diff --git a/codeGeneration/codeGeneration.iml b/codeGeneration/codeGeneration.iml
index 9a8fa347e..928636817 100644
--- a/codeGeneration/codeGeneration.iml
+++ b/codeGeneration/codeGeneration.iml
@@ -5,6 +5,7 @@
     <content url="file://$MODULE_DIR$">
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
     </content>
     <orderEntry type="jdk" jdkName="openjdk-11" jdkType="JavaSDK" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/codeGeneration/test/AsmGenTests.kt b/codeGeneration/test/AsmGenTests.kt
index dc2711456..323f6f848 100644
--- a/codeGeneration/test/AsmGenTests.kt
+++ b/codeGeneration/test/AsmGenTests.kt
@@ -21,6 +21,7 @@ import prog8.compilerinterface.*
 import prog8.parser.SourceCode
 import prog8tests.asmgen.helpers.DummyFunctions
 import prog8tests.asmgen.helpers.DummyMemsizer
+import prog8tests.asmgen.helpers.DummyStringEncoder
 import prog8tests.asmgen.helpers.ErrorReporterForTests
 import java.nio.file.Path
 
@@ -73,7 +74,7 @@ locallabel:
         val block = Block("main", null, mutableListOf(labelInBlock, varInBlock, subroutine), false, Position.DUMMY)
 
         val module = Module(mutableListOf(block), Position.DUMMY, SourceCode.Generated("test"))
-        val program = Program("test", DummyFunctions, DummyMemsizer)
+        val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             .addModule(module)
         module.linkIntoProgram(program)
         return program
diff --git a/codeGeneration/test/helpers/Dummies.kt b/codeGeneration/test/helpers/Dummies.kt
index abcf1f8fe..ccb9d10f3 100644
--- a/codeGeneration/test/helpers/Dummies.kt
+++ b/codeGeneration/test/helpers/Dummies.kt
@@ -7,6 +7,7 @@ import prog8.ast.expressions.InferredTypes
 import prog8.ast.expressions.NumericLiteralValue
 import prog8.compilerinterface.IMemSizer
 import prog8.ast.base.DataType
+import prog8.compilerinterface.IStringEncoding
 
 
 internal val DummyFunctions = object : IBuiltinFunctions {
@@ -24,3 +25,13 @@ internal val DummyFunctions = object : IBuiltinFunctions {
 internal val DummyMemsizer = object : IMemSizer {
     override fun memorySize(dt: DataType): Int = 0
 }
+
+internal val DummyStringEncoder = object : IStringEncoding {
+    override fun encodeString(str: String, altEncoding: Boolean): List<Short> {
+        return emptyList()
+    }
+
+    override fun decodeString(bytes: List<Short>, altEncoding: Boolean): String {
+        return ""
+    }
+}
diff --git a/codeOptimizers/codeOptimizers.iml b/codeOptimizers/codeOptimizers.iml
index 6778075ca..45621612e 100644
--- a/codeOptimizers/codeOptimizers.iml
+++ b/codeOptimizers/codeOptimizers.iml
@@ -5,6 +5,7 @@
     <content url="file://$MODULE_DIR$">
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
     </content>
     <orderEntry type="jdk" jdkName="openjdk-11" jdkType="JavaSDK" />
     <orderEntry type="sourceFolder" forTests="false" />
diff --git a/compiler/src/prog8/compiler/Compiler.kt b/compiler/src/prog8/compiler/Compiler.kt
index c09a9ef4f..84ec61cbb 100644
--- a/compiler/src/prog8/compiler/Compiler.kt
+++ b/compiler/src/prog8/compiler/Compiler.kt
@@ -115,7 +115,7 @@ fun compileProgram(filepath: Path,
         throw x
     }
 
-    val failedProgram = Program("failed", BuiltinFunctionsFacade(BuiltinFunctions), compTarget)
+    val failedProgram = Program("failed", BuiltinFunctionsFacade(BuiltinFunctions), compTarget, compTarget)
     return CompilationResult(false, failedProgram, programName, compTarget, emptyList())
 }
 
