7.2 Adding and editing snippets (LilyPond Contributor’s Guide)

### 7.2 Adding and editing snippets

#### General guidelines

When you create (or find!) a nice snippet, please add it to the Wiki. Go to the LilyPond Wiki and optionally log in – if you haven’t already, create an account. Follow the help instructions on the website so that you know how to proceed.

You should always tag a newly created page with a category at the end of a page. If you think a snippet is particularly informative and should be included in the documentation, suggest it in the snippet’s ‘Discussion’ page. Note that snippets intended for the LilyPond documentation must have a special layout.

Please make sure that the LilyPond code follows our formatting guidelines, see LilyPond formatting.

If a new snippet created for documentation purposes compiles with the current stable LilyPond version, it should be added to the Wiki. If a new snippet created for documentation purposes uses features that are not available in the current stable release of LilyPond, it should be put into directory `Documentation/snippets/new/` instead. In both cases, a reference to the snippet should be added to the documentation. Please ask a documentation editor to add a reference to it in an appropriate place in the docs. (Note – it should appear in the ‘Snippets’ manual automatically, once it has been imported into git and built. See LilyPond Wiki to Git.)

Snippets created or updated in `Documentation/snippets/new/` must be adjusted and copied to directory `Documentation/snippets/`. This should be done by invoking the `makelsr.pl` script – after you have compiled LilyPond. Assuming that your LilyPond build is in the top-level subdirectory `build/`, a proper invocation is

    cd /your/lilypond/git/top/dir
    scripts/auxiliar/makelsr.pl --new

See The `makelsr.pl` script, for more details.

Be sure that ‘`make doc`’ runs successfully before submitting a patch, to prevent breaking compilation (see Generating documentation).

#### Formatting snippets in `Documentation/snippets/new/`

When adding a file to this directory, please use the following template (omitting the explanatory comments) …

    \version "2.xx.yy"

    \header {
      % Use existing Wiki categories other than 'Category:Included in
      % the official documentation' and 'Category:Snippet' (see
      % 'https://wiki.lilypond.community/wiki/Special:Categories' for
      % a list) and omit the 'Category:' prefix.
      categories = "Rhythms, Expressive marks"

      % The documentation string must use Texinfo syntax.  In
      % addition, `\` and `"` must be written as `\\` and `\"`,
      % respectively.
      texidoc = "
    This snippet demonstrates @code{\\foo} ...
    "

      % The snippet title string must be formatted similar to
      % `texidoc`.  However, don't use markup commands like `@emph`
      % or `@code` so that the title can be directly converted to a
      % Wiki page title, which doesn't allow formatting.
      doctitle = "Snippet title"
    }

    <LilyPond code starts here>

… and name the file `snippet-title.ly`.

It is important that the version number you use at the top of the snippet is the minimum LilyPond version that the file compiles with; for example, if the snippet requires 2.25.24, use `\version "2.25.24"`.

Particular attention is also necessary for the `categories` and `doctitle` fields: the categories must match category names used in the Wiki, and the `doctitle` must match the file name (`makelsr.pl` shows a helpful error message if it doesn’t).

The order of `\version`, `\header`, and the LilyPond code must be as shown above, otherwise `makelsr.pl` aborts with an error. The same holds for the order of the `categories`, `texidoc`, and `doctitle` fields within `\header`.

