PML Procedures

PML Customisation User Guide

Variables, Objects, Functions and Methods : PML Functions and Methods : PML Procedures

A PML Procedure is a PML Function that does not return a result.

A function is defined as a procedure by omitting the data type at the end of the define function statement:

define function !!Area( !Length is REAL, !Width is REAL,

!Result is REAL)

!Result = !Length * !Width

Here you are using an output argument, !Result, to return the result rather than using a function return value.

The arguments to the !!Area procedure can be set as follows, and then the procedure invoked with the call command.

!SurfaceArea = REAL()

!Partlength = 7

call !!Area(!PartLength, !PartWidth, !SurfaceArea)

There will be an error if you attempt to assign the result of a PML Procedure because there is no return value to assign. So, for example you can say:

call !!Area(!PartLength, !PartWidth, !SurfaceArea)

!Answer = !SurfaceArea

But you cannot say:


!Answer = !!Area(!PartLength, !PartWidth, !SurfaceArea)	$* WRONG

The ( ) parentheses after the name of a procedure or function must always be present — even for procedures that do not need arguments:

define function !!Initialise()

!TotalWeight = 0

!!MaxWeight = 0

call !!Initialise()

Although the call keyword is strictly speaking optional, its use is recommended with procedures.

Note:

As well as procedures, you can invoke a PML Function that has a return value using call, in which case the function result value is discarded.

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