[Stdlib] Add capitalize() and title() to String and StringSlice#6169
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msaelices wants to merge 6 commits intomodular:mainfrom
Draft
[Stdlib] Add capitalize() and title() to String and StringSlice#6169msaelices wants to merge 6 commits intomodular:mainfrom
msaelices wants to merge 6 commits intomodular:mainfrom
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ArcPointer already implements Identifiable (pointer-identity semantics via __is__/__isnot__). Adding __hash__ based on the inner pointer address makes the identity relation consistent with hashing — two ArcPointers that point to the same allocation always produce the same hash, enabling use as Dict/Set keys. Signed-off-by: Manuel Saelices <[email protected]>
Signed-off-by: Manuel Saelices <[email protected]>
Signed-off-by: Manuel Saelices <[email protected]>
Adds Python-compatible `capitalize()` and `title()` string methods to `StringSlice` (implementation) and `String` (delegating wrappers). - `capitalize()`: returns a copy with the first character uppercased and the rest lowercased. - `title()`: returns a copy where each word's first character is uppercased and the rest are lowercased. Word boundaries are non-alphabetic characters, matching Python's `str.title()` semantics. Both methods are ASCII-only; non-ASCII bytes pass through unchanged. Signed-off-by: Manuel Saelices <[email protected]>
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Pull request overview
This PR extends the stdlib with Python-like string casing helpers (capitalize() / title()) on StringSlice (core implementation) and String (delegating wrappers), and also adds pointer-identity Equatable/Hashable support for ArcPointer with accompanying tests and changelog notes.
Changes:
- Add
StringSlice.capitalize()andStringSlice.title()plusStringwrapper methods. - Make
ArcPointerconform toEquatableandHashable(hashing by pointer identity) and add unit tests for equality/hash behavior. - Update nightly changelog with
ArcPointerhashability note.
Reviewed changes
Copilot reviewed 7 out of 7 changed files in this pull request and generated 6 comments.
Show a summary per file
| File | Description |
|---|---|
| mojo/stdlib/std/collections/string/string_slice.mojo | Implements capitalize() and title() logic on StringSlice. |
| mojo/stdlib/std/collections/string/string.mojo | Adds String wrappers delegating to StringSlice. |
| mojo/stdlib/test/collections/string/test_string_slice.mojo | Adds tests for new StringSlice casing APIs. |
| mojo/stdlib/test/collections/string/test_string.mojo | Adds tests for String casing wrappers. |
| mojo/stdlib/std/memory/arc_pointer.mojo | Adds Equatable/Hashable conformance and pointer-identity hash/eq. |
| mojo/stdlib/test/memory/test_arc.mojo | Adds tests for ArcPointer hashing and equality. |
| mojo/docs/nightly-changelog.md | Documents new ArcPointer Hashable behavior. |
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| # A distinct allocation is a different pointer: its address differs, so its | ||
| # hash value differs (hash is the raw address, so no collision is possible | ||
| # for two simultaneously live allocations). | ||
| var r = ArcPointer(42) | ||
| assert_true(hash(p) != hash(r)) | ||
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| def capitalize(self) -> String: | ||
| """Returns a copy of the string with the first character uppercased and the rest lowercased. | ||
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| Processes ASCII characters only. Non-ASCII characters are passed through unchanged. | ||
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| Returns: | ||
| A new `String` with the first character uppercased and the remaining characters lowercased. | ||
| """ | ||
| if self.byte_length() == 0: | ||
| return String("") | ||
| var result = self.lower() | ||
| var ptr = result.unsafe_ptr_mut() |
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| elif b >= ord("A") and b <= ord("Z"): | ||
| prev_cased = True |
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| def test_capitalize() raises: | ||
| # Basic | ||
| assert_equal(StringSlice("hello world").capitalize(), "Hello world") | ||
| # All upper | ||
| assert_equal(StringSlice("HELLO").capitalize(), "Hello") | ||
| # Mixed | ||
| assert_equal(StringSlice("hELLO").capitalize(), "Hello") | ||
| # Empty | ||
| assert_equal(StringSlice("").capitalize(), "") | ||
| # Non-alpha first char | ||
| assert_equal(StringSlice("123abc").capitalize(), "123abc") | ||
| # Single char | ||
| assert_equal(StringSlice("a").capitalize(), "A") | ||
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| def test_title() raises: | ||
| # Basic | ||
| assert_equal(StringSlice("hello world").title(), "Hello World") | ||
| # Already title case | ||
| assert_equal(StringSlice("Hello World").title(), "Hello World") | ||
| # All caps | ||
| assert_equal(StringSlice("HELLO WORLD").title(), "Hello World") | ||
| # Empty | ||
| assert_equal(StringSlice("").title(), "") | ||
| # Hyphenated | ||
| assert_equal(StringSlice("hello-world").title(), "Hello-World") | ||
| # Apostrophe (Python behavior: apostrophe is non-alpha, so char after it is uppercased) | ||
| assert_equal(StringSlice("it's a test").title(), "It'S A Test") | ||
| # Digits | ||
| assert_equal(StringSlice("123abc def").title(), "123Abc Def") | ||
| # Single word | ||
| assert_equal(StringSlice("hello").title(), "Hello") | ||
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| - `ArcPointer` now conforms to the `Hashable` trait, enabling its use as a | ||
| `Dict` key or `Set` element. The hash is based on the allocation address, | ||
| consistent with pointer-identity semantics (`a is b` implies | ||
| `hash(a) == hash(b)`). |
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| - `ArcPointer` now conforms to the `Hashable` trait, enabling its use as a | ||
| `Dict` key or `Set` element. The hash is based on the allocation address, | ||
| consistent with pointer-identity semantics (`a is b` implies | ||
| `hash(a) == hash(b)`). |
…le() Signed-off-by: Manuel Saelices <[email protected]>
Contributor
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Please see here: #6168 (comment) |
Contributor
Author
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Opened issue #6177 to track the justification for this API as requested. In the meantime, converted PR to draft. |
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Adds Python-compatible
capitalize()andtitle()string methods toStringSlice(implementation) andString(delegating wrappers).capitalize(): first character uppercased, rest lowercased.title(): each word's first character uppercased, rest lowercased. Word boundaries are non-alphabetic characters, matching Python'sstr.title()semantics.Both methods process ASCII characters only; non-ASCII bytes are passed through unchanged.
Tracking issue: #6177. Keeping as draft until consensus is reached there.
Assisted-by: AI