Added support for more types (#1900)

* Added support for more types

dspy/signatures/signature.py

@@ -7,12 +7,13 @@
 from contextlib import ExitStack, contextmanager
 from copy import deepcopy
 from typing import Any, Dict, Tuple, Type, Union  # noqa: UP035
+import importlib
 
 from pydantic import BaseModel, Field, create_model
 from pydantic.fields import FieldInfo
 
 import dsp
-from dspy.adapters.image_utils import Image
+from dspy.adapters.image_utils import Image  # noqa: F401
 from dspy.signatures.field import InputField, OutputField, new_to_old_field
 
 
@@ -355,7 +356,7 @@ def make_signature(
         if type_ is None:
             type_ = str
         # if not isinstance(type_, type) and not isinstance(typing.get_origin(type_), type):
-        if not isinstance(type_, (type, typing._GenericAlias, types.GenericAlias)):
+        if not isinstance(type_, (type, typing._GenericAlias, types.GenericAlias, typing._SpecialForm)):
             raise ValueError(f"Field types must be types, not {type(type_)}")
         if not isinstance(field, FieldInfo):
             raise ValueError(f"Field values must be Field instances, not {type(field)}")
@@ -400,53 +401,106 @@ def _parse_arg_string(string: str, names=None) -> Dict[str, str]:
 
 
 def _parse_type_node(node, names=None) -> Any:
-    """Recursively parse an AST node representing a type annotation.
-
-    without using structural pattern matching introduced in Python 3.10.
-    """
+    """Recursively parse an AST node representing a type annotation."""
 
     if names is None:
-        names = typing.__dict__
+        names = dict(typing.__dict__)
+        names['NoneType'] = type(None)
+
+    def resolve_name(id_: str):
+        # Check if it's a built-in known type or in the provided names
+        if id_ in names:
+            return names[id_]
+
+        # Common built-in types
+        builtin_types = [int, str, float, bool, list, tuple, dict, set, frozenset, complex, bytes, bytearray]
+
+        # Try PIL Image if 'Image' encountered
+        if 'Image' not in names:
+            try:
+                from PIL import Image
+                names['Image'] = Image
+            except ImportError:
+                pass
+
+        # If we have PIL Image and id_ is 'Image', return it
+        if 'Image' in names and id_ == 'Image':
+            return names['Image']
+
+        # Check if it matches any known built-in type by name
+        for t in builtin_types:
+            if t.__name__ == id_:
+                return t
+
+        # Attempt to import a module with this name dynamically
+        # This allows handling of module-based annotations like `dspy.Image`.
+        try:
+            mod = importlib.import_module(id_)
+            names[id_] = mod
+            return mod
+        except ImportError:
+            pass
+
+        # If we don't know the type or module, raise an error
+        raise ValueError(f"Unknown name: {id_}")
 
     if isinstance(node, ast.Module):
-        body = node.body
-        if len(body) != 1:
-            raise ValueError(f"Code is not syntactically valid: {node}")
-        return _parse_type_node(body[0], names)
+        if len(node.body) != 1:
+            raise ValueError(f"Code is not syntactically valid: {ast.dump(node)}")
+        return _parse_type_node(node.body[0], names)
 
     if isinstance(node, ast.Expr):
-        value = node.value
-        return _parse_type_node(value, names)
+        return _parse_type_node(node.value, names)
 
     if isinstance(node, ast.Name):
-        id_ = node.id
-        if id_ in names:
-            return names[id_]
+        return resolve_name(node.id)
 
-        for type_ in [int, str, float, bool, list, tuple, dict, Image]:
-            if type_.__name__ == id_:
-                return type_
-        raise ValueError(f"Unknown name: {id_}")
+    if isinstance(node, ast.Attribute):
+        base = _parse_type_node(node.value, names)
+        attr_name = node.attr
+        if hasattr(base, attr_name):
+            return getattr(base, attr_name)
+        else:
+            raise ValueError(f"Unknown attribute: {attr_name} on {base}")
 
