Regex [(] is valid but compiler throws

[TheFireBlast]

TypeError: reduce of empty array with no initial value

irojs/src/compiler.ts

Line 351 in 355c0e8

let totalGroups = groups.reduce((a, b) => a + b);

getRegexGroups doesn't escape parenthesis inside a character class and returns an empty array.

since validateRegexAndStyleList expects getRegexGroups to return at least one capture group, it throws.

name = foo

contexts [] {
main : context {
	: pattern {
		regex		\= ([(])
		styles []	 = .foo;
	}
}
}
styles [] {
.foo : style {
	color			 = #CCCCCC
	textmate_scope	 = string
}
}