Module type Dune.SYM

The module type for an embedded domain specific language (eDSL) that describes a Dune file.

type 'a repr

A type that represents the stanzas and stanza arguments of a Dune file.

Stanzas

val rule : [ `RuleClause ] repr list -> [ `Stanza ] repr

The rule [rule_clause1 ...] stanza is used to create custom user rules. It tells Dune how to generate a specific set of files from a specific set of dependencies.

val executable : [ `Executable ] repr list -> [ `Stanza ] repr

The executable [name "<name>"; ...] stanza must be used to describe an executable.

"<name>" is a module name that contains the executable's main entry point. There can be additional modules in the current directory; you only need to specify the entry point. Given an executable stanza with name "<name>"; ..., Dune will know how to build "<name>.exe". If requested, it will also know how to build "<name>.bc" and "<name>.bc.js". Dune 2.0 and up also need specific configuration (see the modes optional field below).

val library : [ `Library ] repr list -> [ `Stanza ] repr

The library [name "<library-name>"; ...] stanza must be used to describe OCaml libraries.

"<library-name>" is the real name of the library. It determines the names of the archive files generated for the library as well as the module name under which the library will be available, unless wrapped false is used (see wrapped). It must be a valid OCaml module name, but it doesn't need to start with an uppercase letter.

val install : [ `Install ] repr list -> [ `Stanza ] repr

install copies freshly built artifacts from the workspace to the system.

The install stanza takes three pieces of information:

  1. the list of files to install
  2. the package to attach these files. (This field is optional if your project contains a single package.)
  3. the section in which the files will be installed

See Install for how to specify the three pieces of information.

val pragma : string -> [ `Stanza ] repr -> [ `Stanza ] repr

pragma instruction stanza gives an instruction to the interpreter that modifies the behavior of a Dune stanza.

The standard pragmas are:

  1. "once" - Use this for the dkml-dune-dsl-show interpreter, and any other compliant interpreter, to indicate that the stanza should be included at most once. Often you will have common build rules that should not be include multiple times simply because you have multiple parameter sets.

For the dkml-dune-dsl-show interpreter, a tell-tale sign that you should use "once" is when your rules do not have any parameters "{{ }}" in them.

Rules

val alias : string -> [ `RuleClause ] repr

alias name specifies the rule’s alias is name. Building the alias name means building the targets of this rule and all other rules that share the name.

val targets : [< `S of string | `Split of string ] list -> [ `RuleClause ] repr

targets filenames is a list of filenames that will be produced by the rule.

val target : string -> [ `RuleClause ] repr

target filename is the filename that will be produced by the rule.

val deps : [ `Dep ] repr list -> [ `RuleClause ] repr

deps [dep1; ...] declares dependencies [dep1; ...] required by the rule.

See Dependencies for which dependencies are allowed.

val action : [ `Action ] repr -> [ `RuleClause ] repr

action <action> is what you run to produce the targets from the dependencies.

val rule_enabled_if : [ `BooleanLanguage ] repr -> [ `RuleClause ] repr

rule_enabled_if boolean enables the rule if and only if the boolean evaluates to the string "false".

type mode =
  1. | Standard
  2. | Fallback
  3. | Promote
val mode : mode -> [ `RuleClause ] repr

mode mode can change the default (Standard) behavior when a source file exists with the same name as the rule target.

  • Standard - the standard mode.
  • Fallback - in this mode, when the targets are already present in the source tree, Dune will ignore the rule. It's an error if only a subset of the targets are present in the tree. Fallback rules are commonly used to generate default configuration files that may be generated by a configure script.
  • Promote - in this mode, the files in the source tree will be ignored. Once the rule has been executed, the targets will be copied back to the source tree.
Boolean Language

The Boolean language allows the user to define simple Boolean expressions that Dune can evaluate.

After an expression is evaluated, it must be exactly the string true or false to be considered as a Boolean. Any other value will be treated as an error.

