refactoring symbol lookups

compiler/src/prog8/compiler/astprocessing/AstChecker.kt

@@ -456,7 +456,7 @@ internal class AstChecker(private val program: Program,
         val targetIdentifier = assignTarget.identifier
         if (targetIdentifier != null) {
             val targetName = targetIdentifier.nameInSource
-            when (val targetSymbol = program.namespace.lookup(targetName, assignment)) {
+            when (val targetSymbol = program.namespace.lookup(targetName, assignment.definingScope)) {
                 null -> {
                     errors.err("undefined symbol: ${targetIdentifier.nameInSource.joinToString(".")}", targetIdentifier.position)
                     return
@@ -1073,7 +1073,7 @@ internal class AstChecker(private val program: Program,
     override fun visit(postIncrDecr: PostIncrDecr) {
         if(postIncrDecr.target.identifier != null) {
             val targetName = postIncrDecr.target.identifier!!.nameInSource
-            val target = program.namespace.lookup(targetName, postIncrDecr)
+            val target = program.namespace.lookup(targetName, postIncrDecr.definingScope)
             if(target==null) {
                 val symbol = postIncrDecr.target.identifier!!
                 errors.err("undefined symbol: ${symbol.nameInSource.joinToString(".")}", symbol.position)

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

@@ -42,7 +42,7 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
         if(decl.name in compTarget.machine.opcodeNames)
             errors.err("can't use a cpu opcode name as a symbol: '${decl.name}'", decl.position)
 
-        val existing = program.namespace.lookup(listOf(decl.name), decl)
+        val existing = program.namespace.lookup(listOf(decl.name), decl.definingScope)
         if (existing != null && existing !== decl)
             nameError(decl.name, decl.position, existing)
 
@@ -75,7 +75,8 @@ internal class AstIdentifiersChecker(private val program: Program, private val e
             val paramNames = subroutine.parameters.map { it.name }.toSet()
             val paramsToCheck = paramNames.intersect(namesInSub)
             for(name in paramsToCheck) {
-                val labelOrVar = subroutine.searchLabelOrVariableNotSubscoped(name)
+                // TODO clean this up? no two separate lookups?
+                val labelOrVar = subroutine.searchLabelOrVariableNotSubscoped(name, false)
                 if(labelOrVar!=null && labelOrVar.position != subroutine.position)
                     nameError(name, labelOrVar.position, subroutine)
                 val sub = subroutine.statements.firstOrNull { it is Subroutine && it.name==name}

compiler/test/TestScoping.kt

@@ -62,7 +62,7 @@ class TestScoping {
                             goto labeloutside
                             goto iflabel
                             goto main.start.nested.nestedlabel
-                            ; goto nested.nestedlabel         ; TODO should also work!!
+                            goto nested.nestedlabel
                         }
             iflabel:
                     }

compilerAst/src/prog8/ast/AstToplevel.kt

@@ -84,7 +84,7 @@ interface IStatementContainer {
     fun isEmpty(): Boolean = statements.isEmpty()
     fun isNotEmpty(): Boolean = statements.isNotEmpty()
 
