Removes the special casing for foldl

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

phasm/codestyle.py

@@ -116,10 +116,6 @@ def expression(inp: ourlang.Expression) -> str:
     if isinstance(inp, ourlang.AccessStructMember):
         return f'{expression(inp.varref)}.{inp.member}'
 
-    if isinstance(inp, ourlang.Fold):
-        fold_name = 'foldl' if ourlang.Fold.Direction.LEFT == inp.dir else 'foldr'
-        return f'{fold_name}({inp.func.name}, {expression(inp.base)}, {expression(inp.iter)})'
-
     raise NotImplementedError(expression, inp)
 
 def statement(inp: ourlang.Statement) -> Statements:

phasm/compiler.py

@@ -4,10 +4,11 @@ This module contains the code to convert parsed Ourlang into WebAssembly code
 import struct
 from typing import Dict, List, Optional
 
-from . import codestyle, ourlang, prelude, wasm
+from . import ourlang, prelude, wasm
 from .runtime import calculate_alloc_size, calculate_member_offset
 from .stdlib import alloc as stdlib_alloc
 from .stdlib import types as stdlib_types
+from .type3 import functions as type3functions
 from .type3 import placeholders as type3placeholders
 from .type3 import typeclasses as type3classes
 from .type3 import types as type3types
@@ -335,7 +336,7 @@ def tuple_instantiation(wgn: WasmGenerator, inp: ourlang.TupleInstantiation) ->
 
     # Store each element individually
     offset = 0
-    for element, exp_type3 in zip(inp.elements, args):
+    for element, exp_type3 in zip(inp.elements, args, strict=True):
         if isinstance(exp_type3, type3placeholders.PlaceholderForType):
             assert exp_type3.resolve_as is not None
             assert isinstance(exp_type3.resolve_as, type3types.Type3)
@@ -434,10 +435,10 @@ def expression(wgn: WasmGenerator, inp: ourlang.Expression) -> None:
 
         assert isinstance(inp.type3, type3types.Type3), type3placeholders.TYPE3_ASSERTION_ERROR
 
-        type_var_map: Dict[type3classes.TypeVariable, type3types.Type3] = {}
+        type_var_map: Dict[type3functions.TypeVariable, type3types.Type3] = {}
 
-        for type_var, arg_expr in zip(inp.operator.signature, [inp.left, inp.right, inp]):
-            if not isinstance(type_var, type3classes.TypeVariable):
+        for type_var, arg_expr in zip(inp.operator.signature.args, [inp.left, inp.right, inp], strict=True):
+            if not isinstance(type_var, type3functions.TypeVariable):
                 # Fixed type, not part of the lookup requirements
                 continue
 
@@ -476,8 +477,8 @@ def expression(wgn: WasmGenerator, inp: ourlang.Expression) -> None:
             # FIXME: Duplicate code with BinaryOp
             type_var_map = {}
 
-            for type_var, arg_expr in zip(inp.function.signature, inp.arguments + [inp]):
-                if not isinstance(type_var, type3classes.TypeVariable):
+            for type_var, arg_expr in zip(inp.function.signature.args, inp.arguments + [inp], strict=True):
+                if not isinstance(type_var, type3functions.TypeVariable):
                     # Fixed type, not part of the lookup requirements
                     continue
 
@@ -587,89 +588,85 @@ def expression(wgn: WasmGenerator, inp: ourlang.Expression) -> None:
         )))
         return
 
-    if isinstance(inp, ourlang.Fold):
-        expression_fold(wgn, inp)
-        return
-
     raise NotImplementedError(expression, inp)
 
-def expression_fold(wgn: WasmGenerator, inp: ourlang.Fold) -> None:
-    """
-    Compile: Fold expression
-    """
-    assert isinstance(inp.type3, type3types.Type3), type3placeholders.TYPE3_ASSERTION_ERROR
+# def expression_fold(wgn: WasmGenerator, inp: ourlang.Fold) -> None:
+#     """
+#     Compile: Fold expression
+#     """
+#     assert isinstance(inp.type3, type3types.Type3), type3placeholders.TYPE3_ASSERTION_ERROR
 
-    if inp.iter.type3 is not prelude.bytes_:
-        raise NotImplementedError(expression_fold, inp, inp.iter.type3)
+#     if inp.iter.type3 is not prelude.bytes_:
+#         raise NotImplementedError(expression_fold, inp, inp.iter.type3)
 
-    wgn.add_statement('nop', comment='acu :: u8')
-    acu_var = wgn.temp_var_u8(f'fold_{codestyle.type3(inp.type3)}_acu')
-    wgn.add_statement('nop', comment='adr :: bytes*')
-    adr_var = wgn.temp_var_i32('fold_i32_adr')
-    wgn.add_statement('nop', comment='len :: i32')
-    len_var = wgn.temp_var_i32('fold_i32_len')
+#     wgn.add_statement('nop', comment='acu :: u8')
+#     acu_var = wgn.temp_var_u8(f'fold_{codestyle.type3(inp.type3)}_acu')
+#     wgn.add_statement('nop', comment='adr :: bytes*')
+#     adr_var = wgn.temp_var_i32('fold_i32_adr')
+#     wgn.add_statement('nop', comment='len :: i32')
+#     len_var = wgn.temp_var_i32('fold_i32_len')
 
