Recursive programs in XCAS.

[Han]

Slightly more readable version.

EDIT: Also removed MAKELIST() call since PocketCAS probably does not have that version of the command.

PHP Code:

#cas
comboset(s,n):=
BEGIN
local l;
local sl;
local tl;
local k;
local j;
local m;
local t;

m:=size(s);
l:={};
sl:={};
tl:={};

if n==m then l:={s}; return(l); end;
if n==1 then
    for k from 1 to m do
        l[k]:={s[k]};
    end;
    return(l);
end;
if n>m then l:={}; return(l); end;

for k from 2 to m-n+2 do
    sl:=sub(s,k,m); 
    tl:=comboset(sl,n-1);
    for j from 1 to size(tl) do
        tl[j]:=concat({s[k-1]},tl[j]);
    end;
    l:=concat(l,tl); 
end;

return(l);

END;
#end