.gitignore

@@ -8,6 +8,7 @@ cabal-dev
 *.chs.h
 *.dyn_o
 *.dyn_hi
+*.java
 *.class
 *.local~*
 src/Parser/JavaParser.hs

Test/JavaSources/Main.java

@@ -1,38 +0,0 @@
-// compile all test files using:
-// ls Test/JavaSources/*.java | grep -v ".*Main.java" | xargs -I {} cabal run compiler {}
-// compile (in project root) using:
-// javac -g:none -sourcepath Test/JavaSources/ Test/JavaSources/Main.java 
-// afterwards, run using
-// java -ea -cp Test/JavaSources/ Main
-
-public class Main {
-    public static void main(String[] args)
-    {
-        TestEmpty empty = new TestEmpty();
-        TestFields fields = new TestFields();
-        TestConstructor constructor = new TestConstructor(42);
-        TestMultipleClasses multipleClasses = new TestMultipleClasses();
-        TestRecursion recursion = new TestRecursion(10);
-        TestMalicious malicious = new TestMalicious();
-
-        // constructing a basic class works
-        assert empty != null;
-        // initializers (and default initializers to 0/null) work
-        assert fields.a == 0 && fields.b == 42;
-        // constructor parameters override initializers
-        assert constructor.a == 42;
-        // multiple classes within one file work. Referencing another classes fields/methods works.
-        assert multipleClasses.a.a == 42;
-        // self-referencing classes work.
-        assert recursion.child.child.child.child.child.value == 5;
-        // self-referencing methods work.
-        assert recursion.fibonacci(15) == 610;
-        // intentionally dodgy expressions work
-        assert malicious.assignNegativeIncrement(42) == -42;
-        assert malicious.tripleAddition(1, 2, 3) == 6;
-        for(int i = 0; i < 3; i++)
-        {
-            assert malicious.cursedFormatting(i) == i;
-        }
-    }
-}

Test/JavaSources/TestConstructor.java

@@ -1,9 +0,0 @@
-public class TestConstructor
-{
-    public int a = -1;
-
-    public TestConstructor(int initial_value)
-    {
-        a = initial_value;
-    }
-}

Test/JavaSources/TestEmpty.java

@@ -1,4 +0,0 @@
-public class TestEmpty
-{
-    
-}

Test/JavaSources/TestFields.java

@@ -1,5 +0,0 @@
-public class TestFields
-{
-    public int a;
-    public int b = 42;
-}

Test/JavaSources/TestMalicious.java

@@ -1,41 +0,0 @@
-public class TestMalicious {
-    public int assignNegativeIncrement(int n)
-    {
-        return n=-++n+1;
-    }
-
-    public int tripleAddition(int a, int b, int c)
-    {
-        return a+++b+++c++;
-    }
-
-    public int cursedFormatting(int n)
-    {
-        if
-        
-        
-        (n == 0)
-        
-        {
-            
-            return                      ((((0))));
-        }
-
-        else 
-
-        
-        if(n == 
-        
-        1)
-                    {
-            return 
-            
-            
-            1;
-                    }else                 {
-            return 
-            2
-            ;
-                    }
-    }
-}

Test/JavaSources/TestMultipleClasses.java

@@ -1,9 +0,0 @@
-public class TestMultipleClasses
-{
-    public AnotherTestClass a = new AnotherTestClass();
-}
-
-class AnotherTestClass
-{
-    public int a = 42;
-}

Test/JavaSources/TestRecursion.java

@@ -1,27 +0,0 @@
-public class TestRecursion {
-
-    public int value = 0;
-    public TestRecursion child = null;
-
-    public TestRecursion(int n)
-    {
-        value = n;
-
-        if(n > 0)
-        {
-            child = new TestRecursion(n - 1);
-        }
-    }
-
-    public int fibonacci(int n)
-    {
-        if(n < 2)
-        {
-            return n;
-        }
-        else
-        {
-            return fibonacci(n - 1) + this.fibonacci(n - 2);
-        }
-    }    
-}

Test/TestByteCodeGenerator.hs

@@ -0,0 +1,118 @@
+module TestByteCodeGenerator where
+
+import Test.HUnit
+import ByteCode.ClassFile.Generator
+import ByteCode.ClassFile
+import ByteCode.Constants
+import Ast
+
+nakedClass = Class "Testklasse" [] []
+expectedClass = ClassFile {
+        constantPool = [
+            ClassInfo 4,
+            MethodRefInfo 1 3,
+            NameAndTypeInfo 5 6,
+            Utf8Info "java/lang/Object",
+            Utf8Info "<init>",
+            Utf8Info "()V",
+            Utf8Info "Code",
+            ClassInfo 9,
+            Utf8Info "Testklasse"
+        ],
+        accessFlags = accessPublic,
+        thisClass = 8,
+        superClass = 1,
+        fields = [],
+        methods = [],
+        attributes = []
+    }
+
+classWithFields = Class "Testklasse" [] [VariableDeclaration "int" "testvariable" Nothing]
+expectedClassWithFields = ClassFile {
+        constantPool = [
+            ClassInfo 4,
+            MethodRefInfo 1 3,
+            NameAndTypeInfo 5 6,
+            Utf8Info "java/lang/Object",
+            Utf8Info "<init>",
+            Utf8Info "()V",
+            Utf8Info "Code",
+            ClassInfo 9,
+            Utf8Info "Testklasse",
+            FieldRefInfo 8 11,
+            NameAndTypeInfo 12 13,
+            Utf8Info "testvariable",
+            Utf8Info "I"
+        ],
+        accessFlags = accessPublic,
+        thisClass = 8,
+        superClass = 1,
+        fields = [
+            MemberInfo {
+                memberAccessFlags = accessPublic,
+                memberNameIndex = 12,
+                memberDescriptorIndex = 13,
+                memberAttributes = []
+            }
+        ],
+        methods = [],
+        attributes = []
+    }
+
+method = MethodDeclaration "int" "add_two_numbers" [
+    ParameterDeclaration "int" "a",
+    ParameterDeclaration "int" "b" ]
+    (Block [Return (Just (BinaryOperation Addition (Reference "a") (Reference "b")))])
+
+
+classWithMethod = Class "Testklasse" [method] []
+expectedClassWithMethod = ClassFile {
+        constantPool = [
+            ClassInfo 4,
+            MethodRefInfo 1 3,
+            NameAndTypeInfo 5 6,
+            Utf8Info "java/lang/Object",
+            Utf8Info "<init>",
+            Utf8Info "()V",
+            Utf8Info "Code",
+            ClassInfo 9,
+            Utf8Info "Testklasse",
+            FieldRefInfo 8 11,
+            NameAndTypeInfo 12 13,
+            Utf8Info "add_two_numbers",
+            Utf8Info "(II)I"
+        ],
+        accessFlags = accessPublic,
+        thisClass = 8,
+        superClass = 1,
+        fields = [],
+        methods = [
+            MemberInfo {
+                memberAccessFlags = accessPublic,
+                memberNameIndex = 12,
+                memberDescriptorIndex = 13,
+                memberAttributes = [
+                    CodeAttribute {
+                        attributeMaxStack = 420,
+                        attributeMaxLocals = 420,
+                        attributeCode = [Opiadd]
+                    }
+                ]
+            }
+        ],
+        attributes = []
+    }
+
+testBasicConstantPool = TestCase $ assertEqual "basic constant pool" expectedClass $ classBuilder nakedClass emptyClassFile
+testFields = TestCase $ assertEqual "fields in constant pool" expectedClassWithFields $ classBuilder classWithFields emptyClassFile
+testMethodDescriptor = TestCase $ assertEqual "method descriptor" "(II)I" (methodDescriptor method)
+testMethodAssembly = TestCase $ assertEqual "method assembly" expectedClassWithMethod (classBuilder classWithMethod emptyClassFile)
+testFindMethodIndex = TestCase $ assertEqual "find method" (Just 0) (findMethodIndex expectedClassWithMethod "add_two_numbers")
+
+tests = TestList [
+    TestLabel "Basic constant pool" testBasicConstantPool,
+    TestLabel "Fields constant pool" testFields,
+    TestLabel "Method descriptor building" testMethodDescriptor,
+    TestLabel "Method assembly" testMethodAssembly,
+    TestLabel "Find method by name" testFindMethodIndex
+    ]

Test/TestSuite.hs

@@ -2,11 +2,13 @@ module Main where
 
 import Test.HUnit
 import TestLexer
+import TestByteCodeGenerator
 import TestParser
 
