[m-dev.] For review: minor additions to array.m, std_util.m, string.m

[Ralph Becket]

Hopefully nobody will object...

Ralph



Estimated hours taken: 3
	[Mainly down to getting reaquainted with remote CVS]

Miscellaneous small library improvements.

library/string.m
	Added string__length/1 function.

library/array.m
	Added `in' mode versions of array.m functions with `array_ui' modes.
	This is handy for immutable arrays.

library/std_util.m
	Added func `id/1' that computes the identity function.
	Added pred `isnt/2' to invert sense of semidet preds for higher
	order programming.  For example, where one might write
		Odds  = list__filter(odd, Xs)
	one could now also write
		Evens = list__filter(isnt(odd), Xs)

Index: string.m
===================================================================
RCS file: /home/mercury1/repository/mercury/library/string.m,v
retrieving revision 1.120
diff -u -u -r1.120 string.m
--- string.m	2000/03/20 09:01:49	1.120
+++ string.m	2000/04/11 16:45:43
@@ -1988,6 +1988,8 @@
 
 :- interface.
 
+:- func string__length(string) = int.
+
 :- func string__append(string, string) = string.
 
 :- func string__char_to_string(char) = string.
@@ -2044,6 +2046,9 @@
 %
----------------------------------------------------------------------------
%
 
 :- implementation.
+
+string__length(S) = L :-
+    string__length(S, L).
 
 string__append(S1, S2) = S3 :-
 	string__append(S1, S2, S3).
Index: std_util.m
===================================================================
RCS file: /home/mercury1/repository/mercury/library/std_util.m,v
retrieving revision 1.187
diff -u -u -r1.187 std_util.m
--- std_util.m	2000/04/02 06:37:15	1.187
+++ std_util.m	2000/04/11 16:46:01
@@ -225,6 +225,17 @@
 
 
%---------------------------------------------------------------------------
--%
 
+	% isnt(Pred, X) <=> not Pred(X)
+	%
+	% This is useful in higher order programming, e.g.
+	% 	Odds  = list__filter(odd, Xs)
+	% 	Evens = list__filter(isnt(odd), Xs)
+	%
+:- pred isnt(pred(T), T).
+:- mode isnt(pred(in) is semidet, in) is semidet.
+
+%--------------------------------------------------------------------------
---%
+
 	% `semidet_succeed' is exactly the same as `true', except that
 	% the compiler thinks that it is semi-deterministic.  You can
 	% use calls to `semidet_succeed' to suppress warnings about
@@ -3154,6 +3165,10 @@
     % Function exponentiation.
 :- func pow(func(T) = T, int, T) = T.
 
+    % The identity function.
+    %
+:- func id(T) = T.
+
 %
----------------------------------------------------------------------------
%
 %
----------------------------------------------------------------------------
%
 
@@ -3173,3 +3188,8 @@
 
 pow(F, N, X) =
     ( if N = 0 then X else pow(F, N - 1, F(X)) ).
+
+isnt(P, X) :-
+	not P(X).
+
+id(X) = X.
Index: array.m
===================================================================
RCS file: /home/mercury1/repository/mercury/library/array.m,v
retrieving revision 1.68
diff -u -u -r1.68 array.m
--- array.m	2000/03/10 01:21:29	1.68
+++ array.m	2000/04/11 16:46:07
@@ -768,15 +768,19 @@
 
 :- func array__min(array(_T)) = int.
 :- mode array__min(array_ui) = out is det.
+:- mode array__min(in) = out is det.
 
 :- func array__max(array(_T)) = int.
 :- mode array__max(array_ui) = out is det.
+:- mode array__max(in) = out is det.
 
 :- func array__size(array(_T)) = int.
 :- mode array__size(array_ui) = out is det.
+:- mode array__size(in) = out is det.
 
 :- func array__lookup(array(T), int) = T.
 :- mode array__lookup(array_ui, in) = out is det.
+:- mode array__lookup(in, in) = out is det.
 
 :- func array__set(array(T), int, T) = array(T).
 :- mode array__set(array_di, in, in) = array_uo is det.
@@ -787,6 +791,7 @@
 
 :- func array__copy(array(T)) = array(T).
 :- mode array__copy(array_ui) = array_uo is det.
+:- mode array__copy(in) = array_uo is det.
 
 :- func array__resize(array(T), int, T) = array(T).
 :- mode array__resize(array_di, in, in) = array_uo is det.
@@ -799,12 +804,15 @@
 
 :- func array__to_list(array(T)) = list(T).
 :- mode array__to_list(array_ui) = out is det.
+:- mode array__to_list(in) = out is det.
 
 :- func array__fetch_items(array(T), int, int) = list(T).
 :- mode array__fetch_items(array_ui, in, in) = out is det.
+:- mode array__fetch_items(in, in, in) = out is det.
 
 :- func array__bsearch(array(T), T, func(T,T) = comparison_result) =
maybe(int).
 :- mode array__bsearch(array_ui, in, func(in,in) = out is det) = out is
det.
+:- mode array__bsearch(in, in, func(in,in) = out is det) = out is det.
 
 :- func array__map(func(T1) = T2, array(T1)) = array(T2).
 :- mode array__map(func(in) = out is det, array_di) = array_uo is det.

--
Ralph Becket      |      MSR Cambridge      |      rbeck at microsoft.com 
--------------------------------------------------------------------------
mercury-developers mailing list
Post messages to:       mercury-developers at cs.mu.oz.au
Administrative Queries: owner-mercury-developers at cs.mu.oz.au
Subscriptions:          mercury-developers-request at cs.mu.oz.au
--------------------------------------------------------------------------