710320e3dc
Although "macOS" is the correct name for Apple's current desktop OS, we've decided to go with "Mac OS" to cover all of Apple's Unix-like desktop OS versions. The label "Mac OS" is more readable, clear in context (i.e., unlikely to be confused with the Mac OSes that proceeded Mac OS X), and as likely to match Apple's future OS names as anything.
48 lines
2.1 KiB
Racket
48 lines
2.1 KiB
Racket
#lang scribble/doc
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@(require scribble/bnf "mz.rkt")
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@title[#:tag "unixpaths"]{@|AllUnix| Paths}
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In a path on @|AllUnix|, a @litchar{/} separates elements of the path,
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@litchar{.} as a path element always means the directory indicated by
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preceding path, and @litchar{..} as a path element always means the
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parent of the directory indicated by the preceding path. A leading
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@litchar{~} in a path is not treated specially, but
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@racket[expand-user-path] can be used to convert a leading @litchar{~}
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element to a user-specific directory. No other character or byte has a
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special meaning within a path. Multiple adjacent @litchar{/} are
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equivalent to a single @litchar{/} (i.e., they act as a single path
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separator).
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A path root is always @litchar{/}. A path starting with @litchar{/} is
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an absolute, complete path, and a path starting with any other
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character is a relative path.
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Any pathname that ends with a @litchar{/} syntactically refers to a
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directory, as does any path whose last element is @litchar{.} or
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@litchar{..}.
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A @|AllUnix| path is @techlink{cleanse}d by replacing multiple adjacent
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@litchar{/}s with a single @litchar{/}.
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For @racket[(bytes->path-element _bstr)], @racket[bstr] must not
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contain any @litchar{/}, otherwise the @exnraise[exn:fail:contract].
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The result of @racket[(path-element->bytes _path)] or
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@racket[(path-element->string _path)] is always the same as the result
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of @racket[(path->bytes _path)] and @racket[(path->string
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_path)]. Since that is not the case for other platforms, however,
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@racket[path-element->bytes] and @racket[path-element->string] should
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be used when converting individual path elements.
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On Mac OS, Finder aliases are zero-length files.
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@section[#:tag "unixpathrep"]{Unix Path Representation}
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A path on @|AllUnix| is natively a byte string. For presentation to
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users and for other string-based operations, a path is converted
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to/from a string using the current locale's encoding with @litchar{?}
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(encoding) or @code{#\uFFFD} (decoding) in place of errors. Beware
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that the encoding may not accommodate all possible paths as
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distinct strings.
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