XLISP if

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# if

Type: | - | special form (fsubr)
Source: | - | xlcont.c

## Syntax

(if test-expr then-expr [else-expr])
  test-expr - an expression
  then-expr - the THEN clause, an expression
  else-expr - the ELSE clause, an optional expression
  returns - the value of the selected expression

## Description

The 'if' special form evaluates the 'test-expr'. If 'test-expr' evaluates to a non-NIL value, then 'then-expr' is evaluated and returned as the result. If 'test-expr' evaluates to NIL and there is an 'else-expr', then the 'else-expr' is evaluated and its result is returned. If there is no 'else-expr' and 'test-expr' evaluates to NIL , then NIL is returned as a result.

## Examples

    (if T (print "will print")     ; prints  "will print"
          (print "won't print"))

    (if NIL (print "won't print")
            (print "will print"))  ; prints  "will print"

    (if 'a T NIL)                  ; returns T

    (if NIL 'nope 'yep)            ; returns YEP

See the if special form in the XLISP 2.0 manual.

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Nyquist / XLISP 2.0 - Contents | Tutorials | Examples | Reference