emphasise that parseStringOperator(const std::string&) parses a string, not a file, by calling the argument appropriately

The prefix like "$m:" signifies type in WCCL, but in Variables code it comes from template argument; in this particular example, the <Match> type.

add SentenceContext::get_sentence_ptr to allow acces to the senetnce shared_ptr that's already there anyway

A condition that repeateadly matches an array of conditions returning resulting vector of vectors.

MatchResult - change constructor so when you provide Match it defaults to matched = true.
TokenCondition - be a bit defensive about possibility of inner predicates changing $_

It's a tuple boolean/Match Value - "is it matched?"/"actual match"