NAME

boolean – type containing symbols t and nil (type)    

SYNOPSIS

ARGUMENTS and VALUES

n/a       

VALID CONTEXT

n/a    

BINDING TYPES AFFECTED

n/a   

DESCRIPTION

The type boolean contains the symbols t and nil, which represent true and false, respectively.    

AFFECTED BY

(none)  

EXCEPTIONAL SITUATIONS

(none)   

NOTES

Conditional operations, such as if, permit the use of generalized booleans, not just booleans; any non-nil value, not just t, counts as true for a generalized boolean. However, as a matter of convention, the symbol t is considered the canonical value to use even for a generalized boolean when no better choice presents itself.     

EXAMPLES

 
(none)     

SEE ALSO

t(3cl), nil(3cl), if(3cl), not(3cl), complement(3cl)    

AUTHOR and COPYRIGHT

Substantial portions of this page are taken from draft proposed American National Standard for Information Systems—Programming Language—Common Lisp, X3J13/94-101R, Version 15.17R, Fri 12-Aug-1994 6:35pm EDT; no copyright indicated.

Additional clarification and comments by Michael Marking <marking@tatanka.com>, http://www.tatanka.com/software/cl-manpages/; alternatively, https://github.com/wakinyantanka/cl-manpages/. Copyright 2017 Michael Marking as both an original and a derivative work.

Licensed under Creative Commons Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0).

This page last revised Sunday 26 March 2017.