#### LilyPond Contributor’s Guide v2.26.0 (stable-branch).

- 1 Introduction to contributing
  - 1.1 Help us
  - 1.2 Overview of work flow
  - 1.3 Summary for experienced developers
  - 1.4 Mentors
- 2 Quick start
  - 2.1 LilyDev
    - Installing LilyDev in VirtualBox
    - Configuring LilyDev in VirtualBox
  - 2.2 Compiling with LilyDev
  - 2.3 Now start work!
- 3 Working with source code
  - 3.1 Setting up
    - 3.1.1 Installing Git
    - 3.1.2 Creating a GitLab account and setting up SSH
    - 3.1.3 Cloning and forking the repository
    - 3.1.4 Configuring Git
  - 3.2 Git cheat sheet
  - 3.3 Lifecycle of a merge request
    - 3.3.1 Uploading a patch for review
    - 3.3.2 Automated testing
    - 3.3.3 Patch countdown
    - 3.3.4 Merging to master
    - 3.3.5 Abandoned patches
  - 3.4 Writing good commit messages
  - 3.5 Commit access
  - 3.6 Further Git documentation resources
  - 3.7 Repository directory structure
- 4 Compiling
  - 4.1 Overview of compiling
  - 4.2 Requirements
    - 4.2.1 Requirements for running LilyPond
    - 4.2.2 Requirements for compiling LilyPond
      - Fedora
      - Linux Mint
      - OpenSUSE
      - Ubuntu
      - Other
    - 4.2.3 Requirements for building documentation
  - 4.3 Getting the source code
  - 4.4 Configuring `make`
    - 4.4.1 Build modes
    - 4.4.2 Running `autogen.sh`
    - 4.4.3 Running `configure`
      - Configuration options
      - Checking build dependencies
      - Configuring target directories
  - 4.5 Compiling LilyPond
    - 4.5.1 Using `make`
    - 4.5.2 Saving time with the `-j` option
    - 4.5.3 Useful `make` variables
  - 4.6 Post-compilation options
    - 4.6.1 Installing LilyPond from a local build
    - 4.6.2 Generating documentation
      - Documentation editor’s edit/compile cycle
      - Building documentation
      - Building a single document
      - Saving time with `CPU_COUNT`
      - Installing documentation
      - Building documentation without compiling
    - 4.6.3 Testing LilyPond binary
  - 4.7 Problems
  - 4.8 Concurrent stable and development versions
    - 4.8.1 Replacing the notation fonts in development versions
  - 4.9 Build system
- 5 Documentation work
  - 5.1 Introduction to documentation work
  - 5.2 `\version` in documentation files
  - 5.3 Documentation suggestions
  - 5.4 Texinfo introduction and usage policy
    - 5.4.1 Texinfo introduction
    - 5.4.2 Documentation files
    - 5.4.3 Sectioning commands
    - 5.4.4 Menus
    - 5.4.5 LilyPond formatting
    - 5.4.6 Text formatting
    - 5.4.7 Syntax survey
      - Comments
      - Cross-references
      - External links
      - Fixed-width font
      - Indexing
      - Lists
      - Special characters
      - Miscellany
    - 5.4.8 Other text concerns
  - 5.5 Documentation policy
    - 5.5.1 Books
    - 5.5.2 Section organization
    - 5.5.3 Checking cross-references
    - 5.5.4 General writing
    - 5.5.5 Technical writing style
  - 5.6 Tips for writing documentation
    - 5.6.1 Working on subsections
    - 5.6.2 Searching
  - 5.7 Scripts to ease documentation work
    - 5.7.1 Building only one section of the documentation
    - 5.7.2 Updating documentation with `convert-ly`
  - 5.8 Documentation strings in the Internals Reference
  - 5.9 Translating the documentation
    - 5.9.1 Getting started with documentation translation
      - Translation requirements
      - Which documentation can be translated
      - Starting translation in a new language
    - 5.9.2 Documentation translation details
      - Files to be translated
      - Translating the website and other Texinfo documentation
      - Adding a Texinfo manual