+
 tests = TestList [
-        TestLabel "TestLexer" TestLexer.tests,
-        TestLabel "TestParser" TestParser.tests
-    ]
+    TestLabel "TestLexer" TestLexer.tests,
+    TestLabel "TestParser" TestParser.tests,
+    TestLabel "TestByteCodeGenerator" TestByteCodeGenerator.tests]
 
 main = do runTestTTAndExit Main.tests

project.cabal

@@ -10,8 +10,7 @@ executable compiler
                         array,
                         HUnit,
                         utf8-string,
-                        bytestring,
-                        filepath
+                        bytestring
     default-language:   Haskell2010
     hs-source-dirs:     src
     build-tool-depends: alex:alex, happy:happy
@@ -20,11 +19,14 @@ executable compiler
                         Ast,
                         Example,
                         Typecheck,
-                        ByteCode.Util,
                         ByteCode.ByteUtil,
                         ByteCode.ClassFile,
-                        ByteCode.Assembler,
-                        ByteCode.Builder,
+                        ByteCode.Generation.Generator,
+                        ByteCode.Generation.Assembler.ExpressionAndStatement,
+                        ByteCode.Generation.Assembler.Method,
+                        ByteCode.Generation.Builder.Class,
+                        ByteCode.Generation.Builder.Field,
+                        ByteCode.Generation.Builder.Method,
                         ByteCode.Constants
 
 test-suite tests
@@ -35,17 +37,15 @@ test-suite tests
                         array,
                         HUnit,
                         utf8-string,
-                        bytestring,
-                        filepath
+                        bytestring
     build-tool-depends: alex:alex, happy:happy
     other-modules:      Parser.Lexer,
                         Parser.JavaParser,
                         Ast,
                         TestLexer,
                         TestParser,
-                        ByteCode.Util,
+                        TestByteCodeGenerator,
                         ByteCode.ByteUtil,
                         ByteCode.ClassFile,
-                        ByteCode.Assembler,
-                        ByteCode.Builder,
+                        ByteCode.ClassFile.Generator,
                         ByteCode.Constants

