diff options
| -rw-r--r-- | src/boot.clj | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/src/boot.clj b/src/boot.clj index c5548980..eac2ad4b 100644 --- a/src/boot.clj +++ b/src/boot.clj @@ -1092,6 +1092,30 @@ ([] (. clojure.lang.PersistentArrayMap EMPTY)) ([& args] (new clojure.lang.PersistentArrayMap (to-array args)))) +(defmacro for + ([seq-expr expr] (list `for seq-expr `true expr)) + ([seq-exprs filter-expr expr] + (let [items (take-nth 2 seq-exprs) + seqs (take-nth 2 (drop 1 seq-exprs)) + gseqs (map (fn [x] (gensym (strcat (name x) "seq__"))) items) + gs (map (fn [x] (gensym (strcat (name x) "s__"))) items) + limit (dec (count items)) + gloop (gensym "loop__") + recur-list (fn [lvl] (concat (take (dec lvl) gs) [(list `rest (nth gs (dec lvl)))] (drop lvl gseqs))) + emit (fn [lvl] + (list 'if (nth gs lvl) + (if (= limit lvl) + `(let [~@(interleave items (map (fn [xs] (list `first xs)) gs))] + (if ~filter-expr + (lazy-cons ~expr (~gloop ~@(recur-list (inc lvl)))) + (recur ~@(recur-list (inc lvl))))) + (emit (inc lvl))) + (when (pos? lvl) + (list* `recur (recur-list lvl)))))] + `(let [~@(interleave gseqs seqs) + ~gloop (fn [~@gs] ~(emit 0))] + (~gloop ~@gseqs))))) + (export '( load-file load list cons conj defn @@ -1153,5 +1177,6 @@ ns-resolve resolve all-ns ns-name array-map + for )) |