[m-rev.] diff: add string.is_all_alnum/1

[Julien Fischer]

Add string.is_all_alnum/1.

library/string.m:
 	Add a predicate for testing whether a string contains
 	only alphabetic chracters or digits.

 	Avoid excessive module qualification.

NEWS:
 	Annouce the addition.

Julien.

diff --git a/NEWS b/NEWS
index 7e0f548..bd96059 100644
--- a/NEWS
+++ b/NEWS
@@ -82,6 +82,10 @@ Changes to the Mercury standard library:

     - infinity/0

+* The following predicate has been added to the string module:
+
+   - is_all_alnum/1
+
  Changes to the Mercury compiler:

  * We have enabled stricter checking of non-ground final insts to reject more
diff --git a/library/string.m b/library/string.m
index 9a1f080..bbf1817 100644
--- a/library/string.m
+++ b/library/string.m
@@ -425,6 +425,11 @@
      %
  :- pred is_all_alpha(string::in) is semidet.

+    % True if string contains only alphabetic characters [A-Za-z] and digits
+    % [0-9].
+    %
+:- pred is_all_alnum(string::in) is semidet.
+
      % True if string contains only alphabetic characters [A-Za-z] and
      % underscores.
      %
@@ -2130,22 +2135,22 @@ string.uncapitalize_first(S0, S) :-
          S = S0
      ).

-string.all_match(P, String) :-
+all_match(P, String) :-
      all_match_2(P, String, 0).

  :- pred all_match_2(pred(char)::in(pred(in) is semidet), string::in, int::in)
      is semidet.

-string.all_match_2(P, String, I) :-
+all_match_2(P, String, I) :-
      ( string.unsafe_index_next(String, I, J, Char) ->
          P(Char),
-        string.all_match_2(P, String, J)
+        all_match_2(P, String, J)
      ;
          true
      ).

-string.is_all_alpha(S) :-
-    string.all_match(char.is_alpha, S).
+is_all_alpha(S) :-
+    all_match(char.is_alpha, S).

      % The C version is faster than the Mercury version.
  :- pragma foreign_proc("C",
@@ -2180,8 +2185,11 @@ string.is_all_alpha(S) :-
      }
  ").

-string.is_all_alpha_or_underscore(S) :-
-    string.all_match(char.is_alpha_or_underscore, S).
+is_all_alnum(S) :-
+    all_match(char.is_alnum, S).
+
+is_all_alpha_or_underscore(S) :-
+    all_match(char.is_alpha_or_underscore, S).

      % The C version is faster than the Mercury version.
  :- pragma foreign_proc("C",
@@ -2218,8 +2226,8 @@ string.is_all_alpha_or_underscore(S) :-
      }
  ").

-string.is_all_alnum_or_underscore(S) :-
-    string.all_match(char.is_alnum_or_underscore, S).
+is_all_alnum_or_underscore(S) :-
+    all_match(char.is_alnum_or_underscore, S).

      % The C version is faster than the Mercury version.
  :- pragma foreign_proc("C",
@@ -2259,8 +2267,8 @@ string.is_all_alnum_or_underscore(S) :-
      }
  ").

-string.is_all_digits(S) :-
-    string.all_match(char.is_digit, S).
+is_all_digits(S) :-
+    all_match(char.is_digit, S).

      % The C version is faster than the Mercury version.
  :- pragma foreign_proc("C",