REBOL Document

All - Function Summary

Summary:

Shortcut AND. Evaluates and returns at the first FALSE or NONE.

Usage:

all block

Arguments:

block - Block of expressions (must be: block)

Description:

Evaluates each expression in a block until one of the expressions returns NONE or FALSE, in which case a NONE is returned. Otherwise, the value of the last expression will be returned. 


    print all [1 none]
    none


    print all [none 1]
    none


    print all [1 2]
    2


    print all [10 > 1 "yes"]
    yes


    print all [1 > 10 "yes"]
    none


    time: 10:30
    if all [time > 10:00 time < 11:00] [print "time is now"]
    time is now

No other expressions are evaluated beyond the point where a value fails: 


    a: 0
    all [none a: 2]
    print a
    0


    a: 0
    all [1 a: 2]
    print a
    2


    day: 10
    time: 9:45
    ready: all [day > 5  time < 10:00  time: 12:00]
    print time
    12:00

Related:

and - Returns the first value ANDed with the second.
any - Shortcut OR. Evaluates and returns the first value that is not FALSE or NONE.
or - Returns the first value ORed with the second.

<Back | Index | Next>

Copyright 2004 REBOL Technologies