src/ByteCode/Assembler.hs

@@ -1,276 +0,0 @@
-module ByteCode.Assembler where
-
-import ByteCode.Constants
-import ByteCode.ClassFile (ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
-import ByteCode.Util
-import Ast
-import Data.Char
-import Data.List
-import Data.Word
-
-type Assembler a = ([ConstantInfo], [Operation], [String]) -> a -> ([ConstantInfo], [Operation], [String])
-
-assembleExpression :: Assembler Expression
-assembleExpression (constants, ops, lvars) (TypedExpression _ (BinaryOperation op a b))
-    | elem op [Addition, Subtraction, Multiplication, Division, Modulo, BitwiseAnd, BitwiseOr, BitwiseXor, And, Or] = let
-            (aConstants, aOps, _) = assembleExpression (constants, ops, lvars) a
-            (bConstants, bOps, _) = assembleExpression (aConstants, aOps, lvars) b
-        in
-            (bConstants, bOps ++ [binaryOperation op], lvars)
-    | elem op [CompareEqual, CompareNotEqual, CompareLessThan, CompareLessOrEqual, CompareGreaterThan, CompareGreaterOrEqual] = let
-            (aConstants, aOps, _) = assembleExpression (constants, ops, lvars) a
-            (bConstants, bOps, _) = assembleExpression (aConstants, aOps, lvars) b
-            cmp_op = comparisonOperation op 9
-            cmp_ops = [cmp_op, Opsipush 0, Opgoto 6, Opsipush 1]
-        in
-            (bConstants, bOps ++ cmp_ops, lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ (BinaryOperation NameResolution (TypedExpression atype a) (TypedExpression btype (FieldVariable b)))) = let
-        (fConstants, fieldIndex) = getFieldIndex constants (atype, b, datatypeDescriptor btype)
-        (aConstants, aOps, _) = assembleExpression (fConstants, ops, lvars) (TypedExpression atype a)
-    in
-        (aConstants, aOps ++ [Opgetfield (fromIntegral fieldIndex)], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ (CharacterLiteral literal)) =
-    (constants, ops ++ [Opsipush (fromIntegral (ord literal))], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ (BooleanLiteral literal)) =
-    (constants, ops ++ [Opsipush (if literal then 1 else 0)], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ (IntegerLiteral literal))
-    | literal <= 32767 && literal >= -32768 = (constants, ops ++ [Opsipush (fromIntegral literal)], lvars)
-    | otherwise = (constants ++ [IntegerInfo (fromIntegral literal)], ops ++ [Opldc_w (fromIntegral (1 + length constants))], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ NullLiteral) =
-    (constants, ops ++ [Opaconst_null], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression etype (UnaryOperation Not expr)) = let
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-        newConstant = fromIntegral (1 + length exprConstants)
-    in case etype of
-        "int" -> (exprConstants ++ [IntegerInfo 0x7FFFFFFF], exprOps ++ [Opldc_w newConstant, Opixor], lvars)
-        "char" -> (exprConstants, exprOps ++ [Opsipush 0xFFFF, Opixor], lvars)
-        "boolean" -> (exprConstants, exprOps ++ [Opsipush 0x01, Opixor], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression _ (UnaryOperation Minus expr)) = let
-        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-    in
-        (exprConstants, exprOps ++ [Opineg], lvars)
-
-assembleExpression (constants, ops, lvars) (TypedExpression dtype (LocalVariable name))
-    | name == "this" = (constants, ops ++ [Opaload 0], lvars)
-    | otherwise = let
-            localIndex = findIndex ((==) name) lvars
-            isPrimitive = elem dtype ["char", "boolean", "int"]
-        in case localIndex of
-            Just index -> (constants, ops ++ if isPrimitive then [Opiload (fromIntegral index)] else [Opaload (fromIntegral index)], lvars)
-            Nothing -> error ("No such local variable found in local variable pool: " ++ name)
-
-assembleExpression (constants, ops, lvars) (TypedExpression dtype (StatementExpressionExpression stmtexp)) =
-        assembleStatementExpression (constants, ops, lvars) stmtexp
-
-assembleExpression _ expr = error ("unimplemented: " ++ show expr)
-
-assembleNameChain :: Assembler Expression
-assembleNameChain input (TypedExpression _ (BinaryOperation NameResolution (TypedExpression atype a) (TypedExpression _ (FieldVariable _)))) =
-        assembleExpression input (TypedExpression atype a)
-assembleNameChain input expr = assembleExpression input expr
-
-
-assembleStatementExpression :: Assembler StatementExpression
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (Assignment (TypedExpression dtype receiver) expr)) = let
-        target = resolveNameChain (TypedExpression dtype receiver)
-    in case target of
-        (TypedExpression dtype (LocalVariable name)) -> let
-                localIndex = findIndex ((==) name) lvars
-                (constants_a, ops_a, _) = assembleExpression (constants, ops, lvars) expr
-                isPrimitive = elem dtype ["char", "boolean", "int"]
-            in case localIndex of
-                Just index -> (constants_a, ops_a ++ if isPrimitive then [Opdup, Opistore (fromIntegral index)] else [Opastore (fromIntegral index)], lvars)
-                Nothing -> error ("No such local variable found in local variable pool: " ++ name)
-        (TypedExpression dtype (FieldVariable name)) -> let
-                owner = resolveNameChainOwner (TypedExpression dtype receiver)
-            in case owner of
-                (TypedExpression otype _) -> let
-                        (constants_f, fieldIndex) = getFieldIndex constants (otype, name, datatypeDescriptor dtype)
-                        (constants_r, ops_r, _) = assembleNameChain (constants_f, ops, lvars) (TypedExpression dtype receiver)
-                        (constants_a, ops_a, _) = assembleExpression (constants_r, ops_r, lvars) expr
-                    in
-                        (constants_a, ops_a ++ [Opdup_x1, Opputfield (fromIntegral fieldIndex)], lvars)
-                something_else -> error ("expected TypedExpression, but got: " ++ show something_else)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PreIncrement (TypedExpression dtype receiver))) = let
-        target = resolveNameChain (TypedExpression dtype receiver)
-    in case target of
-        (TypedExpression dtype (LocalVariable name)) -> let 
-                localIndex = findIndex ((==) name) lvars
-                expr = (TypedExpression dtype (LocalVariable name))
-                (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-            in case localIndex of
-                Just index -> (exprConstants, exprOps ++ [Opsipush 1, Opiadd, Opdup, Opistore (fromIntegral index)], lvars)
-                Nothing -> error("No such local variable found in local variable pool: " ++ name)
-        (TypedExpression dtype (FieldVariable name)) -> let
-                owner = resolveNameChainOwner (TypedExpression dtype receiver)
-            in case owner of
-                (TypedExpression otype _) -> let
-                        (constants_f, fieldIndex) = getFieldIndex constants (otype, name, datatypeDescriptor dtype)
-                        (constants_r, ops_r, _) = assembleNameChain (constants_f, ops, lvars) (TypedExpression dtype receiver)
-                    in
-                        (constants_r, ops_r ++ [Opdup, Opgetfield (fromIntegral fieldIndex), Opsipush 1, Opiadd, Opdup_x1, Opputfield (fromIntegral fieldIndex)], lvars)
-                something_else -> error ("expected TypedExpression, but got: " ++ show something_else)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PreDecrement (TypedExpression dtype receiver))) = let
-        target = resolveNameChain (TypedExpression dtype receiver)
-    in case target of
-        (TypedExpression dtype (LocalVariable name)) -> let 
-                localIndex = findIndex ((==) name) lvars
-                expr = (TypedExpression dtype (LocalVariable name))
-                (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-            in case localIndex of
-                Just index -> (exprConstants, exprOps ++ [Opsipush 1, Opisub, Opdup, Opistore (fromIntegral index)], lvars)
-                Nothing -> error("No such local variable found in local variable pool: " ++ name)
-        (TypedExpression dtype (FieldVariable name)) -> let
-                owner = resolveNameChainOwner (TypedExpression dtype receiver)
-            in case owner of
-                (TypedExpression otype _) -> let
-                        (constants_f, fieldIndex) = getFieldIndex constants (otype, name, datatypeDescriptor dtype)
-                        (constants_r, ops_r, _) = assembleNameChain (constants_f, ops, lvars) (TypedExpression dtype receiver)
-                    in
-                        (constants_r, ops_r ++ [Opdup, Opgetfield (fromIntegral fieldIndex), Opsipush 1, Opisub, Opdup_x1, Opputfield (fromIntegral fieldIndex)], lvars)
-                something_else -> error ("expected TypedExpression, but got: " ++ show something_else)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PostIncrement (TypedExpression dtype receiver))) = let
-        target = resolveNameChain (TypedExpression dtype receiver)
-    in case target of
-        (TypedExpression dtype (LocalVariable name)) -> let 
-                localIndex = findIndex ((==) name) lvars
-                expr = (TypedExpression dtype (LocalVariable name))
-                (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-            in case localIndex of
-                Just index -> (exprConstants, exprOps ++ [Opdup, Opsipush 1, Opiadd, Opistore (fromIntegral index)], lvars)
-                Nothing -> error("No such local variable found in local variable pool: " ++ name)
-        (TypedExpression dtype (FieldVariable name)) -> let
-                owner = resolveNameChainOwner (TypedExpression dtype receiver)
-            in case owner of
-                (TypedExpression otype _) -> let
-                        (constants_f, fieldIndex) = getFieldIndex constants (otype, name, datatypeDescriptor dtype)
-                        (constants_r, ops_r, _) = assembleNameChain (constants_f, ops, lvars) (TypedExpression dtype receiver)
-                    in
-                        (constants_r, ops_r ++ [Opdup, Opgetfield (fromIntegral fieldIndex), Opdup_x1, Opsipush 1, Opiadd, Opputfield (fromIntegral fieldIndex)], lvars)
-                something_else -> error ("expected TypedExpression, but got: " ++ show something_else)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression _ (PostDecrement (TypedExpression dtype receiver))) = let
-        target = resolveNameChain (TypedExpression dtype receiver)
-    in case target of
-        (TypedExpression dtype (LocalVariable name)) -> let 
-                localIndex = findIndex ((==) name) lvars
-                expr = (TypedExpression dtype (LocalVariable name))
-                (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
-            in case localIndex of
-                Just index -> (exprConstants, exprOps ++ [Opdup, Opsipush 1, Opisub, Opistore (fromIntegral index)], lvars)
-                Nothing -> error("No such local variable found in local variable pool: " ++ name)
-        (TypedExpression dtype (FieldVariable name)) -> let
-                owner = resolveNameChainOwner (TypedExpression dtype receiver)
-            in case owner of
-                (TypedExpression otype _) -> let
-                        (constants_f, fieldIndex) = getFieldIndex constants (otype, name, datatypeDescriptor dtype)
-                        (constants_r, ops_r, _) = assembleNameChain (constants_f, ops, lvars) (TypedExpression dtype receiver)
-                    in
-                        (constants_r, ops_r ++ [Opdup, Opgetfield (fromIntegral fieldIndex), Opdup_x1, Opsipush 1, Opisub, Opputfield (fromIntegral fieldIndex)], lvars)
-                something_else -> error ("expected TypedExpression, but got: " ++ show something_else)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression rtype (MethodCall (TypedExpression otype receiver) name params)) = let
-        (constants_r, ops_r, lvars_r) = assembleExpression (constants, ops, lvars) (TypedExpression otype receiver)
-        (constants_p, ops_p, lvars_p) = foldl assembleExpression (constants_r, ops_r, lvars_r) params
-        (constants_m, methodIndex) = getMethodIndex constants_p (otype, name, methodDescriptorFromParamlist params rtype)
-    in
-        (constants_m, ops_p ++ [Opinvokevirtual (fromIntegral methodIndex)], lvars_p)
-
-assembleStatementExpression
-    (constants, ops, lvars)
-    (TypedStatementExpression rtype (ConstructorCall name params)) = let
-        (constants_c, classIndex) = getClassIndex constants name
-        (constants_p, ops_p, lvars_p) = foldl assembleExpression (constants_c, ops ++ [Opnew (fromIntegral classIndex), Opdup], lvars) params
-        (constants_m, methodIndex) = getMethodIndex constants_p (name, "<init>", methodDescriptorFromParamlist params "void")
-    in
-        (constants_m, ops_p ++ [Opinvokespecial (fromIntegral methodIndex)], lvars_p)
-
-
-assembleStatement :: Assembler Statement
-assembleStatement (constants, ops, lvars) (TypedStatement stype (Return expr)) = case expr of
-    Nothing -> (constants, ops ++ [Opreturn], lvars)
-    Just expr -> let
-            (expr_constants, expr_ops, _) = assembleExpression (constants, ops, lvars) expr
-        in
-            (expr_constants, expr_ops ++ [returnOperation stype], lvars)
-
-assembleStatement (constants, ops, lvars) (TypedStatement _ (Block statements)) =
-    foldl assembleStatement (constants, ops, lvars) statements
-
-assembleStatement (constants, ops, lvars) (TypedStatement dtype (If expr if_stmt else_stmt)) = let
-        (constants_cmp, ops_cmp, _) = assembleExpression (constants, [], lvars) expr
-        (constants_ifa, ops_ifa, _) = assembleStatement (constants_cmp, [], lvars) if_stmt
-        (constants_elsea, ops_elsea, _) = case else_stmt of
-            Nothing -> (constants_ifa, [], lvars)
-            Just stmt -> assembleStatement (constants_ifa, [], lvars) stmt
-        -- +6 because we insert 2 gotos, one for if, one for else
-        if_length = sum (map opcodeEncodingLength ops_ifa)
-        -- +3 because we need to account for the goto in the if statement.
-        else_length = sum (map opcodeEncodingLength ops_elsea)
-    in case dtype of
-        "void" -> (constants_ifa, ops ++ ops_cmp ++ [Opsipush 0, Opif_icmpeq (if_length + 6)] ++ ops_ifa ++ [Opgoto (else_length + 3)] ++ ops_elsea, lvars)
-        otherwise -> (constants_ifa, ops ++ ops_cmp ++ [Opsipush 0, Opif_icmpeq (if_length + 3)] ++ ops_ifa ++ ops_elsea, lvars)
-
-assembleStatement (constants, ops, lvars) (TypedStatement _ (While expr stmt)) = let
-        (constants_cmp, ops_cmp, _) = assembleExpression (constants, [], lvars) expr
-        (constants_stmta, ops_stmta, _) = assembleStatement (constants_cmp, [], lvars) stmt
-        -- +3 because we insert 2 gotos, one for the comparison, one for the goto back to the comparison
-        stmt_length = sum (map opcodeEncodingLength ops_stmta) + 6
-        entire_length = stmt_length + sum (map opcodeEncodingLength ops_cmp)
-    in
-        (constants_stmta, ops ++ ops_cmp ++ [Opsipush 0, Opif_icmpeq stmt_length] ++ ops_stmta ++ [Opgoto (-entire_length)], lvars)
-
-assembleStatement (constants, ops, lvars) (TypedStatement _ (LocalVariableDeclaration (VariableDeclaration dtype name expr))) = let
-        isPrimitive = elem dtype ["char", "boolean", "int"]
-        (constants_init, ops_init, _) = case expr of
-            Just exp -> assembleExpression (constants, ops, lvars) exp
-            Nothing -> (constants, ops ++ if isPrimitive then [Opsipush 0] else [Opaconst_null], lvars)
-        localIndex = fromIntegral (length lvars)
-        storeLocal = if isPrimitive then [Opistore localIndex] else [Opastore localIndex]
-    in
-        (constants_init, ops_init ++ storeLocal, lvars ++ [name])
-
-assembleStatement (constants, ops, lvars) (TypedStatement _ (StatementExpressionStatement expr)) = let
-        (constants_e, ops_e, lvars_e) = assembleStatementExpression (constants, ops, lvars) expr
-    in
-        (constants_e, ops_e ++ [Oppop], lvars_e)
-
-assembleStatement _ stmt = error ("Not yet implemented: " ++ show stmt)
-
-
-assembleMethod :: Assembler MethodDeclaration
-assembleMethod (constants, ops, lvars) (MethodDeclaration returntype name _ (TypedStatement _ (Block statements)))
-    | name == "<init>"  = let
-            (constants_a, ops_a, lvars_a) = foldl assembleStatement (constants, ops, lvars) statements
-            init_ops = [Opaload 0, Opinvokespecial 2]
-        in
-            (constants_a, init_ops ++ ops_a ++ [Opreturn], lvars_a)
-    | otherwise = case returntype of
-        "void" -> let
-                (constants_a, ops_a, lvars_a) = foldl assembleStatement (constants, ops, lvars) statements
-            in
-                (constants_a, ops_a ++ [Opreturn], lvars_a)
-        otherwise -> foldl assembleStatement (constants, ops, lvars) statements
-assembleMethod _ (MethodDeclaration _ _ _ stmt) = error ("Typed block expected for method body, got: " ++ show stmt) 

