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19.3 Logical Pathnames

19.3.1 Syntax of Logical Pathname Namestrings​

The syntax of a logical pathname namestring is as follows. (Note that unlike many notational descriptions in this document, this is a syntactic description of character sequences, not a structural description of objects.)

logical-pathname::=[↓host host-marker]

[↓relative-directory-marker] {↓directory directory-marker}*

[↓name] [type-marker ↓type [version-marker ↓version]]

host::=↓word

directory::=↓word | ↓wildcard-word | ↓wild-inferiors-word

name::=↓word | ↓wildcard-word

type::=↓word | ↓wildcard-word

version::=↓pos-int | newest-word | wildcard-version

host-marker—a colon.

relative-directory-marker—a semicolon.

directory-marker—a semicolon.

type-marker—a dot.

version-marker—a dot.

wild-inferiors-word—The two character sequence “**” (two asterisks).

newest-word—The six character sequence “newest” or the six character sequence “NEWEST”. wildcard-version—an asterisk.

wildcard-word—one or more asterisks, uppercase letters, digits, and hyphens, including at least one asterisk, with no two asterisks adjacent.

word—one or more uppercase letters, digits, and hyphens.

pos-int—a positive integer .

19.3.1.1 Additional Information about Parsing Logical Pathname Namestrings​

19.3.1.1.1 The Host part of a Logical Pathname Namestring​

The host must have been defined as a logical pathname host; this can be done by using setf of logical-pathname-translations.

The logical pathname host name "SYS" is reserved for the implementation. The existence and meaning of SYS: logical pathnames is implementation-defined.

19.3.1.1.2 The Device part of a Logical Pathname Namestring​

There is no syntax for a logical pathname device since the device component of a logical pathname is always :unspecific; see Section 19.3.2.1 (Unspecific Components of a Logical Pathname).

19.3.1.1.3 The Directory part of a Logical Pathname Namestring​

If a relative-directory-marker precedes the directories, the directory component parsed is as relative; otherwise, the directory component is parsed as absolute.

If a wild-inferiors-marker is specified, it parses into :wild-inferiors.

19.3.1.1.4 The Type part of a Logical Pathname Namestring​

The type of a logical pathname for a source file is "LISP". This should be translated into whatever type is appropriate in a physical pathname.

19.3.1.1.5 The Version part of a Logical Pathname Namestring​

Some file systems do not have versions. Logical pathname translation to such a file system ignores the version. This implies that a program cannot rely on being able to store more than one version of a file named by a logical pathname.

If a wildcard-version is specified, it parses into :wild.

19.3.1.1.6 Wildcard Words in a Logical Pathname Namestring​

Each asterisk in a wildcard-word matches a sequence of zero or more characters. The wildcard-word “*” parses into :wild; other wildcard-words parse into strings.

19.3.1.1.7 Lowercase Letters in a Logical Pathname Namestring​

When parsing words and wildcard-words, lowercase letters are translated to uppercase.

19.3.1.1.8 Other Syntax in a Logical Pathname Namestring​

The consequences of using characters other than those specified here in a logical pathname namestring are unspecified.

The consequences of using any value not specified here as a logical pathname component are unspecified.

19.3.2 Logical Pathname Components​

19.3.2.1 Unspecific Components of a Logical Pathname​

The device component of a logical pathname is always :unspecific; no other component of a logical pathname can be :unspecific.

19.3.2.2 Null Strings as Components of a Logical Pathname​

The null string, "", is not a valid value for any component of a logical pathname.