@@ -155,7 +155,7 @@ fun parseImports(filepath: Path,
                  sourceDirs: List<String>): Triple<Program, CompilationOptions, List<Path>> {
     println("Compiler target: ${compTarget.name}. Parsing...")
     val bf = BuiltinFunctionsFacade(BuiltinFunctions)
-    val programAst = Program(filepath.nameWithoutExtension, bf, compTarget)
+    val programAst = Program(filepath.nameWithoutExtension, bf, compTarget, compTarget)
     bf.program = programAst
 
     val importer = ModuleImporter(programAst, compTarget.name, errors, sourceDirs)
diff --git a/compiler/test/ModuleImporterTests.kt b/compiler/test/ModuleImporterTests.kt
index fb7714c19..e9e6098b3 100644
--- a/compiler/test/ModuleImporterTests.kt
+++ b/compiler/test/ModuleImporterTests.kt
@@ -17,6 +17,7 @@ import prog8tests.ast.helpers.*
 import prog8tests.helpers.ErrorReporterForTests
 import prog8tests.helpers.DummyFunctions
 import prog8tests.helpers.DummyMemsizer
+import prog8tests.helpers.DummyStringEncoder
 import kotlin.io.path.*
 import kotlin.test.assertContains
 import kotlin.test.assertFailsWith
@@ -31,7 +32,7 @@ class TestModuleImporter {
     private lateinit var program: Program
     @BeforeEach
     fun beforeEach() {
-        program = Program("foo", DummyFunctions, DummyMemsizer)
+        program = Program("foo", DummyFunctions, DummyMemsizer, DummyStringEncoder)
     }
 
     private fun makeImporter(errors: IErrorReporter?, vararg searchIn: String): ModuleImporter {
diff --git a/compiler/test/TestMemory.kt b/compiler/test/TestMemory.kt
index c75d8c4b9..ac21d098f 100644
--- a/compiler/test/TestMemory.kt
+++ b/compiler/test/TestMemory.kt
@@ -17,6 +17,7 @@ import prog8.compilerinterface.isInRegularRAMof
 import prog8.parser.SourceCode
 import prog8tests.helpers.DummyFunctions
 import prog8tests.helpers.DummyMemsizer
+import prog8tests.helpers.DummyStringEncoder
 import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
@@ -70,7 +71,7 @@ class TestMemory {
 
     @Test
     fun testInValidRamC64_memory_identifiers() {
-        val program = Program("test", DummyFunctions, DummyMemsizer)
+        val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
         var target = createTestProgramForMemoryRefViaVar(program, 0x1000, VarDeclType.VAR)
 
         assertTrue(target.isInRegularRAMof(C64Target.machine))
@@ -109,7 +110,7 @@ class TestMemory {
         val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
         val subroutine = Subroutine("test", mutableListOf(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, false, mutableListOf(decl, assignment), Position.DUMMY)
         val module = Module(mutableListOf(subroutine), Position.DUMMY, SourceCode.Generated("test"))
-        val program = Program("test", DummyFunctions, DummyMemsizer)
+        val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             .addModule(module)
         module.linkIntoProgram(program)
         assertTrue(target.isInRegularRAMof(C64Target.machine))
@@ -123,7 +124,7 @@ class TestMemory {
         val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
         val subroutine = Subroutine("test", mutableListOf(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, false, mutableListOf(decl, assignment), Position.DUMMY)
         val module = Module(mutableListOf(subroutine), Position.DUMMY, SourceCode.Generated("test"))
-        val program = Program("test", DummyFunctions, DummyMemsizer)
+        val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             .addModule(module)
         module.linkIntoProgram(program)
         assertTrue(target.isInRegularRAMof(C64Target.machine))
@@ -137,7 +138,7 @@ class TestMemory {
         val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
         val subroutine = Subroutine("test", mutableListOf(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, false, mutableListOf(decl, assignment), Position.DUMMY)
         val module = Module(mutableListOf(subroutine), Position.DUMMY, SourceCode.Generated("test"))
-        val program = Program("test", DummyFunctions, DummyMemsizer)
+        val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             .addModule(module)
         module.linkIntoProgram(program)
         assertFalse(target.isInRegularRAMof(C64Target.machine))
@@ -151,7 +152,7 @@ class TestMemory {
         val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
         val subroutine = Subroutine("test", mutableListOf(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, false, mutableListOf(decl, assignment), Position.DUMMY)
         val module = Module(mutableListOf(subroutine), Position.DUMMY, SourceCode.Generated("test"))
-        val program = Program("test", DummyFunctions, DummyMemsizer)
+        val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             .addModule(module)
         module.linkIntoProgram(program)
         assertTrue(target.isInRegularRAMof(C64Target.machine))
@@ -166,7 +167,7 @@ class TestMemory {
         val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
         val subroutine = Subroutine("test", mutableListOf(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, false, mutableListOf(decl, assignment), Position.DUMMY)
         val module = Module(mutableListOf(subroutine), Position.DUMMY, SourceCode.Generated("test"))
-        val program = Program("test", DummyFunctions, DummyMemsizer)
+        val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             .addModule(module)
         module.linkIntoProgram(program)
         assertTrue(target.isInRegularRAMof(C64Target.machine))
@@ -181,7 +182,7 @@ class TestMemory {
         val assignment = Assignment(target, NumericLiteralValue.optimalInteger(0, Position.DUMMY), Position.DUMMY)
         val subroutine = Subroutine("test", mutableListOf(), emptyList(), emptyList(), emptyList(), emptySet(), null, false, false, mutableListOf(decl, assignment), Position.DUMMY)
         val module = Module(mutableListOf(subroutine), Position.DUMMY, SourceCode.Generated("test"))
-        val program = Program("test", DummyFunctions, DummyMemsizer)
+        val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             .addModule(module)
         module.linkIntoProgram(program)
         assertFalse(target.isInRegularRAMof(C64Target.machine))
diff --git a/compiler/test/helpers/Dummies.kt b/compiler/test/helpers/Dummies.kt
index c0209f950..9a8128584 100644
--- a/compiler/test/helpers/Dummies.kt
+++ b/compiler/test/helpers/Dummies.kt
@@ -7,6 +7,7 @@ import prog8.ast.expressions.Expression
 import prog8.ast.expressions.InferredTypes
 import prog8.ast.expressions.NumericLiteralValue
 import prog8.compilerinterface.IMemSizer
+import prog8.compilerinterface.IStringEncoding
 