src/ByteCode/Builder.hs

@@ -1,117 +0,0 @@
-module ByteCode.Builder where
-
-import ByteCode.Constants
-import ByteCode.ClassFile (ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
-import ByteCode.Assembler
-import ByteCode.Util
-import Ast
-import Data.Char
-import Data.List
-import Data.Word
-
-type ClassFileBuilder a = a -> ClassFile -> ClassFile
-
-fieldBuilder :: ClassFileBuilder VariableDeclaration
-fieldBuilder (VariableDeclaration datatype name _) input = let
-        baseIndex = 1 + length (constantPool input)
-        constants = [
-                FieldRefInfo (fromIntegral (thisClass input)) (fromIntegral (baseIndex + 1)),
-                NameAndTypeInfo (fromIntegral (baseIndex + 2)) (fromIntegral (baseIndex + 3)),
-                Utf8Info name,
-                Utf8Info (datatypeDescriptor datatype)
-            ]
-        field = MemberInfo {
-            memberAccessFlags = accessPublic,
-            memberNameIndex = (fromIntegral (baseIndex + 2)),
-            memberDescriptorIndex = (fromIntegral (baseIndex + 3)),
-            memberAttributes = []
-            }
-    in
-        input {
-            constantPool = (constantPool input) ++ constants,
-            fields = (fields input) ++ [field]
-        }
-
-
-
-methodBuilder :: ClassFileBuilder MethodDeclaration
-methodBuilder (MethodDeclaration returntype name parameters statement) input = let
-        baseIndex = 1 + length (constantPool input)
-        constants = [
-                MethodRefInfo (fromIntegral (thisClass input)) (fromIntegral (baseIndex + 1)),
-                NameAndTypeInfo (fromIntegral (baseIndex + 2)) (fromIntegral (baseIndex + 3)),
-                Utf8Info name,
-                Utf8Info (methodDescriptor (MethodDeclaration returntype name parameters (Block [])))
-            ]
-
-        method = MemberInfo {
-            memberAccessFlags = accessPublic,
-            memberNameIndex = (fromIntegral (baseIndex + 2)),
-            memberDescriptorIndex = (fromIntegral (baseIndex + 3)),
-            memberAttributes = []
-            }
-    in 
-        input {
-            constantPool = (constantPool input) ++ constants,
-            methods = (methods input) ++ [method]
-        }
-        
-
-
-methodAssembler :: ClassFileBuilder MethodDeclaration
-methodAssembler (MethodDeclaration returntype name parameters statement) input = let
-        methodConstantIndex = findMethodIndex input name
-    in case methodConstantIndex of
-        Nothing -> error ("Cannot find method entry in method pool for method: " ++ name)
-        Just index -> let
-                declaration = MethodDeclaration returntype name parameters statement
-                paramNames = "this" : [name | ParameterDeclaration _ name <- parameters]
-            in case (splitAt index (methods input)) of
-                (pre, []) -> input
-                (pre, method : post) -> let
-                        (_, bytecode, _) = assembleMethod (constantPool input, [], paramNames) declaration
-                        assembledMethod = method {
-                            memberAttributes = [
-                                CodeAttribute {
-                                    attributeMaxStack = 420,
-                                    attributeMaxLocals = 420,
-                                    attributeCode = bytecode
-                                }
-                            ]
-                        }
-                    in
-                        input {
-                            methods = pre ++ (assembledMethod : post)
-                        }
-
-
-classBuilder :: ClassFileBuilder Class
-classBuilder (Class name methods fields) _ = let
-        baseConstants = [
-            ClassInfo 4,
-            MethodRefInfo 1 3,
-            NameAndTypeInfo 5 6,
-            Utf8Info "java/lang/Object",
-            Utf8Info "<init>",
-            Utf8Info "()V",
-            Utf8Info "Code"
-            ]
-        nameConstants = [ClassInfo 9, Utf8Info name]
-        nakedClassFile = ClassFile {
-            constantPool = baseConstants ++ nameConstants,
-            accessFlags = accessPublic,
-            thisClass = 8,
-            superClass = 1,
-            fields = [],
-            methods = [],
-            attributes = []
-        }
-
-        methodsWithInjectedConstructor = injectDefaultConstructor methods
-        methodsWithInjectedInitializers = injectFieldInitializers name fields methodsWithInjectedConstructor
-
-        classFileWithFields = foldr fieldBuilder nakedClassFile fields
-        classFileWithMethods = foldr methodBuilder classFileWithFields methodsWithInjectedInitializers
-        classFileWithAssembledMethods = foldr methodAssembler classFileWithMethods methodsWithInjectedInitializers
-    in
-        classFileWithAssembledMethods

src/ByteCode/ByteUtil.hs

@@ -1,6 +1,7 @@
-module ByteCode.ByteUtil where
+module ByteCode.ByteUtil(unpackWord16, unpackWord32) where
 
 import Data.Word ( Word8, Word16, Word32 )
+import Data.Int
 import Data.Bits
 
 unpackWord16 :: Word16 -> [Word8]

src/ByteCode/ClassFile.hs

@@ -6,16 +6,15 @@ module ByteCode.ClassFile(
     Operation(..),
     serialize,
     emptyClassFile,
-    opcodeEncodingLength,
-    className
+    opcodeEncodingLength
 ) where
 
 import Data.Word
 import Data.Int
 import Data.ByteString (unpack)
 import Data.ByteString.UTF8 (fromString)
-import ByteCode.Constants
 import ByteCode.ByteUtil
+import ByteCode.Constants
 
 data ConstantInfo = ClassInfo Word16
                   | FieldRefInfo Word16 Word16
@@ -29,13 +28,11 @@ data Operation = Opiadd
                | Opisub
                | Opimul
                | Opidiv
-               | Opirem
                | Opiand
                | Opior
                | Opixor
                | Opineg
                | Opdup
-               | Opnew Word16
                | Opif_icmplt Word16
                | Opif_icmple Word16
                | Opif_icmpgt Word16
@@ -46,10 +43,7 @@ data Operation = Opiadd
                | Opreturn
                | Opireturn
                | Opareturn
-               | Opdup_x1
-               | Oppop
                | Opinvokespecial Word16
-               | Opinvokevirtual Word16
                | Opgoto Word16
                | Opsipush Word16
                | Opldc_w Word16
@@ -97,26 +91,16 @@ emptyClassFile = ClassFile {
         attributes = []
     }
 
-className :: ClassFile -> String
-className classFile = let
-        classInfo = (constantPool classFile)!!(fromIntegral (thisClass classFile))
-    in case classInfo of
-        Utf8Info className -> className
-        otherwise -> error ("expected Utf8Info but got: " ++ show otherwise)
-        
-
 opcodeEncodingLength :: Operation -> Word16
 opcodeEncodingLength Opiadd                 = 1
 opcodeEncodingLength Opisub                 = 1
 opcodeEncodingLength Opimul                 = 1
 opcodeEncodingLength Opidiv                 = 1
-opcodeEncodingLength Opirem                 = 1
 opcodeEncodingLength Opiand                 = 1
 opcodeEncodingLength Opior                  = 1
 opcodeEncodingLength Opixor                 = 1
 opcodeEncodingLength Opineg                 = 1
 opcodeEncodingLength Opdup                  = 1
-opcodeEncodingLength (Opnew _)              = 3
 opcodeEncodingLength (Opif_icmplt _)        = 3
 opcodeEncodingLength (Opif_icmple _)        = 3
 opcodeEncodingLength (Opif_icmpgt _)        = 3
@@ -127,10 +111,7 @@ opcodeEncodingLength Opaconst_null          = 1
 opcodeEncodingLength Opreturn               = 1
 opcodeEncodingLength Opireturn              = 1
 opcodeEncodingLength Opareturn              = 1
-opcodeEncodingLength Opdup_x1               = 1
-opcodeEncodingLength Oppop                  = 1
 opcodeEncodingLength (Opinvokespecial _)    = 3
-opcodeEncodingLength (Opinvokevirtual _)    = 3
 opcodeEncodingLength (Opgoto _)             = 3
 opcodeEncodingLength (Opsipush _)           = 3
 opcodeEncodingLength (Opldc_w _)            = 3
@@ -166,13 +147,11 @@ instance Serializable Operation where
     serialize Opisub                    = [0x64]
     serialize Opimul                    = [0x68]
     serialize Opidiv                    = [0x6C]
-    serialize Opirem                    = [0x70]
     serialize Opiand                    = [0x7E]
     serialize Opior                     = [0x80]
     serialize Opixor                    = [0x82]
     serialize Opineg                    = [0x74]
     serialize Opdup                     = [0x59]
-    serialize (Opnew index)             = 0xBB : unpackWord16 index
     serialize (Opif_icmplt branch)      = 0xA1 : unpackWord16 branch
     serialize (Opif_icmple branch)      = 0xA4 : unpackWord16 branch
     serialize (Opif_icmpgt branch)      = 0xA3 : unpackWord16 branch
@@ -183,10 +162,7 @@ instance Serializable Operation where
     serialize Opreturn                  = [0xB1]
     serialize Opireturn                 = [0xAC]
     serialize Opareturn                 = [0xB0]
-    serialize Opdup_x1                  = [0x5A]
-    serialize Oppop                     = [0x57]
     serialize (Opinvokespecial index)   = 0xB7 : unpackWord16 index
-    serialize (Opinvokevirtual index)   = 0xB6 : unpackWord16 index
     serialize (Opgoto index)            = 0xA7 : unpackWord16 index
     serialize (Opsipush index)          = 0x11 : unpackWord16 index
     serialize (Opldc_w index)           = 0x13 : unpackWord16 index

