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| -rw-r--r-- | doc/manual/src/architecture/store/objects.md | 23 | ||||
| -rw-r--r-- | doc/manual/src/architecture/store/related-work.md | 24 |
2 files changed, 24 insertions, 23 deletions
diff --git a/doc/manual/src/architecture/store/objects.md b/doc/manual/src/architecture/store/objects.md index e4f49a170..caa00d862 100644 --- a/doc/manual/src/architecture/store/objects.md +++ b/doc/manual/src/architecture/store/objects.md @@ -31,29 +31,6 @@ In particular, every file system object falls into these three cases: A bare file or symlink as the "root" file system object is allowed. -### Comparison with Git - -This is close to Git's model, but with one crucial difference: -Git puts the "permission" info within the directory map's values instead of making it part of the file (blob, in it's parlance) object. - - data GitObject - = Blob ByteString - | Tree (Map FileName (Persission, FSO)) - - data Persission - = Directory -- IFF paired with tree - -- Iff paired with blob, one of: - | RegFile - | ExecutableFile - | Symlink - -So long as the root object is a directory, the representations are isomorphic. -There is no "wiggle room" the git way since whenever the permission info wouldn't matter (e.g. the child object being mapped to is a directory), the permission info must be a sentinel value. - -However, if the root object is a blob, there is loss of fidelity. -Since the permission info is used to distinguish executable files, non-executable files, and symlinks, but there isn't a "parent" directory of the root to contain that info, these 3 cases cannot be distinguished. - -Git's model matches Unix tradition, but Nix's model is more natural. ## References diff --git a/doc/manual/src/architecture/store/related-work.md b/doc/manual/src/architecture/store/related-work.md index b64b41988..92b7d480e 100644 --- a/doc/manual/src/architecture/store/related-work.md +++ b/doc/manual/src/architecture/store/related-work.md @@ -25,6 +25,30 @@ Do we have open terms? Do we hve thunks vs expressions distinction? c.f. John Shutt's modern fexprs, when the syntax can "leak". +## Comparison with Git file system model + +This is close to Git's model, but with one crucial difference: +Git puts the "permission" info within the directory map's values instead of making it part of the file (blob, in it's parlance) object. + + data GitObject + = Blob ByteString + | Tree (Map FileName (Persission, FSO)) + + data Persission + = Directory -- IFF paired with tree + -- Iff paired with blob, one of: + | RegFile + | ExecutableFile + | Symlink + +So long as the root object is a directory, the representations are isomorphic. +There is no "wiggle room" the git way since whenever the permission info wouldn't matter (e.g. the child object being mapped to is a directory), the permission info must be a sentinel value. + +However, if the root object is a blob, there is loss of fidelity. +Since the permission info is used to distinguish executable files, non-executable files, and symlinks, but there isn't a "parent" directory of the root to contain that info, these 3 cases cannot be distinguished. + +Git's model matches Unix tradition, but Nix's model is more natural. + ## Machine models TODO |