Removes the special casing for foldl

Had to implement both functions as arguments and type
place holders (variables) for type constructors.

Had to implement functions as a type as well.

Still have to figure out how to pass functions around.

phasm/compiler.py

@@ -17,6 +17,7 @@ from .type3.types import (
     TypeApplication_Struct,
     TypeApplication_TypeInt,
     TypeApplication_TypeStar,
+    TypeConstructor_Function,
     TypeConstructor_StaticArray,
     TypeConstructor_Tuple,
 )
@@ -313,9 +314,9 @@ def expression(wgn: WasmGenerator, mod: ourlang.Module, inp: ourlang.Expression)
                 type_var_map[type_var] = arg_expr.type3
                 continue
 
-                if isinstance(type_var, FunctionArgument):
-                    # Fixed type, not part of the lookup requirements
-                    continue
+            if isinstance(type_var, FunctionArgument):
+                # Fixed type, not part of the lookup requirements
+                continue
 
             raise NotImplementedError(type_var, arg_expr.type3)
 
@@ -355,6 +356,21 @@ def expression(wgn: WasmGenerator, mod: ourlang.Module, inp: ourlang.Expression)
                 raise NotImplementedError(str(inp.function), type_var_map)
             return
 
+        if isinstance(inp.function, ourlang.FunctionParam):
+            assert isinstance(inp.function.type3.application.constructor, TypeConstructor_Function)
+
+            params = [
+                type3(x).to_wat()
+                for x in inp.function.type3.application.arguments
+            ]
+
+            result = params.pop()
+
+            params_str = ' '.join(params)
+            wgn.add_statement('local.get', '${}'.format(inp.function.name))
+            wgn.add_statement(f'call_indirect (param {params_str}) (result {result})')
+            return
+
         wgn.add_statement('call', '${}'.format(inp.function.name))
         return
 

phasm/ourlang.py

@@ -151,10 +151,10 @@ class FunctionCall(Expression):
     """
     __slots__ = ('function', 'arguments', )
 
-    function: Union['Function', Type3ClassMethod]
+    function: Union['Function', 'FunctionParam', Type3ClassMethod]
     arguments: List[Expression]
 
-    def __init__(self, function: Union['Function', Type3ClassMethod]) -> None:
+    def __init__(self, function: Union['Function', 'FunctionParam', Type3ClassMethod]) -> None:
         super().__init__()
 
         self.function = function
@@ -378,15 +378,15 @@ class Module:
     """
     A module is a file and consists of functions
     """
-    __slots__ = ('data', 'types',  'struct_definitions', 'constant_defs', 'functions', 'functions_table', 'operators', )
+    __slots__ = ('data', 'types',  'struct_definitions', 'constant_defs', 'functions', 'operators', 'functions_table', )
 
     data: ModuleData
     types: dict[str, Type3]
     struct_definitions: Dict[str, StructDefinition]
     constant_defs: Dict[str, ModuleConstantDef]
     functions: Dict[str, Function]
-    functions_table: dict[Function, int]
     operators: Dict[str, Type3ClassMethod]
+    functions_table: dict[Function, int]
 
     def __init__(self) -> None:
         self.data = ModuleData()

phasm/parser.py

@@ -447,7 +447,8 @@ class OurVisitor:
                 return VariableReference(cdef)
 
             if node.id in module.functions:
-                return FunctionReference(module.functions[node.id])
+                fun = module.functions[node.id]
+                return FunctionReference(fun)
 
             _raise_static_error(node, f'Undefined variable {node.id}')
 
@@ -474,21 +475,18 @@ class OurVisitor:
         if not isinstance(node.func.ctx, ast.Load):
             _raise_static_error(node, 'Must be load context')
 
-        func: Union[Function, Type3ClassMethod]
+        func: Union[Function, FunctionParam, Type3ClassMethod]
 
         if node.func.id in PRELUDE_METHODS:
             func = PRELUDE_METHODS[node.func.id]
+        elif node.func.id in our_locals:
+            func = our_locals[node.func.id]
         else:
             if node.func.id not in module.functions:
                 _raise_static_error(node, 'Call to undefined function')
 
             func = module.functions[node.func.id]
 
