INTERFACE APN;

IMPORT Pathname, Word;

CONST Brand = "APNModule 0.1";

TYPE Type = {Posix, Win, Native, Default, Unknown};

TYPE
  T <: Default;
  Default = OBJECT
  METHODS
    init(pn : TEXT; type := Type.Default) : T;
    denotation(type := Type.Default) : Pathname.T;
    isValid() : BOOLEAN;
    isAbsolute() : BOOLEAN;
  END;

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PROCEDURE New(pn : TEXT; type := Type.Default) : T;

Return a newly allocated APN.T object with contents `pn'

PROCEDURE Equal(p, q : T) : BOOLEAN;

returns true if p and q are textually equal

PROCEDURE Hash(pn : T) : Word.T;

hash function for pathnames

PROCEDURE Valid(pn: T): BOOLEAN;

Return TRUE iff pn conforms to the pathname syntax of this operating system.

--------------------------------------------------------------------------

PROCEDURE Absolute(pn: T): BOOLEAN;

Return TRUE iff pn is an absolute pathname. Equivalent to Decompose(pn).getlo() # NIL, but faster.

PROCEDURE Prefix(pn: T): T;

Return a pathname equal to pn up to, but not including, the final arc name. If pn consists only of a root directory name, Prefix(pn) returns pn.

PROCEDURE Last(pn: T): T;

Return the final arc name in pn. If pn consists only of a root directory name, Last(pn) returns the empty string.

PROCEDURE Base(pn: T): T;

Return a pathname equal to pn except with Last(pn) replaced by its base.

PROCEDURE Join(pn, base: T; ext: TEXT): T;
PROCEDURE JoinS(pn:T; base, ext: TEXT): T;

Return a pathname formed by prepending pn to base (if pn is not NIL) and appending ext to base (if ext is not NIL). More precisely, this is equivalent to the following, in which a is a local variable of type Arcs:

      IF pn = NIL THEN a := NIL
      ELSE
        IF Absolute(base) THEN Cause checked runtime error END;
        a := Decompose(pn)
      END;
      IF ext # NIL THEN base := base & "." & ext END;
      RETURN Compose(
        TextSeq.Cat(a, TextSeq.Sub(Decompose(base), 1)))


 

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PROCEDURE LastBase(pn: T): T;

Return the base of the final arc name of pn. It is a checked runtime error if pn is empty or consists only of a root directory name.

PROCEDURE LastExt(pn: T): TEXT;

Return the extension of the last arc name of pn. It is a checked runtime error if pn is empty or consists only of a root directory name.

PROCEDURE ReplaceExt(pn: T; ext: TEXT): T;

Return a pathname equal to pn except with the extension of the final arc name replaced with ext, which must be non-NIL.

PROCEDURE Denotation(pn : T; type := Type.Default) : Pathname.T;

VAR caseSensitivePathnames : BOOLEAN;

This value will be set to true on POSIX and FALSE on WIN32 systems by default. It may be changed to influence the pathname comparisons (Equal) and the internal representation (all lowercase if false).

END APN.