Guix Workflow Language Reference Manual

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Guix Workflow Language

This document describes the Guix Workflow Language version 0.2.0.


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1 Introduction

This package provides the Guix Workflow Language (GWL), a scientific computing extension to the Guix package manager. It combines the specification of work units and their relationship to one another with the reproducible software deployment facilities of the functional package manager GNU Guix. A GWL workflow will always run in a reproducible environment that GNU Guix automatically prepares. The GWL extends your Guix installation with a single new sub-command: guix workflow.

In the GWL there are two concepts we need to know about: processes and workflows. We describe a computation (running a program, or evaluating a Scheme expression) using a process. A workflow describes how individual processes relate to each other (e.g. “process B must run after process A, and process C must run before process A”).

GWL workflows are executable code. The workflow language is embedded in the powerful general purpose language Guile Scheme, so you can compute arbitrarily complex process and workflow definitions. The GWL supports a classic Lisp syntax as well as a Python-like syntax called Wisp.


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2 Installation

There really is no point in using the GWL without Guix. If you already have a Guix installation, you can install the GWL with guix install gwl.

The Guix Workflow Language uses the GNU build system. To install it from a release tarball just unpack it and run the usual commands:

./configure
make
make install

If you want to build the sources from the source repository you need to bootstrap the build system first. Run autoreconf -vif first and then perform the above steps.

Note that in order for Guix to learn about the “workflow” sub-command provided by the GWL, the Guile module (guix scripts workflow) must be found in a directory on the GUILE_LOAD_PATH.


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3 A Simple Workflow

To get a little taste of what the workflow language looks like, let’s start by writing a simple workflow.

Here is a simple workflow example:

process greet
  packages "hello"
  # { hello }

process sleep
  packages "coreutils"
  # {
    echo "Sleeping..."
    sleep 10
  }

process eat (with something)
  name
    string-append "eat-" something
  # {
    echo "Eating {{something}}"
  }

process bye
  # { echo "Farewell, world!" }

workflow simple-wisp
  processes
    let
      :
        eat-fruit : eat "fruit"
        eat-veges : eat "vegetables"
      graph
        eat-fruit -> greet
        eat-veges -> greet
        sleep     -> eat-fruit eat-veges
        bye       -> sleep

This white-space sensitive syntax is called Wisp and if your familiar with Python or YAML you should feel right at home. To use this syntax simply save your workflow to a file ending on .w, .wisp, or .gwl.

The workflow language really is a domain specific language (DSL) embedded in Guile Scheme, so if you’re a Lisper you may prefer to write your workflows directly in Scheme while basking in its parenthetical glow:

(import (gnu packages base))

(define-public greet
  (make-process
   (name "greet")
   (packages (list hello))
   (procedure '(system "hello"))))

(define-public sleep
  (make-process
   (name "sleep")
   (packages (list coreutils))
    (procedure
     '(begin
        (display "Sleeping...\n")
        (system "sleep 10")))))

(define-public (eat something)
  (make-process
   (name (string-append "eat-" something))
   (procedure
    `(format #t "Eating ~a\n" ,something))))

(define-public bye
  (make-process
   (name "bye")
   (procedure
    '(display "Farewell, world!\n"))))

(make-workflow
 (name "simple")
 (processes
  (let ((eat-fruit (eat "fruit"))
        (eat-veges (eat "vegetables")))
    (graph (eat-fruit -> greet)
           (eat-veges -> greet)
           (sleep     -> eat-fruit eat-veges)
           (bye       -> sleep)))))

Everything you can express in Scheme can also be expressed with the Wisp syntax, so the choice is down to personal preference.


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4 Defining a Process

In the GWL a “process” is a combination of some kind of command or script to be executed, the software packages that need to be available when executing the commands, and declarations of inputs and generated outputs. A process has a name, and optionally a synopsis and a description, for display purposes.

We create a process with the make-process constructor like this:

make-process
  name "hello"
  procedure
     ' display "hello"

This creates a process with the name “hello”, which will print the string "hello" once the process is executed. The procedure field holds the Scheme code that does all the work of saying “hello”. We will talk about the procedure field a little later and show how to write code snippets in languages other than Scheme.