src/ByteCode/Generation/Assembler/ExpressionAndStatement.hs

@@ -0,0 +1,228 @@
+module ByteCode.Generation.Assembler.ExpressionAndStatement where
+
+import Ast
+import ByteCode.ClassFile(ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
+import ByteCode.Generation.Generator
+import Data.List
+import Data.Char
+import ByteCode.Generation.Builder.Field
+
+assembleExpression :: Assembler Expression
+assembleExpression (constants, ops, lvars) (TypedExpression _ (BinaryOperation op a b))
+    | elem op [Addition, Subtraction, Multiplication, Division, BitwiseAnd, BitwiseOr, BitwiseXor] = let
+            (aConstants, aOps, _) = assembleExpression (constants, ops, lvars) a
+            (bConstants, bOps, _) = assembleExpression (aConstants, aOps, lvars) b
+        in
+            (bConstants, bOps ++ [binaryOperation op], lvars)
+    | elem op [CompareEqual, CompareNotEqual, CompareLessThan, CompareLessOrEqual, CompareGreaterThan, CompareGreaterOrEqual] = let
+            (aConstants, aOps, _) = assembleExpression (constants, ops, lvars) a
+            (bConstants, bOps, _) = assembleExpression (aConstants, aOps, lvars) b
+            cmp_op = comparisonOperation op 9
+            cmp_ops = [cmp_op, Opsipush 0, Opgoto 6, Opsipush 1]
+        in
+            (bConstants, bOps ++ cmp_ops, lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ (CharacterLiteral literal)) =
+    (constants, ops ++ [Opsipush (fromIntegral (ord literal))], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ (BooleanLiteral literal)) =
+    (constants, ops ++ [Opsipush (if literal then 1 else 0)], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ (IntegerLiteral literal))
+    | literal <= 32767 && literal >= -32768 = (constants, ops ++ [Opsipush (fromIntegral literal)], lvars)
+    | otherwise = (constants ++ [IntegerInfo (fromIntegral literal)], ops ++ [Opldc_w (fromIntegral (1 + length constants))], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ NullLiteral) =
+    (constants, ops ++ [Opaconst_null], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression etype (UnaryOperation Not expr)) = let
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+        newConstant = fromIntegral (1 + length exprConstants)
+    in case etype of
+        "int" -> (exprConstants ++ [IntegerInfo 0x7FFFFFFF], exprOps ++ [Opldc_w newConstant, Opixor], lvars)
+        "char" -> (exprConstants, exprOps ++ [Opsipush 0xFFFF, Opixor], lvars)
+        "boolean" -> (exprConstants, exprOps ++ [Opsipush 0x01, Opixor], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ (UnaryOperation Minus expr)) = let
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+    in
+        (exprConstants, exprOps ++ [Opineg], lvars)
+
+assembleExpression (constants, ops, lvars) (TypedExpression _ (FieldVariable name)) = let
+        fieldIndex = findFieldIndex constants name
+    in case fieldIndex of
+        Just index -> (constants, ops ++ [Opaload 0, Opgetfield (fromIntegral index)], lvars)
+        Nothing -> error ("No such field found in constant pool: " ++ name)
+
+assembleExpression (constants, ops, lvars) (TypedExpression dtype (LocalVariable name)) = let
+        localIndex = findIndex ((==) name) lvars
+        isPrimitive = elem dtype ["char", "boolean", "int"]
+    in case localIndex of
+        Just index -> (constants, ops ++ if isPrimitive then [Opiload (fromIntegral index)] else [Opaload (fromIntegral index)], lvars)
+        Nothing -> error ("No such local variable found in local variable pool: " ++ name)
+
+assembleExpression (constants, ops, lvars) (TypedExpression dtype (StatementExpressionExpression stmtexp)) =
+        assembleStatementExpression (constants, ops, lvars) stmtexp
+
+assembleExpression _ expr = error ("unimplemented: " ++ show expr)
+
+
+
+
+-- TODO untested
+assembleStatementExpression :: Assembler StatementExpression
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (Assignment (TypedExpression dtype (LocalVariable name)) expr)) = let
+        localIndex = findIndex ((==) name) lvars
+        (constants_a, ops_a, _) = assembleExpression (constants, ops, lvars) expr
+        isPrimitive = elem dtype ["char", "boolean", "int"]
+    in case localIndex of
+        Just index -> (constants_a, ops_a ++ if isPrimitive then [Opistore (fromIntegral index)] else [Opastore (fromIntegral index)], lvars)
+        Nothing -> error ("No such local variable found in local variable pool: " ++ name)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (Assignment (TypedExpression dtype (FieldVariable name)) expr)) = let
+        fieldIndex = findFieldIndex constants name
+        (constants_a, ops_a, _) = assembleExpression (constants, ops ++ [Opaload 0], lvars) expr
+    in case fieldIndex of
+        Just index -> (constants_a, ops_a ++ [Opputfield (fromIntegral index)], lvars)
+        Nothing -> error ("No such field variable found in constant pool: " ++ name)
+
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PreIncrement (TypedExpression dtype (LocalVariable name)))) = let
+        localIndex = findIndex ((==) name) lvars
+        expr = (TypedExpression dtype (LocalVariable name))
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+        incrOps = exprOps ++ [Opsipush 1, Opiadd, Opdup]
+    in case localIndex of
+        Just index -> (exprConstants, incrOps ++ [Opistore (fromIntegral index)], lvars)
+        Nothing -> error("No such local variable found in local variable pool: " ++ name)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PostIncrement (TypedExpression dtype (LocalVariable name)))) = let
+        localIndex = findIndex ((==) name) lvars
+        expr = (TypedExpression dtype (LocalVariable name))
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+        incrOps = exprOps ++ [Opdup, Opsipush 1, Opiadd]
+    in case localIndex of
+        Just index -> (exprConstants, incrOps ++ [Opistore (fromIntegral index)], lvars)
+        Nothing -> error("No such local variable found in local variable pool: " ++ name)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PreDecrement (TypedExpression dtype (LocalVariable name)))) = let
+        localIndex = findIndex ((==) name) lvars
+        expr = (TypedExpression dtype (LocalVariable name))
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+        incrOps = exprOps ++ [Opsipush 1, Opiadd, Opisub]
+    in case localIndex of
+        Just index -> (exprConstants, incrOps ++ [Opistore (fromIntegral index)], lvars)
+        Nothing -> error("No such local variable found in local variable pool: " ++ name)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PostDecrement (TypedExpression dtype (LocalVariable name)))) = let
+        localIndex = findIndex ((==) name) lvars
+        expr = (TypedExpression dtype (LocalVariable name))
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops, lvars) expr
+        incrOps = exprOps ++ [Opdup, Opsipush 1, Opisub]
+    in case localIndex of
+        Just index -> (exprConstants, incrOps ++ [Opistore (fromIntegral index)], lvars)
+        Nothing -> error("No such local variable found in local variable pool: " ++ name)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PreIncrement (TypedExpression dtype (FieldVariable name)))) = let
+        fieldIndex = findFieldIndex constants name
+        expr = (TypedExpression dtype (FieldVariable name))
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops ++ [Opaload 0], lvars) expr
+        incrOps = exprOps ++ [Opsipush 1, Opiadd, Opdup]
+    in case fieldIndex of
+        Just index -> (exprConstants, incrOps ++ [Opputfield (fromIntegral index)], lvars)
+        Nothing -> error("No such field variable found in field variable pool: " ++ name)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PostIncrement (TypedExpression dtype (FieldVariable name)))) = let
+        fieldIndex = findFieldIndex constants name
+        expr = (TypedExpression dtype (FieldVariable name))
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops ++ [Opaload 0], lvars) expr
+        incrOps = exprOps ++ [Opdup, Opsipush 1, Opiadd]
+    in case fieldIndex of
+        Just index -> (exprConstants, incrOps ++ [Opputfield (fromIntegral index)], lvars)
+        Nothing -> error("No such field variable found in field variable pool: " ++ name)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PreDecrement (TypedExpression dtype (FieldVariable name)))) = let
+        fieldIndex = findFieldIndex constants name
+        expr = (TypedExpression dtype (FieldVariable name))
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops ++ [Opaload 0], lvars) expr
+        incrOps = exprOps ++ [Opsipush 1, Opiadd, Opisub]
+    in case fieldIndex of
+        Just index -> (exprConstants, incrOps ++ [Opputfield (fromIntegral index)], lvars)
+        Nothing -> error("No such field variable found in field variable pool: " ++ name)
+
+assembleStatementExpression
+    (constants, ops, lvars)
+    (TypedStatementExpression _ (PostDecrement (TypedExpression dtype (FieldVariable name)))) = let
+        fieldIndex = findFieldIndex constants name
+        expr = (TypedExpression dtype (FieldVariable name))
+        (exprConstants, exprOps, _) = assembleExpression (constants, ops ++ [Opaload 0], lvars) expr
+        incrOps = exprOps ++ [Opdup, Opsipush 1, Opisub]
+    in case fieldIndex of
+        Just index -> (exprConstants, incrOps ++ [Opputfield (fromIntegral index)], lvars)
+        Nothing -> error("No such field variable found in field variable pool: " ++ name)
+
+
+
+
+
+assembleStatement :: Assembler Statement
+assembleStatement (constants, ops, lvars) (TypedStatement stype (Return expr)) = case expr of
+    Nothing -> (constants, ops ++ [Opreturn], lvars)
+    Just expr -> let
+            (expr_constants, expr_ops, _) = assembleExpression (constants, ops, lvars) expr
+        in
+            (expr_constants, expr_ops ++ [returnOperation stype], lvars)
+assembleStatement (constants, ops, lvars) (TypedStatement _ (Block statements)) =
+    foldl assembleStatement (constants, ops, lvars) statements
+assembleStatement (constants, ops, lvars) (TypedStatement _ (If expr if_stmt else_stmt)) = let
+        (constants_cmp, ops_cmp, _) = assembleExpression (constants, [], lvars) expr
+        (constants_ifa, ops_ifa, _) = assembleStatement (constants_cmp, [], lvars) if_stmt
+        (constants_elsea, ops_elsea, _) = case else_stmt of
+            Nothing -> (constants_ifa, [], lvars)
+            Just stmt -> assembleStatement (constants_ifa, [], lvars) stmt
+        -- +6 because we insert 2 gotos, one for if, one for else
+        if_length = sum (map opcodeEncodingLength ops_ifa) + 6
+        -- +3 because we need to account for the goto in the if statement.
+        else_length = sum (map opcodeEncodingLength ops_elsea) + 3
+    in
+        (constants_ifa, ops ++ ops_cmp ++ [Opsipush 0, Opif_icmpeq if_length] ++ ops_ifa ++ [Opgoto else_length] ++ ops_elsea, lvars)
+assembleStatement (constants, ops, lvars) (TypedStatement _ (While expr stmt)) = let
+        (constants_cmp, ops_cmp, _) = assembleExpression (constants, [], lvars) expr
+        (constants_stmta, ops_stmta, _) = assembleStatement (constants_cmp, [], lvars) stmt
+        -- +3 because we insert 2 gotos, one for the comparison, one for the goto back to the comparison
+        stmt_length = sum (map opcodeEncodingLength ops_stmta) + 6
+        entire_length = stmt_length + sum (map opcodeEncodingLength ops_cmp)
+    in
+        (constants_stmta, ops ++ ops_cmp ++ [Opsipush 0, Opif_icmpeq stmt_length] ++ ops_stmta ++ [Opgoto (-entire_length)], lvars)
+assembleStatement (constants, ops, lvars) (TypedStatement _ (LocalVariableDeclaration (VariableDeclaration dtype name expr))) = let
+        isPrimitive = elem dtype ["char", "boolean", "int"]
+        (constants_init, ops_init, _) = case expr of
+            Just exp -> assembleExpression (constants, ops, lvars) exp
+            Nothing -> (constants, ops ++ if isPrimitive then [Opsipush 0] else [Opaconst_null], lvars)
+        localIndex = fromIntegral (length lvars)
+        storeLocal = if isPrimitive then [Opistore localIndex] else [Opastore localIndex]
+    in
+        (constants_init, ops_init ++ storeLocal, lvars ++ [name])
+
+assembleStatement (constants, ops, lvars) (TypedStatement _ (StatementExpressionStatement expr)) =
+    assembleStatementExpression (constants, ops, lvars) expr
+
+assembleStatement _ stmt = error ("Not yet implemented: " ++ show stmt)

