feat: QueryCursor iterators

[bennypowers]

Closes #30

[bennypowers]

I'm not sure about the tests here, there's probably a better way to test IterCaptures

[bennypowers]

I tried something similar in a project i'm working on and got some super weird errors

func allMatches(qc *ts.QueryCursor, q *ts.Query, node *ts.Node, text []byte) iter.Seq2[*ts.QueryMatch, *ts.Query] {
	qm := qc.Matches(q, node, text)
	return func(yield func (qm *ts.QueryMatch, q *ts.Query) bool) {
		for {
			m := qm.Next()
			if m == nil {
				break
			}
			if !yield(m, q) {
				return
			}
		}
	}
}

in the yield call i got a panic:

1. Thread stopped due to exception ()
   Description: Error getting throw reason: could not find symbol value for s
   Stack trace:
   Stack:
   	3  0x00007faf6f3cd11c in C.__pthread_kill_implementation
   	    at /usr/src/debug/glibc-2.41-5.fc42.x86_64/nptl/pthread_kill.c:43
   	4  0x00007faf6f373afe in C.raise
   	    at ../sysdeps/posix/raise.c:26
   	5  0x00007faf6f35b6d0 in C.abort
   	    at /usr/src/debug/glibc-2.41-5.fc42.x86_64/stdlib/abort.c:73
   	6  0x00007faf6f35b639 in C.__assert_perror_fail
   	    at /usr/src/debug/glibc-2.41-5.fc42.x86_64/assert/assert-perr.c:31

edit: ok i need to learn more about go resource management. for now I'm doing this so i can close the resources when finished at the call site

func QueryMatches(queryName string,
									language *ts.Language,
									text []byte,
									node *ts.Node) (*ts.Query, *ts.QueryCursor, iter.Seq2[*ts.QueryMatch, *ts.Query]) {
	queryText, err := loadQueryFile(queryName)
	if err != nil {
		log.Fatal(nil)
	}
	q, qerr := ts.NewQuery(language, queryText)
	if qerr != nil {
		log.Fatal(qerr)
	}
	qc := ts.NewQueryCursor()
	qm := qc.Matches(q, node, text)
	return q, qc, func(yield func (qm *ts.QueryMatch, q *ts.Query) bool) {
		for {
			m := qm.Next()
			if m == nil {
				break
			}
			if !yield(m, q) {
				return
			}
		}
	}
}

I'm demoting this back to draft until i grok this better.

[bennypowers]

Ok having played around with this, it was pebcak. I believe this code does what it says it does, I was just not properly managing the treesitter c object lifetimes