Handling optional inputs to procedures?

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Question:Handling optional inputs to procedures?

Posted: Ronan 1336 Product: Maple

February 25 2024

How should optional input parameters be handled for procedures. The example has three optional inputs

vars:=[x,y] , clr:="b" and prnt:="y" . if one wants to change prnt to"n", vars and clr values must be entered.

{vars:=[x,y] } , { clr:="b" } and{ prnt:="y"} this is a good method because one just enteres prnt="n". But have to remember the input parameter name prnt.

I have a 3rd option, but it is to complicated and probably unreliable to use in practice. and with more than 3 optional inputs too difficult to code.

I am wondering are the other approaches and what is the prefered methodology. I have about 30+ procedures to apply this to in a package.

Edit:- I can change the prnt to boolean true, false instead of "y" , "n". That would make the all the optional inputs different types.

In Test1 its should be vars::list:=[x,y] not vars::{list , `string`}:=[x,y]

(1)

NULL

Test1 := proc (A, B, vars::{list, string} := [x, y], clr::string := Geomclr, prnt::string := "y") if vars::string then clr := vars; vars := [x, y] end if; if clr = "y" or clr = "n" then prnt := clr; clr := Geomclr end if; print(clr); if prnt = "y" then print("good") end if; A*vars[1]+B*vars[2] end proc

(2)

Error, (in Test1) invalid left hand side in assignment

(3)

NULL

Test2 := proc (A, B, { vars::{list} := [x, y], clr::string := Geomclr, prnt::string := "y" }) print(clr); if prnt = "y" then print("good") end if; A*vars[1]+A*vars[2] end proc