The mapping between the raw Dune expressions and the DSL (OCaml) is:

* template is a string template, like "%{ocaml-config:system}" * not is the

val template : string -> [ `BooleanLanguage ] repr

string template like "%{ocaml-config:system}" or a constant like "macos"

val not : [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr

Negate the boolean

val all : [ `BooleanLanguage ] repr list -> [ `BooleanLanguage ] repr

All of the booleans must be true; equivalently, all the booleans are AND-ed together.

val any : [ `BooleanLanguage ] repr list -> [ `BooleanLanguage ] repr

At least one of the booleans must be true; equivalently, all the booleans are OR-ed together.

val eq : [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr

Equals

val ne : [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr

Not equals

val lt : [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr

Less than

val gt : [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr

Greater than

val le : [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr

Less than or equal to

val ge : [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr -> [ `BooleanLanguage ] repr

Greater than or equal to

Dependencies
val glob_files : string -> [ `Dep ] repr

glob_files glob depends on all files matched by glob.

You can use globs to declare dependencies on a set of files. Note that globs will match files that exist in the source tree as well as buildable targets, so for instance you can depend on "*.cmi".

The glob syntax is interpreted as follows:

  • "\\<char>" matches exactly "<char>", even if it’s a special character ("*", "?", ...).
  • "*" matches any sequence of characters, except if it comes first, in which case it matches any character that is not . followed by anything.
  • "**" matches any character that is not . followed by anything, except if it comes first, in which case it matches anything.
  • "?" matches any single character.
  • "[<set>]" matches any character that is part of "<set>".
  • "[!<set>]" matches any character that is not part of "<set>".
  • "{<glob1>,<glob2>,...,<globn>}" matches any string that is matched by one of "<glob1>", "<glob2>", etc.
val named_dep : name:string -> string -> [ `Dep ] repr

named_dep ~name file depends on the file and labels the file as name.

The name label may be used in the rule's action. For example, if name = "the-cookbook" then the expression %{the-cookbook} can be used in the action.

val alias_dep : string -> [ `Dep ] repr

alias_dep alias depends on the alias named alias.

val file_dep : string -> [ `Dep ] repr

file_dep file depends on the file named file.

val file_deps : [< `S of string | `Split of string ] list -> [ `Dep ] repr

file_deps [`S file1; `S file2; ...] depends on the list of files file1; file2; ....

Actions
val echo : string list -> [ `Action ] repr

echo [s1; s2; ...] writes the strings s1; s2; ... to the standard output separated by a space.

val with_stdin_from : string -> [ `Action ] repr -> [ `Action ] repr

with_stdin_from filename action redirects the input of action action from the file named filename.

val with_stdout_to : string -> [ `Action ] repr -> [ `Action ] repr

with_stdout_to filename action redirects the output of action action to the file named filename.

val progn : [ `Action ] repr list -> [ `Action ] repr

progn [action1; action2; ...] executes several actions action1; ... in sequence

val copy : src:string -> dest:string -> [ `Action ] repr

copy ~src ~dest copies the src file to dest

val run : [< `S of string | `Split of string ] list -> [ `Action ] repr

run [`S prog; `S arg1; `S arg2; ...] runs the program prog and gives it arguments arg1; arg2; ....

val diff : actual:string -> expected:string -> [ `Action ] repr

diff ~actual ~expected is similar to run ["diff"; "<actual>"; "<expected>"] but is better and allows promotion. See Diffing and promotion for more details.

val diff_q : actual:string -> expected:string -> [ `Action ] repr

diff_q ~actual ~expected is the "diff?" action in a "dune" file, and is similar to run ["diff"; "<actual>"; "<expected>"] except that "<expected>" should be produced by a part of the same action rather than be a dependency, is optional and will be consumed by diff_q. See Diffing and promotion for more details.

val setenv : name:string -> value:string -> [ `Action ] repr -> [ `Action ] repr

setenv ~name ~value action sets the environment variable name to value in the action action

Executables and Libraries

This section has expressions that work in both executable and library stanzas.

val public_name : string -> [< `Executable | `Library ] repr

public_name is the name under which the library can be referred as a dependency when it is installed outside of the current workspace, or is the name of the executable when it is installed outside of the current workspace.

public_name for Libraries

Without a (public_name ...) field the library won’t be installed by Dune. The public name must start with the package name it’s part of and optionally followed by a dot, then anything else you want.

public_name for Executables

Without a (public_name ...) field the executable won’t be installed by Dune.

val name : string -> [< `Executable | `Library ] repr

name is the module name that contains the executable’s main entry point, or the real name of the library.

name for Libraries

It determines the names of the archive files generated for the library as well as the module name under which the library will be available, unless (wrapped false) is used (see wrapped). It must be a valid OCaml module name, but it doesn’t need to start with an uppercase letter.

name for Executables

There can be additional modules in the current directory; you only need to specify the entry point. Given an executable stanza with (name <name>), Dune will know how to build "<name>.exe".

val libraries : [< `S of string | `Split of string ] list -> [< `Executable | `Library ] repr

libraries [`S lib1; `S lib2; ...] specifies the library's dependencies

val modules : [ `OrderedSet ] repr -> [< `Executable | `Library ] repr

modules ordered_set specifies what modules are part of the library.

