add function replace_nodes to Tree

[zzc0430]

This can be used to replace tokens in a Tree that satisfy a specified rule.

[erezsh]

Add tests.

[zzc0430]

Add tests.

added 388fd80

[erezsh]

Let's call it replace_tokens.

Also in the tests, you are changing tree2 in-place, which could break other tests if run in a different order.

[zzc0430]

Let's call it replace_tokens.

Also in the tests, you are changing tree2 in-place, which could break other tests if run in a different order.

done 545b808, caea780

[erezsh]

*deepcopy

[zzc0430]

*deepcopy

5ab7313

[erezsh]

@MegaIng Do we really need the special behavior for None? The callback can just return the parameter as is, if no changes are necessary. (I don't think it matters in terms of performance)

[MegaIng]

True, probably not needed.

To get the type checking to work:

• replace Token in the signature with the Leaf generic parameter.
• instead of isinstance(..., Token) just use an else statement.

This slightly changes the semantics, but I think it's more useful.

[zzc0430]

True, probably not needed.

To get the type checking to work:

• replace Token in the signature with the Leaf generic parameter.
• instead of isinstance(..., Token) just use an else statement.

This slightly changes the semantics, but I think it's more useful.

c21139c

[erezsh]

Tbh I'm not convinced this is a useful method. I can't imagine many situations where it's desirable.

But here's how it should look, if it was ever accepted: (more or less)

    def replace_values(self, replacer: 'Callable[[_Leaf_T], _Leaf_T]') -> None:
        """Replace all leaf values in the tree using the result of ``replacer(value)``.

        The callback receives each leaf and should return its replacement,
        or the same value unchanged if no replacement is desired.

        Example:
            >>> tree.replace_values(lambda v: v.update(value="y") if v == "x" else v)
        """
        for index, child in enumerate(self.children):
            if isinstance(child, Tree):
                child.replace_values(replacer)
            else:
                result = replacer(child)
                if result is not child:
                    self.children[index] = result