Filenames and Pathnames (MIT/GNU Scheme 10.1.4)

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#### 15.1.1 Filenames and Pathnames

Pathname objects are usually created by parsing filenames (character strings) into component parts. MIT/GNU Scheme provides operations that convert filenames into pathnames and vice versa.

procedure: ->pathname object

  Returns a pathname that is the equivalent of object. Object must be a pathname or a string. If object is a pathname, it is returned. If object is a string, this procedure returns the pathname that corresponds to the string; in this case it is equivalent to `(parse-namestring object #f #f)`.

      (->pathname "foo")          ⇒  #[pathname 65 "foo"]
      (->pathname "/usr/morris")  ⇒  #[pathname 66 "/usr/morris"]

procedure: parse-namestring thing [host [defaults]]

  This turns thing into a pathname. Thing must be a pathname or a string. If thing is a pathname, it is returned. If thing is a string, this procedure returns the pathname that corresponds to the string, parsed according to the syntax of the file system specified by host.

  This procedure does not do defaulting of pathname components.

  The optional arguments are used to determine what syntax should be used for parsing the string. In general this is only really useful if your implementation of MIT/GNU Scheme supports more than one file system, otherwise you would use `->pathname`. If given, host must be a host object or `#f`, and defaults must be a pathname. Host specifies the syntax used to parse the string. If host is not given or `#f`, the host component from defaults is used instead; if defaults is not given, the host component from `param:default-pathname-defaults` is used.

procedure: ->namestring pathname

  `->namestring` returns a newly allocated string that is the filename corresponding to pathname.

      (->namestring (->pathname "/usr/morris/minor.van"))
           ⇒  "/usr/morris/minor.van"

procedure: pathname-simplify pathname

  Returns a pathname that locates the same file or directory as pathname, but is in some sense simpler. Note that `pathname-simplify` might not always be able to simplify the pathname, e.g. on unix with symbolic links the directory `/usr/morris/../` need not be the same as `/usr/`. In cases of uncertainty the behavior is conservative, returning the original or a partly simplified pathname.

      (pathname-simplify "/usr/morris/../morris/dance")
           ⇒  #[pathname "/usr/morris/dance"]

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