Break up `Settings` into smaller structs

As far as I can tell, the fields within `Settings` aren't *intrinsicly*
related. They just happen to be initialized the same way (in particular
prior to the rest of `DynFlags`), and that is why they are grouped
together.

Within `Settings`, however, there are groups of settings that clearly do
share something in common, regardless of how they anything is
initialized.

In the spirit of GHC being a library, where the end cosumer may choose
to initialize this configuration in arbitrary ways, I made some new data
types for thoses groups internal to `Settings`, and used them to define
`Settings` instead. Hopefully this is a baby step towards a general
decoupling of the stateful and stateless parts of GHC.

1 files changed, 16 insertions, 0 deletions

diff --git a/compiler/main/FileSettings.hs b/compiler/main/FileSettings.hs
new file mode 100644
index 0000000000..f531d206a9
--- /dev/null
+++ b/compiler/main/FileSettings.hs
@@ -0,0 +1,16 @@
+module FileSettings
+  ( FileSettings (..)
+  ) where
+
+import GhcPrelude
+
+-- | Paths to various files and directories used by GHC, including those that
+-- provide more settings.
+data FileSettings = FileSettings
+  { fileSettings_ghcUsagePath        :: FilePath       -- ditto
+  , fileSettings_ghciUsagePath       :: FilePath       -- ditto
+  , fileSettings_toolDir             :: Maybe FilePath -- ditto
+  , fileSettings_topDir              :: FilePath       -- ditto
+  , fileSettings_tmpDir              :: String      -- no trailing '/'
+  , fileSettings_systemPackageConfig :: FilePath
+  }