CODEWITHSUNDEEP
openedgeprogress-4gl
Rajesh khanna
Rajesh khanna

Reputation: 21

Difference between the internal procedures and functions in Progress4gl?

Both internal procedures and functions are accepting the parameters to give the output. So what is the use of using Internal procedures instead of functions.

Upvotes: 1

Views: 1426

Answers (3)

Tom Bascom
Tom Bascom

Reputation: 14020

The question acknowledges that both functions and internal procedures allow OUTPUT parameters and asks "what is the use" of internal procedures instead of functions.

To me, this implies that the poster is contemplating always using functions and deprecating internal procedures and is asking: "what would I lose if I do that?"

Two things spring to mind:

  1. Sort of the opposite of Jean-Christophe Cardot's point: you would lose some automatic type conversions and syntactic flexibility about the parameter lists. Some people see that flexibility in a negative light. Others see it as a positive.

  2. You need to "forward declare" your functions or use dynamic invocations. With an internal procedure you can RUN it without providing a declaration earlier in the code.

If you tend to think that strict type checking is useful then these are probably not benefits that you think of as being lost. If you prefer more flexible behaviors, then you may regret choosing functions rather than internal procedures.

Upvotes: 0

Jean-Christophe Cardot
Jean-Christophe Cardot

Reputation: 46

Also functions (like methods) parameters and return value type are checked at compile time, which removes some potential problems at run time later.

Upvotes: 0

K_mns
K_mns

Reputation: 701

A user-defined function is used when you want to perform some calculation and return a single value. In this respect it is the same as a built-in ABL function, like the SUBSTRING or EXP functions. Putting this calculation code in a FUNCTION block instead of inline in your code allows you to put it in one place and reference it multiple times without code duplication.

An internal procedure is also an encapsulated piece of code that does some work, but it is more general-purpose. While a function must return a single value, an internal procedure may or may not have input parameters or output parameters.

https://docs.progress.com/category/openedge-archives

Upvotes: 1

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