private String debugHiddenBefore(AST ast) { if (!(ast instanceof antlr.CommonASTWithHiddenTokens)) { return ""; } antlr.CommonHiddenStreamToken parent = ((antlr.CommonASTWithHiddenTokens) ast).getHiddenBefore(); if (parent == null) { return ""; } antlr.CommonHiddenStreamToken child = null; do { child = parent; parent = child.getHiddenBefore(); } while (parent != null); return debugHiddenTokens(child); }