[m-rev.] Minor addition to string.m

[Ralph Becket]

Forgot about this one:


diff -u library/string.m library/string.m
--- library/string.m	30 Jan 2003 03:51:06 -0000
+++ library/string.m	31 Jan 2003 06:13:59 -0000
@@ -284,30 +284,29 @@
 
 :- func string__chomp(string) = string.
 %	string__chomp(String):
-%	`String' minus any trailing newline characters; equivalent
-%	to string__strip__suffix(pred('\n'::in) is semidet, String).
+%	`String' minus any single trailing newline character.
 
-:- func string__strip_whitespace_prefix(string) = string.
-%	string__strip_whitespace_prefix(String):
+:- func string__lstrip(string) = string.
+%	string__lstrip(String):
 %	`String' minus any initial whitespace characters.
 
-:- func string__strip_whitespace_suffix(string) = string.
-%	string__strip_whitespace_suffix(String):
+:- func string__rstrip(string) = string.
+%	string__rstrip(String):
 %	`String' minus any trailing whitespace characters.
 
-:- func string__strip_surrounding_whitespace(string) = string.
-%	string__strip_surrounding_whitespace(String):
-%	`String' minus any whitespace prefix and suffix characters.
-
-:- func string__strip_prefix(pred(char),          string) = string.
-:- mode string__strip_prefix(pred(in) is semidet, in    ) = out is det.
-%	string__strip_prefix(Pred, String):
+:- func string__strip(string) = string.
+%	string__strip(String):
+%	`String' minus any initial and trailing whitespace characters.
+
+:- func string__lstrip(pred(char),          string) = string.
+:- mode string__lstrip(pred(in) is semidet, in    ) = out is det.
+%	string__lstrip(Pred, String):
 %	`String' minus the maximal prefix consisting entirely of
 %	chars satisfying `Pred'.
 
-:- func string__strip_suffix(pred(char),          string) = string.
-:- mode string__strip_suffix(pred(in) is semidet, in    ) = out is det.
-%	string__strip_suffix(Pred, String):
+:- func string__rstrip(pred(char),          string) = string.
+:- mode string__rstrip(pred(in) is semidet, in    ) = out is det.
+%	string__rstrip(Pred, String):
 %	`String' minus the maximal suffix consisting entirely of
 %	chars satisfying `Pred'.
 
@@ -3855,30 +3854,30 @@
 
 %-----------------------------------------------------------------------------%
 
-chomp(S) = strip_suffix(pred('\n'::in) is semidet, S).
+chomp(S) = ( if index(S, length(S), '\n') then left(S, length(S) - 1) else S ).
 
 %-----------------------------------------------------------------------------%
 
-strip_whitespace_suffix(S) = strip_suffix(is_whitespace, S).
+rstrip(S) = rstrip(is_whitespace, S).
 
 %-----------------------------------------------------------------------------%
 
-strip_whitespace_prefix(S) = strip_prefix(is_whitespace, S).
+lstrip(S) = lstrip(is_whitespace, S).
 
 %-----------------------------------------------------------------------------%
 
-strip_surrounding_whitespace(S0) = S :-
+strip(S0) = S :-
 	L = prefix_length(is_whitespace, S0),
 	R = suffix_length(is_whitespace, S0),
 	S = substring(S0, L, length(S0) - L - R).
 
 %-----------------------------------------------------------------------------%
 
-strip_suffix(P, S) = substring(S, 0, length(S) - suffix_length(P, S)).
+rstrip(P, S) = left(S, length(S) - suffix_length(P, S)).
 
 %-----------------------------------------------------------------------------%
 
-strip_prefix(P, S)  = substring(S, 0, prefix_length(P, S)).
+lstrip(P, S)  = right(S, length(S) - prefix_length(P, S)).
 
 %-----------------------------------------------------------------------------%
 
@@ -3889,8 +3888,11 @@
 :- mode prefix_length_2(in,  in,  pred(in  ) is semidet, in)     = out is det.
 
 prefix_length_2(I, N, P, S) =
-	( if I < N, P(S ^ elem(I)) then prefix_length_2(I + 1, N, P, S)
-				   else I
+	( if   I < N			% XXX We need ordered conjunction.
+	  then ( if P(S ^ unsafe_elem(I)) then prefix_length_2(I + 1, N, P, S)
+					  else I
+	       )
+	  else I
 	).
 
 %-----------------------------------------------------------------------------%
@@ -3902,8 +3904,11 @@
 :- mode suffix_length_2(in,  in,  pred(in  ) is semidet, in)     = out is det.
 
 suffix_length_2(I, N, P, S) =
-	( if 0 =< I, P(S ^ elem(I)) then suffix_length_2(I - 1, N, P, S)
-				    else N - (I + 1)
+	( if   0 =< I			% XXX We need ordered conjunction.
+	  then ( if P(S ^ unsafe_elem(I)) then suffix_length_2(I - 1, N, P, S)
+					  else N - (I + 1)
+	       )
+	  else N - (I + 1)
 	).
 
 
only in patch2:
--- NEWS	27 Jan 2003 09:20:42 -0000	1.298
+++ NEWS	5 Feb 2003 01:04:21 -0000
@@ -16,7 +16,9 @@
   with `mmc --make'.
 
 Changes to the Mercury standard library:
-* Nothing yet.
+* Several new functions have been added to the string module, namely
+  elem/2, unsafe_elem/2, chomp/1, lstrip/1, lstrip/2, rstrip/1, rstrip/2,
+  strip/1, prefix_length/2, and suffix_length/2.
 
 Portability improvements:
 * Nothing yet.
@@ -60,6 +62,10 @@
   chapter of the Mercury Language Reference Manual.
 
 Changes to the Mercury standard library:
+
+* Several new functions have been added to the string module, namely
+  elem/2, unsafe_elem/2, chomp/1, lstrip/1, lstrip/2, rstrip/1, rstrip/2,
+  strip/1, prefix_length/2, and suffix_length/2.
 
 * We've added a new library module, `array2d'.
 
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