By default, Dune will use all the .ml/.re files in the same directory as the dune file. This includes ones present in the file system as well as ones generated by user rules. You can restrict this list by using a modules ordered_set field. modules uses the Ordered Sets Language, where elements are module names and don't need to start with an uppercase letter. For instance, to exclude module Foo, use modules (difference (standard) (set_of ["foo"])); in a real Dune file you would write that same expression as "(modules (:standard \ foo))"

See Ordered Sets for the operations you can perform.

type compilation_mode =
  1. | Byte
  2. | Native
  3. | Best
    (*

    compilation_mode must be byte, native, or best, where best is native with a fallback to bytecode when native compilation isn't available.

    *)
type binary_kind =
  1. | C
  2. | Exe
  3. | Object
  4. | Shared_object
  5. | Js
  6. | Plugin
    (*

    binary_kind is one of:

    • C for producing OCaml bytecode embedded in a C file
    • Exe for normal executables
    • Object for producing static object files that can be manually linked into C applications
    • Shared_object for producing object files that can be dynamically loaded into an application. This mode can be used to write a plugin in OCaml for a non-OCaml application.
    • Js for producing JavaScript from bytecode executables, see explicit_js_mode.
    • Plugin for producing a plugin (.cmxs if native or .cma if bytecode).
    *)
val modes : [< `C | `Exe | `Object | `Shared_object | `Byte | `Native | `Js | `Plugin | `Byte_complete | `Mode of compilation_mode * binary_kind ] list -> [< `Executable | `Library ] repr

The modes field allows selecting which linking modes will be used to link executables. Each mode is a pair (<compilation-mode> <binary-kind>), where <compilation-mode> describes whether the bytecode or native code backend of the OCaml compiler should be used and <binary-kind> describes what kind of file should be produced.

Refer to compilation_mode and binary_kind for precise semantics.

For instance the following executables stanza will produce bytecode executables and native shared objects:

(executable
  (name "a")
  (modes [`Mode (Byte, Exe); `Mode (Native; Shared_object)]))

Additionally, you can use the following shorthands:

  • `C for (byte c)
  • `Exe for (best exe)
  • `Object for (best object)
  • `Shared_object for (best shared_object)
  • `Byte for (byte exe)
  • `Native for (native exe)
  • `Js for (byte js)
  • `Plugin for (best plugin)

Lastly, use the special mode `Byte_complete for building a bytecode executable as a native self-contained executable, i.e., an executable that doesn't require the ocamlrun program to run and doesn't require the C stubs to be installed as shared object files.

val ocamlopt_flags : [ `OCamlOptFlag ] repr list -> [< `Executable | `Library ] repr
val wrapped : bool -> [< `Executable | `Library ] repr

wrapped false or wrapped true specifies whether the library modules should be available only through the top-level library module, or if they should all be exposed at the top level.

The default is wrapped true, and it's highly recommended to keep it this way. Because OCaml top-level modules must all be unique when linking an executables, polluting the top-level namespace will make your library unusable with other libraries if there is a module name clash. This option is only intended for libraries that manually prefix all their modules by the library name and to ease porting of existing projects to Dune.

val preprocess : [ `PreprocessSpec ] repr -> [< `Executable | `Library ] repr

preprocess spec specifies how to preprocess files when needed. The default is no_preprocessing.

The full list of specifications is in Preprocessing.

Preprocessing
val no_preprocessing : [ `PreprocessSpec ] repr

no_preprocessing tells Dune to give files as-is to the compiler

val pps : [< `S of string | `Split of string ] list -> [ `PreprocessSpec ] repr

pps [`S ppx1; `S ppx2; ...] preprocesses files using the given list of PPX rewriters

val staged_pps : [< `S of string | `Split of string ] list -> [ `PreprocessSpec ] repr

staged_pps [`S ppx1; `S ppx2; ...] preprocesses files using the given list of PPX rewriters after dependency analysis.