-    wgn.add_statement('nop', comment='acu = base')
-    expression(wgn, inp.base)
-    wgn.local.set(acu_var)
+#     wgn.add_statement('nop', comment='acu = base')
+#     expression(wgn, inp.base)
+#     wgn.local.set(acu_var)
 
-    wgn.add_statement('nop', comment='adr = adr(iter)')
-    expression(wgn, inp.iter)
-    wgn.local.set(adr_var)
+#     wgn.add_statement('nop', comment='adr = adr(iter)')
+#     expression(wgn, inp.iter)
+#     wgn.local.set(adr_var)
 
-    wgn.add_statement('nop', comment='len = len(iter)')
-    wgn.local.get(adr_var)
-    wgn.i32.load()
-    wgn.local.set(len_var)
+#     wgn.add_statement('nop', comment='len = len(iter)')
+#     wgn.local.get(adr_var)
+#     wgn.i32.load()
+#     wgn.local.set(len_var)
 
-    wgn.add_statement('nop', comment='i = 0')
-    idx_var = wgn.temp_var_i32(f'fold_{codestyle.type3(inp.type3)}_idx')
-    wgn.i32.const(0)
-    wgn.local.set(idx_var)
+#     wgn.add_statement('nop', comment='i = 0')
+#     idx_var = wgn.temp_var_i32(f'fold_{codestyle.type3(inp.type3)}_idx')
+#     wgn.i32.const(0)
+#     wgn.local.set(idx_var)
 
-    wgn.add_statement('nop', comment='if i < len')
-    wgn.local.get(idx_var)
-    wgn.local.get(len_var)
-    wgn.i32.lt_u()
-    with wgn.if_():
-        # From here on, adr_var is the address of byte we're referencing
-        # This is akin to calling stdlib_types.__subscript_bytes__
-        # But since we already know we are inside of bounds,
-        # can just bypass it and load the memory directly.
-        wgn.local.get(adr_var)
-        wgn.i32.const(3) # Bytes header -1, since we do a +1 every loop
-        wgn.i32.add()
-        wgn.local.set(adr_var)
+#     wgn.add_statement('nop', comment='if i < len')
+#     wgn.local.get(idx_var)
+#     wgn.local.get(len_var)
+#     wgn.i32.lt_u()
+#     with wgn.if_():
+#         # From here on, adr_var is the address of byte we're referencing
+#         # This is akin to calling stdlib_types.__subscript_bytes__
+#         # But since we already know we are inside of bounds,
+#         # can just bypass it and load the memory directly.
+#         wgn.local.get(adr_var)
+#         wgn.i32.const(3) # Bytes header -1, since we do a +1 every loop
+#         wgn.i32.add()
+#         wgn.local.set(adr_var)
 
-        wgn.add_statement('nop', comment='while True')
-        with wgn.loop():
-            wgn.add_statement('nop', comment='acu = func(acu, iter[i])')
-            wgn.local.get(acu_var)
+#         wgn.add_statement('nop', comment='while True')
+#         with wgn.loop():
+#             wgn.add_statement('nop', comment='acu = func(acu, iter[i])')
+#             wgn.local.get(acu_var)
 
-            # Get the next byte, write back the address
-            wgn.local.get(adr_var)
-            wgn.i32.const(1)
-            wgn.i32.add()
-            wgn.local.tee(adr_var)
-            wgn.i32.load8_u()
+#             # Get the next byte, write back the address
+#             wgn.local.get(adr_var)
+#             wgn.i32.const(1)
+#             wgn.i32.add()
+#             wgn.local.tee(adr_var)
+#             wgn.i32.load8_u()
 
-            wgn.add_statement('call', f'${inp.func.name}')
-            wgn.local.set(acu_var)
+#             wgn.add_statement('call', f'${inp.func.name}')
+#             wgn.local.set(acu_var)
 
-            wgn.add_statement('nop', comment='i = i + 1')
-            wgn.local.get(idx_var)
-            wgn.i32.const(1)
-            wgn.i32.add()
-            wgn.local.set(idx_var)
+#             wgn.add_statement('nop', comment='i = i + 1')
+#             wgn.local.get(idx_var)
+#             wgn.i32.const(1)
+#             wgn.i32.add()
+#             wgn.local.set(idx_var)
 
-            wgn.add_statement('nop', comment='if i >= len: break')
-            wgn.local.get(idx_var)
-            wgn.local.get(len_var)
-            wgn.i32.lt_u()
-            wgn.br_if(0)
+#             wgn.add_statement('nop', comment='if i >= len: break')
+#             wgn.local.get(idx_var)
+#             wgn.local.get(len_var)
+#             wgn.i32.lt_u()
+#             wgn.br_if(0)
 
