HW1 submission

java-type-checker/java_type_checker/expressions.py

@@ -23,14 +23,18 @@ def check_types(self):
         """
         raise NotImplementedError(type(self).__name__ + " must implement check_types()")
 
-
 class Variable(Expression):
     """ An expression that reads the value of a variable, e.g. `x` in the expression `x + 5`.
     """
     def __init__(self, name, declared_type):
         self.name = name                    #: The name of the variable
         self.declared_type = declared_type  #: The declared type of the variable (Type)
 
+    def static_type(self):
+        return self.declared_type
+
+    def check_types(self):
+        pass
 
 class Literal(Expression):
     """ A literal value entered in the code, e.g. `5` in the expression `x + 5`.
@@ -39,11 +43,18 @@ def __init__(self, value, type):
         self.value = value  #: The literal value, as a string
         self.type = type    #: The type of the literal (Type)
 
+    def static_type(self):
+        return self.type
+
+    def check_types(self):
+        pass
 
 class NullLiteral(Literal):
     def __init__(self):
         super().__init__("null", Type.null)
 
+    def static_type(self):
+        return Type.null
 
 class MethodCall(Expression):
     """
@@ -55,6 +66,41 @@ def __init__(self, receiver, method_name, *args):
         self.method_name = method_name  #: The name of the method to call (String)
         self.args = args                #: The method arguments (list of Expressions)
 
+    def static_type(self):
+        return self.receiver.static_type().method_named(self.method_name).return_type
+
+    def check_types(self):
+        for arg in self.args:
+            arg.check_types()
+
+        objectTypeName = self.receiver.static_type().name
+
+        if not self.receiver.declared_type.is_subtype_of(Type.object):
+            raise JavaTypeError(
+                "Type {0} does not have methods".format(
+                    self.receiver.declared_type.name)
+            )
+
+# test_flags_too_few/many_arguments
+        expected_arg_types = self.receiver.static_type().method_named(self.method_name).argument_types
+
+        if len(expected_arg_types) == len(self.args):
+            pass
+        else:
+            raise TypeError(
+                "Wrong number of arguments for {0}: expected {1}, got {2}".format(
+                    objectTypeName + "." + self.method_name + "()",
+                    len(expected_arg_types),
+                    len(self.args)))
+
+#
+        for i in range(len(self.args)):
+            if not self.args[i].static_type().is_subtype_of(expected_arg_types[i]):
+                raise JavaTypeError("{0}.{1}() expects arguments of type {2}, but got {3}".format(
+                        objectTypeName,
+                        self.method_name,
+                        names(expected_arg_types),
+                        names([arg.static_type() for arg in self.args])))
 
 class ConstructorCall(Expression):
     """
@@ -64,6 +110,37 @@ def __init__(self, instantiated_type, *args):
         self.instantiated_type = instantiated_type  #: The type to instantiate (Type)
         self.args = args                            #: Constructor arguments (list of Expressions)
 
+    def static_type(self):
+        return self.instantiated_type
+
+    def check_types(self):
+        if self.instantiated_type.is_subtype_of(Type.object):
+            pass
+        else:
+            raise JavaTypeError(
+                "Type {0} is not instantiable".format(self.instantiated_type.name)
+            )
+
+        if self.instantiated_type == Type.null:
+            raise JavaTypeError("Type null is not instantiable")
+
+        expected_arg_types = self.instantiated_type.constructor.argument_types
+        if len(expected_arg_types) == len(self.args):
+            pass
+        else:
+            raise JavaTypeError(
+                "Wrong number of arguments for {0} constructor: expected {1}, got {2}".format(
+                    self.instantiated_type.name,
+                    len(expected_arg_types),
+                    len(self.args))
+            )
+
+        for i in range(len(self.args)):
+            if not self.args[i].static_type().is_subtype_of(expected_arg_types[i]):
+                raise JavaTypeError("{0} constructor expects arguments of type {1}, but got {2}".format(
+                    self.instantiated_type.name,
+                    names(expected_arg_types),
+                    names([arg.static_type() for arg in self.args])))
 
 class JavaTypeError(Exception):
     """ Indicates a compile-time type error in an expression.

