anders429 / substring Goto Github PK

Should be able to exclude len() for example:

string.substring_len(3)

Could be a shorthand for string.substring(3, string.len())

There are different kinds of substrings that can be supported by this library. Currently, the implementation supports substrings with respect to chars, but some users will likely want substrings with respect to graphemes instead. Word and sentence substrings could also be supported using the relevant unicode standards.

Altogether, I see the following substring variants being possible:

• CharSubstring: respect to chars, which are unicode scalar values.
• GraphemeSubstring: respect to graphemes (using unicode-segmentation).
• WordSubstring: respect to words (using unicode-segmentation).
• SentenceSubstring: respect to sentences (using unicode-segmentation).
• ByteSubstring: respecting individual bytes (equivalent to slicing the string).

Since we are already looking at a breaking change with #9, the Substring trait can be renamed to CharSubstring (so there is no ambiguity between substring variants). The unicode-segmentation variants (grapheme, word, and sentence) can be guarded behind a unicode feature (or perhaps separate features for each?). The byte variant can be held off on for now, since it really isn't needed and presents issues with properly-formed strings.

This solution will give maximum clarity as to what this crate offers, and will give flexibility for users to choose from the various types of substrings offered.

The parameters for the substring method can be changed to a RangeBounds. This will allow for providing inclusive end points, as well as providing unbounded start/end points (as has been requested in #5).

This would be a breaking change, but I think it will make the library a bit easier to use. I would rather do this than introduce several methods for each specific case. It will also raise MSRV to match what is required for RangeBounds.

Support for negative indexing would be helpful.

Example:

string.substring(-5, -3)

On the string "hello world" this would return "wo".