struct finished

README.md

@@ -22,6 +22,7 @@ which aims to provide many conveniences over raw assembly code (even when using
 - constant folding in expressions (compile-time evaluation)
 - conditional branches
 - when statement to provide a 'jump table' alternative to if/elseif chains
+- structs to group together sets of variables and manipulate them at once
 - automatic type conversions
 - floating point operations  (uses the C64 Basic ROM routines for this)
 - abstracting away low level aspects such as ZeroPage handling, program startup, explicit memory addresses

compiler/src/prog8/ast/AstToplevel.kt

@@ -71,6 +71,21 @@ class GlobalNamespace(val modules: List<Module>): Node, INameScope {
             return builtinPlaceholder
         }
 
+        if(scopedName.size>1) {
+            // a scoped name can a) refer to a member of a struct, or b) refer to a name in another module.
+            // try the struct first.
+            val thing = lookup(scopedName.dropLast(1), localContext) as? VarDecl
+            val struct = thing?.struct
+            if (struct != null) {
+                if(struct.statements.any { (it as VarDecl).name == scopedName.last()}) {
+                    // return ref to the mangled name variable
+                    val mangled = mangledStructMemberName(thing.name, scopedName.last())
+                    val mangledVar = thing.definingScope().getLabelOrVariable(mangled)
+                    return mangledVar
+                }
+            }
+        }
+
         val stmt = localContext.definingModule().lookup(scopedName, localContext)
         return when (stmt) {
             is Label, is VarDecl, is Block, is Subroutine -> stmt

compiler/src/prog8/ast/Interfaces.kt

@@ -137,7 +137,7 @@ interface INameScope {
             //   - the name of a symbol somewhere else starting from the root of the namespace.
 
             // check struct first
-            if(scopedName.size==2) {        // TODO support for referencing structs in other scopes
+            if(scopedName.size==2) {        // TODO support for referencing structs in other scopes . see GlobalNamespace?
                 val mangledname = mangledStructMemberName(scopedName[0], scopedName[1])
                 val vardecl = localContext.definingScope().getLabelOrVariable(mangledname)
                 if(vardecl!=null)

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

@@ -350,6 +350,17 @@ internal class AstChecker(private val program: Program,
             }
         }
 
+        val sourceIdent = assignment.value as? IdentifierReference
+        val targetIdent = assignment.target.identifier
+        if(sourceIdent!=null && targetIdent!=null) {
+            val sourceVar = sourceIdent.targetVarDecl(program.namespace)
+            val targetVar = targetIdent.targetVarDecl(program.namespace)
+            if(sourceVar?.struct!=null && targetVar?.struct!=null) {
+                if(sourceVar.struct!==targetVar.struct)
+                    checkResult.add(ExpressionError("assignment of different struct types", assignment.position))
+            }
+        }
+
         var resultingAssignment = assignment
         resultingAssignment = processAssignmentTarget(resultingAssignment, assignment.target)
         return super.visit(resultingAssignment)
@@ -1275,8 +1286,8 @@ internal class AstChecker(private val program: Program,
             else {
                 if(decl.zeropage)
                     checkResult.add(SyntaxError("struct can not contain zeropage members", decl.position))
-                if(decl.datatype==DataType.STRUCT)
-                    checkResult.add(SyntaxError("structs can not be nested", decl.position))
+                if(decl.datatype !in NumericDatatypes)
+                    checkResult.add(SyntaxError("structs can only contain numerical types", decl.position))
             }
         }
 

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

@@ -62,6 +62,9 @@ internal class AstIdentifiersChecker(private val namespace: INameScope) : IAstMo
             if(decl.structHasBeenFlattened)
                 return decl    // don't do this multiple times
 
