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#############################################################################
##
#W Iterated.gi FGA package Christian Sievers
##
## Method installations for variants of Iterated
##
## Maybe this should move to the GAP library
##
#Y 2003 - 2012
##
#############################################################################
##
#M Iterated( <list>, <func>, <obj> )
##
## applies <func> to <list> iteratively as Iterated does, but uses
## <obj> as initial value.
##
InstallOtherMethod( Iterated,
[ IsList, IsFunction, IsObject ],
function (list, f, init)
local x;
for x in list do
init := f(init, x);
od;
return init;
end );
#############################################################################
##
#M IteratedF( <list>, <func> )
##
## applies <func> to <list> iteratively as Iterated does, but stops
## and returns fail when <func> returns fail.
InstallMethod( IteratedF,
[ IsList, IsFunction ],
function (list, f)
local res, i;
if IsEmpty( list ) then
Error( "IteratedF: <list> must contain at least one element" );
fi;
res := list[1];
for i in [ 2 .. Length( list ) ] do
if res = fail then
break;
fi;
res := f( res, list[i] );
od;
return res;
end );
#############################################################################
##
#M IteratedF( <list>, <func>, <obj> )
##
## applies <func> to <list> iteratively as Iterated does, but stops
## and returns fail when <func> returns fail, and uses <obj> as
## initial value.
InstallOtherMethod( IteratedF,
[ IsList, IsFunction, IsObject ],
function (list, f, init)
local x;
for x in list do
init := f(init, x);
if init=fail then
break;
fi;
od;
return init;
end );
#############################################################################
##
#E
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