The new function g works as follows. The value of g args, say, is obtained by evaluation of (fun opts)(args'), where args' is obtained from args by removing the options of the form X=>A (where X is a name of an optional argument), and opts is a hash table of the same form as defs in which the default values have been replaced by the user-supplied values, e.g., the value stored under the key X has been replaced by A.
Remark: defs can also be simply a list of options.
In the following example we use a simple definition for fun so we can see everything that fun receives.
i1 : g = {a=>1, b=>2} >> opts -> args -> {args, opts} o1 = g o1 : FunctionClosure |
i2 : g x o2 = {x, OptionTable{a => 1}} b => 2 o2 : List |
i3 : g(x,y,b=>66) o3 = {(x, y), OptionTable{a => 1 }} b => 66 o3 : List |
i4 : g(t,u,a=>44,b=>77) o4 = {(t, u), OptionTable{a => 44}} b => 77 o4 : List |