Often we will want to refer to previously created processes later, for example to combine them in a workflow definition. To do that we need to bind the created processes to variable names. Here we bind the above process to a variable named hello:

define hello
  make-process
    name "hello"
    procedure
       ' display "hello"

This is a very common thing to do, so the GWL offers a shorter syntax for not only creating a process but also binding it to a variable. The following example is equivalent to the above definition:

process hello
  procedure
     ' display "hello"

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4.1 process Fields

Both make-process and process accept the same fields, which we describe below.

name

The readable name of the process as a string. This is used for display purposes and to select processes by name. When the process constructor is used, the name field need not be provided explicitly.

version

This field holds an arbitrary version string. This can be used to disambiguate between different implementations of a process when searching by name.

synopsis

A short summary of what this process intends to accomplish.

description

A longer description about the purpose of this process.

packages

This field is used to specify what software packages need to be available when executing the process. Packages can either be Guix package specifications — such as the string "guile@3.0" for Guile version 3.0 — or package variable names. When using package variable names, you need to make sure to import the appropriate Guix module at the top of your workflow file, e.g. (import (gnu packages guile)) for the variable guile.

The packages field accepts a list of packages as well as multiple values (an “implicit list”). All of the following specifications are valid. A single package:

process
  packages "guile"
  …

More than one package:

process
  packages "guile" "python"
  …

A single list of packages:

process
  packages
    list "guile" "python"
  …
inputs

This field holds inputs to the process. Commonly, this will be a list of file names that the process requires to be present. The GWL can automatically connect processes by matching up their declared inputs and outputs, so that processes generating certain outputs are executed before those that declare the same item as an input.

As with the packages field, the inputs field accepts an “implicit list” of multiple values as well as an explicit list. Additionally, individual inputs can be “tagged” or named by prefixing it with a keyword (see Keywords in GNU Guile Reference Manual). Here’s an example of an implicit list of inputs spread across multiple lines where two inputs have been tagged:

process
  inputs
    . genome: "hg19.fa"
    . "cookie-recipes.txt"
    . samples: "foo.fq"
  …

The leading period is Wisp syntax to continue the previous line. You can, of course, do without the periods, but this may look a little more cluttered:

process
  inputs genome: "hg19.fa" "cookie-recipes.txt" samples: "foo.fq"
  …

Why tag inputs at all? Because you can reference them in other parts of your process definition without having to awkwardly traverse the whole list of inputs. Here is one way to select the first input that was tagged with the samples: keyword:

pick genome: inputs

To select the second item after the tag genome: do this:

pick second genome: inputs

or using a numerical zero-based index:

pick 1 genome: inputs

Code Snippets for a convenient way to access named items in code snippets without having to define your picks beforehand.

outputs

This field holds a list of outputs that are expected to appear after executing the process. Usually this will be a list of file names. Just like the inputs field, this field accepts a plain list, an implicit list of one or more values, and lists with named items.

The GWL can automatically connect processes by matching up their declared inputs and outputs, so that processes generating certain outputs are executed before those that declare the same item as an input.

output-path

This is a directory prefix for all outputs.

run-time

This field is used to specify run-time resource estimates, such as the memory requirement of the process or the maximum time it should run. This is especially useful when submitting jobs to an HPC cluster scheduler such as Grid Engine, as these schedulers may give higher priority to jobs that declare a short run time.

procedure

This field holds an expression of code that should be run when the process is executed. This is the “work” that a process should perform. By default that’s a quoted Scheme expression, but code snippets in other languages are also supported (see Code Snippets).

Here’s an example of a process with a procedure that writes a haiku to a file:

process haiku
  outputs "haiku.txt"
  synopsis "Write a haiku to a file"
  description
    . "This process writes a haiku by Gary Hotham \
to the file \"haiku.txt\"."
  procedure
    ` with-output-to-file ,outputs
        lambda ()
          display "\
the library book
overdue?
slow falling snow"

The Scheme expression here is quasiquoted (with a leading `) to allow for unquoting (with ,) of variables, such as outputs.