src/ByteCode/Generation/Assembler/Method.hs

@@ -0,0 +1,20 @@
+module ByteCode.Generation.Assembler.Method where
+
+import Ast
+import ByteCode.ClassFile(ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
+import ByteCode.Generation.Generator
+import ByteCode.Generation.Assembler.ExpressionAndStatement
+
+assembleMethod :: Assembler MethodDeclaration
+assembleMethod (constants, ops, lvars) (MethodDeclaration _ name _ (TypedStatement _ (Block statements)))
+    | name == "<init>" = let
+            (constants_a, ops_a, lvars_a) = foldl assembleStatement (constants, ops, lvars) statements
+            init_ops = [Opaload 0, Opinvokespecial 2]
+        in
+            (constants_a, init_ops ++ ops_a ++ [Opreturn], lvars_a)
+    | otherwise = let
+            (constants_a, ops_a, lvars_a) = foldl assembleStatement (constants, ops, lvars) statements
+            init_ops = [Opaload 0]
+        in
+            (constants_a, init_ops ++ ops_a, lvars_a)
+assembleMethod _ (MethodDeclaration _ _ _ stmt) = error ("Block expected for method body, got: " ++ show stmt) 

src/ByteCode/Generation/Builder/Class.hs

@@ -0,0 +1,44 @@
+module ByteCode.Generation.Builder.Class where
+
+import ByteCode.Generation.Builder.Field
+import ByteCode.Generation.Builder.Method
+import ByteCode.Generation.Generator
+import Ast
+import ByteCode.ClassFile(ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
+import ByteCode.Constants
+
+injectDefaultConstructor :: [MethodDeclaration] -> [MethodDeclaration]
+injectDefaultConstructor pre
+    | any (\(MethodDeclaration _ name _ _) -> name == "<init>") pre = pre
+    | otherwise = pre ++ [MethodDeclaration "void" "<init>" [] (TypedStatement "void" (Block []))]
+
+
+classBuilder :: ClassFileBuilder Class
+classBuilder (Class name methods fields) _ = let
+        baseConstants = [
+            ClassInfo 4,
+            MethodRefInfo 1 3,
+            NameAndTypeInfo 5 6,
+            Utf8Info "java/lang/Object",
+            Utf8Info "<init>",
+            Utf8Info "()V",
+            Utf8Info "Code"
+            ]
+        nameConstants = [ClassInfo 9, Utf8Info name]
+        nakedClassFile = ClassFile {
+            constantPool = baseConstants ++ nameConstants,
+            accessFlags = accessPublic,
+            thisClass = 8,
+            superClass = 1,
+            fields = [],
+            methods = [],
+            attributes = []
+        }
+
+        methodsWithInjectedConstructor = injectDefaultConstructor methods
+
+        classFileWithFields = foldr fieldBuilder nakedClassFile fields
+        classFileWithMethods = foldr methodBuilder classFileWithFields methodsWithInjectedConstructor
+        classFileWithAssembledMethods = foldr methodAssembler classFileWithMethods methodsWithInjectedConstructor
+    in
+        classFileWithAssembledMethods

src/ByteCode/Generation/Builder/Field.hs

@@ -0,0 +1,46 @@
+module ByteCode.Generation.Builder.Field where
+
+import Ast
+import ByteCode.ClassFile(ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
+import ByteCode.Generation.Generator
+import ByteCode.Constants
+import Data.List
+
+findFieldIndex :: [ConstantInfo] -> String -> Maybe Int
+findFieldIndex constants name = let
+        fieldRefNameInfos = [
+                -- we only skip one entry to get the name since the Java constant pool
+                -- is 1-indexed (why)
+                (index, constants!!(fromIntegral index + 1))
+                | (index, FieldRefInfo _ _) <- (zip [1..] constants)
+            ]
+        fieldRefNames = map (\(index, nameInfo) -> case nameInfo of
+            Utf8Info fieldName -> (index, fieldName)
+            something_else -> error ("Expected UTF8Info but got" ++ show something_else))
+                fieldRefNameInfos
+        fieldIndex = find (\(index, fieldName) -> fieldName == name) fieldRefNames
+    in case fieldIndex of
+        Just (index, _) -> Just index
+        Nothing -> Nothing
+
+
+fieldBuilder :: ClassFileBuilder VariableDeclaration
+fieldBuilder (VariableDeclaration datatype name _) input = let
+        baseIndex = 1 + length (constantPool input)
+        constants = [
+                FieldRefInfo (fromIntegral (thisClass input)) (fromIntegral (baseIndex + 1)),
+                NameAndTypeInfo (fromIntegral (baseIndex + 2)) (fromIntegral (baseIndex + 3)),
+                Utf8Info name,
+                Utf8Info (datatypeDescriptor datatype)
+            ]
+        field = MemberInfo {
+            memberAccessFlags = accessPublic,
+            memberNameIndex = (fromIntegral (baseIndex + 2)),
+            memberDescriptorIndex = (fromIntegral (baseIndex + 3)),
+            memberAttributes = []
+            }
+    in
+        input {
+            constantPool = (constantPool input) ++ constants,
+            fields = (fields input) ++ [field]
+        }

src/ByteCode/Generation/Builder/Method.hs

@@ -0,0 +1,80 @@
+module ByteCode.Generation.Builder.Method where
+
+import Ast
+import ByteCode.ClassFile(ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
+import ByteCode.Generation.Generator
+import ByteCode.Generation.Assembler.Method
+import ByteCode.Constants
+import Data.List
+
+methodDescriptor :: MethodDeclaration -> String
+methodDescriptor (MethodDeclaration returntype _ parameters _) = let
+        parameter_types = [datatype | ParameterDeclaration datatype _ <- parameters]
+    in
+        "("
+        ++ (concat (map methodParameterDescriptor parameter_types))
+        ++ ")"
+        ++ methodParameterDescriptor returntype
+
+methodParameterDescriptor :: String -> String
+methodParameterDescriptor "void" = "V"
+methodParameterDescriptor "int" = "I"
+methodParameterDescriptor "char" = "C"
+methodParameterDescriptor "boolean" = "B"
+methodParameterDescriptor x = "L" ++ x ++ ";"
+
+memberInfoIsMethod :: [ConstantInfo] -> MemberInfo -> Bool
+memberInfoIsMethod constants info = elem '(' (memberInfoDescriptor constants info)
+
+findMethodIndex :: ClassFile -> String -> Maybe Int
+findMethodIndex classFile name = let
+        constants = constantPool classFile
+    in
+        findIndex (\method -> ((memberInfoIsMethod constants method) && (memberInfoName constants method) == name)) (methods classFile)
+
+
+methodBuilder :: ClassFileBuilder MethodDeclaration
+methodBuilder (MethodDeclaration returntype name parameters statement) input = let
+        baseIndex = 1 + length (constantPool input)
+        constants = [
+                Utf8Info name,
+                Utf8Info (methodDescriptor (MethodDeclaration returntype name parameters (Block [])))
+            ]
+
+        method = MemberInfo {
+            memberAccessFlags = accessPublic,
+            memberNameIndex = (fromIntegral baseIndex),
+            memberDescriptorIndex = (fromIntegral (baseIndex + 1)),
+            memberAttributes = []
+            }
+    in 
+        input {
+            constantPool = (constantPool input) ++ constants,
+            methods = (methods input) ++ [method]
+        }
+        
+
+
+methodAssembler :: ClassFileBuilder MethodDeclaration
+methodAssembler (MethodDeclaration returntype name parameters statement) input = let
+        methodConstantIndex = findMethodIndex input name
+    in case methodConstantIndex of
+        Nothing -> error ("Cannot find method entry in method pool for method: " ++ name)
+        Just index -> let
+                declaration = MethodDeclaration returntype name parameters statement
+                paramNames = "this" : [name | ParameterDeclaration _ name <- parameters]
+                (pre, method : post) = splitAt index (methods input)
+                (_, bytecode, _) = assembleMethod (constantPool input, [], paramNames) declaration
+                assembledMethod = method {
+                    memberAttributes = [
+                        CodeAttribute {
+                            attributeMaxStack = 420,
+                            attributeMaxLocals = 420,
+                            attributeCode = bytecode
+                        }
+                    ]
+                }
+            in
+                input {
+                    methods = pre ++ (assembledMethod : post)
+                }