-        exp_arg_count = len(func.signature.args) - 1
-
-        if exp_arg_count != len(node.args):
-            _raise_static_error(node, f'Function {node.func.id} requires {exp_arg_count} arguments but {len(node.args)} are given')
-
         result = FunctionCall(func)
         result.arguments.extend(
             self.visit_Module_FunctionDef_expr(module, function, our_locals, arg_expr)
@@ -616,6 +614,22 @@ class OurVisitor:
             _raise_static_error(node, f'Unrecognized type {node.id}')
 
         if isinstance(node, ast.Subscript):
+            if isinstance(node.value, ast.Name) and node.value.id == 'Callable':
+                func_arg_types: list[ast.expr]
+
+                if isinstance(node.slice, ast.Name):
+                    func_arg_types = [node.slice]
+                elif isinstance(node.slice, ast.Tuple):
+                    func_arg_types = node.slice.elts
+                else:
+                    _raise_static_error(node, 'Must subscript using a list of types')
+
+                # Function type
+                return prelude.function(*[
+                    self.visit_type(module, e)
+                    for e in func_arg_types
+                ])
+
             if isinstance(node.slice, ast.Slice):
                 _raise_static_error(node, 'Must subscript using an index')
             if not isinstance(node.slice, ast.Constant):

phasm/prelude/__init__.py

@@ -188,7 +188,9 @@ determined length, and each argument can be different.
 """
 
 def fn_on_create(args: tuple[Type3, ...], typ: Type3) -> None:
-    pass # ? instance_type_class(InternalPassAsPointer, typ)
+    # Not really a pointer; but still a i32
+    # (It's actually a table lookup)
+    instance_type_class(InternalPassAsPointer, typ)
 
 function = TypeConstructor_Function('function', on_create=fn_on_create)
 """
@@ -473,7 +475,7 @@ instance_type_class(IntNum, f64, methods={
     'neg': stdtypes.f64_intnum_neg,
 })
 
-Integral = Type3Class('Eq', (a, ), methods={
+Integral = Type3Class('Integral', (a, ), methods={
 }, operators={
     '//': [a, a, a],
     '%': [a, a, a],

phasm/type3/constraints.py

@@ -159,7 +159,7 @@ class SameTypeConstraint(ConstraintBase):
         return (
             ' == '.join('{t' + str(idx) + '}' for idx in range(len(self.type_list))),
             {
-                't' + str(idx): typ.name if isinstance(typ, ourlang.Function) else typ
+                't' + str(idx): typ
                 for idx, typ in enumerate(self.type_list)
             },
         )
@@ -257,9 +257,6 @@ class SameFunctionArgumentConstraint(ConstraintBase):
             if isinstance(tv, Type3) or tv in type_var_map
         ]
 
-        print('self.func_arg.args', self.func_arg.args)
-        print('exp_type_arg_list', exp_type_arg_list)
-
         if len(exp_type_arg_list) != len(self.func_arg.args):
             return RequireTypeSubstitutes()
 

phasm/type3/constraintsgenerator.py

@@ -23,9 +23,10 @@ from .functions import (
     FunctionSignature,
     TypeVariable,
     TypeVariableApplication_Unary,
+    TypeVariableContext,
 )
 from .placeholders import PlaceholderForType
-from .types import Type3, TypeApplication_Struct
+from .types import Type3, TypeApplication_Struct, TypeConstructor_Function
 
 ConstraintGenerator = Generator[ConstraintBase, None, None]
 