-    # return acu
-    wgn.local.get(acu_var)
+#     # return acu
+#     wgn.local.get(acu_var)
 
 def statement_return(wgn: WasmGenerator, inp: ourlang.StatementReturn) -> None:
     """

phasm/ourlang.py

@@ -1,10 +1,10 @@
 """
 Contains the syntax tree for ourlang
 """
-import enum
 from typing import Dict, Iterable, List, Optional, Union
 
 from . import prelude
+from .type3.functions import FunctionSignature, TypeVariableContext
 from .type3.placeholders import PlaceholderForType, Type3OrPlaceholder
 from .type3.typeclasses import Type3ClassMethod
 from .type3.types import Type3
@@ -222,36 +222,6 @@ class AccessStructMember(Expression):
         self.struct_type3 = struct_type3
         self.member = member
 
-class Fold(Expression):
-    """
-    A (left or right) fold
-    """
-    class Direction(enum.Enum):
-        """
-        Which direction to fold in
-        """
-        LEFT = 0
-        RIGHT = 1
-
-    dir: Direction
-    func: 'Function'
-    base: Expression
-    iter: Expression
-
-    def __init__(
-            self,
-            dir_: Direction,
-            func: 'Function',
-            base: Expression,
-            iter_: Expression,
-        ) -> None:
-        super().__init__()
-
-        self.dir = dir_
-        self.func = func
-        self.base = base
-        self.iter = iter_
-
 class Statement:
     """
     A statement within a function
@@ -300,21 +270,22 @@ class FunctionParam:
     name: str
     type3: Type3OrPlaceholder
 
-    def __init__(self, name: str, type3: Optional[Type3]) -> None:
+    def __init__(self, name: str, type3: Type3) -> None:
         self.name = name
-        self.type3 = PlaceholderForType([self]) if type3 is None else type3
+        self.type3 = type3
 
 class Function:
     """
     A function processes input and produces output
     """
-    __slots__ = ('name', 'lineno', 'exported', 'imported', 'statements', 'returns_type3', 'posonlyargs', )
+    __slots__ = ('name', 'lineno', 'exported', 'imported', 'statements', 'signature', 'returns_type3', 'posonlyargs', )
 
     name: str
     lineno: int
     exported: bool
     imported: Optional[str]
     statements: List[Statement]
+    signature: FunctionSignature
     returns_type3: Type3
     posonlyargs: List[FunctionParam]
 
@@ -324,6 +295,7 @@ class Function:
         self.exported = False
         self.imported = None
         self.statements = []
+        self.signature = FunctionSignature(TypeVariableContext(), [])
         self.returns_type3 = prelude.none # FIXME: This could be a placeholder
         self.posonlyargs = []
 
@@ -354,12 +326,14 @@ class StructConstructor(Function):
     def __init__(self, struct_type3: Type3) -> None:
         super().__init__(f'@{struct_type3.name}@__init___@', -1)
 
-        self.returns_type3 = struct_type3
-
         st_args = prelude.struct.did_construct(struct_type3)
         assert st_args is not None
         for mem, typ in st_args.items():
             self.posonlyargs.append(FunctionParam(mem, typ, ))
+            self.signature.args.append(typ)
+
+        self.returns_type3 = struct_type3
+        self.signature.args.append(struct_type3)
 
         self.struct_type3 = struct_type3
 

phasm/parser.py

@@ -14,7 +14,6 @@ from .ourlang import (
     ConstantStruct,
     ConstantTuple,
     Expression,
-    Fold,
     Function,
     FunctionCall,
     FunctionParam,
@@ -159,9 +158,18 @@ class OurVisitor:
         _not_implemented(not node.args.posonlyargs, 'FunctionDef.args.posonlyargs')
 
         for arg in node.args.args:
+            if arg.annotation is None:
+                _raise_static_error(node, 'Must give a argument type')
+
+            arg_type = self.visit_type(module, arg.annotation)
+
+            # if isisntance(arg_type, TypeVariable):
+            #   arg_type = PlaceHolderForType()
+
+            function.signature.args.append(arg_type)
             function.posonlyargs.append(FunctionParam(
                 arg.arg,
-                self.visit_type(module, arg.annotation) if arg.annotation else None,
+                arg_type,
             ))
 
         _not_implemented(not node.args.vararg, 'FunctionDef.args.vararg')
@@ -202,11 +210,11 @@ class OurVisitor:
                 else:
                     function.imported = 'imports'
 
-        if node.returns is not None: # Note: `-> None` would be a ast.Constant
-            function.returns_type3 = self.visit_type(module, node.returns)
-        else:
-            # FIXME: Mostly works already, needs to fix Function.returns_type3 and have it updated
-            raise NotImplementedError('Function without an explicit return type')
+        if node.returns is None: # Note: `-> None` would be a ast.Constant
+            _raise_static_error(node, 'Must give a return type')
+        return_type = self.visit_type(module, node.returns)
+        function.signature.args.append(return_type)
+        function.returns_type3 = return_type
 
