Enumerates the simple on-or-off dynamic flags

Test whether a DynFlag is set

Set a DynFlag

Unset a DynFlag

Test whether a WarningFlag is set

Set a WarningFlag

Unset a WarningFlag

Test whether a ExtensionFlag is set

Set a ExtensionFlag

Unset a ExtensionFlag

Contains not only a collection of DynFlags but also a plethora of information relating to the compilation of a single file or GHC session

The target code type of the compilation (if any).

Whenever you change the target, also make sure to set ghcLink to something sensible.

HscNothing can be used to avoid generating any output, however, note that:

• This will not run the desugaring step, thus no warnings generated in this step will be output. In particular, this includes warnings related to pattern matching. You can run the desugarer manually using GHC.desugarModule.
• If a program uses Template Haskell the typechecker may try to run code from an imported module. This will fail if no code has been generated for this module. You can use GHC.needsTemplateHaskell to detect whether this might be the case and choose to either switch to a different target or avoid typechecking such modules. (The latter may preferable for security reasons.)

Will this target result in an object file on the disk?

The HscTarget value corresponding to the default way to create object files on the current platform.

The GhcMode tells us whether we're doing multi-module compilation (controlled via the GHC API) or one-shot (single-module) compilation. This makes a difference primarily to the Finder: in one-shot mode we look for interface files for imported modules, but in multi-module mode we look for source files in order to check whether they need to be recompiled.

What to do in the link step, if there is one.

When invoking external tools as part of the compilation pipeline, we pass these a sequence of options on the command-line. Rather than just using a list of Strings, we use a type that allows us to distinguish between filepaths and 'other stuff'. The reason for this is that this type gives us a handle on transforming filenames, and filenames only, to whatever format they're expected to be on a particular platform.

These -f<blah> flags can all be reversed with -fno-<blah>

These -f<blah> flags can all be reversed with -fno-<blah>

These -f<blah> flags can all be reversed with -fno-<blah>

These -Xblah flags can all be reversed with -XNoblah

Some modules have dependencies on others through the DynFlags rather than textual imports

The various Safe Haskell modes

Test if Safe Haskell is on in some form

Is the Safe Haskell safe language in use

Are all direct imports required to be safe for this Safe Haskell mode? Direct imports are when the code explicitly imports a module

Are all implicit imports required to be safe for this Safe Haskell mode? Implicit imports are things in the prelude. e.g System.IO when print is used.

The normal DynFlags. Note that they is not suitable for use in this form and must be fully initialized by GHC.newSession first.

Used by GHC.newSession to partially initialize a new DynFlags value

Retrieve the options corresponding to a particular opt_* field in the correct order

Gets the verbosity flag for the current verbosity level. This is fed to other tools, so GHC-specific verbosity flags like -ddump-most are not included

Sets the DynFlags to be appropriate to the optimisation level

Parse dynamic flags from a list of command line arguments. Returns the the parsed DynFlags, the left-over arguments, and a list of warnings. Throws a UsageError if errors occurred during parsing (such as unknown flags or missing arguments).

Like parseDynamicFlagsCmdLine but does not allow the package flags (-package, -hide-package, -ignore-package, -hide-all-packages, -package-conf). Used to parse flags set in a modules pragma.