 internal val DummyFunctions = object : IBuiltinFunctions {
     override val names: Set<String> = emptySet()
@@ -23,3 +24,13 @@ internal val DummyFunctions = object : IBuiltinFunctions {
 internal val DummyMemsizer = object : IMemSizer {
     override fun memorySize(dt: DataType): Int = 0
 }
+
+internal val DummyStringEncoder = object : IStringEncoding {
+    override fun encodeString(str: String, altEncoding: Boolean): List<Short> {
+        return emptyList()
+    }
+
+    override fun decodeString(bytes: List<Short>, altEncoding: Boolean): String {
+        return ""
+    }
+}
diff --git a/compilerAst/src/prog8/ast/AstToplevel.kt b/compilerAst/src/prog8/ast/AstToplevel.kt
index 91d97cab7..9f34ad87b 100644
--- a/compilerAst/src/prog8/ast/AstToplevel.kt
+++ b/compilerAst/src/prog8/ast/AstToplevel.kt
@@ -8,6 +8,7 @@ import prog8.ast.statements.*
 import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstVisitor
 import prog8.compilerinterface.IMemSizer
+import prog8.compilerinterface.IStringEncoding
 import prog8.parser.SourceCode
 
 const val internedStringsModuleName = "prog8_interned_strings"
@@ -287,7 +288,8 @@ interface Node {
 
 class Program(val name: String,
               val builtinFunctions: IBuiltinFunctions,
-              val memsizer: IMemSizer
+              val memsizer: IMemSizer,
+              val encoding: IStringEncoding
 ): Node {
     private val _modules = mutableListOf<Module>()
 
diff --git a/compilerAst/src/prog8/ast/expressions/AstExpressions.kt b/compilerAst/src/prog8/ast/expressions/AstExpressions.kt
index 5a47e0665..827599fcf 100644
--- a/compilerAst/src/prog8/ast/expressions/AstExpressions.kt
+++ b/compilerAst/src/prog8/ast/expressions/AstExpressions.kt
@@ -514,7 +514,10 @@ class CharLiteral(val value: Char,
     }
 
     override fun referencesIdentifier(vararg scopedName: String) = false
-    override fun constValue(program: Program): NumericLiteralValue? = null  // TODO: CharLiteral.constValue can't be NumericLiteralValue... unless we re-add string encoder to program?
+    override fun constValue(program: Program): NumericLiteralValue {
+        val bytevalue = program.encoding.encodeString(value.toString(), altEncoding).single()
+        return NumericLiteralValue(DataType.UBYTE, bytevalue, position)
+    }
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
 