         _not_implemented(not node.type_comment, 'FunctionDef.type_comment')
 
@@ -467,7 +475,7 @@ class OurVisitor:
 
         raise NotImplementedError(f'{node} as expr in FunctionDef')
 
-    def visit_Module_FunctionDef_Call(self, module: Module, function: Function, our_locals: OurLocals, node: ast.Call) -> Union[Fold, FunctionCall, UnaryOp]:
+    def visit_Module_FunctionDef_Call(self, module: Module, function: Function, our_locals: OurLocals, node: ast.Call) -> Union[FunctionCall, UnaryOp]:
         if node.keywords:
             _raise_static_error(node, 'Keyword calling not supported') # Yet?
 
@@ -490,35 +498,35 @@ class OurVisitor:
             )
             unary_op.type3 = prelude.u32
             return unary_op
-        elif node.func.id == 'foldl':
-            if 3 != len(node.args):
-                _raise_static_error(node, f'Function {node.func.id} requires 3 arguments but {len(node.args)} are given')
+        # elif node.func.id == 'foldl':
+        #     if 3 != len(node.args):
+        #         _raise_static_error(node, f'Function {node.func.id} requires 3 arguments but {len(node.args)} are given')
 
-            # TODO: This is not generic, you cannot return a function
-            subnode = node.args[0]
-            if not isinstance(subnode, ast.Name):
-                raise NotImplementedError(f'Calling methods that are not a name {subnode}')
-            if not isinstance(subnode.ctx, ast.Load):
-                _raise_static_error(subnode, 'Must be load context')
-            if subnode.id not in module.functions:
-                _raise_static_error(subnode, 'Reference to undefined function')
-            func = module.functions[subnode.id]
-            if 2 != len(func.posonlyargs):
-                _raise_static_error(node, f'Function {node.func.id} requires a function with 2 arguments but a function with {len(func.posonlyargs)} args is given')
+        #     # TODO: This is not generic, you cannot return a function
+        #     subnode = node.args[0]
+        #     if not isinstance(subnode, ast.Name):
+        #         raise NotImplementedError(f'Calling methods that are not a name {subnode}')
+        #     if not isinstance(subnode.ctx, ast.Load):
+        #         _raise_static_error(subnode, 'Must be load context')
+        #     if subnode.id not in module.functions:
+        #         _raise_static_error(subnode, 'Reference to undefined function')
+        #     func = module.functions[subnode.id]
+        #     if 2 != len(func.posonlyargs):
+        #         _raise_static_error(node, f'Function {node.func.id} requires a function with 2 arguments but a function with {len(func.posonlyargs)} args is given')
 
-            return Fold(
-                Fold.Direction.LEFT,
-                func,
-                self.visit_Module_FunctionDef_expr(module, function, our_locals, node.args[1]),
-                self.visit_Module_FunctionDef_expr(module, function, our_locals, node.args[2]),
-            )
+        #     return Fold(
+        #         Fold.Direction.LEFT,
+        #         func,
+        #         self.visit_Module_FunctionDef_expr(module, function, our_locals, node.args[1]),
+        #         self.visit_Module_FunctionDef_expr(module, function, our_locals, node.args[2]),
+        #     )
         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.posonlyargs) if isinstance(func, Function) else len(func.signature) - 1
+        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')

phasm/prelude/__init__.py

@@ -2,7 +2,12 @@
 The prelude are all the builtin types, type classes and methods
 """
 
-from ..type3.typeclasses import Type3Class, TypeVariable, instance_type_class
+from ..type3.typeclasses import (
+    Type3Class,
+    TypeConstructorVariable,
+    TypeVariable,
+    instance_type_class,
+)
 from ..type3.types import (
     Type3,
     TypeConstructor_StaticArray,
@@ -121,7 +126,8 @@ PRELUDE_TYPES: dict[str, Type3] = {
 }
 
 a = TypeVariable('a')
-
+b = TypeVariable('b')
+t = TypeConstructorVariable('t')
 
 InternalPassAsPointer = Type3Class('InternalPassAsPointer', [a], methods={}, operators={})
 """
@@ -247,6 +253,10 @@ Sized_ = Type3Class('Sized', [a], methods={
 
 instance_type_class(Sized_, bytes_)
 
+Foldable = Type3Class('Foldable', [t], methods={
+    'foldl': [[a, b, b], b, t(a), b],
+}, operators={})
+
 PRELUDE_TYPE_CLASSES = {
     'Eq': Eq,
     'Ord': Ord,

phasm/type3/constraints.py

@@ -186,7 +186,7 @@ class TupleMatchConstraint(ConstraintBase):
 
             return [
                 SameTypeConstraint(arg, oth_arg)
-                for arg, oth_arg in zip(self.args, tp_args)
+                for arg, oth_arg in zip(self.args, tp_args, strict=True)
             ]
 
         raise NotImplementedError(exp_type)
@@ -241,14 +241,10 @@ class MustImplementTypeClassConstraint(ConstraintBase):
     """
     __slots__ = ('type_class3', 'type3', )
 