-    fun searchLabelOrVariableNotSubscoped(name: String): Statement? {         // TODO return INamedStatement instead?  and rename to searchSymbol ?
+    fun searchLabelOrVariableNotSubscoped(name: String, alsoSubroutine: Boolean): Statement? {         // TODO return INamedStatement instead?  and rename to searchSymbol ?
         // this is called quite a lot and could perhaps be optimized a bit more,
         // but adding a memoization cache didn't make much of a practical runtime difference...
         for (stmt in statements) {
@@ -98,44 +98,48 @@ interface IStatementContainer {
                 is Label -> {
                     if(stmt.name==name) return stmt
                 }
+                is Subroutine -> {
+                    if(alsoSubroutine && stmt.name==name)
+                        return stmt
+                }
                 is AnonymousScope -> {
-                    val found = stmt.searchLabelOrVariableNotSubscoped(name)
+                    val found = stmt.searchLabelOrVariableNotSubscoped(name, alsoSubroutine)
                     if(found!=null)
                         return found
                 }
                 is IfStatement -> {
-                    val found = stmt.truepart.searchLabelOrVariableNotSubscoped(name) ?: stmt.elsepart.searchLabelOrVariableNotSubscoped(name)
+                    val found = stmt.truepart.searchLabelOrVariableNotSubscoped(name, alsoSubroutine) ?: stmt.elsepart.searchLabelOrVariableNotSubscoped(name, alsoSubroutine)
                     if(found!=null)
                         return found
                 }
                 is BranchStatement -> {
-                    val found = stmt.truepart.searchLabelOrVariableNotSubscoped(name) ?: stmt.elsepart.searchLabelOrVariableNotSubscoped(name)
+                    val found = stmt.truepart.searchLabelOrVariableNotSubscoped(name, alsoSubroutine) ?: stmt.elsepart.searchLabelOrVariableNotSubscoped(name, alsoSubroutine)
                     if(found!=null)
                         return found
                 }
                 is ForLoop -> {
-                    val found = stmt.body.searchLabelOrVariableNotSubscoped(name)
+                    val found = stmt.body.searchLabelOrVariableNotSubscoped(name, alsoSubroutine)
                     if(found!=null)
                         return found
                 }
                 is WhileLoop -> {
-                    val found = stmt.body.searchLabelOrVariableNotSubscoped(name)
+                    val found = stmt.body.searchLabelOrVariableNotSubscoped(name, alsoSubroutine)
                     if(found!=null)
                         return found
                 }
                 is RepeatLoop -> {
-                    val found = stmt.body.searchLabelOrVariableNotSubscoped(name)
+                    val found = stmt.body.searchLabelOrVariableNotSubscoped(name, alsoSubroutine)
                     if(found!=null)
                         return found
                 }
                 is UntilLoop -> {
-                    val found = stmt.body.searchLabelOrVariableNotSubscoped(name)
+                    val found = stmt.body.searchLabelOrVariableNotSubscoped(name, alsoSubroutine)
                     if(found!=null)
                         return found
                 }
                 is WhenStatement -> {
                     stmt.choices.forEach {
-                        val found = it.statements.searchLabelOrVariableNotSubscoped(name)
+                        val found = it.statements.searchLabelOrVariableNotSubscoped(name, alsoSubroutine)
                         if(found!=null)
                             return found
                     }
@@ -151,59 +155,80 @@ interface IStatementContainer {
 
     val allDefinedSymbols: List<Pair<String, Statement>>
         get() {
-            return statements.mapNotNull {
+            return statements.filterIsInstance<INamedStatement>().map { Pair(it.name, it as Statement) }
-                when (it) {
-                    is Label -> it.name to it
-                    is VarDecl -> it.name to it
-                    is Subroutine -> it.name to it
-                    is Block -> it.name to it
-                    else -> null
-                }
-            }
         }
 }
 
 interface INameScope: IStatementContainer, INamedStatement {
     fun subScope(name: String): INameScope?  = statements.firstOrNull { it is INameScope && it.name==name } as? INameScope
 
-    fun lookup(scopedName: List<String>, localContext: Node) : Statement? {             // TODO return INamedStatement instead?
+    fun lookup(scopedName: List<String>, localScope: INameScope) : Statement? {             // TODO return INamedStatement instead?
-        if(scopedName.size>1) {
+        return if(scopedName.size>1)
-            // a scoped name refers to a name in another module.
+            lookupQualified(scopedName, localScope)
-            // it's a qualified name, look it up from the root of the module's namespace (consider all modules in the program)
+        else {
-            for(module in localContext.definingModule.program.modules) {
+            lookupUnqualified(scopedName[0], localScope)
-                var scope: INameScope? = module
-                for(name in scopedName.dropLast(1)) {
-                    scope = scope?.subScope(name)
-                    if(scope==null)
-                        break
-                }
-                if(scope!=null) {
-                    val result = scope.searchLabelOrVariableNotSubscoped(scopedName.last())
-                    if(result!=null)
-                        return result
-                    return scope.subScope(scopedName.last()) as Statement?
-                }
-            }
-            return null
-        } else {
-            // unqualified name
-            // find the scope the localContext is in, look in that first
-            var statementScope = localContext
-            while(statementScope !is ParentSentinel) {
-                val localScope = statementScope.definingScope
-                val result = localScope.searchLabelOrVariableNotSubscoped(scopedName[0])
-                if (result != null)
-                    return result
-                val subscope = localScope.subScope(scopedName[0]) as Statement?
-                if (subscope != null)
-                    return subscope
-                // not found in this scope, look one higher up
-                statementScope = statementScope.parent
-            }
-            return null
         }
     }
 
