it's now possible in more places to assign arrays and put array literals without the need to define explicit variable.

compiler/src/prog8/ast/base/Extensions.kt

@@ -19,8 +19,8 @@ internal fun Program.processAstBeforeAsmGeneration(errors: ErrorReporter) {
     fixer.applyModifications()
 }
 
-internal fun Program.reorderStatements() {
-    val reorder = StatementReorderer(this)
+internal fun Program.reorderStatements(errors: ErrorReporter) {
+    val reorder = StatementReorderer(this, errors)
     reorder.visit(this)
     reorder.applyModifications()
 }

compiler/src/prog8/ast/processing/AstChecker.kt

@@ -756,8 +756,13 @@ internal class AstChecker(private val program: Program,
             return e is StringLiteralValue
         }
 
-        if(!array.value.all { it is NumericLiteralValue || it is AddressOf || isPassByReferenceElement(it) })
-            errors.err("array literal contains invalid types", array.position)
+        if(array.parent is VarDecl) {
+            if (!array.value.all { it is NumericLiteralValue || it is AddressOf || isPassByReferenceElement(it) })
+                errors.err("array literal for variable initialization contains invalid types", array.position)
+        } else if(array.parent is ForLoop) {
+            if (!array.value.all { it.constValue(program) != null })
+                errors.err("array literal for iteration must contain constants. Try using a separate array variable instead?", array.position)
+        }
 
         super.visit(array)
     }

compiler/src/prog8/ast/processing/AstVariousTransforms.kt

@@ -86,7 +86,7 @@ internal class AstVariousTransforms(private val program: Program) : AstWalker()
             val arrayDt = array.type
             if(!arrayDt.istype(vardecl.datatype)) {
                 val cast = array.cast(vardecl.datatype)
-                if (cast != null && cast!=array)
+                if (cast != null && cast !== array)
                     return listOf(IAstModification.ReplaceNode(vardecl.value!!, cast, vardecl))
             }
         } else {
@@ -94,7 +94,7 @@ internal class AstVariousTransforms(private val program: Program) : AstWalker()
             if(arrayDt.isKnown) {
                 // this array literal is part of an expression, turn it into an identifier reference
                 val litval2 = array.cast(arrayDt.typeOrElse(DataType.STRUCT))
-                if(litval2!=null && litval2!=array) {
+                if(litval2!=null) {
                     val vardecl2 = VarDecl.createAuto(litval2)
                     val identifier = IdentifierReference(listOf(vardecl2.name), vardecl2.position)
                     return listOf(

compiler/src/prog8/ast/processing/StatementReorderer.kt

@@ -6,7 +6,7 @@ import prog8.ast.expressions.*
 import prog8.ast.statements.*
 
 
-internal class StatementReorderer(val program: Program) : AstWalker() {
+internal class StatementReorderer(val program: Program, val errors: ErrorReporter) : AstWalker() {
     // Reorders the statements in a way the compiler needs.
     // - 'main' block must be the very first statement UNLESS it has an address set.
     // - library blocks are put last.
@@ -84,20 +84,31 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
     override fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> {
         val valueType = assignment.value.inferType(program)
         val targetType = assignment.target.inferType(program, assignment)
+        var assignments = emptyList<Assignment>()
+
         if(targetType.istype(DataType.STRUCT) && (valueType.istype(DataType.STRUCT) || valueType.typeOrElse(DataType.STRUCT) in ArrayDatatypes )) {
-            val assignments = if (assignment.value is ArrayLiteralValue) {
-                flattenStructAssignmentFromStructLiteral(assignment, program)    //  'structvar = [ ..... ] '
+            assignments = if (assignment.value is ArrayLiteralValue) {
+                flattenStructAssignmentFromStructLiteral(assignment)    //  'structvar = [ ..... ] '
             } else {
-                flattenStructAssignmentFromIdentifier(assignment, program)    //   'structvar1 = structvar2'
+                flattenStructAssignmentFromIdentifier(assignment)    //   'structvar1 = structvar2'
             }
-            if(assignments.isNotEmpty()) {
-                val modifications = mutableListOf<IAstModification>()
-                assignments.reversed().mapTo(modifications) { IAstModification.InsertAfter(assignment, it, parent) }
-                modifications.add(IAstModification.Remove(assignment, parent))
-                return modifications
+        }
+
+        if(targetType.typeOrElse(DataType.STRUCT) in ArrayDatatypes && valueType.typeOrElse(DataType.STRUCT) in ArrayDatatypes ) {
+            assignments = if (assignment.value is ArrayLiteralValue) {
+                flattenArrayAssignmentFromArrayLiteral(assignment)    //  'arrayvar = [ ..... ] '
+            } else {
+                flattenArrayAssignmentFromIdentifier(assignment)    //   'arrayvar1 = arrayvar2'
             }
         }
 