-    type_class3: Union[str, typeclasses.Type3Class]
+    type_class3: typeclasses.Type3Class
     type3: placeholders.Type3OrPlaceholder
 
-    DATA = {
-        'bytes': {'Foldable'},
-    }
-
-    def __init__(self, type_class3: Union[str, typeclasses.Type3Class], type3: placeholders.Type3OrPlaceholder, comment: Optional[str] = None) -> None:
+    def __init__(self, type_class3: typeclasses.Type3Class, type3: placeholders.Type3OrPlaceholder, comment: Optional[str] = None) -> None:
         super().__init__(comment=comment)
 
         self.type_class3 = type_class3
@@ -262,12 +258,8 @@ class MustImplementTypeClassConstraint(ConstraintBase):
         if isinstance(typ, placeholders.PlaceholderForType):
             return RequireTypeSubstitutes()
 
-        if isinstance(self.type_class3, typeclasses.Type3Class):
         if self.type_class3 in typ.classes:
             return None
-        else:
-            if self.type_class3 in self.__class__.DATA.get(typ.name, set()):
-                return None
 
         return Error(f'{typ.name} does not implement the {self.type_class3} type class')
 
@@ -369,11 +361,11 @@ class LiteralFitsConstraint(ConstraintBase):
 
                 res.extend(
                     LiteralFitsConstraint(x, y)
-                    for x, y in zip(tp_args, self.literal.value)
+                    for x, y in zip(tp_args, self.literal.value, strict=True)
                 )
                 res.extend(
                     SameTypeConstraint(x, y.type3)
-                    for x, y in zip(tp_args, self.literal.value)
+                    for x, y in zip(tp_args, self.literal.value, strict=True)
                 )
 
                 return res
@@ -417,11 +409,11 @@ class LiteralFitsConstraint(ConstraintBase):
 
             res.extend(
                 LiteralFitsConstraint(x, y)
-                for x, y in zip(st_args.values(), self.literal.value)
+                for x, y in zip(st_args.values(), self.literal.value, strict=True)
             )
             res.extend(
                 SameTypeConstraint(x_t, y.type3, comment=f'{self.literal.struct_name}.{x_n}')
-                for (x_n, x_t, ), y in zip(st_args.items(), self.literal.value)
+                for (x_n, x_t, ), y in zip(st_args.items(), self.literal.value, strict=True)
             )
 
             return res

phasm/type3/constraintsgenerator.py

@@ -6,8 +6,9 @@ The constraints solver can then try to resolve all constraints.
 from typing import Generator, List
 
 from .. import ourlang, prelude
+from . import functions as functions
 from . import placeholders as placeholders
-from . import typeclasses as type3typeclasses
+from . import typeclasses as typeclasses
 from . import types as type3types
 from .constraints import (
     CanBeSubscriptedConstraint,
@@ -55,81 +56,51 @@ def expression(ctx: Context, inp: ourlang.Expression) -> ConstraintGenerator:
 
         raise NotImplementedError(expression, inp, inp.operator)
 
-    if isinstance(inp, ourlang.BinaryOp):
-        type_var_map = {
-            x: placeholders.PlaceholderForType([])
-            for x in inp.operator.signature
-            if isinstance(x, type3typeclasses.TypeVariable)
-        }
+    if isinstance(inp, ourlang.BinaryOp) or isinstance(inp, ourlang.FunctionCall):
+        signature = inp.operator.signature if isinstance(inp, ourlang.BinaryOp) else inp.function.signature
+        arguments = [inp.left, inp.right] if isinstance(inp, ourlang.BinaryOp) else inp.arguments
 
-        yield from expression(ctx, inp.left)
-        yield from expression(ctx, inp.right)
-
-        for type_var in inp.operator.type3_class.args:
-            assert type_var in type_var_map # When can this happen?
-
-            yield MustImplementTypeClassConstraint(
-                inp.operator.type3_class,
-                type_var_map[type_var],
-            )
-
-        for sig_part, arg_expr in zip(inp.operator.signature, [inp.left, inp.right, inp]):
-            if isinstance(sig_part, type3typeclasses.TypeVariable):
-                yield SameTypeConstraint(type_var_map[sig_part], arg_expr.type3)
-                continue
-
-            if isinstance(sig_part, type3types.Type3):
-                yield SameTypeConstraint(sig_part, arg_expr.type3)
-                continue
-
-            raise NotImplementedError(sig_part)
-        return
-
-    if isinstance(inp, ourlang.FunctionCall):
-        if isinstance(inp.function, type3typeclasses.Type3ClassMethod):
-            # FIXME: Duplicate code with BinaryOp
+        func_name = f'({inp.operator.name})' if isinstance(inp, ourlang.BinaryOp) else inp.function.name
 
         type_var_map = {
             x: placeholders.PlaceholderForType([])
-                for x in inp.function.signature
-                if isinstance(x, type3typeclasses.TypeVariable)
+            for x in signature.args
+            if isinstance(x, functions.TypeVariable)
         }
 
-            for call_arg in inp.arguments:
+        for call_arg in arguments:
             yield from expression(ctx, call_arg)
 
-            for type_var in inp.function.type3_class.args:
+        for type_var, constraint_list in signature.context.constraints.items():
             assert type_var in type_var_map # When can this happen?
 
