refactor: Use ._with_* for internal API methods

[dangotbanned]

Closes #2248

What type of PR is this? (check all applicable)

• 💾 Refactor
• ✨ Feature
• 🐛 Bug Fix
• 🔧 Optimization
• 📝 Documentation
• ✅ Test
• 🐳 Other

Related issues

• Closes Consistently prefix (_?)with_ for "this, but with x changed"  #2248

Checklist

• Code follows style guide (ruff)
• Tests added
• Documented the changes

If you have comments or can explain your changes, please do so below

• First pass of renaming
• Pruning any unused trailing commas

[dangotbanned]

@MarcoGorelli @FBruzzesi

Thought I'd try and rip the bandage off quickly to resolve this - hope that's okay 🙂

[dangotbanned]

Note

Pretty sure all the LazyExprNameNamespaces can share something like EagerExprNameNamespace

EagerExprNameNamespace

narwhals/narwhals/_compliant/expr.py

Lines 997 to 1040 in 47d0d80

	class EagerExprNameNamespace(
	EagerExprNamespace[EagerExprT], NameNamespace[EagerExprT], Generic[EagerExprT]
	):
	def keep(self) -> EagerExprT:
	return self._from_callable(lambda name: name, alias=False)
	def map(self, function: AliasName) -> EagerExprT:
	return self._from_callable(function)
	def prefix(self, prefix: str) -> EagerExprT:
	return self._from_callable(lambda name: f"{prefix}{name}")
	def suffix(self, suffix: str) -> EagerExprT:
	return self._from_callable(lambda name: f"{name}{suffix}")
	def to_lowercase(self) -> EagerExprT:
	return self._from_callable(str.lower)
	def to_uppercase(self) -> EagerExprT:
	return self._from_callable(str.upper)
	@staticmethod
	def _alias_output_names(func: AliasName, /) -> AliasNames:
	def fn(output_names: Sequence[str], /) -> Sequence[str]:
	return [func(name) for name in output_names]
	return fn
	def _from_callable(self, func: AliasName, /, *, alias: bool = True) -> EagerExprT:
	expr = self.compliant
	return type(expr)(
	lambda df: [
	series.alias(func(name))
	for series, name in zip(expr(df), expr._evaluate_output_names(df))
	],
	depth=expr._depth,
	function_name=expr._function_name,
	evaluate_output_names=expr._evaluate_output_names,
	alias_output_names=self._alias_output_names(func) if alias else None,
	backend_version=expr._backend_version,
	implementation=expr._implementation,
	version=expr._version,
	call_kwargs=expr._call_kwargs,
	)

[MarcoGorelli]

thanks @dangotbanned