diff --git a/compilerInterfaces/src/prog8/compilerinterface/IStringEncoding.kt b/compilerAst/src/prog8/compilerinterface/IStringEncoding.kt
similarity index 100%
rename from compilerInterfaces/src/prog8/compilerinterface/IStringEncoding.kt
rename to compilerAst/src/prog8/compilerinterface/IStringEncoding.kt
diff --git a/compilerAst/test/TestAstToSourceText.kt b/compilerAst/test/TestAstToSourceText.kt
index 20ccc0f40..b322e0b1a 100644
--- a/compilerAst/test/TestAstToSourceText.kt
+++ b/compilerAst/test/TestAstToSourceText.kt
@@ -11,6 +11,7 @@ import prog8.parser.Prog8Parser.parseModule
 import prog8.parser.SourceCode
 import prog8tests.ast.helpers.DummyFunctions
 import prog8tests.ast.helpers.DummyMemsizer
+import prog8tests.ast.helpers.DummyStringEncoder
 import kotlin.test.assertContains
 
 
@@ -18,7 +19,7 @@ import kotlin.test.assertContains
 class TestAstToSourceText {
 
     private fun generateP8(module: Module) : String {
-        val program = Program("test", DummyFunctions, DummyMemsizer)
+        val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             .addModule(module)
 
         var generatedText = ""
diff --git a/compilerAst/test/TestProg8Parser.kt b/compilerAst/test/TestProg8Parser.kt
index 4c442f263..73f87a1d9 100644
--- a/compilerAst/test/TestProg8Parser.kt
+++ b/compilerAst/test/TestProg8Parser.kt
@@ -6,6 +6,7 @@ import org.junit.jupiter.api.TestInstance
 import prog8.ast.IFunctionCall
 import prog8.ast.Module
 import prog8.ast.Node
+import prog8.ast.Program
 import prog8.ast.base.DataType
 import prog8.ast.base.Position
 import prog8.ast.expressions.CharLiteral
@@ -16,9 +17,9 @@ import prog8.ast.statements.*
 import prog8.parser.ParseError
 import prog8.parser.Prog8Parser.parseModule
 import prog8.parser.SourceCode
-import prog8tests.ast.helpers.assumeNotExists
-import prog8tests.ast.helpers.assumeReadableFile
-import prog8tests.ast.helpers.fixturesDir
+import prog8tests.ast.helpers.*
+import prog8tests.ast.helpers.DummyFunctions
+import prog8tests.ast.helpers.DummyMemsizer
 import kotlin.io.path.Path
 import kotlin.io.path.isRegularFile
 import kotlin.io.path.name
@@ -582,6 +583,16 @@ class TestProg8Parser {
         }
     }
 
+    @Test
+    fun testCharLiteralConstValue() {
+        val char1 = CharLiteral('A', false, Position.DUMMY)
+        val char2 = CharLiteral('z', true, Position.DUMMY)
+
+        val program = Program("test", DummyFunctions, DummyMemsizer, AsciiStringEncoder)
+        assertEquals(65, char1.constValue(program).number.toInt())
+        assertEquals(122, char2.constValue(program).number.toInt())
+    }
+
     @Test
     fun testLiteralValueComparisons() {
         val ten = NumericLiteralValue(DataType.UWORD, 10, Position.DUMMY)
diff --git a/compilerAst/test/ast/ProgramTests.kt b/compilerAst/test/ast/ProgramTests.kt
index 6694ab6fa..27896f26e 100644
--- a/compilerAst/test/ast/ProgramTests.kt
+++ b/compilerAst/test/ast/ProgramTests.kt
@@ -1,6 +1,5 @@
 package prog8tests.ast.ast
 
-
 import org.hamcrest.MatcherAssert.assertThat
 import org.hamcrest.Matchers.containsString
 import org.hamcrest.Matchers.equalTo
@@ -14,6 +13,7 @@ import prog8.ast.internedStringsModuleName
 import prog8.parser.SourceCode
 import prog8tests.ast.helpers.DummyFunctions
 import prog8tests.ast.helpers.DummyMemsizer
+import prog8tests.ast.helpers.DummyStringEncoder
 import kotlin.test.assertContains
 import kotlin.test.assertFailsWith
 import kotlin.test.assertSame
@@ -26,7 +26,7 @@ class ProgramTests {
     inner class Constructor {
         @Test
         fun withNameBuiltinsAndMemsizer() {
-            val program = Program("foo", DummyFunctions, DummyMemsizer)
+            val program = Program("foo", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             assertThat(program.modules.size, equalTo(1))
             assertThat(program.modules[0].name, equalTo(internedStringsModuleName))
             assertSame(program, program.modules[0].program)
@@ -39,7 +39,7 @@ class ProgramTests {
     inner class AddModule {
         @Test
         fun withEmptyModule() {
-            val program = Program("foo", DummyFunctions, DummyMemsizer)
+            val program = Program("foo", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             val m1 = Module(mutableListOf(), Position.DUMMY, SourceCode.Generated("bar"))
 
             val retVal = program.addModule(m1)
@@ -63,7 +63,7 @@ class ProgramTests {
     inner class MoveModuleToFront {
         @Test
         fun withInternedStringsModule() {
-            val program = Program("foo", DummyFunctions, DummyMemsizer)
+            val program = Program("foo", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             val m = program.modules[0]
             assertThat(m.name, equalTo(internedStringsModuleName))
 