+    private fun lookupQualified(scopedName: List<String>, startScope: INameScope): Statement? {
+        // a scoped name refers to a name in another namespace.
+        // look "up" from our current scope to search for the correct one.
+        if(scopedName==listOf("nested", "nestedlabel"))
+            println("$scopedName")      // TODO weg
+
+        // TODO FIX qualified lookup.
+
+        var statementScope = startScope
+        while(statementScope !is GlobalNamespace) {
+            if(statementScope !is Module && statementScope.name==scopedName[0]) {
+                // drill down to get the full scope
+                var scope: INameScope? = statementScope
+                for (name in scopedName.drop(1).dropLast(1)) {
+                    scope = scope!!.subScope(name)
+                    if (scope == null)
+                        return null
+                }
+                return scope!!.searchLabelOrVariableNotSubscoped(scopedName.last(), true)
+            } else {
+                statementScope = (statementScope as Node).definingScope
+            }
+        }
+
+        // not found, try again but now assume it's a globally scoped name starting with the name of a block
+        for(module in (startScope as Node).definingModule.program.modules) {
+            module.statements.forEach {
+                if(it is Block && it.name==scopedName[0])
+                    return it.lookup(scopedName, it)
+            }
+        }
+        return null
+    }
+
+    private fun lookupUnqualified(name: String, startScope: INameScope): Statement? {
+        val builtinFunctionsNames = (startScope as Node).definingModule.program.builtinFunctions.names
+        if(name in builtinFunctionsNames) {
+            // builtin functions always exist, return a dummy placeholder for them
+            val builtinPlaceholder = Label("builtin::$name", startScope.position)
+            builtinPlaceholder.parent = ParentSentinel
+            return builtinPlaceholder
+        }
+
+        // search for the unqualified name in the current scope (and possibly in any anonymousscopes it may contain)
+        // if it's not found there, jump up one higher in the namespaces and try again.
+        var statementScope = startScope
+        while(statementScope !is GlobalNamespace) {
+            val symbol = statementScope.searchLabelOrVariableNotSubscoped(name, true)
+            if(symbol!=null)
+                return symbol
+            else
+                statementScope = (statementScope as Node).definingScope
+        }
+        return null
+    }
+
+//    private fun getNamedSymbol(name: String): Statement? =
+//        statements.singleOrNull { it is INamedStatement && it.name==name }
+
     val containsCodeOrVars get() = statements.any { it !is Directive || it.directive == "%asminclude" || it.directive == "%asm" }
     val containsNoCodeNorVars get() = !containsCodeOrVars
 }
@@ -263,7 +288,7 @@ class Program(val name: String,
     private val _modules = mutableListOf<Module>()
 
     val modules: List<Module> = _modules
-    val namespace: GlobalNamespace = GlobalNamespace(modules, builtinFunctions.names)
+    val namespace: GlobalNamespace = GlobalNamespace(modules)
 
     init {
         // insert a container module for all interned strings later
@@ -414,7 +439,7 @@ open class Module(final override var statements: MutableList<Statement>,
 }
 
 
-class GlobalNamespace(val modules: Iterable<Module>, private val builtinFunctionNames: Set<String>): Node, INameScope {
+class GlobalNamespace(val modules: Iterable<Module>): Node, INameScope {
     override val name = "<<<global>>>"
     override val position = Position("<<<global>>>", 0, 0, 0)
     override val statements = mutableListOf<Statement>()        // not used
@@ -427,22 +452,6 @@ class GlobalNamespace(val modules: Iterable<Module>, private val builtinFunction
     override fun replaceChildNode(node: Node, replacement: Node) {
         throw FatalAstException("cannot replace anything in the namespace")
     }
-
-    override fun lookup(scopedName: List<String>, localContext: Node): Statement? {         // TODO return INamedStatement instead?
-        if (scopedName.size == 1 && scopedName[0] in builtinFunctionNames) {
-            // builtin functions always exist, return a dummy localContext for them
-            val builtinPlaceholder = Label("builtin::${scopedName.last()}", localContext.position)
-            builtinPlaceholder.parent = ParentSentinel
-            return builtinPlaceholder
-        }
-
-        // lookup something from the module.
-        return when (val stmt = localContext.definingModule.lookup(scopedName, localContext)) {
-            is Label, is VarDecl, is Block, is Subroutine -> stmt
-            null -> null
-            else -> throw SyntaxError("invalid identifier target type", stmt.position)
-        }
-    }
 }
 