     if isinstance(node, ast.Subscript):
         base_type = _parse_type_node(node.value, names)
-        arg_type = _parse_type_node(node.slice, names)
-        return base_type[arg_type]
+        slice_node = node.slice
+        if isinstance(slice_node, ast.Index):  # For older Python versions
+            slice_node = slice_node.value
+
+        if isinstance(slice_node, ast.Tuple):
+            arg_types = tuple(_parse_type_node(elt, names) for elt in slice_node.elts)
+        else:
+            arg_types = (_parse_type_node(slice_node, names),)
+
+        # Special handling for Union, Optional
+        if base_type is typing.Union:
+            return typing.Union[arg_types]
+        if base_type is typing.Optional:
+            if len(arg_types) != 1:
+                raise ValueError("Optional must have exactly one type argument")
+            return typing.Optional[arg_types[0]]
+
+        return base_type[arg_types]
 
     if isinstance(node, ast.Tuple):
-        elts = node.elts
-        return tuple(_parse_type_node(elt, names) for elt in elts)
+        return tuple(_parse_type_node(elt, names) for elt in node.elts)
+
+    if isinstance(node, ast.Constant):
+        return node.value
 
-    if isinstance(node, ast.Call) and node.func.id == "Field":
+    if isinstance(node, ast.Call) and isinstance(node.func, ast.Name) and node.func.id == "Field":
         keys = [kw.arg for kw in node.keywords]
-        values = [kw.value.value for kw in node.keywords]
+        values = []
+        for kw in node.keywords:
+            if isinstance(kw.value, ast.Constant):
+                values.append(kw.value.value)
+            else:
+                values.append(_parse_type_node(kw.value, names))
         return Field(**dict(zip(keys, values)))
 
-    if isinstance(node, ast.Attribute) and node.attr == "Image":
-        return Image
-
-    raise ValueError(f"Code is not syntactically valid: {node}")
-
+    raise ValueError(f"Unhandled AST node type in annotation: {ast.dump(node)}")
 
 def infer_prefix(attribute_name: str) -> str:
     """Infer a prefix from an attribute name."""

tests/signatures/test_signature.py

@@ -1,5 +1,5 @@
 import textwrap
-from typing import List
+from typing import Any, Dict, List, Optional, Tuple, Union
 