Not always will Scheme be the best choice for a process procedure. Sometimes all you want to do is fire off a few shell commands. While this is, of course, possible to express in Scheme, it is admittedly somewhat verbose. For convenience we offer a simple and surprisingly short syntax for this common use case. As a bonus you can even leave off the field name “procedure” and write your code snippet right there. How? Code Snippets.


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4.2 Process templates

When defining many similar processes, it can be useful to parameterize a single process template. This can be accomplished by defining a procedure that takes any number of arguments and returns a parameterized process. Here’s how to do this somewhat verbosely in plain Scheme:

(define (build-me-a-process thing)
  "Return a process that displays THING."
  (make-process
    (name (string-append "show-" thing))
    (procedure `(display ,thing))))

;; Now use this procedure to build concrete processes.
(define show-fruit
  (build-me-a-process "fruit"))
(define show-kitchen
  (build-me-a-process "kitchen"))
(define show-table
  (build-me-a-process "table"))

As this is a somewhat common thing to do in real workflows, the GWL provides simplified syntax to express the same concepts with a little less effort:

process build-me-a-process (with thing)
  name
    string-append "show-" thing
  procedure
    ` display ,thing

define show-fruit
  build-me-a-process "fruit"
define show-kitchen
  build-me-a-process "kitchen"
define show-table
  build-me-a-process "table"

The result is the same: you get a procedure build-me-a-process that you can use to define a number of similar processes. In the end you have the three processes show-fruit, show-kitchen, and show-table.


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4.3 Useful procedures

The (gwl utils) module provides a number of useful helpers that are intended to simplify common tasks when defining processes. The helpers defined by this module are all available by default.

Scheme Procedure: on collection higher proc

The on procedure is an alternative way to express the application of a higher order function to some collection. The only purpose of this procedure is to improve legibility when using Wisp syntax, as it allows one to avoid leading dots. The following two expressions are equivalent:

;; With "on"
on numbers map
   lambda (number)
     + number 10

;; Without "on"
map
  lambda (number)
    + number 10
  . samples
Scheme Procedure: expand file-name-part

This procedure returns a list of file names by combining any number of file name parts given as arguments. A file name part can either be a string or a list of strings. This is very useful when you need to generate a list of input or output file names.

(expand "/home/"
        '("me" "you" "them")
        "/data/"
        '("old" "new"))

=> '("/home/me/data/old"
     "/home/me/data/new"
     "/home/you/data/old"
     "/home/you/data/new"
     "/home/them/data/old"
     "/home/them/data/new")
Scheme Procedure: pick [n] key collection

This procedure allows you to pick a named item from a collection by looking for the specified keyword key. Optionally, you can provide a selector procedure or index n as the first argument. Without a selector the first item matching the given key will be returned. When the selector is * all items following the key (up to the next tag) will be returned. If the selector is a number it is used as a zero-based index into the list of items following the key. If the selector is a procedure it is applied to the list of items following the key.

define collection
  list
    . "one"
    . "two"
    . "three"
    . mine: "four"
    . "five"
    . yours: "six"

pick mine: collection

; => "four"

pick * mine: collection

; => '("four" "five")

pick second mine: collection

; => "five"

pick 0 yours: collection

; => "six"
Scheme Syntax: load-workflow file

This macro lets you load a workflow from the given file. The file must evaluate to a workflow value. This macro is useful for when you want to extend previously defined workflows. The argument file is expected to be a file name relative to the file invoking load-workflow.


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5 Code Snippets

The Guix Workflow Language is embedded in Guile Scheme, so it makes sense to use Scheme to define the work that a process should perform. Sometimes it may be more convenient, though, to express the procedure in a different language, such as GNU R, Python, or maybe even in Bash.

The GWL provides special syntax for embedding code snippets. The special syntax is provided in the (gwl sugar) module, and is loaded by default. Here is an example of a process that runs an embedded Bash shell script:

process run-bash
  packages "bash"
  # bash { echo "hello from bash!" }

Notice how the “procedure” field name was not used here, because the code snippet came last. This cuts down on boilerplate.