+            if(decl.struct!!.statements.any { (it as VarDecl).datatype !in NumericDatatypes})
+                return decl     // a non-numeric member, not supported. proper error is given by AstChecker later
+
             val decls: MutableList<IStatement> = decl.struct!!.statements.withIndex().map {
                 val member = it.value as VarDecl
                 val initvalue = if(decl.value!=null) (decl.value as LiteralValue).arrayvalue!![it.index] else null
@@ -245,4 +248,14 @@ internal class AstIdentifiersChecker(private val namespace: INameScope) : IAstMo
         return super.visit(addressOf)
     }
 
+    override fun visit(structDecl: StructDecl): IStatement {
+        for(member in structDecl.statements){
+            val decl = member as? VarDecl
+            if(decl!=null && decl.datatype !in NumericDatatypes)
+                checkResult.add(SyntaxError("structs can only contain numerical types", decl.position))
+        }
+
+        return super.visit(structDecl)
+    }
+
 }

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

@@ -2,14 +2,58 @@ package prog8.ast.processing
 
 import kotlin.comparisons.nullsLast
 import prog8.ast.*
-import prog8.ast.base.DataType
-import prog8.ast.base.FatalAstException
+import prog8.ast.base.*
 import prog8.ast.base.initvarsSubName
-import prog8.ast.base.printWarning
 import prog8.ast.expressions.*
 import prog8.ast.statements.*
 import prog8.functions.BuiltinFunctions
 
+
+fun flattenStructAssignment(structAssignment: Assignment, program: Program): List<Assignment> {
+    val identifier = structAssignment.target.identifier!!
+    val identifierName = identifier.nameInSource.single()
+    val targetVar = identifier.targetVarDecl(program.namespace)!!
+    val struct = targetVar.struct!!
+    val sourceVar = (structAssignment.value as IdentifierReference).targetVarDecl(program.namespace)!!
+    if(!sourceVar.isArray && sourceVar.struct==null)
+        throw FatalAstException("can only assign arrays or structs to structs")
+    if(sourceVar.isArray) {
+        val sourceArray = (sourceVar.value as LiteralValue).arrayvalue!!
+        return struct.statements.zip(sourceArray).map { member ->
+            val decl = member.first as VarDecl
+            val mangled = mangledStructMemberName(identifierName, decl.name)
+            val idref = IdentifierReference(listOf(mangled), structAssignment.position)
+            val assign = Assignment(AssignTarget(null, idref, null, null, structAssignment.position),
+                    null, member.second, member.second.position)
+            assign.linkParents(structAssignment)
+            assign
+        }
+    }
+    else {
+        // struct memberwise copy
+        val sourceStruct = sourceVar.struct!!
+        if(sourceStruct!==targetVar.struct) {
+            // structs are not the same in assignment
+            return listOf()     // error will be printed elsewhere
+        }
+        return struct.statements.zip(sourceStruct.statements).map { member ->
+            val targetDecl = member.first as VarDecl
+            val sourceDecl = member.second as VarDecl
+            if(targetDecl.name != sourceDecl.name)
+                throw FatalAstException("struct member mismatch")
+            val mangled = mangledStructMemberName(identifierName, targetDecl.name)
+            val idref = IdentifierReference(listOf(mangled), structAssignment.position)
+            val sourcemangled = mangledStructMemberName(sourceVar.name, sourceDecl.name)
+            val sourceIdref = IdentifierReference(listOf(sourcemangled), structAssignment.position)
+            val assign = Assignment(AssignTarget(null, idref, null, null, structAssignment.position),
+                    null, sourceIdref, member.second.position)
+            assign.linkParents(structAssignment)
+            assign
+        }
+    }
+}
+
+
 internal class StatementReorderer(private val program: Program): IAstModifyingVisitor {
     // Reorders the statements in a way the compiler needs.
     // - 'main' block must be the very first statement UNLESS it has an address set.
@@ -174,12 +218,28 @@ internal class StatementReorderer(private val program: Program): IAstModifyingVi
         // see if a typecast is needed to convert the value's type into the proper target type
         val valuetype = assignment.value.inferType(program)
         val targettype = assignment.target.inferType(program, assignment)
-        if(targettype!=null && valuetype!=null && valuetype!=targettype) {
-            if(valuetype isAssignableTo targettype) {
-                assignment.value = TypecastExpression(assignment.value, targettype, true, assignment.value.position)
-                assignment.value.linkParents(assignment)
+        if(targettype!=null && valuetype!=null) {
+            if(valuetype!=targettype) {
+                if (valuetype isAssignableTo targettype) {
+                    assignment.value = TypecastExpression(assignment.value, targettype, true, assignment.value.position)
+                    assignment.value.linkParents(assignment)
+                }
+                // if they're not assignable, we'll get a proper error later from the AstChecker
+            }
+        }
+
+        // struct assignments will be flattened
+        if(valuetype==DataType.STRUCT && targettype==DataType.STRUCT) {
+            val assignments = flattenStructAssignment(assignment, program)
+            if(assignments.isEmpty()) {
+                // something went wrong (probably incompatible struct types)
+                // we'll get an error later from the AstChecker
+                return assignment
+            } else {
+                val scope = AnonymousScope(assignments.toMutableList(), assignment.position)
+                scope.linkParents(assignment.parent)
+                return scope
             }
-            // if they're not assignable, we'll get a proper error later from the AstChecker
         }
 
