VSLisp Programmers Guide: Invocation

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## 3. Invocation

To run default standalone interpreter, just type '`VSLisp`':

> `

>     $ VSLisp
>     VSLisp, V4.0 (c) by VSL, 1994-2000
>     Lisp>>

> `

Use command line parameter '`-i filename`' to specify script name.

## 3.1 VSLisp scripts

VSLisp executable script may look like this one:

> `

>     #!/usr/bin/VSLisp -i
>     (print '"Hello World")
>     (exit)

> `

You must insert '`(exit)`' at the end of any script for compatibility - VSLisp may start interactive interpreter after loading script.

Command line parameters list is defined in a Lisp symbol `*pars*`.

## 3.2 Interaction

In interactive mode VSLisp standalone interpreter waits for lists to evaluate. Interactive session may look like:

> `

>     [vsl@ontil vsl]$ VSLisp
>     VSLisp, V4.0 (c) by VSL, 1994-2000
>     Lisp>> (defun Fak (x) (if (= x 0) 1 (* x (Fak (- x 1)))))
>      << ( lambda ( x) ( if ( = x 0) 1 ( * x ( Fak ( - x 1)))))
>     Lisp>> (Fak 10)
>      << 3.6288e+06
>     Lisp>> (Fak 5)
>      << 120
>     Lisp>>

> `

`NOTE:` Only lists will be evaluated, atoms just ignored. e.g., you cannot do something like this:

> `

>     Lisp>> (setq a 100)
>      << 100
>     Lisp>> a

> `

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