[q-lang-cvs] q/stdlib prelude.q,1.19,1.20

[Albert G. <ag...@us...>]

Update of /cvsroot/q-lang/q/stdlib
In directory sc8-pr-cvs7.sourceforge.net:/tmp/cvs-serv31575

Modified Files:
	prelude.q 
Log Message:
overhaul of enumeration operations

Index: prelude.q
===================================================================
RCS file: /cvsroot/q-lang/q/stdlib/prelude.q,v
retrieving revision 1.19
retrieving revision 1.20
diff -C2 -d -r1.19 -r1.20
*** prelude.q	9 Jun 2006 04:15:41 -0000	1.19
--- prelude.q	9 Jun 2006 11:20:04 -0000	1.20
***************
*** 133,137 ****
  [X:Num,Y:Num..Z:Num]	= numsby (Y-X) X Z;
  
! /* Enumeration operations for streams. */
  
  {X:Num..}		= numstream X;
--- 133,145 ----
  [X:Num,Y:Num..Z:Num]	= numsby (Y-X) X Z;
  
! /* Additional list enumeration operations on characters. These are not
!    implemented as builtins and are actually pretty useless because of
!    efficiency issues, but we provide them here anyway. */
! 
! [X:Char..]		= list {X..};
! [X:Char,Y:Char..]	= list {X,Y..};
! enum_from X:Char	= list (streamenum_from X);
! 
! /* Stream enumeration operations on numbers. */
  
  {X:Num..}		= numstream X;
***************
*** 144,147 ****
--- 152,171 ----
  streamenum X:Num Y:Num	= takewhile (<=Y) (numstream X);
  
+ /* Stream enumeration operations on characters. */
+ 
+ {X:Char..}		= takewhile ischar (iterate (+1) X);
+ {X:Char,Y:Char..}	= takewhile ischar (iterate (+D) X) if D<>0
+ 			    where D = Y-X;
+ streamenum_from X:Char	= takewhile ischar (iterate (+1) X);
+ 
+ {X:Char..Y:Char}	= takewhile (<=Y) Xs
+ 			    where Xs:Stream = {X..};
+ {X:Char,Y:Char..Z:Char}	= takewhile (<=Z) Xs where Xs:Stream = {X,Y..} if D>0
+ 			    where D = Y-X;
+ 			= takewhile (>=Z) Xs where Xs:Stream = {X,Y..} if D<0
+ 			    where D = Y-X;
+ streamenum X:Char Y:Char= takewhile (<=Y) Xs
+ 			    where Xs:Stream = streamenum_from X;
+ 
  /* These will work with arbitrary enumeration types. */