src/ByteCode/Generation/Generator.hs

@@ -0,0 +1,73 @@
+module ByteCode.Generation.Generator(
+    datatypeDescriptor,
+    memberInfoName,
+    memberInfoDescriptor,
+    returnOperation,
+    binaryOperation,
+    comparisonOperation,
+    ClassFileBuilder,
+    Assembler
+) where
+
+import ByteCode.Constants
+import ByteCode.ClassFile (ClassFile (..), ConstantInfo (..), MemberInfo(..), Operation(..), Attribute(..), opcodeEncodingLength)
+import Ast
+import Data.Char
+import Data.List
+import Data.Word
+
+type ClassFileBuilder a = a -> ClassFile -> ClassFile
+type Assembler a = ([ConstantInfo], [Operation], [String]) -> a -> ([ConstantInfo], [Operation], [String])
+
+datatypeDescriptor :: String -> String
+datatypeDescriptor "void" = "V"
+datatypeDescriptor "int" = "I"
+datatypeDescriptor "char" = "C"
+datatypeDescriptor "boolean" = "B"
+datatypeDescriptor x = "L" ++ x
+
+memberInfoDescriptor :: [ConstantInfo] -> MemberInfo -> String
+memberInfoDescriptor constants MemberInfo {
+    memberAccessFlags = _,
+    memberNameIndex = _,
+    memberDescriptorIndex = descriptorIndex,
+    memberAttributes = _ } = let
+            descriptor = constants!!((fromIntegral descriptorIndex) - 1)
+        in case descriptor of
+            Utf8Info descriptorText -> descriptorText
+            _ -> ("Invalid Item at Constant pool index " ++ show descriptorIndex)
+
+
+memberInfoName :: [ConstantInfo] -> MemberInfo -> String
+memberInfoName constants MemberInfo {
+    memberAccessFlags = _,
+    memberNameIndex = nameIndex,
+    memberDescriptorIndex = _,
+    memberAttributes = _ } = let
+            name = constants!!((fromIntegral nameIndex) - 1)
+        in case name of
+            Utf8Info nameText -> nameText
+            _ -> ("Invalid Item at Constant pool index " ++ show nameIndex)
+
+
+returnOperation :: DataType -> Operation
+returnOperation dtype
+    | elem dtype ["int", "char", "boolean"] = Opireturn
+    | otherwise                             = Opareturn
+
+binaryOperation :: BinaryOperator -> Operation
+binaryOperation Addition       = Opiadd
+binaryOperation Subtraction    = Opisub
+binaryOperation Multiplication = Opimul
+binaryOperation Division       = Opidiv
+binaryOperation BitwiseAnd     = Opiand
+binaryOperation BitwiseOr      = Opior
+binaryOperation BitwiseXor     = Opixor
+
+comparisonOperation :: BinaryOperator -> Word16 -> Operation
+comparisonOperation CompareEqual          branchLocation = Opif_icmpeq branchLocation
+comparisonOperation CompareNotEqual       branchLocation = Opif_icmpne branchLocation
+comparisonOperation CompareLessThan       branchLocation = Opif_icmplt branchLocation
+comparisonOperation CompareLessOrEqual    branchLocation = Opif_icmple branchLocation
+comparisonOperation CompareGreaterThan    branchLocation = Opif_icmpgt branchLocation
+comparisonOperation CompareGreaterOrEqual branchLocation = Opif_icmpge branchLocation