+            for constraint in constraint_list:
+                if isinstance(constraint, functions.TypeVariableConstraint_TypeHasTypeClass):
                     yield MustImplementTypeClassConstraint(
-                    inp.function.type3_class,
+                        constraint.type_class3,
                         type_var_map[type_var],
                     )
+                    continue
 
-            for sig_part, arg_expr in zip(inp.function.signature, inp.arguments + [inp]):
-                if isinstance(sig_part, type3typeclasses.TypeVariable):
-                    yield SameTypeConstraint(type_var_map[sig_part], arg_expr.type3)
+                raise NotImplementedError(constraint)
+
+        for arg_no, (sig_part, arg_expr) in enumerate(zip(signature.args, arguments + [inp], strict=True)):
+            if arg_no == len(arguments):
+                comment = f'The type of a function call to {func_name} is the same as the type that the function returns'
+            else:
+                comment = f'The type of the value passed to argument {arg_no} of function {func_name} should match the type of that argument'
+
+            if isinstance(sig_part, functions.TypeVariable):
+                yield SameTypeConstraint(type_var_map[sig_part], arg_expr.type3, comment=comment)
                 continue
 
             if isinstance(sig_part, type3types.Type3):
-                    yield SameTypeConstraint(sig_part, arg_expr.type3)
+                yield SameTypeConstraint(sig_part, arg_expr.type3, comment=comment)
                 continue
 
             raise NotImplementedError(sig_part)
         return
 
-        yield SameTypeConstraint(inp.function.returns_type3, inp.type3,
-            comment=f'The type of a function call to {inp.function.name} is the same as the type that the function returns')
-
-        assert len(inp.arguments) == len(inp.function.posonlyargs) # FIXME: Make this a Constraint
-
-        for fun_arg, call_arg in zip(inp.function.posonlyargs, inp.arguments):
-            yield from expression(ctx, call_arg)
-            yield SameTypeConstraint(fun_arg.type3, call_arg.type3,
-                comment=f'The type of the value passed to argument {fun_arg.name} of function {inp.function.name} should match the type of that argument')
-
-        return
-
     if isinstance(inp, ourlang.TupleInstantiation):
         r_type = []
         for arg in inp.elements:
@@ -161,16 +132,6 @@ def expression(ctx: Context, inp: ourlang.Expression) -> ConstraintGenerator:
             comment=f'The type of a struct member reference is the same as the type of struct member {inp.struct_type3.name}.{inp.member}')
         return
 
-    if isinstance(inp, ourlang.Fold):
-        yield from expression(ctx, inp.base)
-        yield from expression(ctx, inp.iter)
-
-        yield SameTypeConstraint(inp.func.posonlyargs[0].type3, inp.func.returns_type3, inp.base.type3, inp.type3,
-            comment='foldl :: Foldable t => (b -> a -> b) -> b -> t a -> b')
-        yield MustImplementTypeClassConstraint('Foldable', inp.iter.type3)
-
-        return
-
     raise NotImplementedError(expression, inp)
 
 def statement_return(ctx: Context, fun: ourlang.Function, inp: ourlang.StatementReturn) -> ConstraintGenerator:

phasm/type3/functions.py

@@ -0,0 +1,67 @@
+from typing import TYPE_CHECKING, Any, Iterable, List, Union
+
+if TYPE_CHECKING:
+    from .typeclasses import Type3Class
+    from .types import Type3
+
+
+class TypeVariable:
+    """
+    Types variable are used in function definition.
+
+    They are used in places where you don't know the exact type.
+    They are different from PlaceholderForType, as those are instanced
+    during type checking. These type variables are used solely in the
+    function's definition
+    """
+    __slots__ = ('letter', )
+
+    letter: str
+
+    def __init__(self, letter: str) -> None:
+        assert len(letter) == 1, f'{letter} is not a valid type variable'
+        self.letter = letter
+
+    def __hash__(self) -> int:
+        return hash(self.letter)
+
+    def __eq__(self, other: Any) -> bool:
+        if not isinstance(other, TypeVariable):
+            raise NotImplementedError
+
+        return self.letter == other.letter
+
+    def __repr__(self) -> str:
+        return f'TypeVariable({repr(self.letter)})'
+
+class TypeVariableConstraintBase:
+    __slots__ = ()
+
+class TypeVariableConstraint_TypeHasTypeClass(TypeVariableConstraintBase):
+    __slots__ = ('type_class3', )
+
+    def __init__(self, type_class3: 'Type3Class') -> None:
+        self.type_class3 = type_class3
+
+class TypeVariableContext:
+    __slots__ = ('constraints', )
+
+    constraints: dict[TypeVariable, list[TypeVariableConstraintBase]]
+
+    def __init__(self) -> None:
+        self.constraints = {}
+
+    def __copy__(self) -> 'TypeVariableContext':
+        result = TypeVariableContext()
+        result.constraints.update(self.constraints)
+        return result
+
+class FunctionSignature:
+    __slots__ = ('context', 'args', )
+
+    context: TypeVariableContext
+    args: List[Union['Type3', TypeVariable]]
+
+    def __init__(self, context: TypeVariableContext, args: Iterable[Union['Type3', TypeVariable]]) -> None:
+        self.context = context.__copy__()
+        self.args = list(args)

