Name: OR

Section: Relational Operators

Synopsis:

<or &rest expr...>

Description:

or evaluates each EXPR given until one of them evaluates to a non-empty string, or until they are all exhausted. The result is the result of the last evaluation. Evaluating just <or> returns the empty string.

Examples:

<or>                    ==> 
<or this that>          ==> this
<unset-var foo>
<or <get-var foo> this> ==> this
<or this <get-var foo>> ==> this
<set-var foo=bar>
<or <get-var foo> this> ==> bar

<or> could have been defined in Meta-HTML as follows:

<define-tag or &unevalled &rest expressions[] whitespace=delete>
  <foreach :expr expressions>
    <set-var result = <get-var-eval :expr>>
    <if <get-var-once result>
        <break>>
  </foreach>
  <get-var-once result>
</define-tag>

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