std-vl-p


Synopsis

(std-vl-p)

Description

Predicate if the Visual Lisp or Vital Lisp Runtime System is loaded and the function was called under this RTS or IDE. It can not be used to decide if the Runtime System is available at all, only if it is currently in effect.

VL is the abbrevation for Visual Lisp or Vital Lisp.

VLISP is the abbrevation for Visual Lisp only.

VILL is the abbrevation for Vital Lisp only.

It's implemented using a special feature only available under these systems:

If a lambda function is a list or a USUBR.

Cached version

This function is only called once, the result is stored in the global symbol *DEF-VL*. All subsequent calls just return a result dependent on the value of this symbol.

Arguments

None

Return Value

T or nil.

Side Effects

Works with the global symbol *DEF-VL*.

Module

Defined in STDINIT