Unfinished Bitness

In this post I explore the use of PROCedures and FUNCtions in Action!

Procedures and Functions

Action! gives the ability to create both procedures and functions. similar to BASIC subroutines, or C functions, or any number of other languages that support structured subroutine mechanisms.  A very simple program may not need either type.  The difference between a procedure and function is that functions return a value.  Each can accept up to five parameters.

Procedures in Action! are created using the construct:

PROC name([parameter,...])
RETURN

Functions in Action! are created using the construct:

type FUNC name([parameter,...])
RETURN (value)

In writing these I learned that every program must contain a procedure.    Though I’m not sure why the simple print’s didn’t require it.  The programs presented here are in proper Action! form.

Procedures

A simple program that uses a procedure.  This passes two parameters to a procedure called MyCalc which in turn multiples the two together then divides the result by 2, then finally displays the result (which should be 25):

MODULE

PROC MyCalc(INT a,b)
  INT r=[0] 
  r=(a*b)/2 
  Print("Result=") 
  PrintF("%I",r) 
RETURN 

PROC Main() 
  MyCalc(5,10) 
RETURN

Functions

This is a function implementation of the same calculation as the procedure above, but rather than output the result to the screen, it returns the result for assignment to a third variable, which in turn is output to the screen.

MODULE

INT FUNC MyCalc(INT a,b)
  INT r=[0]
  r=(a*b)/2
RETURN(r)

PROC Main()
  INT c=[0]
  c=MyCalc(5,10)
  Print("Result=")
  PrintIE(c)
RETURN

Next I’ll look at a number guessing game to contrast with the BASIC and Assembly versions I wrote about before.