include "complete.m";
complete := load Complete Complete->PATH;

Completion: adt {
    advance:  int;    # whether forward progress has been made
    complete: int;    # whether the completion now represents a file or directory
    str:      string; # string to advance, suffixed " " (file) or "/" (directory)
    nmatch:   int;    # number of files that matched
    filename: array of string;    # their names
};

init:     fn();
complete: fn(dir, s: string): (ref Completion, string);

Init must be called before any other operation of the module.

Given a directory dir and a string s, complete returns a tuple (c, err), where c is an analysis of the file names in that directory that begin with the string s. The field nmatch will be set to the number of files that match the prefix and filename will be filled in with their names. If the file named is a directory, a slash character will be appended to it. On an error, c is nil and err is a diagnostic string.

If no files match the string, nmatch will be zero, but complete will return the full set of files in the directory.

The flag advance reports whether the string s can be extended without changing the set of files that match. If true, str will be set to the extension; that is, the value of str may be appended to s by the caller to extend the embryonic file name unambiguously.

The flag complete reports whether the extended file name uniquely identifies a file. If true, str will be suffixed with a blank, or a slash and a blank, depending on whether the resulting file name identifies a plain file or a directory.