F.9 Info Format: Printindex

An index in Info format is a kind of menu, with an additional directive at the beginning to mark it as an index menu.

    <printindex> =
* Menu:

<index entry>*

The <index entry> items are similar to normal menu entries, but the free-format description is replaced by the line number of where the entries occurs in the text:

    <index entry> =
* <entry text>: <node-spec>. <line-spec>

    <line-spec> =
<lparen>line <lineno><rparen>

The initial part, ‘<entry text>: <entry node>.’, should be on a single line. The <entry text> is the index term.

Even though <entry text> is followed by a colon, it may itself contain colons, so Info readers should try to include as much of the line as possible in the <entry text>. (However, <entry text> may not contain the DEL characters that may occur in <node-spec>.)

<lineno> is an unsigned integer, given relative to the start of the <entry node>. An optional line break may occur before ‘<line-spec>’.

Here is an example:

* Menu:

* thunder:           Weather Phenomena.             (line 5)

This means that an index entry for ‘thunder’ appears at line 5 of the node ‘Weather Phenomena’.