Code snippets are introduced with # interpreter {, where interpreter is the command line for running an interpreter, such as /bin/bash -c. Code snippets must end with a closing brace, }.

Make sure that the package inputs include a package providing the interpreter. For convenience we provide the special interpreters bash, R, and python, so that you don’t have to specify a more complicated command line. When no interpreter is provided the generic shell interpreter /bin/sh will be used:

process run-sh
  # { echo "hello from a shell!" }

Within code snippets a special syntax is supported for accessing variables. Any uninterrupted value enclosed in double braces is considered a reference to a variable, which may also be the name of other process fields. In the following example, the shell snippet refers to the name and inputs fields of the current process:

process run-bash
  packages "bash"
  inputs
    . "a"
    . "b"
    . "c"
  # bash {
    echo "The name of this process: {{name}}."
    echo "The data inputs are: {{inputs}}."
  }

You can even access named or tagged values in lists. In the following example, the shell snippet refers to only selected values of the inputs field of the current process:

process run-bash
  packages "bash"
  inputs
    . "a"
    . mine: "b"
    . "c"
    . yours: "d"
  # bash {
    echo "This is mine: {{inputs:mine}}, and this is yours: {{inputs:yours}}."
  }

As expected, this will output the following text when run:

This is mine: b, and this is yours: d.

You can also access tagged sub-lists with the :: accessor:

process frobnicate
  packages "frobnicator"
  inputs
    . genome: "hg19.fa"
    . samples: "a" "b" "c"
  outputs
    . "result"
  # {
    frobnicate -g {{inputs:genome}} --files {{inputs::samples}} > {{outputs}}
  }

This process will cause the following command to be executed:

frobnicate -g hg19.fa --files a b c > result

You can also access process meta data through environment variables. The following variables may be set:


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6 Defining a Workflow

A workflow is a combination of processes that run in a certain order or simultaneously. You can specify the dependencies of processes manually or let the GWL figure it out by matching up the declared inputs and outputs of all processes.

A workflow definition will look something like this:

workflow do-stuff
  processes
    . this
    . that
    . something-else

This defines a workflow with the name “do-stuff”, binds it to a variable do-stuff, and declares that it consists of the three processes this, that, and something-else. All of these processes will be run at the same time. This may not be what you want when the processes depend on each other.

If the processes all declare inputs and outputs, the GWL can connect the processes and ensure that only independent processes are run simultaneously. Use the auto-connect procedure on your processes:

workflow do-stuff
  processes
    auto-connect
      . this
      . that
      . something-else

You can also explicitly construct a graph of processes with the aptly named graph macro. The following workflow definition lets the process combine run after generate-A and generate-B, which will both run in parallel. The process compress will run after combine, and thus at the very end.

workflow frobnicate
  processes
    graph
      combine -> generate-A generate-B
      compress -> combine

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7 Process Engines

Once you have defined a workflow, there are different ways to run the processes it consists of. The simplest way is to turn the workflow into a Guile script that sets up the desired environment and then executes the workflow processes on the current machine. This is what the simple-engine does.

The grid-engine is similar to the simple-engine in that it generates a shell script, with the difference that it also includes resource variable definitions for submission to a Grid Engine scheduling system. The resource variables are derived from the process run-time field.


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8 Invoking guix workflow

The Guix Workflow Language extends your Guix installation with a new sub-command: guix workflow. Here are some of the options the command accepts:

--input=name[=file]
-i name[=file]

A workflow may have so-called free inputs, inputs that are not provided by any of the workflow’s processes. By default, the GWL will pick files from the current working directory that match the names of free inputs. This option can be used to map a file with an arbitrary name to a free input in the workflow with the given name. This option can be provided more than once.

In the following example, the free input called genome is mapped to the file /data/hg19.fa before running the workflow defined in analysis.w:

guix workflow --input=genome=/data/hg19.fa --run=analysis.w
--output=location
-o location

This option currently has no effect.

