Other features

Introspection

display_resolution

You can check how a call will be resolved with f.display_resolution(*args, **kwargs):

from numbers import Number
from ovld import ovld, Dependent


@ovld(priority=1000)
def f(x: object): ...

@ovld
def f(x: Number): ...

@ovld
def f(x: Dependent[int, lambda x: x < 0]): ...

@ovld
def f(x: int): ...

@ovld
def f(x: str): ...

@ovld(priority=-1)
def f(x: object): ...

f.display_resolution(123)
print("=" * 50)
f.display_resolution("hello")

Displays this:

#1 [1000:0] f[*]
          @ /Users/olivier/code/ovld/resolve.py:6      #1: High priority function called FIRST
!= [0:3]    f[<lambda>()]
          @ /Users/olivier/code/ovld/resolve.py:14     #!=: Fall THROUGH this because 123 is not negative
#2 [0:2]    f[int]
          @ /Users/olivier/code/ovld/resolve.py:18     #2: int is more specific than Number
#3 [0:1]    f[Number]
          @ /Users/olivier/code/ovld/resolve.py:10     #3: Number is more specific than object
#4 [-1:0]   f[*]
          @ /Users/olivier/code/ovld/resolve.py:26     #4: Lesser priority
Resolution: f[*] will be called first.
==================================================
#1 [1000:0] f[*]
          @ /Users/olivier/code/ovld/resolve.py:6
#2 [0:1]    f[str]
          @ /Users/olivier/code/ovld/resolve.py:22
#3 [-1:0]   f[*]
          @ /Users/olivier/code/ovld/resolve.py:26
Resolution: f[*] will be called first.

display_resolution will also show any ambiguous resolutions.

display_methods

Use f.display_methods() to print out the complete list of registered methods.

Tracebacks

ovld automagically renames functions so that the stack trace is more informative. For instance, running the add function defined earlier on bad inputs:

add([[[1]]], [[[[2]]]])

Will produce the following traceback (Python 3.12):

Traceback (most recent call last):
  File "/Users/olivier/code/ovld/add.py", line 24, in <module>
    add([[[1]]], [[[[2]]]])
  File "/Users/olivier/code/ovld/src/ovld/core.py", line 57, in first_entry
    return method(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "<ovld-1426249837422956194>", line 9, in add.dispatch
  File "/Users/olivier/code/ovld/add.py", line 6, in add[list, list]
    return [add(a, b) for a, b in zip(x, y)]
            ^^^^^^^^^
  File "/Users/olivier/code/ovld/add.py", line 6, in add[list, list]
    return [add(a, b) for a, b in zip(x, y)]
            ^^^^^^^^^
  File "/Users/olivier/code/ovld/add.py", line 6, in add[list, list]
    return [add(a, b) for a, b in zip(x, y)]
            ^^^^^^^^^
  File "/Users/olivier/code/ovld/add.py", line 21, in add[*, *]
    return x + y
           ~~^~~
TypeError: unsupported operand type(s) for +: 'int' and 'list'

• The functions on the stack have names like add.dispatch, add[list, list] and add[*, *] (* stands for object), which lets you better understand what happened just from the stack trace. It also helps distinguish various paths when profiling.
• When calling the function recursively, or with recurse or call_next, the dispatch logic is inlined, leading to a flatter and less noisy stack. (This inlining also reduces ovld's overhead.)