@@ -56,15 +57,31 @@ def expression_binary_op(ctx: Context, inp: ourlang.BinaryOp, phft: PlaceholderF
     )
 
 def expression_function_call(ctx: Context, inp: ourlang.FunctionCall, phft: PlaceholderForType) -> ConstraintGenerator:
+    if isinstance(inp.function, ourlang.FunctionParam):
+        assert isinstance(inp.function.type3.application.constructor, TypeConstructor_Function)
+        signature = FunctionSignature(
+            TypeVariableContext(),
+            inp.function.type3.application.arguments,
+        )
+    else:
+        signature = inp.function.signature
+
     return _expression_function_call(
             ctx,
             inp.function.name,
-            inp.function.signature,
+            signature,
             inp.arguments,
             inp,
             phft,
         )
 
+def expression_function_reference(ctx: Context, inp: ourlang.FunctionReference, phft: PlaceholderForType) -> ConstraintGenerator:
+    yield SameTypeConstraint(
+        prelude.function(*(x.type3 for x in inp.function.posonlyargs), inp.function.returns_type3),
+        phft,
+        comment=f'typeOf("{inp.function.name}") == typeOf({inp.function.name})',
+    )
+
 def _expression_function_call(
         ctx: Context,
         func_name: str,
@@ -189,13 +206,6 @@ def _expression_function_call(
         raise NotImplementedError(sig_part)
     return
 
-def expression_function_reference(ctx: Context, inp: ourlang.FunctionReference, phft: PlaceholderForType) -> ConstraintGenerator:
-    yield SameTypeConstraint(
-        prelude.function(*(x.type3 for x in inp.function.posonlyargs), inp.function.returns_type3),
-        phft,
-        comment=f'typeOf("{inp.function.name}") == typeOf({inp.function.name})',
-    )
-
 def expression(ctx: Context, inp: ourlang.Expression, phft: PlaceholderForType) -> ConstraintGenerator:
     if isinstance(inp, ourlang.Constant):
         yield from constant(ctx, inp, phft)

phasm/type3/types.py

@@ -241,7 +241,7 @@ class TypeConstructor_Tuple(TypeConstructor_TypeStar):
 
 class TypeConstructor_Function(TypeConstructor_TypeStar):
     def make_name(self, key: Tuple[Type3, ...]) -> str:
-        return '(' + ' -> '.join(x.name for x in key) + ')'
+        return 'Callable[' + ', '.join(x.name for x in key) + ']'
 
 class TypeConstructor_Struct(TypeConstructor_Base[tuple[tuple[str, Type3], ...]]):
     """

phasm/wasm.py

@@ -186,8 +186,8 @@ class Module(WatSerializable):
     """
     def __init__(self) -> None:
         self.imports: List[Import] = []
-        self.functions: List[Function] = []
         self.table: dict[int, str] = {}
+        self.functions: List[Function] = []
         self.memory = ModuleMemory()
 
     def to_wat(self) -> str:

tests/integration/test_lang/test_second_order_functions.py

@@ -0,0 +1,182 @@
+import pytest
+
+from phasm.type3.entry import Type3Exception
+
+from ..helpers import Suite
+
+
+@pytest.mark.integration_test
+def test_sof_in_code_0_arg():
+    code_py = """
+def thirteen() -> i32:
+    return 13
+
+def action(applicable: Callable[i32]) -> i32:
+    return applicable()
+
+@exported
+def testEntry() -> i32:
+    return action(thirteen)
+"""
+
+    result = Suite(code_py).run_code()
+
+    assert 13 == result.returned_value
+
+@pytest.mark.integration_test
+def test_sof_in_code_1_arg():
+    code_py = """
+def double(left: i32) -> i32:
+    return left * 2
+
+def action(applicable: Callable[i32, i32], left: i32) -> i32:
+    return applicable(left)
+
+@exported
+def testEntry() -> i32:
+    return action(double, 13)
+"""
+
+    result = Suite(code_py).run_code()
+
+    assert 26 == result.returned_value
+
+@pytest.mark.integration_test
+def test_sof_in_code_2_arg():
+    code_py = """
+def add(left: i32, right: i32) -> i32:
+    return left + right
+
+def action(applicable: Callable[i32, i32, i32], left: i32, right: i32) -> i32:
+    return applicable(left, right)
+
+@exported
+def testEntry() -> i32:
+    return action(add, 13, 14)
+"""
+
+    result = Suite(code_py).run_code()
+
+    assert 27 == result.returned_value
+
+@pytest.mark.integration_test
+def test_sof_in_code_3_arg():
+    code_py = """
+def add(left: i32, mid: i32, right: i32) -> i32:
+    return left + mid + right
+
+def action(applicable: Callable[i32, i32, i32, i32], left: i32, mid: i32, right: i32) -> i32:
+    return applicable(left, mid, right)
+
+@exported
+def testEntry() -> i32:
+    return action(add, 13, 14, 15)
+"""
+
+    result = Suite(code_py).run_code()
+
+    assert 42 == result.returned_value
+
+@pytest.mark.integration_test
+def test_sof_wrong_argument_type():
+    code_py = """
+def double(left: f32) -> f32:
+    return left * 2
+
+def action(applicable: Callable[i32, i32], left: i32) -> i32:
+    return applicable(left)
+
+@exported
+def testEntry() -> i32:
+    return action(double, 13)
+"""
+
+    with pytest.raises(Type3Exception, match=r'Callable\[f32, f32\] must be Callable\[i32, i32\] instead'):
+        Suite(code_py).run_code()
+
+@pytest.mark.integration_test
+def test_sof_wrong_return():
+    code_py = """
+def double(left: i32) -> i32:
+    return left * 2
+
+def action(applicable: Callable[i32, i32], left: i32) -> f32:
+    return applicable(left)
+
+@exported
+def testEntry() -> i32:
+    return action(double, 13)
+"""
+
+    with pytest.raises(Type3Exception, match=r'f32 must be i32 instead'):
+        Suite(code_py).run_code()
+
+@pytest.mark.integration_test
+@pytest.mark.skip('FIXME: Probably have the remainder be the a function type')
+def test_sof_wrong_not_enough_args_call():
+    code_py = """
+def add(left: i32, right: i32) -> i32:
+    return left + right
+
+def action(applicable: Callable[i32, i32, i32], left: i32) -> i32:
+    return applicable(left)
+
+@exported
+def testEntry() -> i32:
+    return action(add, 13)
+"""
+
+    with pytest.raises(Type3Exception, match=r'f32 must be i32 instead'):
+        Suite(code_py).run_code()
+
+@pytest.mark.integration_test
+def test_sof_wrong_not_enough_args_refere():
+    code_py = """
+def double(left: i32) -> i32:
+    return left * 2
+
+def action(applicable: Callable[i32, i32, i32], left: i32, right: i32) -> i32:
+    return applicable(left, right)
+
+@exported
+def testEntry() -> i32:
+    return action(double, 13, 14)
+"""
+
+    with pytest.raises(Type3Exception, match=r'Callable\[i32, i32\] must be Callable\[i32, i32, i32\] instead'):
+        Suite(code_py).run_code()
+
+@pytest.mark.integration_test
+@pytest.mark.skip('FIXME: Probably have the remainder be the a function type')
+def test_sof_wrong_too_many_args_call():
+    code_py = """
+def thirteen() -> i32:
+    return 13
+
+def action(applicable: Callable[i32], left: i32) -> i32:
+    return applicable(left)
+
+@exported
+def testEntry() -> i32:
+    return action(thirteen, 13)
+"""
+
+    with pytest.raises(Type3Exception, match=r'f32 must be i32 instead'):
+        Suite(code_py).run_code()
+
+@pytest.mark.integration_test
+def test_sof_wrong_too_many_args_refere():
+    code_py = """
+def double(left: i32) -> i32:
+    return left * 2
+
+def action(applicable: Callable[i32]) -> i32:
+    return applicable()
+
+@exported
+def testEntry() -> i32:
+    return action(double)
+"""
+
+    with pytest.raises(Type3Exception, match=r'Callable\[i32, i32\] must be Callable\[i32\] instead'):
+        Suite(code_py).run_code()