         return super.visit(assignment)

compiler/src/prog8/compiler/Compiler.kt

@@ -4,6 +4,7 @@ import prog8.ast.*
 import prog8.ast.base.*
 import prog8.ast.base.RegisterOrPair.*
 import prog8.ast.expressions.*
+import prog8.ast.processing.flattenStructAssignment
 import prog8.ast.statements.*
 import prog8.compiler.intermediate.IntermediateProgram
 import prog8.compiler.intermediate.Opcode
@@ -1464,26 +1465,6 @@ internal class Compiler(private val program: Program) {
         popValueIntoTarget(stmt.target, datatype)
     }
 
-    private fun flattenStructAssignment(structAssignment: Assignment, program: Program): List<Assignment> {
-        val identifier = structAssignment.target.identifier!!
-        val identifierName = identifier.nameInSource.single()
-        val targetVar = identifier.targetVarDecl(program.namespace)!!
-        val struct = targetVar.struct!!
-        val sourceVar = (structAssignment.value as IdentifierReference).targetVarDecl(program.namespace)!!
-        if(!sourceVar.isArray)
-            throw CompilerException("can only assign arrays to structs")
-        val sourceArray = (sourceVar.value as LiteralValue).arrayvalue!!
-        return struct.statements.zip(sourceArray).map { member ->
-            val decl = member.first as VarDecl
-            val mangled = mangledStructMemberName(identifierName, decl.name)
-            val idref = IdentifierReference(listOf(mangled), structAssignment.position)
-            val assign = Assignment(AssignTarget(null, idref, null, null, structAssignment.position),
-                    null, member.second, member.second.position)
-            assign.linkParents(structAssignment)
-            assign
-        }
-    }
-
     private fun pushHeapVarAddress(value: IExpression, removeLastOpcode: Boolean) {
         when (value) {
             is LiteralValue -> throw CompilerException("can only push address of string or array (value on the heap)")

compiler/src/prog8/optimizer/CallGraph.kt

@@ -1,6 +1,7 @@
 package prog8.optimizer
 
 import prog8.ast.*
+import prog8.ast.base.DataType
 import prog8.ast.base.ParentSentinel
 import prog8.ast.base.VarDeclType
 import prog8.ast.base.initvarsSubName
@@ -122,6 +123,10 @@ class CallGraph(private val program: Program): IAstVisitor {
             // make sure autogenerated vardecls are in the used symbols
             addNodeAndParentScopes(decl)
         }
+
+        if(decl.datatype==DataType.STRUCT)
+            addNodeAndParentScopes(decl)
+
         super.visit(decl)
     }
 