phasm/type3/typeclasses.py

@@ -1,5 +1,11 @@
 from typing import Any, Dict, Iterable, List, Mapping, Optional, Union
 
+from .functions import (
+    FunctionSignature,
+    TypeVariable,
+    TypeVariableConstraint_TypeHasTypeClass,
+    TypeVariableContext,
+)
 from .types import Type3, TypeConstructor, TypeConstructor_Struct
 
 
@@ -24,6 +30,27 @@ class TypeVariable:
     def __repr__(self) -> str:
         return f'TypeVariable({repr(self.letter)})'
 
+class TypeConstructorVariable:
+    __slots__ = ('letter', )
+
+    letter: str
+
+    def __init__(self, letter: str) -> None:
+        assert len(letter) == 1, f'{letter} is not a valid type variable'
+        self.letter = letter
+
+    def __hash__(self) -> int:
+        return hash(self.letter)
+
+    def __eq__(self, other: Any) -> bool:
+        if not isinstance(other, TypeVariable):
+            raise NotImplementedError
+
+        return self.letter == other.letter
+
+    def __repr__(self) -> str:
+        return f'TypeVariable({repr(self.letter)})'
+
 class TypeReference:
     __slots__ = ('name', )
 
@@ -45,26 +72,27 @@ class TypeReference:
     def __repr__(self) -> str:
         return f'TypeReference({repr(self.name)})'
 
+Signature = List[Union[Type3, TypeVariable, list[TypeVariable]]]
+
 class Type3ClassMethod:
-    __slots__ = ('type3_class', 'name', 'signature', )
+    __slots__ = ('name', 'signature', )
 
-    type3_class: 'Type3Class'
     name: str
-    signature: List[Union[Type3, TypeVariable]]
+    signature: FunctionSignature
+
+    def __init__(self, name: str, signature: FunctionSignature) -> None:
 
-    def __init__(self, type3_class: 'Type3Class', name: str, signature: Iterable[Union[Type3, TypeVariable]]) -> None:
-        self.type3_class = type3_class
         self.name = name
-        self.signature = list(signature)
+        self.signature = signature
 
     def __repr__(self) -> str:
-        return f'Type3ClassMethod({repr(self.type3_class)}, {repr(self.name)}, {repr(self.signature)})'
+        return f'Type3ClassMethod({repr(self.name)}, {repr(self.signature)})'
 
 class Type3Class:
     __slots__ = ('name', 'args', 'methods', 'operators', 'inherited_classes', )
 
     name: str
-    args: List[TypeVariable]
+    args: List[Union[TypeVariable, TypeConstructorVariable]]
     methods: Dict[str, Type3ClassMethod]
     operators: Dict[str, Type3ClassMethod]
     inherited_classes: List['Type3Class']
@@ -72,19 +100,33 @@ class Type3Class:
     def __init__(
             self,
             name: str,
-            args: Iterable[TypeVariable],
-            methods: Mapping[str, Iterable[Union[Type3, TypeVariable]]],
-            operators: Mapping[str, Iterable[Union[Type3, TypeVariable]]],
+            args: Iterable[Union[TypeVariable, TypeConstructorVariable]],
+            methods: Mapping[str, Signature],
+            operators: Mapping[str, Signature],
             inherited_classes: Optional[List['Type3Class']] = None,
         ) -> None:
         self.name = name
         self.args = list(args)
+
+        context = TypeVariableContext()
+        for arg in args:
+            context.constraints[arg] = [
+                TypeVariableConstraint_TypeHasTypeClass(self)
+            ]
+
+        # FIXME: Multi parameter class types
+        # To fix this, realise that an instantiation of a multi paramater type class
+        # means that the instantiation depends on the combination of type classes
+        # and so we can't store the type classes on the types anymore
+        # This also means constraints should store a tuple of types as its key
+        assert len(context.constraints) <= 1
+
         self.methods = {
-            k: Type3ClassMethod(self, k, v)
+            k: Type3ClassMethod(k, FunctionSignature(context, v))
             for k, v in methods.items()
         }
         self.operators = {
-            k: Type3ClassMethod(self, k, v)
+            k: Type3ClassMethod(k, FunctionSignature(context, v))
             for k, v in operators.items()
         }
         self.inherited_classes = inherited_classes or []

tests/integration/helpers.py

@@ -64,7 +64,7 @@ class Suite:
             write_header(sys.stderr, 'Memory (pre alloc)')
             runner.interpreter_dump_memory(sys.stderr)
 