 import pydantic
 import pytest
@@ -279,3 +279,125 @@ class CustomSignature2(dspy.Signature):
     assert CustomSignature2.instructions == "I am a malicious instruction."
     assert CustomSignature2.fields["sentence"].json_schema_extra["desc"] == "I am an malicious input!"
     assert CustomSignature2.fields["sentiment"].json_schema_extra["prefix"] == "Sentiment:"
+
+
+def test_typed_signatures_basic_types():
+    # Simple built-in types
+    sig = Signature("input1: int, input2: str -> output: float")
+    assert "input1" in sig.input_fields
+    assert sig.input_fields["input1"].annotation == int
+    assert "input2" in sig.input_fields
+    assert sig.input_fields["input2"].annotation == str
+    assert "output" in sig.output_fields
+    assert sig.output_fields["output"].annotation == float
+
+
+def test_typed_signatures_generics():
+    # More complex generic types
+    sig = Signature("input_list: List[int], input_dict: Dict[str, float] -> output_tuple: Tuple[str, int]")
+    assert "input_list" in sig.input_fields
+    assert sig.input_fields["input_list"].annotation == List[int]
+    assert "input_dict" in sig.input_fields
+    assert sig.input_fields["input_dict"].annotation == Dict[str, float]
+    assert "output_tuple" in sig.output_fields
+    assert sig.output_fields["output_tuple"].annotation == Tuple[str, int]
+
+
+def test_typed_signatures_unions_and_optionals():
+    sig = Signature("input_opt: Optional[str], input_union: Union[int, None] -> output_union: Union[int, str]")
+    assert "input_opt" in sig.input_fields
+    # Optional[str] is actually Union[str, None]
+    # Depending on the environment, it might resolve to Union[str, None] or Optional[str], either is correct.
+    # We'll just check for a Union containing str and NoneType:
+    input_opt_annotation = sig.input_fields["input_opt"].annotation
+    assert (input_opt_annotation == Optional[str] or 
+            (getattr(input_opt_annotation, '__origin__', None) is Union and str in input_opt_annotation.__args__ and type(None) in input_opt_annotation.__args__))
+
+    assert "input_union" in sig.input_fields
+    input_union_annotation = sig.input_fields["input_union"].annotation
+    assert (getattr(input_union_annotation, '__origin__', None) is Union and 
+            int in input_union_annotation.__args__ and type(None) in input_union_annotation.__args__)
+
+    assert "output_union" in sig.output_fields
+    output_union_annotation = sig.output_fields["output_union"].annotation
+    assert (getattr(output_union_annotation, '__origin__', None) is Union and
+            int in output_union_annotation.__args__ and str in output_union_annotation.__args__)
+
+
+def test_typed_signatures_any():
+    sig = Signature("input_any: Any -> output_any: Any")
+    assert "input_any" in sig.input_fields
+    assert sig.input_fields["input_any"].annotation == Any
+    assert "output_any" in sig.output_fields
+    assert sig.output_fields["output_any"].annotation == Any
+
+
+def test_typed_signatures_nested():
+    # Nested generics and unions
+    sig = Signature("input_nested: List[Union[str, int]] -> output_nested: Tuple[int, Optional[float], List[str]]")
+    input_nested_ann = sig.input_fields["input_nested"].annotation
+    assert getattr(input_nested_ann, '__origin__', None) is list
+    assert len(input_nested_ann.__args__) == 1
+    union_arg = input_nested_ann.__args__[0]
+    assert getattr(union_arg, '__origin__', None) is Union
+    assert str in union_arg.__args__ and int in union_arg.__args__
+
+    output_nested_ann = sig.output_fields["output_nested"].annotation
+    assert getattr(output_nested_ann, '__origin__', None) is tuple
+    assert output_nested_ann.__args__[0] == int
+    # The second arg is Optional[float], which is Union[float, None]
+    second_arg = output_nested_ann.__args__[1]
+    assert getattr(second_arg, '__origin__', None) is Union
+    assert float in second_arg.__args__ and type(None) in second_arg.__args__
+    # The third arg is List[str]
+    third_arg = output_nested_ann.__args__[2]
+    assert getattr(third_arg, '__origin__', None) is list
+    assert third_arg.__args__[0] == str
+
+
+def test_typed_signatures_from_dict():
+    # Creating a Signature directly from a dictionary with types
+    fields = {
+        "input_str_list": (List[str], InputField()),
+        "input_dict_int": (Dict[str, int], InputField()),
+        "output_tup": (Tuple[int, float], OutputField()),
+    }
+    sig = Signature(fields)
+    assert "input_str_list" in sig.input_fields
+    assert sig.input_fields["input_str_list"].annotation == List[str]
+    assert "input_dict_int" in sig.input_fields
+    assert sig.input_fields["input_dict_int"].annotation == Dict[str, int]
+    assert "output_tup" in sig.output_fields
+    assert sig.output_fields["output_tup"].annotation == Tuple[int, float]
+
+
+def test_typed_signatures_complex_combinations():
+    # Test a very complex signature with multiple nested constructs
+    # input_complex: Dict[str, List[Optional[Tuple[int, str]]]] -> output_complex: Union[List[str], Dict[str, Any]]
+    sig = Signature("input_complex: Dict[str, List[Optional[Tuple[int, str]]]] -> output_complex: Union[List[str], Dict[str, Any]]")
+    input_complex_ann = sig.input_fields["input_complex"].annotation
+    assert getattr(input_complex_ann, '__origin__', None) is dict
+    key_arg, value_arg = input_complex_ann.__args__
+    assert key_arg == str
+    # value_arg: List[Optional[Tuple[int, str]]]
+    assert getattr(value_arg, '__origin__', None) is list
+    inner_union = value_arg.__args__[0]
+    # inner_union should be Optional[Tuple[int, str]]
+    # which is Union[Tuple[int, str], None]
+    assert getattr(inner_union, '__origin__', None) is Union
+    tuple_type = [t for t in inner_union.__args__ if t != type(None)][0]
+    assert getattr(tuple_type, '__origin__', None) is tuple
+    assert tuple_type.__args__ == (int, str)
+
+    output_complex_ann = sig.output_fields["output_complex"].annotation
+    assert getattr(output_complex_ann, '__origin__', None) is Union
+    assert len(output_complex_ann.__args__) == 2
+    possible_args = set(output_complex_ann.__args__)
+    # Expecting List[str] and Dict[str, Any]
+    # Because sets don't preserve order, just check membership.
+    # Find the List[str] arg
+    list_arg = next(a for a in possible_args if getattr(a, '__origin__', None) is list)
+    dict_arg = next(a for a in possible_args if getattr(a, '__origin__', None) is dict)
+    assert list_arg.__args__ == (str,)
+    k, v = dict_arg.__args__
+    assert k == str and v == Any