take_while, drop_while

--- a/src/HOL/Tools/SMT/cvc3_solver.ML	Thu Sep 30 09:45:18 2010 +0200
+++ b/src/HOL/Tools/SMT/cvc3_solver.ML	Thu Sep 30 18:37:29 2010 +0200
@@ -27,7 +27,7 @@
   let
     val empty_line = (fn "" => true | _ => false)
     val split_first = (fn [] => ("", []) | l :: ls => (l, ls))
-    val (l, _) = split_first (dropwhile empty_line output)
+    val (l, _) = split_first (drop_while empty_line output)
   in
     if is_unsat l then @{cprop False}
     else if is_sat l then raise_cex true

--- a/src/HOL/Tools/SMT/smt_solver.ML	Thu Sep 30 09:45:18 2010 +0200
+++ b/src/HOL/Tools/SMT/smt_solver.ML	Thu Sep 30 18:37:29 2010 +0200
@@ -160,7 +160,7 @@
     val (res, err) = with_timeout ctxt (run ctxt cmd args) input
     val _ = trace_msg ctxt (pretty "SMT solver:") err
 
-    val ls = rev (dropwhile (equal "") (rev res))
+    val ls = rev (drop_while (equal "") (rev res))
     val _ = trace_msg ctxt (pretty "SMT result:") ls
   in ls end
 

--- a/src/HOL/Tools/SMT/yices_solver.ML	Thu Sep 30 09:45:18 2010 +0200
+++ b/src/HOL/Tools/SMT/yices_solver.ML	Thu Sep 30 18:37:29 2010 +0200
@@ -23,7 +23,7 @@
   let
     val empty_line = (fn "" => true | _ => false)
     val split_first = (fn [] => ("", []) | l :: ls => (l, ls))
-    val (l, _) = split_first (dropwhile empty_line output)
+    val (l, _) = split_first (drop_while empty_line output)
   in
     if String.isPrefix "unsat" l then @{cprop False}
     else if String.isPrefix "sat" l then raise_cex true

--- a/src/HOL/Tools/refute.ML	Thu Sep 30 09:45:18 2010 +0200
+++ b/src/HOL/Tools/refute.ML	Thu Sep 30 18:37:29 2010 +0200
@@ -2772,7 +2772,7 @@
               (* go back up the stack until we find a level where we can go *)
               (* to the next sibling node                                   *)
               let
-                val offsets' = dropwhile
+                val offsets' = drop_while
                   (fn off' => off' mod size_elem = size_elem - 1) offsets
               in
                 case offsets' of

--- a/src/Pure/Isar/code.ML	Thu Sep 30 09:45:18 2010 +0200
+++ b/src/Pure/Isar/code.ML	Thu Sep 30 18:37:29 2010 +0200
@@ -1049,7 +1049,7 @@
     val c = const_eqn thy thm;
     fun update_subsume thy (thm, proper) eqns = 
       let
-        val args_of = dropwhile is_Var o rev o snd o strip_comb
+        val args_of = drop_while is_Var o rev o snd o strip_comb
           o map_types Type.strip_sorts o fst o Logic.dest_equals o Thm.plain_prop_of;
         val args = args_of thm;
         val incr_idx = Logic.incr_indexes ([], Thm.maxidx_of thm + 1);

--- a/src/Pure/library.ML	Thu Sep 30 09:45:18 2010 +0200
+++ b/src/Pure/library.ML	Thu Sep 30 18:37:29 2010 +0200
@@ -83,7 +83,8 @@
   val take: int -> 'a list -> 'a list
   val drop: int -> 'a list -> 'a list
   val chop: int -> 'a list -> 'a list * 'a list
-  val dropwhile: ('a -> bool) -> 'a list -> 'a list
+  val take_while: ('a -> bool) -> 'a list -> 'a list
+  val drop_while: ('a -> bool) -> 'a list -> 'a list
   val nth: 'a list -> int -> 'a
   val nth_map: int -> ('a -> 'a) -> 'a list -> 'a list
   val nth_drop: int -> 'a list -> 'a list
@@ -421,8 +422,11 @@
   | chop _ [] = ([], [])
   | chop n (x :: xs) = chop (n - 1) xs |>> cons x;
 
-fun dropwhile P [] = []
-  | dropwhile P (ys as x::xs) = if P x then dropwhile P xs else ys;
+fun drop_while P [] = []
+  | drop_while P (ys as x :: xs) = if P x then drop_while P xs else ys;
+
+fun take_while P [] = []
+  | take_while P (x :: xs) = if P x then x :: take_while P xs else [];
 
 (*return nth element of a list, where 0 designates the first element;
   raise Subscript if list too short*)