Support for gutterSettings

[timhillgit]

syntect currently reads from gutter and gutterForeground when loading themes:

syntect/src/highlighting/theme_load.rs

Lines 254 to 257 in c61ce60

	"gutter" => settings.gutter = Color::parse_settings(value).ok(),
	"gutterForeground" => {
	settings.gutter_foreground = Color::parse_settings(value).ok()
	}

But many themes instead store their gutter settings in a gutterSettings key. See for instance the base16 themes at https://github.com/chriskempson/base16-textmate/tree/master/Themes . gutterSettings seems to be more popular than gutterForeground. A GitHub search for themes with gutterSettings returns 3k hits while a search for gutterForeground returns 1.5k. Adding this would probably solve #315

[timhillgit]

I'm extremely new to Rust but I think something like the following should work:

syntect/src/highlighting/theme_load.rs

Lines 312 to 320 in 48b6316

	if let Some(Settings::Object(obj)) = obj.remove("gutterSettings") {
	for (key, value) in obj {
	match &key[..] {
	"background" => settings.gutter = Color::parse_settings(value).ok(),
	"foreground" => settings.gutter_foreground = Color::parse_settings(value).ok(),
	_ => (),
	}
	}
	}

. Happy to open up a PR if something like this would be accepted

[keith-hall]

Just to note that implementing this would mean syntect will do something that Sublime Text doesn't. The ST docs only reference gutter and gutterForeground and nothing about gutterSettings: http://www.sublimetext.com/docs/color_schemes_tmtheme.html#global_settings

[timhillgit]

Ahh, that's a good catch. It looks like this is one of the few areas where the TextMate 2 format diverges from Sublime Text. So at the very least I don't think we'd want gutterSettings to take priority over gutter and gutterForeground. I'll see if there's a good way to have gutterSettings act as a backup.