| THE META-HTML LANGUAGE REFERENCE MANUAL

Arithmetic Operators | [TOC] | String Operators

## Section Intro: Relational Operators

Synopsis:

Relational operators

in Meta-HTML return information about the relationship between two items. There are three logical operators, `and`, `or`, and `not`.

There are several other operators which compare numeric values; the section Arithmetic Operators cover those in detail.

Commands:

and eq | gt lt | not | or

### Function Documentation

`<and EXPR ...>` | Simple

Evaluates the EXPRs until one of them results in the empty string, or they are all exhausted.

The result of this expression is the last value evaluated.

`<eq ARG1 ARG2>` | Simple

Returns the string `"true"` when the number value of ARG1 is equal to the number value of ARG2.

`<gt ARG1 ARG2>` | Simple

Returns the string `"true"` when the numeric value of ARG-1 is greater than the numeric value of ARG-2.

`<lt ARG1 ARG2>` | Simple

Returns the string `"true"` when the numeric value of ARG-1 is less than the numeric value of ARG-2.

`<not [BODY]>` | Simple

BODY is evaluated. If the result is the empty string, then the string "true" is returned, otherwise, nothing is returned. The BODY is simply the entire contents of the simple tag, without the word "not" in it. Thus, in typical usage, one might write:

      <when <not <get-var foo>>>
         <comment> Complain that FOO is missing. </comment>
      </when>

`<or EXPR ...>` | Simple

Evaluates the EXPRs until one of them results in a non-empty value, or they are all exhausted.

The result of this expression is the last value evaluated.

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The META-HTML Reference Manual V1.4 Copyright © 1995, 1996, Brian J. Fox, 1996, 1997 Universal Access Inc.
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