Commit graph

3 commits

Author SHA1 Message Date
John Ericson
319ec6f84a Support Windows paths in canonPath and absPath
`canonPath` and `absPath` work on native paths, and so should switch
between supporting Unix paths and Windows paths accordingly.

The templating is because `CanonPath`, which shares the implementation,
should always be Unix style. It is the pure "nix-native" path type for
virtual file operations --- it is part of Nix's "business logic", and
should not vary with the host OS accordingly.
2024-02-16 10:31:36 -05:00
John Ericson
4531585275 Factor out the Unix-specific parts of canonPathInner
This prepares the code to also support Windows paths in the next commit.
2024-02-16 10:12:07 -05:00
John Ericson
d17e1d9737 Purify CanonPath
The core `CanonPath` constructors were using `absPath`, but `absPath` in
some situations does IO which is not appropriate. It turns out that
these constructors avoided those situations, and thus were pure, but it
was far from obvious this was the case.

To remedy the situation, abstract the core algorithm from `canonPath` to
use separately in `CanonPath` without any IO. No we know by-construction
that those constructors are pure.

That leaves `CanonPath::fromCWD` as the only operation which uses IO /
is impure. Add docs on it, and `CanonPath` as a whole, explaining the
situation.

This is also necessary to support Windows paths on windows without
messing up `CanonPath`. But, I think it is good even without that.

Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
2024-02-16 09:47:25 -05:00