replaced ML_Lex.read_antiq by more concise ML_Lex.read, which includes full read/report with explicit position information;
ML_Context.eval/expression expect explicit ML_Lex source, which allows surrounding further text without loosing position information;
fall back on ML_Context.eval_text if there is no position or no surrounding text;
proper Args.name_source_position for method "tactic" and "raw_tactic";
tuned;

 s/\\([a-zA-Z]+)\s*/$1/g;

 s/\$//g;

 s/^BOOKMARK/\\BOOKMARK/g;