--- short-description: Meson's API to integrate Meson support into an IDE ... # IDE integration Meson has exporters for Visual Studio and XCode, but writing a custom backend for every IDE out there is not a scalable approach. To solve this problem, Meson provides an API that makes it easy for any IDE or build tools to integrate Meson builds and provide an experience comparable to a solution native to the IDE. All the resources required for such a IDE integration can be found in the `meson-info` directory in the build directory. The first thing to do when setting up a Meson project in an IDE is to select the source and build directories. For this example we assume that the source resides in an Eclipse-like directory called `workspace/project` and the build tree is nested inside it as `workspace/project/build`. First, we initialize Meson by running the following command in the source directory. meson builddir With this command meson will configure the project and also generate introspection information that is stored in `intro-*.json` files in the `meson-info` directory. The introspection dump will be automatically updated when meson is (re)configured, or the build options change. Thus, an IDE can watch for changes in this directory to know when something changed. Note that `meson-info.json` guaranteed to be the last file written. The `meson-info` directory should contain the following files: | File | Description | | ------------------------------ | ------------------------------------------------------------------- | | `intro-benchmarks.json` | Lists all benchmarks | | `intro-buildoptions.json` | Contains a full list of meson configuration options for the project | | `intro-buildsystem_files.json` | Full list of all meson build files | | `intro-dependencies.json` | Lists all dependencies used in the project | | `intro-installed.json` | Contains mapping of files to their installed location | | `intro-projectinfo.json` | Stores basic information about the project (name, version, etc.) | | `intro-targets.json` | Full list of all build targets | | `intro-tests.json` | Lists all tests with instructions how to run them | The content of the JSON files is further specified in the remainder of this document. ## The `targets` section The most important file for an IDE is probably `intro-targets.json`. Here each target with its sources and compiler parameters is specified. The JSON format for one target is defined as follows: ```json { "name": "Name of the target", "id": "The internal ID meson uses", "type": "", "defined_in": "/Path/to/the/targets/meson.build", "subproject": null, "filename": ["list", "of", "generated", "files"], "build_by_default": true / false, "target_sources": [], "extra_files": ["/path/to/file1.hpp", "/path/to/file2.hpp"], "installed": true / false, } ``` If the key `installed` is set to `true`, the key `install_filename` will also be present. It stores the installation location for each file in `filename`. If one file in `filename` is not installed, its corresponding install location is set to `null`. The `subproject` key specifies the name of the subproject this target was defined in, or `null` if the target was defined in the top level project. *(New in 0.56.0)* The `extra_files` key lists all files specified via the `extra_files` kwarg of a build target. See [`executable()`](Reference-manual.md#executable). A target usually generates only one file. However, it is possible for custom targets to have multiple outputs. ### Target sources The `intro-targets.json` file also stores a list of all source objects of the target in the `target_sources`. With this information, an IDE can provide code completion for all source files. ```json { "language": "language ID", "compiler": ["The", "compiler", "command"], "parameters": ["list", "of", "compiler", "parameters"], "sources": ["list", "of", "all", "source", "files", "for", "this", "language"], "generated_sources": ["list", "of", "all", "source", "files", "that", "where", "generated", "somewhere", "else"] } ``` It should be noted that the compiler parameters stored in the `parameters` differ from the actual parameters used to compile the file. This is because the parameters are optimized for the usage in an IDE to provide autocompletion support, etc. It is thus not recommended to use this introspection information for actual compilation. ### Possible values for `type` The following table shows all valid types for a target. | value of `type` | Description | | ---------------- | --------------------------------------------------------------------------------------------- | | `executable` | This target will generate an executable file | | `static library` | Target for a static library | | `shared library` | Target for a shared library | | `shared module` | A shared library that is meant to be used with dlopen rather than linking into something else | | `custom` | A custom target | | `run` | A Meson run target | | `jar` | A Java JAR target | ### Using `--targets` without a build directory It is also possible to get most targets without a build directory. This can be done by running `meson introspect --targets /path/to/meson.build`. The generated output is similar to running the introspection with a build directory or reading the `intro-targets.json`. However, there are some key differences: - The paths in `filename` now are _relative_ to the future build directory - The `install_filename` key is completely missing - There is only one entry in `target_sources`: - With the language set to `unknown` - Empty lists for `compiler` and `parameters` and `generated_sources` - The `sources` list _should_ contain all sources of the target There is no guarantee that the sources list in `target_sources` is correct. There might be differences, due to internal limitations. It is also not guaranteed that all targets will be listed in the output. It might even be possible that targets are listed, which won't exist when meson is run normally. This can happen if a target is defined inside an if statement. Use this feature with care. ## Build Options The list of all build options (build type, warning level, etc.) is stored in the `intro-buildoptions.json` file. Here is the JSON format for each option. ```json { "name": "name of the option", "description": "the description", "type": "type ID", "value": "value depends on type", "section": "section ID", "machine": "machine ID" } ``` The supported types are: - string - boolean - combo - integer - array For the type `combo` the key `choices` is also present. Here all valid values for the option are stored. The possible values for `section` are: - core - backend - base - compiler - directory - user - test The `machine` key specifies the machine configuration for the option. Possible values are: - any - host - build To set the options, use the `meson configure` command. Since Meson 0.50.0 it is also possible to get the default buildoptions without a build directory by providing the root `meson.build` instead of a build directory to `meson introspect --buildoptions`. Running `--buildoptions` without a build directory produces the same output as running it with a freshly configured build directory. However, this behavior is not guaranteed if subprojects are present. Due to internal limitations all subprojects are processed even if they are never used in a real meson run. Because of this options for the subprojects can differ. ## The dependencies section The list of all _found_ dependencies can be acquired from `intro-dependencies.json`. Here, the name, version, compiler and linker arguments for a dependency are listed. ### Scanning for dependecie with `--scan-dependencies` It is also possible to get most dependencies used without a build directory. This can be done by running `meson introspect --scan-dependencies /path/to/meson.build`. The output format is as follows: ```json [ { "name": "The name of the dependency", "required": true, "version": [">=1.2.3"], "conditional": false, "has_fallback": false } ] ``` The `required` keyword specifies whether the dependency is marked as required in the `meson.build` (all dependencies are required by default). The `conditional` key indicates whether the `dependency()` function was called inside a conditional block. In a real meson run these dependencies might not be used, thus they _may_ not be required, even if the `required` key is set. The `has_fallback` key just indicates whether a fallback was directly set in the `dependency()` function. The `version` key always contains a list of version requirements from the `meson.build` and **not** the actual version of the dependency on disc. The version list is empty if no version was specified in the `meson.build`. ## Tests Compilation and unit tests are done as usual by running the `meson compile` and `meson test` commands. A JSON formatted result log can be found in `workspace/project/builddir/meson-logs/testlog.json`. When these tests fail, the user probably wants to run the failing test in a debugger. To make this as integrated as possible, extract the tests from the `intro-tests.json` and `intro-benchmarks.json` files. This provides you with all the information needed to run the test: what command to execute, command line arguments, environment variable settings and how to process the output. ```json { "name": "name of the test", "workdir": "the working directory (can be null)", "timeout": "the test timeout", "suite": ["list", "of", "test", "suites"], "is_parallel": true / false, "protocol": "exitcode" / "tap", "cmd": ["command", "to", "run"], "depends": ["target1-id", "target2-id"], "env": { "VARIABLE1": "value 1", "VARIABLE2": "value 2" } } ``` The `depends` entry *(since 0.56.0)* contains target ids; they can be looked up in the targets introspection data. The executable pointed to by `cmd` is also included in the entry, as are any arguments to the test that are build products. ## Build system files It is also possible to get Meson build files used in your current project. This can be done by running `meson introspect --buildsystem-files /path/to/builddir`. The output format is as follows: ```json [ "/Path/to/the/targets/meson.build", "/Path/to/the/targets/meson_options.txt", "/Path/to/the/targets/subdir/meson.build" ] ``` # Programmatic interface Meson also provides the `meson introspect` for project introspection via the command line. Use `meson introspect -h` to see all available options. This API can also work without a build directory for the `--projectinfo` command. # AST of a `meson.build` Since meson *0.55.0* it is possible to dump the AST of a `meson.build` as a JSON object. The interface for this is `meson introspect --ast /path/to/meson.build`. Each node of the AST has at least the following entries: | Key | Description | | ------------ | ------------------------------------------------------- | | `node` | Type of the node (see following table) | | `lineno` | Line number of the node in the file | | `colno` | Column number of the node in the file | | `end_lineno` | Marks the end of the node (may be the same as `lineno`) | | `end_colno` | Marks the end of the node (may be the same as `colno`) | Possible values for `node` with additional keys: | Node type | Additional keys | | -------------------- | ------------------------------------------------ | | `BooleanNode` | `value`: bool | | `IdNode` | `value`: str | | `NumberNode` | `value`: int | | `StringNode` | `value`: str | | `ContinueNode` | | | `BreakNode` | | | `ArgumentNode` | `positional`: node list; `kwargs`: accept_kwargs | | `ArrayNode` | `args`: node | | `DictNode` | `args`: node | | `EmptyNode` | | | `OrNode` | `left`: node; `right`: node | | `AndNode` | `left`: node; `right`: node | | `ComparisonNode` | `left`: node; `right`: node; `ctype`: str | | `ArithmeticNode` | `left`: node; `right`: node; `op`: str | | `NotNode` | `right`: node | | `CodeBlockNode` | `lines`: node list | | `IndexNode` | `object`: node; `index`: node | | `MethodNode` | `object`: node; `args`: node; `name`: str | | `FunctionNode` | `args`: node; `name`: str | | `AssignmentNode` | `value`: node; `var_name`: str | | `PlusAssignmentNode` | `value`: node; `var_name`: str | | `ForeachClauseNode` | `items`: node; `block`: node; `varnames`: list | | `IfClauseNode` | `ifs`: node list; `else`: node | | `IfNode` | `condition`: node; `block`: node | | `UMinusNode` | `right`: node | | `TernaryNode` | `condition`: node; `true`: node; `false`: node | We do not guarantee the stability of this format since it is heavily linked to the internal Meson AST. However, breaking changes (removal of a node type or the removal of a key) are unlikely and will be announced in the release notes. # Existing integrations - [Gnome Builder](https://wiki.gnome.org/Apps/Builder) - [KDevelop](https://www.kdevelop.org) - [Eclipse CDT](https://www.eclipse.org/cdt/) (experimental) - [Meson Cmake Wrapper](https://github.com/prozum/meson-cmake-wrapper) (for cmake IDEs) (currently unmaintained !!) - [Meson-UI](https://github.com/michaelbadcrumble/meson-ui) (Meson build GUI) - [Meson Syntax Highlighter](https://plugins.jetbrains.com/plugin/13269-meson-syntax-highlighter) plugin for JetBrains IDEs. - [asabil.meson](https://open-vsx.org/extension/asabil/meson) extension for VS Code/Codium - [Qt Creator](https://doc.qt.io/qtcreator/creator-project-meson.html)