2012

Table Of Contents

Use Conditional Expressions in Macros

You can add conditional expressions to a macro by using a command that

introduces macro expressions written in DIESEL (Direct Interpretively Evaluated

String Expression Language).

The format is:

$M=expression

Introducing the macro with $M= tells AutoCAD to evaluate a string as a DIESEL

expression, and that expression is the DIESEL expression. The following

example defines a conditional expression in a macro:

FILLMODE $M=$(-,1,$(getvar,fillmode))

The macro switches the FILLMODE system variable on and off by subtracting

the current value of FILLMODE from 1 and returning the resulting value to

the FILLMODE system variable. You can use this method to toggle system

variables whose valid values are 1 or 0.

Termination of Macros That Contain Conditional Expressions

If you use the DIESEL string language to perform “if-then” tests, conditions

might exist where you do not want the normal terminating space or semicolon

(resulting in Enter). If you add ^Z to the end of the macro, AutoCAD does not

automatically add a space (Enter) to the end of the macro expression.

As with other control characters in commands, the ^Z used here is a string

composed of ^ (a caret) and Z and is not equivalent to pressing Ctrl+Z.

In the following examples, ^Z is used as a macro terminator.

^C^C$M=$(if,$(=,$(getvar,tilemode),0),$S=mview _mspace )^Z

^C^C$M=$(if,$(=,$(getvar,tilemode),0),$S=mview _pspace )^Z

If these macros did not end with ^Z, AutoCAD would automatically add a

space (ENTER), repeating the last command entered.