Matt S Trout > Rakudo-Star-2012.08_001 > rakudo-star/parrot/ext/nqp-rx/README


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NQP - Not Quite Perl (6) ^

NQP is Copyright (C) 2009 by Patrick R. Michaud. See LICENSE for licensing details.

This is "Not Quite Perl" -- a compiler for quickly generating PIR routines from Perl6-like code. The key feature of NQP is that it's designed to be a very small compiler (as compared with, say, perl6 or Rakudo) and is focused on being a high-level way to create transformers for Parrot (especially hll compilers). In addition, unlike Rakudo, NQP attempts to restrict itself to generating code that can run in Parrot without the existence of any NQP-specific runtime libraries.

Building from source

NQP comes bundled with Parrot, so if you have a recent Parrot distribution you likely also have a copy of NQP. Inside of a Parrot installation NQP is known as parrot-nqp.

To build NQP from source, you'll just need a make utility and Perl 5.8 or newer. To automatically obtain and build Parrot you may also need a Git client.

To obtain NQP directly from its repository:

    $ git clone git://

If you don't have git installed, you can get a tarball or zip of NQP from github by visiting and clicking "Download". Then unpack the tarball or zip.

Once you have a copy of NQP, build it as follows:

    $ cd nqp-rx
    $ perl --gen-parrot
    $ make

This will create a "nqp" or "nqp.exe" executable in the current (nqp-rx) directory. Programs can then be run from the build directory using a command like:

    $ ./nqp

The --gen-parrot option above tells to automatically download and build the most appropriate version of Parrot into a local "parrot/" subdirectory, install that Parrot into the "parrot_install/" subdirectory, and use that for building NQP. It's okay to use the --gen-parrot option on later invocations of; the configure system will re-build Parrot only if a newer version is needed for whatever version of Rakudo you're working with.

You can use --parrot-config=/path/to/parrot_config instead of --gen-parrot to use an already installed Parrot for building NQP. This installed Parrot must include its development environment; typically this is done via Parrot's make install target or by installing prebuilt parrot-devel and/or libparrot-dev packages. The version of the already installed Parrot must satisfy a minimum specified by the NQP being built -- will verify this for you. Released versions of NQP always build against the latest release of Parrot; checkouts of the HEAD revision from github often require a version of Parrot that is newer than the most recent Parrot monthly release.

Once built, NQP's make install target will install NQP and its libraries into the Parrot installation that was used to create it. Until this step is performed, the "nqp" executable created by make above can only be reliably run from the root of NQP's build directory. After make install is performed the executable can be run from any directory (as long as the Parrot installation that was used to create it remains intact).

If the NQP compiler is invoked without an explicit script to run, it enters a small interactive mode that allows statements to be executed from the command line. Each line entered is treated as a separate compilation unit, however (which means that subroutines are preserved after they are defined, but variables are not).

Differences from previous version of NQP

* Sub declarations are now lexical ("my") by default, use "our sub xyz() { ... }" if you want package-scoped subroutines.

* The PIR q<...>; construct is gone. Use Q:PIR or pir::opcode(...) instead.

* The mainline code of modules is no longer tagged as ":load :init" by default. Use INIT { ... } for any code that you want to be run automatically at startup.

* Cuddled else's are no longer valid Perl 6, 'else' requires a space after it.

* Double-quoted strings now interpolate $-variables.

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