 object BuiltinFunctionScopePlaceholder : INameScope {

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

@@ -730,7 +730,7 @@ data class IdentifierReference(val nameInSource: List<String>, override val posi
         if(nameInSource.size==1 && nameInSource[0] in program.builtinFunctions.names)
             BuiltinFunctionStatementPlaceholder(nameInSource[0], position, parent)
         else
-            program.namespace.lookup(nameInSource, this)
+            program.namespace.lookup(nameInSource, this.definingScope)
 
     fun targetVarDecl(program: Program): VarDecl? = targetStatement(program) as? VarDecl
     fun targetSubroutine(program: Program): Subroutine? = targetStatement(program) as? Subroutine
@@ -747,7 +747,7 @@ data class IdentifierReference(val nameInSource: List<String>, override val posi
     }
 
     override fun constValue(program: Program): NumericLiteralValue? {
-        val node = program.namespace.lookup(nameInSource, this)
+        val node = program.namespace.lookup(nameInSource, this.definingScope)
                 ?: throw UndefinedSymbolError(this)
         val vardecl = node as? VarDecl
         if(vardecl==null) {

compilerAst/src/prog8/ast/statements/AstStatements.kt

@@ -395,7 +395,7 @@ data class AssignTarget(var identifier: IdentifierReference?,
 
     fun inferType(program: Program): InferredTypes.InferredType {
         if (identifier != null) {
-            val symbol = program.namespace.lookup(identifier!!.nameInSource, this) ?: return InferredTypes.unknown()
+            val symbol = program.namespace.lookup(identifier!!.nameInSource, this.definingScope) ?: return InferredTypes.unknown()
             if (symbol is VarDecl) return InferredTypes.knownFor(symbol.datatype)
         }
 

examples/test.p8

@@ -1,24 +1,85 @@
+
+%import syslib
+%import textio
+%zeropage basicsafe
+%option no_sysinit
+
+;  Create a custom character set on the C64.
+
 main {
+
     sub start() {
-        goto labeloutside
+        txt.color(1)
+        txt.print("creating charset...\n")
+        charset.make_custom_charset()
 
-        if true {
+        ; activate the new charset in RAM
-            if true {
+        ubyte block = c64.CIA2PRA
-                goto labeloutside
+        const ubyte PAGE1 = ((c64.Screen >> 6) & $F0) | ((charset.CHARSET >> 10) & $0E)
-                goto iflabel
-            }
-iflabel:
-        }
 
-        repeat {
+        c64.CIA2PRA = (block & $FC) | (lsb(c64.Screen >> 14) ^ $03)
-            goto labelinside
+        c64.VMCSB = PAGE1
-labelinside:
-        }
 
-labeloutside:
+        txt.print("\n @ @ @ @\n")
+    }
+}
+
+charset {
+    const uword CHARSET = $2000
+
+    sub copy_rom_charset() {
+        ; copies the charset from ROM to RAM so we can modify it
+
+        sys.set_irqd()
+        ubyte bank = @($0001)
+        @($0001) = bank & %11111011     ; enable CHAREN, so the character rom accessible at $d000
+        sys.memcopy($d000, CHARSET, 256*8*2)  ; copy the charset to RAM
+
+        @($0001) = bank         ; reset previous memory banking
+        sys.clear_irqd()
     }
 
-    start:
+    sub make_custom_charset() {
-    start:
+        copy_rom_charset()
-    start:
+
+        ; make all characters italic
+        ubyte c
+        for c in 0 to 255 {
+            uword ptr = CHARSET + c*$0008
+            @(ptr) >>= 2
+            @(ptr+1) >>= 2
+            @(ptr+2) >>= 1
+            @(ptr+3) >>= 1
+            ;@(ptr+4) >>= 0
+            ;@(ptr+5) >>= 0
+            @(ptr+6) <<= 1
+            @(ptr+7) <<= 1
+
+            ptr = CHARSET + 256*8 + c*$0008
+            @(ptr) >>= 2
+            @(ptr+1) >>= 2
+            @(ptr+2) >>= 1
+            @(ptr+3) >>= 1
+            ;@(ptr+4) >>= 0
+            ;@(ptr+5) >>= 0
+            @(ptr+6) <<= 1
+            @(ptr+7) <<= 1
+        }
+
+        ; add a smiley over the '@'
+
+        ubyte[] smiley = [
+            %00111100,
+            %01000010,
+            %10100101,
+            %10000001,
+            %10100101,
+            %10011001,
+            %01000010,
+            %00111100
+        ]
+
+        sys.memcopy(smiley, CHARSET, len(smiley))
+
+    }
 }