feat!: Char

[ospencer]

Char

This PR adds the Char type to Grain. Like other hip modern languages, a Grain Char is a single Unicode scalar value instead of a single byte. 😎 (For single bytes, we'll probably introduce a Byte type.)

The Char Stdlib

This PR also includes some char utilities in a new Char stdlib.

// The minimum value of Unicode characters
min: Number

// The maximum value of Unicode characters
max: Number

// Returns true if the given number is a valid Unicode scalar value.
// @param n: Number - the value to check
// @returns Bool
isValid

// Returns the Unicode code point for the character
// @param char: Char - the input character
// @returns Number
code

// Returns the Char for the given code point. Fails if the code point is invalid.
// @param codePoint: Number - the Unicode code point
// @returns Char
fromCode

// Returns the next valid Unicode character by code point. Fails if the input character is U+10FFFF.
// @param char: Char - the input character
// @returns Char
succ

// Returns the previous valid Unicode character by code point. Fails if the input character is U+0000.
// @param char: Char - the input character
// @returns Char
pred

Breaking Changes

This PR is a breaking change because String.explode was updated to return an array of characters instead of strings.

Character Literal Syntax

There is currently no syntax to create character literals, as we have yet to decide on a syntax.

[phated]

Just a couple questions

[phated]

Thoughts on succ and pred returning Options?

[ospencer]

Since these only fail in one pretty specific (and uncommon) case, it didn't really seem necessary to me. Feels like the kind of thing you would always just Option.get without doing any checking.

[phated]

Alright, let's make sure to document it and give the reasoning somewhere. I think that's especially important for contributor docs.

[ospencer]

Yeah, for sure.

[phated]

Any reason for having this twice instead of once at the top?

[ospencer]

Not really. This way feels a tad more clear to me since all of the code for the "fast" case is contained within the if. We'd get a few bytes back if we moved it up though.

[phated]

Seems fine. Was just curious.

[phated]

Reasoning seem good to me! 👍