Terminology

  • package: a package is a set of libraries, executables, … that are built and installed as one by opam
  • project: a project is a source tree, maybe containing one or more packages
  • root: the root is the directory from where dune can build things. Dune knows how to build targets that are descendents of the root. Anything outside of the tree starting from the root is considered part of the installed world. How the root is determined is explained in Finding the root.
  • workspace: the workspace is the subtree starting from the root. It can contain any number of projects that will be built simultaneously by dune
  • installed world: anything outside of the workspace, that dune takes for granted and doesn’t know how to build
  • installation: this is the action of copying build artifacts or other files from the <root>/_build directory to the installed world
  • scope: a scope determines where private items are visible. Private items include libraries or binaries that will not be installed. In dune, scopes are sub-trees rooted where at least one <package>.opam file is present. Moreover, scopes are exclusive. Typically, every project defines a single scope. See Scopes for more details
  • build context: a build context is a subdirectory of the <root>/_build directory. It contains all the build artifacts of the workspace built against a specific configuration. Without specific configuration from the user, there is always a default build context, which corresponds to the environment in which dune is executed. Build contexts can be specified by writing a dune-workspace file
  • build context root: the root of a build context named foo is <root>/_build/<foo>
  • alias: an alias is a build target that doesn’t produce any file and has
    configurable dependencies. Aliases are per-directory. However, on the command line, asking for an alias to be built in a given directory will trigger the construction of the alias in all children directories recursively. Dune defines several Built-in Aliases.
  • environment: in dune, each directory has an environment attached to it. The environment determines the default values of various parameters, such as the compilation flags. Inside a scope, each directory inherit the environment from its parent. At the root of every scope, a default environment is used. At any point, the environment can be altered using an env stanza.
  • build profile: a global setting that influence various defaults. It can be set from the command line using --profile <profile> or from dune-workspace files. The following profiles are standard:
    • release which is the profile used for opam releases
    • dev which is the default profile when none is set explicitly, it has stricter warnings that the release one