first_set

Written by Balazs Halasy, 02/05/2004 Updated 05/04/2005 by Graham Brookins

Summary

Returns the first parameter that is set (or FALSE).

Usage

first_set( value1 [, value2 [, ... ] ] )

Parameters

Name	Type	Description	Required
value1	any	A variable/value that should be evaluated.	Yes.
value2	any	Another variable/value that should be evaluated.	No.

Returns

The first value that is set or FALSE.

Description

This operator evaluates all parameters until one of them is found to be set. The parameter that is found to be set will be returned. If none of the parameters are set, the operator will return FALSE.

Examples

Example 1

{if first_set( $a, $b, $c )}
    The truth is out there.
{else}
    The day the earth stood still.
{/if}

As long as $a, $b and $c are undeclared/unset, the following output will be produced: "The day the earth stood still".

Example 2

{first_set( $a, 256, $b )}

As long as $a is undeclared/unset, the following output will be produced: "256".

Contributors

Balazs Halasy Author 02/05/2004
Massimiliano Bariola Commenter 08/04/2005
André Commenter 09/25/2006

Comments (2 historical)

Written by readers of the earlier documentation sites, kept as they were.

This code will give you unexpected results

Massimiliano Bariola · 08/04/2005 02:12 pm
This code:
```
{def $myvar = first_set($myobject.contentobject.data_map.my_integer_var.data_int, 0)}
MYVAR = {$idanag}; {$myobject.contentobject.data_map.my_integer_var.data_int}
```
will display
MYVAR = ; 0
instead of
MYVAR = 0; 0
so, first_set handles 0s as "unset". this either needs to be documented or marked as a bug.
1. Re: This code will give you unexpected results
  
  André · 09/25/2006 08:01 am
  
  I guess moste people will see what this person did wrong here.
  1.$idanag is not defined as far as I can see. Debug is your friend.
  2. a value of 0 = is_set, its not true but it's set. But the ouput would be the same anyway.

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