@@ -196,10 +201,12 @@ class CallGraph(private val program: Program): IAstVisitor {
                 if (matches2 != null) {
                     val target= matches2.groups[2]?.value
                     if (target != null && (target[0].isLetter() || target[0] == '_')) {
-                        val node = program.namespace.lookup(listOf(target.substringBefore('.')), context)
-                        if (node is Subroutine) {
-                            subroutinesCalling[scope] = subroutinesCalling.getValue(scope).plus(node)
-                            subroutinesCalledBy[node] = subroutinesCalledBy.getValue(node).plus(context)
+                        if(target.contains('.')) {
+                            val node = program.namespace.lookup(listOf(target.substringBefore('.')), context)
+                            if (node is Subroutine) {
+                                subroutinesCalling[scope] = subroutinesCalling.getValue(scope).plus(node)
+                                subroutinesCalledBy[node] = subroutinesCalledBy.getValue(node).plus(context)
+                            }
                         }
                     }
                 }

compiler/src/prog8/vm/astvm/VariablesCreator.kt

@@ -40,8 +40,10 @@ class VariablesCreator(private val runtimeVariables: RuntimeVariables, private v
             when (decl.type) {
                 // we can assume the value in the vardecl already has been converted into a constant LiteralValue here.
                 VarDeclType.VAR -> {
-                    val value = RuntimeValue.from(decl.value as LiteralValue, heap)
-                    runtimeVariables.define(decl.definingScope(), decl.name, value)
+                    if(decl.datatype!=DataType.STRUCT) {
+                        val value = RuntimeValue.from(decl.value as LiteralValue, heap)
+                        runtimeVariables.define(decl.definingScope(), decl.name, value)
+                    }
                 }
                 VarDeclType.MEMORY -> {
                     runtimeVariables.defineMemory(decl.definingScope(), decl.name, (decl.value as LiteralValue).asIntegerValue!!)

docs/source/programming.rst

@@ -273,6 +273,38 @@ you have to use the ``str_s`` variants of the string type identifier.
     The same is true for arrays by the way.
 
 
+Structs
+^^^^^^^
+
+A struct is a group of one or more other variables.
+This allows you to reuse the definition and manipulate it as a whole.
+Individual variables in the struct are accessed as you would expect, just
+use a scoped name to refer to them: ``structvariable.membername``.
+
+Structs are a bit limited in Prog8: you can only use numerical variables
+as member of a struct, so strings and arrays and other structs can not be part of a struct.
+Also, it is not possible to use a struct itself inside an array.
+
+Structs are mainly syntactic sugar for repeated groups of vardecls
+and assignments that belong together.
+
+To create a variable of a struct type you need to define the struct itself,
+and then create a variable with it::
+
+    struct Color {
+        ubyte red
+        ubyte green
+        ubyte blue
+    }
+
+    Color rgb = [255,122,0]
+    Color another               ; the init value is optional, like arrays
+
+    another = rgb           ; assign all of the values of rgb to another
+    another.blue = 255      ; set a single member
+
+
+
 Special types: const and memory-mapped
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

docs/source/syntaxreference.rst

@@ -234,7 +234,7 @@ Various examples::
     byte[5]     values  = 255           ; initialize with five 255 bytes
 
     word  @zp   zpword = 9999           ; prioritize this when selecting vars for zeropage storage
-
+    Color       rgb    = [1,255,0]      ; a struct variable
 
 
 Data types
@@ -358,6 +358,22 @@ Syntax is familiar with brackets:  ``arrayvar[x]`` ::
     string[4]       ; the fifth character (=byte) in the string
 
 
+Struct
+^^^^^^
+
+A *struct* has to be defined to specify what its member variables are.
+There are one or more members::
+
+    struct  <structname> {
+        <vardecl>
+        [ <vardecl> ...]
+    }
+
+You can only use numerical variables as member of a struct, so strings and arrays
+and other structs can not be part of a struct. Vice versa, a struct can not occur in an array.
+
+After defining a struct you can use the name of the struct as a data type to declare variables with.
+
 
 Operators
 ---------

docs/source/todo.rst

@@ -52,25 +52,6 @@ Allocate a fixed word in ZP that is the TOS so we can operate on TOS directly
 without having to to index into the stack?
 
