fix #557: use path parser for array index access

Author: yyx990803

src/parse/expression.js

@@ -18,7 +18,7 @@ var wsRE = /\s/g
 var newlineRE = /\n/g
 var saveRE = /[\{,]\s*[\w\$_]+\s*:|'[^']*'|"[^"]*"/g
 var restoreRE = /"(\d+)"/g
-var pathTestRE = /^[A-Za-z_$][\w$]*(\.[A-Za-z_$][\w$]*|\['.*?'\]|\[".*?"\])*$/
+var pathTestRE = /^[A-Za-z_$][\w$]*(\.[A-Za-z_$][\w$]*|\['.*?'\]|\[".*?"\]|\[\d+\])*$/
 var pathReplaceRE = /[^\w$\.]([A-Za-z_$][\w$]*(\.[A-Za-z_$][\w$]*|\['.*?'\]|\[".*?"\])*)/g
 var keywordsRE = new RegExp('^(' + keywords.replace(/,/g, '\\b|') + '\\b)')