@@ -73,14 +73,14 @@ class ProgramTests {
         }
         @Test
         fun withForeignModule() {
-            val program = Program("foo", DummyFunctions, DummyMemsizer)
+            val program = Program("foo", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             val m = Module(mutableListOf(), Position.DUMMY, SourceCode.Generated("bar"))
 
             assertFailsWith<IllegalArgumentException> { program.moveModuleToFront(m) }
         }
         @Test
         fun withFirstOfPreviouslyAddedModules() {
-            val program = Program("foo", DummyFunctions, DummyMemsizer)
+            val program = Program("foo", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             val m1 = Module(mutableListOf(), Position.DUMMY, SourceCode.Generated("bar"))
             val m2 = Module(mutableListOf(), Position.DUMMY, SourceCode.Generated("qmbl"))
             program.addModule(m1)
@@ -92,7 +92,7 @@ class ProgramTests {
         }
         @Test
         fun withSecondOfPreviouslyAddedModules() {
-            val program = Program("foo", DummyFunctions, DummyMemsizer)
+            val program = Program("foo", DummyFunctions, DummyMemsizer, DummyStringEncoder)
             val m1 = Module(mutableListOf(), Position.DUMMY, SourceCode.Generated("bar"))
             val m2 = Module(mutableListOf(), Position.DUMMY, SourceCode.Generated("qmbl"))
             program.addModule(m1)
@@ -108,7 +108,7 @@ class ProgramTests {
     inner class Properties {
         @Test
         fun modules() {
-            val program = Program("foo", DummyFunctions, DummyMemsizer)
+            val program = Program("foo", DummyFunctions, DummyMemsizer, DummyStringEncoder)
 
             val ms1 = program.modules
             val ms2 = program.modules
diff --git a/compilerAst/test/helpers/Dummies.kt b/compilerAst/test/helpers/Dummies.kt
index b0e2148f5..fa59a2d51 100644
--- a/compilerAst/test/helpers/Dummies.kt
+++ b/compilerAst/test/helpers/Dummies.kt
@@ -7,6 +7,7 @@ import prog8.ast.expressions.Expression
 import prog8.ast.expressions.InferredTypes
 import prog8.ast.expressions.NumericLiteralValue
 import prog8.compilerinterface.IMemSizer
+import prog8.compilerinterface.IStringEncoding
 
 internal val DummyFunctions = object : IBuiltinFunctions {
     override val names: Set<String> = emptySet()
@@ -23,3 +24,21 @@ internal val DummyFunctions = object : IBuiltinFunctions {
 internal val DummyMemsizer = object : IMemSizer {
     override fun memorySize(dt: DataType): Int = 0
 }
+
+internal val DummyStringEncoder = object : IStringEncoding {
+    override fun encodeString(str: String, altEncoding: Boolean): List<Short> {
+        return emptyList()
+    }
+
+    override fun decodeString(bytes: List<Short>, altEncoding: Boolean): String {
+        return ""
+    }
+}
+
+internal val AsciiStringEncoder = object : IStringEncoding {
+    override fun encodeString(str: String, altEncoding: Boolean): List<Short> = str.map { it.code.toShort() }
+
+    override fun decodeString(bytes: List<Short>, altEncoding: Boolean): String {
+        return bytes.joinToString()
+    }
+}
diff --git a/compilerInterfaces/compilerInterfaces.iml b/compilerInterfaces/compilerInterfaces.iml
index 2c25b13e2..31645176c 100644
--- a/compilerInterfaces/compilerInterfaces.iml
+++ b/compilerInterfaces/compilerInterfaces.iml
@@ -5,6 +5,7 @@
     <content url="file://$MODULE_DIR$">
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
       <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
     </content>
     <orderEntry type="jdk" jdkName="openjdk-11" jdkType="JavaSDK" />
     <orderEntry type="sourceFolder" forTests="false" />