src/ByteCode/Util.hs

@@ -1,245 +0,0 @@
-module ByteCode.Util where
-
-import Data.Int
-import Ast
-import ByteCode.ClassFile
-import Data.List
-import Data.Maybe (mapMaybe)
-import Data.Word (Word8, Word16, Word32)
-
--- walks the name resolution chain. returns the innermost Just LocalVariable/FieldVariable or Nothing.
-resolveNameChain :: Expression -> Expression
-resolveNameChain (TypedExpression _ (BinaryOperation NameResolution a b)) = resolveNameChain b
-resolveNameChain (TypedExpression dtype (LocalVariable name)) = (TypedExpression dtype (LocalVariable name))
-resolveNameChain (TypedExpression dtype (FieldVariable name)) = (TypedExpression dtype (FieldVariable name))
-resolveNameChain invalidExpression = error ("expected a NameResolution or Local/Field Variable but got: " ++ show(invalidExpression))
-
--- walks the name resolution chain. returns the second-to-last item of the namechain.
-resolveNameChainOwner :: Expression -> Expression
-resolveNameChainOwner (TypedExpression _ (BinaryOperation NameResolution a (TypedExpression dtype (FieldVariable name)))) = a
-resolveNameChainOwner (TypedExpression _ (BinaryOperation NameResolution a b)) = resolveNameChain b
-resolveNameChainOwner invalidExpression = error ("expected a NameResolution or Local/Field Variable but got: " ++ show(invalidExpression))
-
-
-methodDescriptor :: MethodDeclaration -> String
-methodDescriptor (MethodDeclaration returntype _ parameters _) = let
-        parameter_types = [datatype | ParameterDeclaration datatype _ <- parameters]
-    in
-        "("
-        ++ (concat (map datatypeDescriptor parameter_types))
-        ++ ")"
-        ++ datatypeDescriptor returntype
-
-methodDescriptorFromParamlist :: [Expression] -> String -> String
-methodDescriptorFromParamlist parameters returntype = let
-        parameter_types = [datatype | TypedExpression datatype _ <- parameters]
-    in
-        "("
-        ++ (concat (map datatypeDescriptor parameter_types))
-        ++ ")"
-        ++ datatypeDescriptor returntype
-
-memberInfoIsMethod :: [ConstantInfo] -> MemberInfo -> Bool
-memberInfoIsMethod constants info = elem '(' (memberInfoDescriptor constants info)
-
-
-datatypeDescriptor :: String -> String
-datatypeDescriptor "void" = "V"
-datatypeDescriptor "int" = "I"
-datatypeDescriptor "char" = "C"
-datatypeDescriptor "boolean" = "B"
-datatypeDescriptor x = "L" ++ x ++ ";"
-
-
-memberInfoDescriptor :: [ConstantInfo] -> MemberInfo -> String
-memberInfoDescriptor constants MemberInfo {
-    memberAccessFlags = _,
-    memberNameIndex = _,
-    memberDescriptorIndex = descriptorIndex,
-    memberAttributes = _ } = let
-            descriptor = constants!!((fromIntegral descriptorIndex) - 1)
-        in case descriptor of
-            Utf8Info descriptorText -> descriptorText
-            _ -> ("Invalid Item at Constant pool index " ++ show descriptorIndex)
-
-
-memberInfoName :: [ConstantInfo] -> MemberInfo -> String
-memberInfoName constants MemberInfo {
-    memberAccessFlags = _,
-    memberNameIndex = nameIndex,
-    memberDescriptorIndex = _,
-    memberAttributes = _ } = let
-            name = constants!!((fromIntegral nameIndex) - 1)
-        in case name of
-            Utf8Info nameText -> nameText
-            _ -> ("Invalid Item at Constant pool index " ++ show nameIndex)
-
-
-returnOperation :: DataType -> Operation
-returnOperation dtype
-    | elem dtype ["int", "char", "boolean"] = Opireturn
-    | otherwise                             = Opareturn
-
-binaryOperation :: BinaryOperator -> Operation
-binaryOperation Addition       = Opiadd
-binaryOperation Subtraction    = Opisub
-binaryOperation Multiplication = Opimul
-binaryOperation Division       = Opidiv
-binaryOperation Modulo         = Opirem
-binaryOperation BitwiseAnd     = Opiand
-binaryOperation BitwiseOr      = Opior
-binaryOperation BitwiseXor     = Opixor
-binaryOperation And            = Opiand
-binaryOperation Or             = Opior
-
-comparisonOperation :: BinaryOperator -> Word16 -> Operation
-comparisonOperation CompareEqual          branchLocation = Opif_icmpeq branchLocation
-comparisonOperation CompareNotEqual       branchLocation = Opif_icmpne branchLocation
-comparisonOperation CompareLessThan       branchLocation = Opif_icmplt branchLocation
-comparisonOperation CompareLessOrEqual    branchLocation = Opif_icmple branchLocation
-comparisonOperation CompareGreaterThan    branchLocation = Opif_icmpgt branchLocation
-comparisonOperation CompareGreaterOrEqual branchLocation = Opif_icmpge branchLocation
-
-findFieldIndex :: [ConstantInfo] -> String -> Maybe Int
-findFieldIndex constants name = let
-        fieldRefNameInfos = [
-                -- we only skip one entry to get the name since the Java constant pool
-                -- is 1-indexed (why)
-                (index, constants!!(fromIntegral index + 1))
-                | (index, FieldRefInfo classIndex _) <- (zip [1..] constants)
-            ]
-        fieldRefNames = map (\(index, nameInfo) -> case nameInfo of
-            Utf8Info fieldName -> (index, fieldName)
-            something_else -> error ("Expected UTF8Info but got" ++ show something_else))
-                fieldRefNameInfos
-        fieldIndex = find (\(index, fieldName) -> fieldName == name) fieldRefNames
-    in case fieldIndex of
-        Just (index, _) -> Just index
-        Nothing -> Nothing
-
-findMethodRefIndex :: [ConstantInfo] -> String -> Maybe Int
-findMethodRefIndex constants name = let
-        methodRefNameInfos = [
-                -- we only skip one entry to get the name since the Java constant pool
-                -- is 1-indexed (why)
-                (index, constants!!(fromIntegral index + 1))
-                | (index, MethodRefInfo _ _) <- (zip [1..] constants)
-            ]
-        methodRefNames = map (\(index, nameInfo) -> case nameInfo of
-            Utf8Info methodName -> (index, methodName)
-            something_else -> error ("Expected UTF8Info but got " ++ show something_else))
-                methodRefNameInfos
-        methodIndex = find (\(index, methodName) -> methodName == name) methodRefNames
-    in case methodIndex of
-        Just (index, _) -> Just index
-        Nothing -> Nothing
-
-
-findMethodIndex :: ClassFile -> String -> Maybe Int
-findMethodIndex classFile name = let
-        constants = constantPool classFile
-    in
-        findIndex (\method -> ((memberInfoIsMethod constants method) && (memberInfoName constants method) == name)) (methods classFile)
-
-findClassIndex :: [ConstantInfo] -> String -> Maybe Int
-findClassIndex constants name = let
-        classNameIndices = [(index, constants!!(fromIntegral nameIndex - 1)) | (index, ClassInfo nameIndex) <- (zip[1..] constants)]
-        classNames = map (\(index, nameInfo) -> case nameInfo of
-            Utf8Info className -> (index, className)
-            something_else -> error("Expected UTF8Info but got " ++ show something_else))
-                classNameIndices
-        desiredClassIndex = find (\(index, className) -> className == name) classNames
-    in case desiredClassIndex of
-        Just (index, _) -> Just index
-        Nothing -> Nothing
-
-getKnownMembers :: [ConstantInfo] -> [(Int, (String, String, String))]
-getKnownMembers constants = let
-        fieldsClassAndNT = [
-                (index, constants!!(fromIntegral classIndex - 1), constants!!(fromIntegral nameTypeIndex - 1))
-                | (index, FieldRefInfo classIndex nameTypeIndex) <- (zip [1..] constants)
-            ] ++ [
-                (index, constants!!(fromIntegral classIndex - 1), constants!!(fromIntegral nameTypeIndex - 1))
-                | (index, MethodRefInfo classIndex nameTypeIndex) <- (zip [1..] constants)
-            ]
-            
-        fieldsClassNameType = map (\(index, nameInfo, nameTypeInfo) -> case (nameInfo, nameTypeInfo) of
-            (ClassInfo nameIndex, NameAndTypeInfo fnameIndex ftypeIndex) -> (index, (constants!!(fromIntegral nameIndex - 1), constants!!(fromIntegral fnameIndex - 1), constants!!(fromIntegral ftypeIndex - 1)))
-            something_else -> error ("Expected Class and NameType info, but got: " ++ show nameInfo ++ " and " ++ show nameTypeInfo))
-                fieldsClassAndNT
-
-        fieldsResolved = map (\(index, (nameInfo, fnameInfo, ftypeInfo)) -> case (nameInfo, fnameInfo, ftypeInfo) of
-            (Utf8Info cname, Utf8Info fname, Utf8Info ftype) -> (index, (cname, fname, ftype))
-            something_else -> error("Expected UTF8Infos but got " ++ show something_else))
-                fieldsClassNameType    
-    in
-        fieldsResolved
-
--- same as findClassIndex, but inserts a new entry into constant pool if not existing
-getClassIndex :: [ConstantInfo] -> String -> ([ConstantInfo], Int)
-getClassIndex constants name = case findClassIndex constants name of
-    Just index -> (constants, index)
-    Nothing -> (constants ++ [ClassInfo (fromIntegral (length constants)), Utf8Info name], fromIntegral (length constants))
-
--- get the index for a field within a class, creating it if it does not exist.
-getFieldIndex :: [ConstantInfo] -> (String, String, String) -> ([ConstantInfo], Int)
-getFieldIndex constants (cname, fname, ftype) = case findMemberIndex constants (cname, fname, ftype) of
-    Just index -> (constants, index)
-    Nothing -> let
-            (constantsWithClass, classIndex) = getClassIndex constants cname
-            baseIndex = 1 + length constantsWithClass
-        in
-            (constantsWithClass ++ [
-                FieldRefInfo (fromIntegral classIndex) (fromIntegral (baseIndex + 1)),
-                NameAndTypeInfo (fromIntegral (baseIndex + 2)) (fromIntegral (baseIndex + 3)),
-                Utf8Info fname,
-                Utf8Info (datatypeDescriptor ftype)
-            ], baseIndex)
-
-getMethodIndex :: [ConstantInfo] -> (String, String, String) -> ([ConstantInfo], Int)
-getMethodIndex constants (cname, mname, mtype) = case findMemberIndex constants (cname, mname, mtype) of
-    Just index -> (constants, index)
-    Nothing -> let
-            (constantsWithClass, classIndex) = getClassIndex constants cname
-            baseIndex = 1 + length constantsWithClass
-        in
-            (constantsWithClass ++ [
-                MethodRefInfo (fromIntegral classIndex) (fromIntegral (baseIndex + 1)),
-                NameAndTypeInfo (fromIntegral (baseIndex + 2)) (fromIntegral (baseIndex + 3)),
-                Utf8Info mname,
-                Utf8Info mtype
-            ], baseIndex)
-
-findMemberIndex :: [ConstantInfo] -> (String, String, String) -> Maybe Int
-findMemberIndex constants (cname, fname, ftype) = let
-        allMembers = getKnownMembers constants
-        desiredMember = find (\(index, (c, f, ft)) -> (c, f, ft) == (cname, fname, ftype)) allMembers
-    in
-        fmap (\(index, _) -> index) desiredMember
-
-injectDefaultConstructor :: [MethodDeclaration] -> [MethodDeclaration]
-injectDefaultConstructor pre
-    | any (\(MethodDeclaration _ name _ _) -> name == "<init>") pre = pre
-    | otherwise = pre ++ [MethodDeclaration "void" "<init>" [] (TypedStatement "void" (Block []))]
-
-injectFieldInitializers :: String -> [VariableDeclaration] -> [MethodDeclaration] -> [MethodDeclaration]
-injectFieldInitializers classname vars pre = let 
-        initializers = mapMaybe (\(variable) -> case variable of
-                VariableDeclaration dtype name (Just initializer) -> Just (
-                        TypedStatement dtype (
-                            StatementExpressionStatement (
-                                TypedStatementExpression dtype (
-                                    Assignment
-                                        (TypedExpression dtype (BinaryOperation NameResolution (TypedExpression classname (LocalVariable "this")) (TypedExpression dtype (FieldVariable name))))
-                                        initializer
-                                    )
-                                )
-                            )
-                        )
-                otherwise -> Nothing
-            ) vars
-    in
-        map (\(method) -> case method of
-                MethodDeclaration "void" "<init>" params (TypedStatement "void" (Block statements)) -> MethodDeclaration "void" "<init>" params (TypedStatement "void" (Block (initializers ++ statements)))
-                otherwise -> method
-            ) pre

src/Main.hs

@@ -4,30 +4,17 @@ import Example
 import Typecheck
 import Parser.Lexer (alexScanTokens)
 import Parser.JavaParser
-import ByteCode.Builder
+import ByteCode.Generation.Generator
+import ByteCode.Generation.Builder.Class
 import ByteCode.ClassFile
 import Data.ByteString (pack, writeFile)
-import System.Environment
-import System.FilePath.Posix (takeDirectory)
 
 main = do
-    args <- getArgs
-    let filename = if null args
-                   then error "Missing filename, I need to know what to compile"
-                   else args!!0
-    let outputDirectory = takeDirectory filename
-    print ("Compiling " ++ filename)
-    file <- readFile filename
+    file <- readFile "Testklasse.java"
 
     let untypedAST = parse $ alexScanTokens file
-    let typedAST = (typeCheckCompilationUnit untypedAST)
-    let assembledClasses = map (\(typedClass) -> classBuilder typedClass emptyClassFile) typedAST
+    let typedAST = head (typeCheckCompilationUnit untypedAST)
+    let abstractClassFile = classBuilder typedAST emptyClassFile
+    let assembledClassFile = pack (serialize abstractClassFile)
 
-    mapM_ (\(classFile) -> let
-            fileContent = pack (serialize classFile)
-            fileName = outputDirectory ++ "/" ++ (className classFile) ++ ".class"
-        in Data.ByteString.writeFile fileName fileContent
-        ) assembledClasses
-
-
-    
+    Data.ByteString.writeFile "Testklasse.class" assembledClassFile