+        if(assignments.isNotEmpty()) {
+            val modifications = mutableListOf<IAstModification>()
+            assignments.reversed().mapTo(modifications) { IAstModification.InsertAfter(assignment, it, parent) }
+            modifications.add(IAstModification.Remove(assignment, parent))
+            return modifications
+        }
+
         return noModifications
     }
 
@@ -150,15 +161,69 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
         return noModifications
     }
 
-    private fun flattenStructAssignmentFromStructLiteral(structAssignment: Assignment, program: Program): List<Assignment> {
+    private fun flattenArrayAssignmentFromArrayLiteral(assign: Assignment): List<Assignment> {
+        // TODO use a pointer loop instead of individual assignments
+
+        val identifier = assign.target.identifier!!
+        val targetVar = identifier.targetVarDecl(program.namespace)!!
+
+        val alv = assign.value as? ArrayLiteralValue
+        if(targetVar.arraysize==null) {
+            errors.err("array has no defined size", identifier.position)
+            return emptyList()
+        }
+
+        if(alv==null || alv.value.size != targetVar.arraysize!!.constIndex()) {
+            errors.err("element count mismatch", assign.position)
+            return emptyList()
+        }
+
+        return alv.value.withIndex().map { (index, value)->
+            val idx = ArrayIndexedExpression(identifier, ArrayIndex(NumericLiteralValue(DataType.UBYTE, index, assign.position), assign.position), assign.position)
+            Assignment(AssignTarget(null, idx, null, assign.position), value, value.position)
+        }
+    }
+
+    private fun flattenArrayAssignmentFromIdentifier(assign: Assignment): List<Assignment> {
+        // TODO use a pointer loop instead of individual assignments
+
+        val identifier = assign.target.identifier!!
+        val targetVar = identifier.targetVarDecl(program.namespace)!!
+
+        val sourceIdent = assign.value as IdentifierReference
+        val sourceVar = sourceIdent.targetVarDecl(program.namespace)!!
+        if(!sourceVar.isArray) {
+            errors.err("value must be an array",  sourceIdent.position)
+            return emptyList()
+        }
+        if(targetVar.arraysize==null) {
+            errors.err("array has no defined size", identifier.position)
+            return emptyList()
+        }
+
+        val alv = sourceVar.value as? ArrayLiteralValue
+        if(alv==null || alv.value.size != targetVar.arraysize!!.constIndex()) {
+            errors.err("element count mismatch", assign.position)
+            return emptyList()
+        }
+
+        return alv.value.withIndex().map { (index, value)->
+            val idx = ArrayIndexedExpression(identifier, ArrayIndex(NumericLiteralValue(DataType.UBYTE, index, assign.position), assign.position), assign.position)
+            Assignment(AssignTarget(null, idx, null, assign.position), value, value.position)
+        }
+    }
+
+    private fun flattenStructAssignmentFromStructLiteral(structAssignment: Assignment): List<Assignment> {
         val identifier = structAssignment.target.identifier!!
         val identifierName = identifier.nameInSource.single()
         val targetVar = identifier.targetVarDecl(program.namespace)!!
         val struct = targetVar.struct!!
 