java-type-checker/java_type_checker/types.py

@@ -12,7 +12,12 @@ def __init__(self, name, direct_supertypes=[]):
     def is_subtype_of(self, other):
         """ True if this type can be used where the other type is expected.
         """
-        return True  # TODO: implement
+        if self.name == other.name:
+            return True
+        for supertype in self.direct_supertypes:
+            if supertype.is_subtype_of(other):
+                return True
+        return False
 
     def is_supertype_of(self, other):
         """ Convenience counterpart to is_subtype_of().
@@ -72,6 +77,9 @@ class NullType(Type):
     def __init__(self):
         super().__init__("null")
 
+    def method_named(self, name):
+        raise NoSuchMethod("Cannot invoke method {0}() on null".format(name))
+
 
 class NoSuchMethod(Exception):
     pass

python-attr-lookup/python-attr-lookup.iml

@@ -20,5 +20,17 @@
         <SOURCES />
       </library>
     </orderEntry>
+    <orderEntry type="module-library" scope="TEST">
+      <library name="JUnit5.0">
+        <CLASSES>
+          <root url="jar://$MAVEN_REPOSITORY$/org/junit/jupiter/junit-jupiter-api/5.0.0/junit-jupiter-api-5.0.0.jar!/" />
+          <root url="jar://$MAVEN_REPOSITORY$/org/apiguardian/apiguardian-api/1.0.0/apiguardian-api-1.0.0.jar!/" />
+          <root url="jar://$MAVEN_REPOSITORY$/org/opentest4j/opentest4j/1.0.0/opentest4j-1.0.0.jar!/" />
+          <root url="jar://$MAVEN_REPOSITORY$/org/junit/platform/junit-platform-commons/1.0.0/junit-platform-commons-1.0.0.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
   </component>
 </module>

python-attr-lookup/src/plang/PythonObject.java

@@ -47,11 +47,13 @@ public List<PythonObject> getMRO() {
     }
 
     /**
-     * Constructs the MRO. Called only once, the first time we need the MRO; this class memoizes the
+     * Constructs the MRO. Called only once, the first time we need the MRO; this class memorizes the
      * result (i.e. it remembers the list buildMRO() returned and keeps returning it).
      */
     protected List<PythonObject> buildMRO() {
-        throw new UnsupportedOperationException("not implemented yet");
+        List<PythonObject> newMRO = type.buildMRO();
+        newMRO.add(0,this);
+        return newMRO;
     }
 
     /**
@@ -62,7 +64,12 @@ protected List<PythonObject> buildMRO() {
      * @throws PythonAttributeException When there is no attribute on this object with that name.
      */
     public final PythonObject get(String attrName) throws PythonAttributeException {
-        throw new UnsupportedOperationException("not implemented yet");
+        for(PythonObject pyObj : getMRO()){
+            if(pyObj.attrs.containsKey(attrName)){
+                return pyObj.attrs.get(attrName);
+            }
+        }
+        throw new PythonAttributeException(this,attrName);
     }
 
     /**
@@ -74,7 +81,7 @@ public final PythonObject get(String attrName) throws PythonAttributeException {
      * @param value Its new value
      */
     public final void set(String attrName, PythonObject value) {
-        throw new UnsupportedOperationException("not implemented yet");
+        attrs.put(attrName,value);
     }
 
     @Override

python-attr-lookup/src/plang/PythonType.java

@@ -41,15 +41,21 @@ public PythonObject getBase() {
 
     @Override
     protected List<PythonObject> buildMRO() {
-        throw new UnsupportedOperationException("not implemented yet");
+        ArrayList<PythonObject> newMRO = new ArrayList<>();
+        newMRO.add(this);
+        if(base != null) {
+            newMRO.addAll(base.getMRO());
+        }
+        return newMRO;
     }
 
     /**
      * Creates and returns a new instance of this class, i.e. a PythonObject whose type is
      * this PythonType.
+     *
+     * Part 0.1
      */
-    public PythonObject instantiate() {
-        throw new UnsupportedOperationException("not implemented yet");
+    public PythonObject instantiate() { return new PythonObject(this);
     }
 
     @Override