    - 5.9.3 Documentation translation maintenance
      - Check state of translation
      - Updating documentation translation
      - Updating translation committishes
      - Maintaining without updating translations
    - 5.9.4 Technical background
- 6 Website work
  - 6.1 Introduction to website work
  - 6.2 Uploading website
  - 6.3 Debugging website and docs locally
  - 6.4 Translating the website
- 7 LilyPond Wiki work
  - 7.1 Introduction to the LilyPond Wiki
  - 7.2 Adding and editing snippets
  - 7.3 Snippet administration
  - 7.4 The `makelsr.pl` script
  - 7.5 LilyPond Wiki to Git
- 8 Issues
  - 8.1 Introduction to issues
  - 8.2 Triaging bugs
  - 8.3 Issue classification
  - 8.4 Adding issues to the tracker
- 9 Regression tests
  - 9.1 Introduction to regression tests
  - 9.2 Precompiled regression tests
  - 9.3 Compiling regression tests
  - 9.4 Regtest comparison
  - 9.5 Pixel-based regtest comparison
  - 9.6 Finding the cause of a regression
  - 9.7 MusicXML tests
- 10 Programming work
  - 10.1 Overview of LilyPond architecture
  - 10.2 LilyPond programming languages
  - 10.3 Programming without compiling
  - 10.4 Finding functions
  - 10.5 Code style
    - 10.5.1 Languages
    - 10.5.2 Filenames
    - 10.5.3 Code formatting
    - 10.5.4 Naming Conventions
    - 10.5.5 Broken code
    - 10.5.6 Code comments
    - 10.5.7 Handling errors
    - 10.5.8 Localization
  - 10.6 Warnings, Errors, Progress and Debug Output
  - 10.7 Debugging LilyPond
    - 10.7.1 Debugging overview
    - 10.7.2 Debugging C++ code
    - 10.7.3 Debugging Scheme code
    - 10.7.4 Debugging scoring algorithms
    - 10.7.5 Debugging skylines
  - 10.8 Tracing object relationships
  - 10.9 Tracing processing time
  - 10.10 Adding or modifying features
    - 10.10.1 Write the code
    - 10.10.2 Write regression tests
    - 10.10.3 Write convert-ly rule
    - 10.10.4 Automatically update documentation
    - 10.10.5 Manually update documentation
    - 10.10.6 Edit changes.tely
    - 10.10.7 Verify successful build
    - 10.10.8 Verify regression tests
    - 10.10.9 Post patch for comments
    - 10.10.10 Push patch
    - 10.10.11 Closing the issues
  - 10.11 Iterator tutorial
  - 10.12 Engraver tutorial
    - 10.12.1 Useful methods for information processing
    - 10.12.2 Translation process
    - 10.12.3 Listening to music events
    - 10.12.4 Acknowledging grobs
    - 10.12.5 Engraver declaration/documentation
  - 10.13 Callback tutorial
  - 10.14 Understanding pure properties
    - 10.14.1 Purity in LilyPond
    - 10.14.2 Writing a pure function
    - 10.14.3 How purity is defined and stored
    - 10.14.4 Where purity is used
    - 10.14.5 Case studies
    - 10.14.6 Debugging tips
  - 10.15 LilyPond scoping
  - 10.16 Regular expressions
  - 10.17 Scheme->C interface
    - 10.17.1 Comparison
    - 10.17.2 Conversion
  - 10.18 Garbage collection for dummies
  - 10.19 LilyPond miscellany
    - 10.19.1 Spacing algorithms
    - 10.19.2 Info from Han-Wen email
    - 10.19.3 Music functions and Guile debugging
    - 10.19.4 Articulations on EventChord
- 11 Release work
  - 11.1 Development phases
  - 11.2 Release checklist
  - 11.3 Major release checklist
- 12 Modifying the Emmentaler font
  - 12.1 Overview of the Emmentaler font
  - 12.2 Font creation tools
  - 12.3 Adding a new font section
  - 12.4 Adding a new glyph
  - 12.5 Building the changed font
  - 12.6 METAFONT formatting rules
- 13 Administrative policies
  - 13.1 LilyPond is GNU Software
  - 13.2 Environment variables
  - 13.3 Performing yearly copyright update (“grand-replace”)
- Appendix A GNU Free Documentation License