--engine=engine
-e engine

Select the process engine engine as the target of the generated process scripts. See Process Engines.

--prepare=file
-p file

Generate the process scripts and build or download all dependencies, but do not run the workflow process scripts corresponding to the workflow defined in file.

--run=file
-r file

Generate the process scripts, build or download all dependencies, and then run the workflow process scripts corresponding to the workflow defined in file.

--dry-run
-n

Prepare the scripts and the environments but don’t actually run the processes. Only show what commands would be run.

--force
-f

Execute all processes, even if their outputs may have been cached from previous runs.

--container
-c

Run each process inside of an isolated environment with file system virtualization and user namespaces. Only declared input files will be available at execution time, and only declared output files will be stored. This is a great option to use when you want to make sure that your processes only depend on state that you have declared. A downside is that generated output files cannot be written to the target directories directly but are copied from the container to the file system.

--graph=file
-g file

Load the workflow file and generate a graph in Dot-format.

--web-interface
-w

The GWL includes a web interface. This option starts it.


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9 Acknowledgments

Thanks to the following people who contributed to the Guix Workflow Language through bug reports, patches, or through insightful discussions:

Also thanks to the people who reviewed this project for joining the GNU project.

Thank you.


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Appendix A GNU Free Documentation License

Version 1.3, 3 November 2008
Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
http://fsf.org/

Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
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    We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

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    8. Include an unaltered copy of this License.
    9. Preserve the section Entitled “History”, Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled “History” in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
    10. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the “History” section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
    11. For any section Entitled “Acknowledgements” or “Dedications”, Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
    12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
    13. Delete any section Entitled “Endorsements”. Such a section may not be included in the Modified Version.
    14. Do not retitle any existing section to be Entitled “Endorsements” or to conflict in title with any Invariant Section.
    15. Preserve any Warranty Disclaimers.

    If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version’s license notice. These titles must be distinct from any other section titles.

    You may add a section Entitled “Endorsements”, provided it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

    You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

    The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

  6. COMBINING DOCUMENTS

    You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

    The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

    In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements”, and any sections Entitled “Dedications”. You must delete all sections Entitled “Endorsements.”

  7. COLLECTIONS OF DOCUMENTS

    You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

    You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

  8. AGGREGATION WITH INDEPENDENT WORKS

    A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the copyright resulting from the compilation is not used to limit the legal rights of the compilation’s users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

    If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document’s Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

  9. TRANSLATION

    Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

    If a section in the Document is Entitled “Acknowledgements”, “Dedications”, or “History”, the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

  10. TERMINATION

    You may not copy, modify, sublicense, or distribute the Document except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense, or distribute it is void, and will automatically terminate your rights under this License.

    However, if you cease all violation of this License, then your license from a particular copyright holder is reinstated (a) provisionally, unless and until the copyright holder explicitly and finally terminates your license, and (b) permanently, if the copyright holder fails to notify you of the violation by some reasonable means prior to 60 days after the cessation.

    Moreover, your license from a particular copyright holder is reinstated permanently if the copyright holder notifies you of the violation by some reasonable means, this is the first time you have received notice of violation of this License (for any work) from that copyright holder, and you cure the violation prior to 30 days after your receipt of the notice.

    Termination of your rights under this section does not terminate the licenses of parties who have received copies or rights from you under this License. If your rights have been terminated and not permanently reinstated, receipt of a copy of some or all of the same material does not give you any rights to use it.

  11. FUTURE REVISIONS OF THIS LICENSE

    The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.

    Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. If the Document specifies that a proxy can decide which future versions of this License can be used, that proxy’s public statement of acceptance of a version permanently authorizes you to choose that version for the Document.

  12. RELICENSING

    “Massive Multiauthor Collaboration Site” (or “MMC Site”) means any World Wide Web server that publishes copyrightable works and also provides prominent facilities for anybody to edit those works. A public wiki that anybody can edit is an example of such a server. A “Massive Multiauthor Collaboration” (or “MMC”) contained in the site means any set of copyrightable works thus published on the MMC site.

