diff options
Diffstat (limited to 'stdlib/place.tl')
| -rw-r--r-- | stdlib/place.tl | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/stdlib/place.tl b/stdlib/place.tl index 5d601834..fba9a8d6 100644 --- a/stdlib/place.tl +++ b/stdlib/place.tl @@ -374,6 +374,13 @@ ^(placelet ((,pl ,place)) (set ,pl (call (opip ,*opip-args) ,pl))))) +(defmacro ensure (:env env place init-expr) + (with-gensyms (existing) + (with-update-expander (getter setter) place env + ^(iflet ((,existing (,getter))) + ,existing + (,setter ,init-expr))))) + (defmacro defplace (place-destructuring-args body-sym (getter-sym setter-sym update-body) : ((ssetter-sym clobber-body)) |