[Chapter 11] Formats
Author: Randal Schwartz, Tom Christiansen & Larry Wall
Date: 1999-07-02T01:34:11Z

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| Chapter 11 |

# 11. Formats

Contents:
What Is a Format?
Defining a Format
Invoking a Format
More About the Fieldholders
The Top-of-Page Format
Changing Defaults for Formats
Exercises

## 11.1 What Is a Format?

Perl stands, among other things, for "practical extraction and report language." It's time to learn about that "...report language" business.

Perl provides the notion of a simple report writing template, called a format. A format defines a constant part (the column headers, labels, fixed text, or whatever) and a variable part (the current data you're reporting). The shape of the format is very close to the shape of the output, similar to formatted output in COBOL or the `print` `using` clauses of some BASICs.

Using a format consists of doing three things:

1. Defining a format

2. Loading up the data to be printed into the variable portions of the format (fields)

3. Invoking the format

Most often, the first step is done once (in the program text so that it gets defined at compile-time),[1] and the other two steps are performed repeatedly.

> [1] You can also create formats at run-time using the `eval` function, as described in Programming Perl and in the perlform (1) manpage.

10.7 Exercises |  | 11.2 Defining a Format