robotframework · JFoederer · May 7, 2025 · May 21, 2025 · May 22, 2025 · May 29, 2025
diff --git a/atest/robot/keywords/type_conversion/custom_converters.robot b/atest/robot/keywords/type_conversion/custom_converters.robot
@@ -60,6 +60,9 @@ Invalid converters
 Non-type annotation
     Check Test Case    ${TESTNAME}
 
+From registered type
+    Check Test Case    ${TESTNAME}
+
 Using library decorator
     Check Test Case    ${TESTNAME}
 

diff --git a/atest/testdata/keywords/type_conversion/CustomConverters.py b/atest/testdata/keywords/type_conversion/CustomConverters.py
@@ -7,7 +7,7 @@
 except ImportError:
     from typing_extensions import TypedDict
 
-from robot.api.deco import not_keyword
+from robot.api.deco import not_keyword, register_converter
 
 not_keyword(TypedDict)
 
@@ -43,6 +43,30 @@ def parse_bool(value: Union[str, int, bool]):
     return value not in ["false", "", "epätosi", "\u2639", False, 0]
 
 
+class AutoConvertedNumber:
+    """type placeholder"""
+
+
+@register_converter(AutoConvertedNumber)
+def autonumber_from_str(value):
+    try:
+        return ["zero", "one", "two", "three", "four"].index(value.lower())
+    except ValueError:
+        raise ValueError(f"Don't know number {value!r}.")
+
+
+class AutoConvertedSpecialNumber:
+    """type placeholder"""
+
+
+@register_converter(AutoConvertedSpecialNumber, str, type_name='special number')
+def specialnumber_from_str(value, type_info):
+    try:
+        return dict(two=2, three=3, five=5, seven=7, eleven=11)[value.lower()]
+    except KeyError:
+        raise ValueError(f"Number {value!r} isn't a {type_info.name}.")
+
+
 class UsDate(date):
     @classmethod
     def from_string(cls, value) -> date:
@@ -148,6 +172,9 @@ def number(argument: Number, expected: int = 0):
     if argument != expected:
         raise AssertionError(f"Expected value to be {expected!r}, got {argument!r}.")
 
+def special_number(argument: AutoConvertedSpecialNumber, expected: int = 0):
+    if argument != expected:
+        raise AssertionError(f"Expected value to be {expected!r}, got {argument!r}.")
 
 def true(argument: bool):
     assert argument is True

diff --git a/atest/testdata/keywords/type_conversion/CustomConvertersWithRegisteredType.py b/atest/testdata/keywords/type_conversion/CustomConvertersWithRegisteredType.py
@@ -0,0 +1,14 @@
+from CustomConverters import AutoConvertedNumber, AutoConvertedSpecialNumber
+
+
+class CustomConvertersWithRegisteredType:
+    """
+    Library does not state any converters explicitly.
+    Conversion is done from registered type.
+    """
+
+    def from_registered_type(self, value: AutoConvertedNumber, expected: int):
+        assert value == expected, f"value [{value}] == expected [{expected}]"
+
+    def from_registered_type_special(self, value: AutoConvertedSpecialNumber, expected: int):
+        assert value == expected, f"value [{value}] == expected [{expected}]"
diff --git a/atest/testdata/keywords/type_conversion/custom_converters.robot b/atest/testdata/keywords/type_conversion/custom_converters.robot
@@ -2,6 +2,7 @@
 Library           CustomConverters.py
 Library           CustomConverters.StatefulLibrary
 Library           CustomConverters.StatefulGlobalLibrary
+Library           CustomConvertersWithRegisteredType.py
 Library           CustomConvertersWithLibraryDecorator.py
 Library           CustomConvertersWithDynamicLibrary.py
 Library           InvalidCustomConverters.py
@@ -68,6 +69,8 @@ Failing conversion
     True       ${1.0}        type=boolean    arg_type=float
     Class with hints as converter
     ...        ${1.2}        type=ClassWithHintsAsConverter    arg_type=float
+    Special number
+    ...        four          type=AutoConvertedSpecialNumber    error=Number 'four' isn't a special number.
 
 `None` as strict converter
     Strict    ${{CustomConverters.Strict()}}
@@ -103,6 +106,11 @@ Non-type annotation
     Non type annotation    x    x
     Non type annotation    ${2}
 
+From registered type
+    From registered type    zero    0
+    From registered type    four    4
+    From registered type special    seven    7
+
 Using library decorator
     Using library decorator    one    1
     Using library decorator    expected=2    value=two

diff --git a/src/robot/api/deco.py b/src/robot/api/deco.py
@@ -16,6 +16,8 @@
 from typing import Any, Callable, Literal, overload, Sequence, TypeVar, Union
 
 from .interfaces import TypeHints
+from robot.libdocpkg.standardtypes import STANDARD_TYPE_DOCS
+from robot.running.arguments import TypeConverter
 
 F = TypeVar("F", bound=Callable[..., Any])
 K = TypeVar("K", bound=Callable[..., Any])
@@ -201,3 +203,28 @@ def decorator(cls: L) -> L:
         return cls
 
     return decorator
+
+
+@not_keyword
+def register_converter(target_type, *args, type_name=None):
+    def decorator(func):
+        class ConverterProxy(TypeConverter):
+            type = target_type
+            if args: value_types = args
+            doc = func.__doc__ or target_type.__doc__ or target_type.__name__
+            type_name = target_type.__name__
+
+            def __init__(self, type_info, custom_converters=None, languages=None):
+                super().__init__(type_info, custom_converters, languages)
+                if type_name: self.type_info.name = type_name
+
+            def _convert(self, value):
+                if func.__code__.co_argcount == 2:
+                    return func(value, self.type_info)
+                else:
+                    return func(value)
+
+        STANDARD_TYPE_DOCS[target_type] = ConverterProxy.doc
+        TypeConverter.register(ConverterProxy)
+        return func
+    return decorator