 
-structs?
-^^^^^^^^
-
-A user defined struct type would be nice to group a bunch
-of values together (and use it multiple times). Something like::
-
-    struct Point {
-        ubyte   color
-        word[] vec = [0,0,0]
-    }
-
-    Point p1
-    Point p2
-    Point p3
-
-    p1.color = 3
-    p1.vec[2] = 2
-
-
 Misc
 ^^^^
 

examples/swirl.p8

@@ -5,20 +5,24 @@
     const uword width = 40
     const uword height = 25
 
-    sub start()  {
-
+    struct Ball {
         uword anglex
         uword angley
         ubyte color
+    }
+
+    sub start()  {
+
+        Ball ball
 
         while true {
-            ubyte x = msb(sin8u(msb(anglex)) as uword * width)
-            ubyte y = msb(cos8u(msb(angley)) as uword * height)
-            c64scr.setcc(x, y, 81, color)
+            ubyte x = msb(sin8u(msb(ball.anglex)) as uword * width)
+            ubyte y = msb(cos8u(msb(ball.angley)) as uword * height)
+            c64scr.setcc(x, y, 81, ball.color)
 
-            anglex+=800
-            angley+=947
-            color++
+            ball.anglex+=800
+            ball.angley+=947
+            ball.color++
         }
     }
 }

examples/test.p8

@@ -7,79 +7,24 @@
 
     sub start() {
 
-        uword derp =44
-        ubyte[] v = [22,33,44]
-
-        Color foreground    = [1,2,3]
-        c64scr.print_ub(foreground.red)
-        c64.CHROUT(':')
-        c64scr.print_ub(foreground.green)
-        c64.CHROUT(':')
-        c64scr.print_ub(foreground.blue)
-        c64.CHROUT('\n')
-
-
-        Color background
-        Color cursor = [255,255,255]
-
-        foreground.red=99
-        background.blue=foreground.red
-
-        cursor = [1,2,3]    ; assign all members at once
-        cursor = v
-        cursor = foreground   ; @todo memberwise assignment
-
-        c64scr.print_ub(foreground.red)
-        c64.CHROUT(':')
-        c64scr.print_ub(foreground.green)
-        c64.CHROUT(':')
-        c64scr.print_ub(foreground.blue)
-        c64.CHROUT('\n')
-        c64scr.print_ub(background.red)
-        c64.CHROUT(':')
-        c64scr.print_ub(background.green)
-        c64.CHROUT(':')
-        c64scr.print_ub(background.blue)
-        c64.CHROUT('\n')
-        c64scr.print_ub(cursor.red)
-        c64.CHROUT(':')
-        c64scr.print_ub(cursor.green)
-        c64.CHROUT(':')
-        c64scr.print_ub(cursor.blue)
-        c64.CHROUT('\n')
-
-        foo()
-        foo()
-        foo()
-        foo()
-        foo()
-        foo()
-        foo()
+        Color subcol
 
+        A=msb(subcol.red)
+        for ubyte i in 10 to 20 {
+            ;A=subcol.red
+            ;A=blocklevelcolor.green
 
+            ;subcol.blue = Y
+            ;blocklevelcolor.green=Y
+            A=msb(subcol.red)
+        }
         return
     }
 
-    sub foo() {
-        Color localcolor
-        localcolor.red++
-        c64scr.print_ub(localcolor.red)
-        c64.CHROUT(':')
-        c64scr.print_ub(localcolor.green)
-        c64.CHROUT(':')
-        c64scr.print_ub(localcolor.blue)
-        c64.CHROUT('\n')
-    }
-
     struct Color {
         ubyte red
         ubyte green
         ubyte blue
     }
 
-    ; @todo structs as sub args. After strings and arrays as sub-args.
-;    sub foo(Color arg) -> ubyte {
-;        return arg.red+arg.green+arg.blue
-;    }
-
 }