Reply is a lightweight, extensible REPL for Perl. It is plugin-based (see Reply::Plugin), and through plugins supports many advanced features such as coloring and pretty printing, readline support, and pluggable commands.

Devel::CheckCompiler is a tiny module to check whether a compiler is available. It can test for a C99 compiler, or you can tell it to compile a C source file with optional linker flags.

This module exports two functions, nsort and ncmp; they are used in implementing a "natural sorting" algorithm. Under natural sorting, numeric substrings are compared numerically, and other word-characters are compared lexically.

A CPAN::Meta::Requirements object models a set of version constraints like those specified in the META.yml or META.json files in CPAN distributions, and as defined by CPAN::Meta::Spec. It can be built up by adding more and more constraints, and will reduce them to the simplest representation.

This package allows you to define different interpreters for different test scripts with Test::Run.

This module implements an interface to the Linux 2.6.13 and later Inotify file change notification system.

Exporter::Tiny supports many of Sub::Exporter's external-facing features including renaming imported functions with the `-as`, `-prefix` and `-suffix` options; explicit destinations with the `into` option; and alternative installers with the `installer` option. But it's written in only about 40% as many lines of code and with zero non-core dependencies.

Some Perl modules need to ship C libraries together with their Perl code. Although there are mechanisms to compile and link (or glue) C code in your Perl programs, there isn't a clear method to compile standard, self-contained C libraries. This module main goal is to help in that task.

This is Graph, a Perl module for dealing with graphs, the abstract data structures.

Time::Duration::Parse is a module to parse human readable duration strings like "2 minutes" and "3 seconds" to seconds.

This module converts Perl data structures to JSON and vice versa.

The fundamental task of the autoformat subroutine is to identify and rearrange independent paragraphs in a text. Paragraphs typically consist of a series of lines containing at least one non-whitespace character, followed by one or more lines containing only optional whitespace. This is a more liberal definition than many other formatters use: most require an empty line to terminate a paragraph. Paragraphs may also be denoted by bulleting, numbering, or quoting (see the following sections).

The DateTime::Set module provides a date/time sets implementation. It allows, for example, the generation of groups of dates, like "every wednesday", and then find all the dates matching that pattern, within a time range.

Lexical::Persistence introduces persistent lexical variable values for arbitrary calls.

MIME::Charset provides information about character sets used for MIME messages on Internet.

This module tries to provide a coherent API to bring together the various JSON modules currently on CPAN. This module will allow you to code to any JSON API and have it work regardless of which JSON module is actually installed.

MooseX::Object::Pluggable makes your classes pluggable.

Devel::REPL is a modern Perl interactive shell.

File::Temp can be used to create and open temporary files in a safe way.

Async::Interrupt implements a single feature only of interest to advanced perl modules, namely asynchronous interruptions (think "UNIX signals", which are very similar).

Sometimes, modules wish to run code asynchronously (in another thread, or from a signal handler), and then signal the perl interpreter on certain events. One common way is to write some data to a pipe and use an event handling toolkit to watch for I/O events. Another way is to send a signal. Those methods are slow, and in the case of a pipe, also not asynchronous - it won't interrupt a running perl interpreter.

This module implements asynchronous notifications that enable you to signal running perl code from another thread, asynchronously, and sometimes even without using a single syscall.

Hash::MultiValue is an object (and a plain hash reference) that may contain multiple values per key, inspired by MultiDict of WebOb.

This package provides a data pack for Business::ISBN. These data are generated from the RangeMessage.xml file provided by the ISBN Agency.

Class::ErrorHandler provides an error-handling mechanism that is generic enough to be used as the base class for a variety of OO classes. Subclasses inherit its two error-handling methods, error and errstr, to communicate error messages back to the calling program.

Probe::Perl provides methods for obtaining information about the currently running perl interpreter. It originally began life as code in the Module::Build project, but has been externalized here for general use.