502()
 - 6502 codegen should warn about writing to initialized struct instances when using romable code, like with arrays "can only be used as read-only in ROMable code"

examples/test.p8

@@ -5,7 +5,7 @@ main {
     }
     sub start() {
         ^^List l1 = List()
-        cx16.r1 = l1.s^^            ; TODO fix "undefined symbol" error (and fix the unit test too)
+        cx16.r1 = l1.s^^
     }
 }
 

simpleAst/src/prog8/code/ast/AstExpressions.kt

@@ -414,7 +414,7 @@ class PtPointerDeref(type: DataType, val chain: List<String>, val field: String?
         get() = children.single() as PtExpression
 
     init {
-        require(!type.isUndefined)
+        require(!type.isUndefined && !type.isPointer) { "no support for pointer to pointer" }
     }
 }