From: Enrico Tassi <enrico.tassi@inria.fr>
Date: Wed, 10 Jun 2009 11:39:26 +0000 (+0000)
Subject: new function filter_map_acc
X-Git-Tag: make_still_working~3888
X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=commitdiff_plain;h=c6b50e06bd73a29501cafe599551db206193220b;p=helm.git

new function filter_map_acc
---

diff --git a/helm/software/components/extlib/.depend.opt b/helm/software/components/extlib/.depend.opt
index 6d96e61e2..3f72e1d24 100644
--- a/helm/software/components/extlib/.depend.opt
+++ b/helm/software/components/extlib/.depend.opt
@@ -1,3 +1,12 @@
+componentsConf.cmi: 
+hExtlib.cmi: 
+hMarshal.cmi: 
+patternMatcher.cmi: 
+hLog.cmi: 
+trie.cmi: 
+hTopoSort.cmi: 
+refCounter.cmi: 
+graphvizPp.cmi: 
 componentsConf.cmo: componentsConf.cmi 
 componentsConf.cmx: componentsConf.cmi 
 hExtlib.cmo: hExtlib.cmi 
diff --git a/helm/software/components/extlib/hExtlib.ml b/helm/software/components/extlib/hExtlib.ml
index b2092c5b3..8451eb6b8 100644
--- a/helm/software/components/extlib/hExtlib.ml
+++ b/helm/software/components/extlib/hExtlib.ml
@@ -217,6 +217,18 @@ let rec filter_map f =
       | None -> filter_map f tl
       | Some v -> v :: filter_map f tl)
 
+let filter_map_acc f acc l =
+  let acc, res = 
+   List.fold_left
+    (fun (acc, res) t ->
+       match f acc t with
+       | None -> acc, res
+       | Some (acc, x) -> acc, x::res)
+    (acc,[]) l
+  in
+   acc, List.rev res
+;;
+
 let list_rev_map_filter f l =
    let rec aux a = function
       | []       -> a
diff --git a/helm/software/components/extlib/hExtlib.mli b/helm/software/components/extlib/hExtlib.mli
index 20e6c0192..a0b85ca4f 100644
--- a/helm/software/components/extlib/hExtlib.mli
+++ b/helm/software/components/extlib/hExtlib.mli
@@ -84,6 +84,9 @@ val trim_blanks: string -> string (** strip heading and trailing blanks *)
 val list_uniq: 
   ?eq:('a->'a->bool) -> 'a list -> 'a list (** uniq unix filter on lists *)
 val filter_map: ('a -> 'b option) -> 'a list -> 'b list (** filter + map *)
+val filter_map_acc: ('acc -> 'a -> ('acc * 'b) option) -> 'acc -> 'a list ->
+        'acc * 'b list (** fold/filter + map *)
+
 val list_rev_map_filter: ('a -> 'b option) -> 'a list -> 'b list
 val list_rev_map_filter_fold: ('c -> 'a -> 'c * 'b option) -> 'c -> 'a list -> 'c * 'b list
 val list_concat: ?sep:'a list -> 'a list list -> 'a list (**String.concat-like*)