Customization Guide (.pdf) - Documentation & Online Help - Autodesk

The format is:
$M=expression
Introducing the macro with $M= tells AutoCAD LT 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,$(getvar,fillmode))
The macro switches the FILLMODE system variable on and off by subtracting
the current value of FILLMODE from 1 and returning the resulting value to
the FILLMODE system variable. You can use this method to toggle system
variables whose valid values are 1 or 0.
Termination of Macros That Contain Conditional Expressions
If you use the DIESEL string language to perform “if-then” tests, conditions
might exist where you do not want the normal terminating space or semicolon
(resulting in ENTER). If you add ^Z to the end of the macro, AutoCAD LT does
not automatically add a space (ENTER) to the end of the macro expression.
As with other control characters in commands, the ^Z used here is a string
composed of ^ (a caret) and Z and is not equivalent to pressing Ctrl+Z.
In the following examples, ^Z is used as a macro terminator.
^C^C$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 LT would automatically add a
space (ENTER), repeating the last command entered.
See also:
■ Use Special Control Characters in Macros on page 104
■ DIESEL on page 325
Quick Reference
Commands
CUI
Manages the customized user interface elements in the product.
112 | Chapter 4 User Interface Customization