DIESEL (Direct Interpretively Evaluated String Expression Language) expressions take strings as input and generate string results. Use DIESEL in menu macros to make decisions or display text on the status bar.
You can use DIESEL to alter the status bar through the MODEMACRO system variable and in menu items as a macro language instead of AutoLISP ® .
Because DIESEL expressions handle strings exclusively, the USERS1-5 system variables are useful for passing information from an AutoLISP routine to a DIESEL expression. DIESEL expressions are evaluated by AutoLISP routines through the use of the AutoLISP menucmd function.