It is slower than pps, but you must use staged_pps instead of pps in order to force Dune to use the following pipeline:

  1. first stage of code generation
  2. dependency analysis
  3. second step of code generation in parallel with compilation
val future_syntax : [ `PreprocessSpec ] repr

future_syntax is equivalent to no_preprocessing when using one of the most recent versions of the compiler. When using an older one, it is a shim preprocessor that backports some of the newer syntax elements. This allows you to use some of the new OCaml features while keeping compatibility with older compilers.

Ordered Sets

For fields that can take multiple arguments, an [`OrderedSet] repr lets you specify your arguments using set operations. You can:

The authorative reference is Ordered Set Language.

Here are some common sets to get your started:

It is allowed grammatically but is highly discouraged to use split ":standard \ compat". Instead use difference (standard) (each ["compat"]) so the meaning is clear and so that DSL interpreters are exposed to what you actually meant to happen.

val set_of : string list -> [ `OrderedSet ] repr

set_of [arg1; arg2; ...] are zero or more arguments arg1, arg2 and so on.

val standard : [ `OrderedSet ] repr

standard are the standard arguments.

The standard depends on the context in which the arguments are applied. See the relevant documentation for the definition of standard:

val split : string -> [ `OrderedSet ] repr

split "arg1 arg2 ..." are zero or more arguments arg1, arg2 and so on after splitting the given string "arg1 arg2 ..." according to the Lexical conventions of s-expression for identifying atoms in a list.

val union : [ `OrderedSet ] repr list -> [ `OrderedSet ] repr

union [set1; set2; ...] is all the arguments from set1 and also set2 and so on.

val difference : [ `OrderedSet ] repr -> [ `OrderedSet ] repr -> [ `OrderedSet ] repr

difference a_set b_set is all the arguments from a_set that are not in b_set

Libraries Only

val virtual_modules : [ `OrderedSet ] repr -> [ `Library ] repr

virtual_modules ordered_set specifies what modules for which only an interface would be present, and which will have implementations defined in other libraries.

The virtual modules play the role of interfaces or protocols in Dune virtual libraries.

See Ordered Sets for the operations you can perform.

val implements : string -> [ `Library ] repr

implements libname specifies the virtual library the current library (the implementing library) provides an implementation for.

See Dune virtual libraries for more details.

val default_implementation : string -> [ `Library ] repr

default_implementation default_impl selects the default implementation for a virtual library, which is enabled after variant resolution if no suitable implementation has been found.

Executables Only

As of this version there are no executable-only clauses.

Install

val section : string -> [ `Install ] repr

section "share" is the section in which the files will be installed.

The following sections are available:

  • "lib" installs by default to "/lib/<pkgname>/"
  • "lib_root" installs by default to "/lib/"
  • "libexec" installs by default to "/lib/<pkgname>/" with the executable bit set
  • "libexec_root" installs by default to "/lib/" with the executable bit set
  • "bin" installs by default to "/bin/" with the executable bit set
  • "sbin" installs by default to "/sbin/" with the executable bit set
  • "toplevel" installs by default to "/lib/toplevel/"
  • "share" installs by default to "/share/<pkgname>/"
  • "share_root" installs by default to "/share/"
  • "etc" installs by default to "/etc/<pkgname>/"
  • "doc" installs by default to "/doc/<pkgname>/"
  • "stublibs" installs by default to "/lib/stublibs/" with the executable bit set
  • "man" installs by default relative to "/man" with the destination directory extracted from the extension of the source file (so that installing foo.1 is equivalent to a destination of man1/foo.1)
  • "misc" requires files to specify an absolute destination. It will only work when used with opam and the user will be prompted before the installation when it's done via opam. It is deprecated.

The following sections are not yet available in Dune DSL:

  • "(site (<package> <site>))" installs in the <site> directory of <package>. If the prefix isn't the same as the one used when installing <package>, <package> won't find the files.
val install_files : [ `InstallDestination ] repr list -> [ `Install ] repr
Install Destination
val destination_file : filename:string -> destination:string -> [ `InstallDestination ] repr

https://dune.readthedocs.io/en/stable/dune-files.html#install-1.

destination_file ~filename ~destination represents the sub-expression:

(mylib.el as emacs/site-lisp/mylib.el)

in

(files   (mylib.el as emacs/site-lisp/mylib.el))