         val slv = structAssignment.value as? ArrayLiteralValue
-        if(slv==null || slv.value.size != struct.numberOfElements)
-            throw FatalAstException("element count mismatch")
+        if(slv==null || slv.value.size != struct.numberOfElements) {
+            errors.err("element count mismatch", structAssignment.position)
+            return emptyList()
+        }
 
         return struct.statements.zip(slv.value).map { (targetDecl, sourceValue) ->
             targetDecl as VarDecl
@@ -171,7 +236,8 @@ internal class StatementReorderer(val program: Program) : AstWalker() {
         }
     }
 
-    private fun flattenStructAssignmentFromIdentifier(structAssignment: Assignment, program: Program): List<Assignment> {
+    private fun flattenStructAssignmentFromIdentifier(structAssignment: Assignment): List<Assignment> {
+        // TODO use memcopy beyond a certain number of elements
         val identifier = structAssignment.target.identifier!!
         val identifierName = identifier.nameInSource.single()
         val targetVar = identifier.targetVarDecl(program.namespace)!!

compiler/src/prog8/compiler/Main.kt

@@ -171,7 +171,8 @@ private fun processAst(programAst: Program, errors: ErrorReporter, compilerOptio
     errors.handle()
     programAst.constantFold(errors)
     errors.handle()
-    programAst.reorderStatements()
+    programAst.reorderStatements(errors)
+    errors.handle()
     programAst.addTypecasts(errors)
     errors.handle()
     programAst.variousCleanups()

docs/source/programming.rst

@@ -260,6 +260,11 @@ Note that the various keywords for the data type and variable type (``byte``, ``
 can't be used as *identifiers* elsewhere. You can't make a variable, block or subroutine with the name ``byte``
 for instance.
 
+It's possible to assign a new array to another array, this will overwrite all elements in the original
+array with those in the value array. The number and types of elements have to match.
+For large arrays this is a slow operation because every element is copied over. It should probably be avoided.
+
+
 **Arrays at a specific memory location:**
 Using the memory-mapped syntax it is possible to define an array to be located at a specific memory location.
 For instance to reference the first 5 rows of the Commodore 64's screen matrix as an array, you can define::

examples/test.p8

@@ -7,31 +7,40 @@ main {
 
     sub start() {
 
-        repeat 0 {
-            txt.print("repeat0\n")
+        const ubyte c1 = 111
+        const ubyte c2 = 122
+        const ubyte c3 = 133
+        ubyte ii
+
+
+        for ii in [c1, c2, c3] {
+            txt.print_ub(ii)
         }
 
-        repeat 2 {
-            txt.print("repeat2\n")
-        }
+;        ubyte[3] numbers
+;
+;        for ii in [55,44,33] {
+;            txt.print_ub(ii)
+;        }
 
-        ubyte u=3
-
-        repeat u-1 {
-            txt.print("repeat u=2\n")
-        }
-
-        u=2
-        repeat u-1 {
-            txt.print("repeat u=1\n")
-        }
-
-        u=1
-        repeat u-1 {
-            txt.print("repeat u=0\n")
-        }
-
-        txt.chrout('\n')
+;        ubyte a = 99
+;        ubyte b = 88
+;        ubyte c = 77
+;
+;        ;numbers = numbers       ; TODO optimize away
+;
+;        numbers = [c1,c2,c3]
+;        numbers = [1,2,3]
+;        numbers = [a,b,c]
+;
+;        ubyte[] a1 = [c1,c2,c3]
+;        ubyte[3] a2
+;
+;        a2 = [a,b,c]
+;
+;        txt.print_ub(a)
+;        txt.print_ub(b)
+;        txt.print_ub(c)
     }
 
     asmsub testX() {