    “CC-BY-SA” means the Creative Commons Attribution-Share Alike 3.0 license published by Creative Commons Corporation, a not-for-profit corporation with a principal place of business in San Francisco, California, as well as future copyleft versions of that license published by that same organization.

    “Incorporate” means to publish or republish a Document, in whole or in part, as part of another Document.

    An MMC is “eligible for relicensing” if it is licensed under this License, and if all works that were first published under this License somewhere other than this MMC, and subsequently incorporated in whole or in part into the MMC, (1) had no cover texts or invariant sections, and (2) were thus incorporated prior to November 1, 2008.

    The operator of an MMC Site may republish an MMC contained in the site under CC-BY-SA on the same site at any time before August 1, 2009, provided the MMC is eligible for relicensing.

ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page:

  Copyright (C)  year  your name.
  Permission is granted to copy, distribute and/or modify this document
  under the terms of the GNU Free Documentation License, Version 1.3
  or any later version published by the Free Software Foundation;
  with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
  Texts.  A copy of the license is included in the section entitled ``GNU
  Free Documentation License''.

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with…Texts.” line with this:

    with the Invariant Sections being list their titles, with
    the Front-Cover Texts being list, and with the Back-Cover Texts
    being list.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.


Next: , Previous: , Up: Top   [Contents][Index]

Concept Index

Jump to:   (  
A   B   C   D   E   F   G   H   I   L   M   N   O   P   R   S   T   U   V  
Index Entry  Section

(
(gwl utils): Useful procedures

A
accessing multiple named values, code snippets: Code Snippets
accessing named values in variables, code snippets: Code Snippets
accessing variables, code snippets: Code Snippets
auto-connect, workflow order: Defining a Workflow

B
building from source: Installation

C
code snippets: Code Snippets
combining processes in a workflow: Defining a Workflow
container: Invoking guix workflow

D
defining a workflow: Defining a Workflow
defining processes: Defining a Process
description, process field: process Fields

E
environment variables, code snippets: Code Snippets
executing processes: Process Engines
expand file name templates: Useful procedures
expand, helper procedure: Useful procedures

F
file name expansion: Useful procedures

G
generating processes: Process templates
graph, workflow order: Defining a Workflow
grid-engine, Process Engine: Process Engines

H
Helper procedures: Useful procedures

I
implicit list, process.packages: process Fields
inputs, process field: process Fields
installing from source: Installation
isolate processes: Invoking guix workflow

L
language support, code snippets: Code Snippets
load a workflow: Useful procedures
load-workflow: Useful procedures

M
make-process, constructor: Defining a Process

N
name, process field: process Fields
named items, lists: process Fields

O
on, helper procedure: Useful procedures
output-path, process field: process Fields
outputs, process field: process Fields

P
packages, process field: process Fields
pick elements from a list: Useful procedures
pick, helper procedure: Useful procedures
pick, items from a tagged list: process Fields
procedure, process field: process Fields
process meta data, code snippets: Code Snippets
process templates: Process templates
process, constructor: Defining a Process
process, definition macro: Defining a Process
process, valid fields: process Fields
Python, code snippets: Code Snippets

R
R, code snippets: Code Snippets
reorder higher order function application: Useful procedures
run-time, process field: process Fields

S
scripts, embedding: Code Snippets
select tagged items: Useful procedures
select, tagged items in a list: process Fields
shell snippets: Code Snippets
simple-engine, Process Engine: Process Engines
special syntax, code snippets: Code Snippets
string interpolation, code snippets: Code Snippets
synopsis, process field: process Fields

T
tagged items, lists: process Fields
tagged lists: process Fields

U
user namespaces: Invoking guix workflow
Utilities: Useful procedures

V
version, process field: process Fields

Jump to:   (  
A   B   C   D   E   F   G   H   I   L   M   N   O   P   R   S   T   U   V  

Previous: , Up: Top   [Contents][Index]

Programming Index

Jump to:   E   L   O   P  
Index Entry  Section

E
expand: Useful procedures

L
load-workflow: Useful procedures

O
on: Useful procedures

P
pick: Useful procedures

Jump to:   E   L   O   P