Changes between Version 7 and Version 8 of Commentary/Packages

Timestamp:

08/25/09 06:45:19 (4 years ago)

Author:

duncan

Comment:

bring the package Id type/field names up to date, also mention ghc --abi-hash

Commentary/Packages

@@ -30 +30 @@
 == Identifying Packages ==
 
- `PackageName` ("base")::
+ `Cabal.PackageName` ("base")::
     A string.  Defined in `Distribution.Package`.  Does not uniquely identify a package: the package
     database can contain several packages with the same name.
 
- `PackageIdentifier` ("base-4.1.0.0")::
-    A `PackageName` plus a `Version`.  A `PackageIdentifier` names an API.  If two `PackageIdentifiers` are
-    the same, they have the same API.
+ `Cabal.PackageId` ("base-4.1.0.0")::
+    A `PackageName` plus a `Version`.  A `PackageId` names an API.  If two `PackageId`s are
+    the same, they are assumed to have the same API.
     [[BR]][[BR]]
-    `InstalledPackageInfo` contains the field `package :: PackageIdentifier`.
+    `InstalledPackageInfo` contains the field `sourcePackageId :: PackageId`.
     [[BR]][[BR]]
-    In GHC 6.11, the `PackageIdentifier` also uniquely identifies a package instance in the package database, but
+    In GHC 6.11, the `PackageId` also uniquely identifies a package instance in the package database, but
     only by convention (we may lift this restriction in the future, and allow the database to contain
-    multiple package instances with the same `PackageIdentifier` (and different `InstalledPackageId`s).
+    multiple package instances with the same `PackageId` (and different `InstalledPackageId`s).
 
- `InstalledPackageId` ("base-4.1.0.0-1mpgjN"):: 
+ `Cabal.InstalledPackageId` ("base-4.1.0.0-1mpgjN"):: 
     (introduced in GHC 6.12 / Cabal 1.7.2) A string that uniquely identifies a package instance in the database.
     An `InstalledPackageId` identifies an ABI: if two `InstalledPackageIds` are the same, they have the
     same ABI.
     [[BR]][[BR]]
-    `InstalledPackageInfo` contains the field `package :: PackageIdentifier`.
+    `InstalledPackageInfo` contains the field `installedPackageId :: InstalledPackageId`.
     [[BR]][[BR]]
     Dependencies between installed packages are identified by the `InstalledPackageId`.  An `InstalledPackageId` is
-    currently chosen by adding a random suffix to the string representing the `PackageIdentifier` when a package is
-    registered.
+    chosen when a package is registered. It is chosen by calling `ghc --abi-hash` on the compiled modules and appending
+    the hash as a suffix to the string representing the `PackageIdentifier`.
 
- `PackageId` (these currently look like "base-4.1.0.0" in GHC 6.12)::
+ `GHC.PackageId` (these currently look like "base-4.1.0.0" in GHC 6.12)::
     Inside GHC, we use the type `PackageId`, which is a `FastString`.  The (Z-encoding of) `PackageId` prefixes each
     external symbol in the generated code, so that the modules of one package do not clash with those of another package,