New function: find-true.

This is like find-if, but returns the value of the predicate
function rather than the item.

* eval.c (eval_init): Register find-true instrinsic.

* lib.c (find_true): New function.

* lib.c (find_true): Declared.

* stdlib/doc-syms.tl: Updated.

* txr.1: Documented.

1 files changed, 1 insertions, 0 deletions

diff --git a/lib.h b/lib.h
index 512c3462..41181f6c 100644
--- a/lib.h
+++ b/lib.h
@@ -1150,6 +1150,7 @@ val find_if(val pred, val list, val key);
 val rfind_if(val pred, val list, val key);
 val find_max(val seq, val testfun, val keyfun);
 val find_min(val seq, val testfun, val keyfun);
+val find_true(val pred, val list, val keyfun);
 val posqual(val obj, val list);
 val rposqual(val obj, val list);
 val posql(val obj, val list);