Fix lexer

src/lexer.js

@@ -27,7 +27,7 @@ module.exports = class Lexer {
         })
         pos++
       } else if (source[pos].match(/:/)) {
-        let value = /:([^()'"\s]+)/.exec(source)[1].trim()
+        let value = /:([^()'"\s]+)/.exec(source.slice(pos))[1].trim()
         tokens.push({
           type: tokenTypes.ATTRIBUTE,
           line: line,