-            for arg, arg_typ in zip(args, func_args):
+            for arg, arg_typ in zip(args, func_args, strict=True):
                 assert not isinstance(arg_typ, type3placeholders.PlaceholderForType), \
                     'Cannot call polymorphic function from outside'
 
@@ -221,7 +221,7 @@ def _allocate_memory_stored_value(
             assert len(val) == len(tp_args)
 
             offset = adr
-            for val_el_val, val_el_typ in zip(val, tp_args):
+            for val_el_val, val_el_typ in zip(val, tp_args, strict=True):
                 assert not isinstance(val_el_typ, type3placeholders.PlaceholderForType)
 
                 offset += _write_memory_stored_value(runner, offset, val_el_typ, val_el_val)
@@ -424,7 +424,7 @@ def _load_tuple_from_address(runner: runners.RunnerBase, typ_args: tuple[type3ty
 
     return tuple(
         _unpack(runner, arg_typ, arg_bytes)
-        for arg_typ, arg_bytes in zip(typ_args, _split_read_bytes(read_bytes, arg_sizes))
+        for arg_typ, arg_bytes in zip(typ_args, _split_read_bytes(read_bytes, arg_sizes), strict=True)
     )
 
 def _load_struct_from_address(runner: runners.RunnerBase, st_args: dict[str, type3types.Type3], adr: int) -> Any:
@@ -444,5 +444,5 @@ def _load_struct_from_address(runner: runners.RunnerBase, st_args: dict[str, typ
 
     return {
         arg_name: _unpack(runner, arg_typ, arg_bytes)
-        for arg_name, arg_typ, arg_bytes in zip(name_list, typ_list, _split_read_bytes(read_bytes, arg_sizes))
+        for arg_name, arg_typ, arg_bytes in zip(name_list, typ_list, _split_read_bytes(read_bytes, arg_sizes), strict=True)
     }

tests/integration/test_lang/generator.md

@@ -282,7 +282,7 @@ if TYPE_NAME.startswith('tuple_') or TYPE_NAME.startswith('static_array_'):
 elif TYPE_NAME.startswith('struct_'):
     expect_type_error(
         TYPE + ' must be (u32, ) instead',
-        'The type of the value passed to argument x of function helper should match the type of that argument',
+        'The type of the value passed to argument 0 of function helper should match the type of that argument',
     )
 else:
     expect_type_error(
@@ -333,11 +333,11 @@ def testEntry() -> i32:
 if TYPE_NAME.startswith('tuple_') or TYPE_NAME.startswith('static_array_') or TYPE_NAME.startswith('struct_'):
     expect_type_error(
         TYPE + ' must be (u32, ) instead',
-        'The type of the value passed to argument x of function helper should match the type of that argument',
+        'The type of the value passed to argument 0 of function helper should match the type of that argument',
     )
 else:
     expect_type_error(
         TYPE_NAME + ' must be (u32, ) instead',
-        'The type of the value passed to argument x of function helper should match the type of that argument',
+        'The type of the value passed to argument 0 of function helper should match the type of that argument',
     )
 ```

tests/integration/test_lang/test_builtins.py

@@ -1,27 +1,8 @@
-import sys
-
 import pytest
 
-from ..helpers import Suite, write_header
-from ..runners import RunnerWasmtime
+from ..helpers import Suite
 
 
-def setup_interpreter(phash_code: str) -> RunnerWasmtime:
-    runner = RunnerWasmtime(phash_code)
-
-    runner.parse()
-    runner.compile_ast()
-    runner.compile_wat()
-    runner.interpreter_setup()
-    runner.interpreter_load()
-
-    write_header(sys.stderr, 'Phasm')
-    runner.dump_phasm_code(sys.stderr)
-    write_header(sys.stderr, 'Assembly')
-    runner.dump_wasm_wat(sys.stderr)
-
-    return runner
-
 @pytest.mark.integration_test
 def test_foldl_1():
     code_py = """

tests/integration/test_lang/test_typeclass.py

@@ -0,0 +1,20 @@
+import pytest
+
+from phasm.exceptions import StaticError
+
+from ..helpers import Suite
+
+
+@pytest.mark.integration_test
+def test_must_give_type_annotations():
+    code_py = """
+def is_equal(lft, rgt) -> bool:
+    return lft == rgt
+
+def testEntry() -> bool:
+    return is_equal(5, 15)
+"""
+    suite = Suite(code_py)
+
+    with pytest.raises(StaticError, match='Must give a argument type'):
+        suite.run_code()