stringToEnum.zig

const std = @import("std");

fn stringToEnum(comptime T: type, str: []const u8) ?T {
    inline for (@typeInfo(T).Enum.fields) |enumField| {
        if (std.mem.eql(u8, str, enumField.name)) {
            return @intToEnum(T, @intCast(@TagType(T), enumField.value));
        }
    }
    return null;
}

This would be a good addition to std.meta, however it should return error.InvalidEnum (see std.meta.intToEnum) instead of null.