fix: add uint parsing function

[valchx]

In order to get the more precise ParseIntError.InvalidCharacter error instead of ParseIntError.Overflow when a negative number is passed to a usize, uX typed argument, I use the fmt.parseUnsigned function.

[valchx]

Thoughts:
At first, I wanted to write a custom error to specify that the leading character was '-' but I see that there are no custom errors in the parsers.zig file. So falling back on the default errors might be the wiser choice.

[Hejsil]

Thoughs on making int check the signedness of T and call either parseInt or parseUnsigned?

[valchx]

@Hejsil
I'm relatively new to zig, after a bit of looking around the language ref I ended with something like this:

/// A parser that uses `std.fmt.parseInt` or `std.fmt.parseUnsigned` to parse the string into an integer value.
/// See `std.fmt.parseInt` and `std.fmt.parseUnsigned` documentation for more information.
pub fn int(comptime T: type, comptime base: u8) fn ([]const u8) std.fmt.ParseIntError!T {
    return struct {
        fn parse(in: []const u8) std.fmt.ParseIntError!T {
            return switch (@typeInfo(T)) {
                .int => |int_info| if (int_info.signedness == .signed) std.fmt.parseInt(T, in, base) else std.fmt.parseUnsigned(T, in, base),
                else => @compileError("The int parse function only supports integer types."),
            };
        }
    }.parse;
}

What do you think ?

[Hejsil]

I don't think the @compileError is nessesary (the compiler will emit an error on accessing .int anyways), so I would do this:

/// A parser that uses `std.fmt.parseInt` or `std.fmt.parseUnsigned` to parse the string into an integer value.
/// See `std.fmt.parseInt` and `std.fmt.parseUnsigned` documentation for more information.
pub fn int(comptime T: type, comptime base: u8) fn ([]const u8) std.fmt.ParseIntError!T {
    return struct {
        fn parse(in: []const u8) std.fmt.ParseIntError!T {
            return switch (@typeInfo(T).int.signedness) {
                .signed => std.fmt.parseInt(T, in, base)
                .unsigned => std.fmt.parseUnsigned(T, in, base),
            };
        }
    }.parse;
}

[Hejsil]

Thanks! 👍

[valchx]

Thanks for the feedback!