Portability	portable
Maintainer	cabal-devel@haskell.org
Safe Haskell	Safe-Inferred

Distribution.Simple.Compiler

Contents

Haskell implementations
Support for package databases
Support for optimisation levels
Support for language extensions

Description

This should be a much more sophisticated abstraction than it is. Currently it's just a bit of data about the compiler, like it's flavour and name and version. The reason it's just data is because currently it has to be in Read and Show so it can be saved along with the LocalBuildInfo. The only interesting bit of info it contains is a mapping between language extensions and compiler command line flags. This module also defines a PackageDB type which is used to refer to package databases. Most compilers only know about a single global package collection but GHC has a global and per-user one and it lets you create arbitrary other package databases. We do not yet fully support this latter feature.

Synopsis

Haskell implementations

module Distribution.Compiler

data Compiler

Constructors

Compiler
Fields compilerId :: CompilerId Compiler flavour and version. compilerLanguages :: [(Language, Flag)] Supported language standards. compilerExtensions :: [(Extension, Flag)] Supported extensions. compilerProperties :: Map String String A key-value map for properties not covered by the above fields.

Instances

Read Compiler
Show Compiler

showCompilerId :: Compiler -> String

compilerFlavor :: Compiler -> CompilerFlavor

compilerVersion :: Compiler -> Version

Support for package databases

data PackageDB

Some compilers have a notion of a database of available packages. For some there is just one global db of packages, other compilers support a per-user or an arbitrary db specified at some location in the file system. This can be used to build isloated environments of packages, for example to build a collection of related packages without installing them globally.

Constructors

GlobalPackageDB
UserPackageDB
SpecificPackageDB FilePath

Instances

Eq PackageDB
Ord PackageDB
Read PackageDB
Show PackageDB

type PackageDBStack = [PackageDB]

We typically get packages from several databases, and stack them together. This type lets us be explicit about that stacking. For example typical stacks include:

 [GlobalPackageDB]
 [GlobalPackageDB, UserPackageDB]
 [GlobalPackageDB, SpecificPackageDB "package.conf.inplace"]

Note that the GlobalPackageDB is invariably at the bottom since it contains the rts, base and other special compiler-specific packages.

We are not restricted to using just the above combinations. In particular we can use several custom package dbs and the user package db together.

When it comes to writing, the top most (last) package is used.

registrationPackageDB :: PackageDBStack -> PackageDB

Return the package that we should register into. This is the package db at the top of the stack.

absolutePackageDBPaths :: PackageDBStack -> IO PackageDBStack

Make package paths absolute

absolutePackageDBPath :: PackageDB -> IO PackageDB

Support for optimisation levels

data OptimisationLevel

Some compilers support optimising. Some have different levels. For compliers that do not the level is just capped to the level they do support.

Constructors

NoOptimisation
NormalOptimisation
MaximumOptimisation

Instances

Bounded OptimisationLevel
Enum OptimisationLevel
Eq OptimisationLevel
Read OptimisationLevel
Show OptimisationLevel

flagToOptimisationLevel :: Maybe String -> OptimisationLevel

Support for language extensions

type Flag = String

languageToFlags :: Compiler -> Maybe Language -> [Flag]

unsupportedLanguages :: Compiler -> [Language] -> [Language]

extensionsToFlags :: Compiler -> [Extension] -> [Flag]

For the given compiler, return the flags for the supported extensions.

unsupportedExtensions :: Compiler -> [Extension] -> [Extension]

For the given compiler, return the extensions it does not support.

parmakeSupported :: Compiler -> Bool

Does this compiler support parallel --make mode?