Update README.md

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README.md

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 # fpattern
 Filename pattern matching library functions for DOS, Windows, and Unix.
+
+Functions for matching filename patterns to filenames.
+Written in C.
+Provided as an object file (<code>fpattern.obj</code>)
+and a header include source file (<code>fpattern.h</code>).
+
+Filename <i>patterns</i> are composed of regular (printable) characters which
+may comprise a filename, as well as special <i>pattern matching</i> characters.
+A filename patterns is a special kind of <i>regular expression</i>, except that
+it is not as general and is designed to match only file and directory names instead
+of arbitrary text strings.
+The syntax is borrowed from Unix, and is a superset of the MS-DOS and Windows syntax.
+
+<b>Special pattern characters</b>
+
+<pre>
+    .           Matches a period (.).
+                Note that a period in a filename is not treated any
+                differently than any other character.
+
+    ?           Any.
+                Matches any single character except '/' or '\'.
+
+    *           Closure.
+                Matches zero or more occurences of any characters other
+                than '/' or '\'.  Leading '*' characters are allowed.
+
+    SUB         Substitute (control-Z).
+                Similar to '*', this matches zero or more occurences of
+                any characters other than '/', '\', or '.'.  Leading
+                '^Z' characters are allowed.
+
+    [ab]        Set.
+                Matches the single character 'a' or 'b'.
+                If the dash '-' character is to be included, it must
+                immediately follow the opening bracket '['.  If the
+                closing bracket ']' character is to be included, it must
+                be preceded by a quote '`'.
+
+    [a-z]       Range.
+                Matches a single character in the range 'a' to 'z'.
+                Ranges and sets may be combined within the same set of
+                brackets.
+
+    [!R]        Exclusive range.
+                Matches a single character not in the range 'R'.
+                If range 'R' includes the dash '-' character, the dash
+                must immediately follow the caret '!'.
+
+    !           Not.
+                Makes the following pattern (up to the next '/') match
+                any filename except those what it would normally match.
+
+    /           Path separator (UNIX and DOS).
+                Matches a '/' or '\' pathname (directory) separator.
+                Multiple separators are treated like a single separator.
+                A leading separator indicates an absolute pathname.
+
+    \           Path separator (DOS).
+                Same as the '/' character.  Note that this character
+                must be escaped if used within string constants ("\\").
+
+    \           Quote (UNIX).
+                Makes the next character a regular (nonspecial)
+                character.  Note that to match the quote character
+                itself, it must be quoted.  Note that this character
+                must be escaped if used within string constants ("\\").
+
+    `           Quote (DOS).
+                Makes the next character a regular (nonspecial)
+                character.  Note that to match the quote character
+                itself, it must be quoted.
+</pre>
+
+On DOS and Windows (Win32) systems,
+upper and lower case alphabetic characters are considered identical,
+i.e., 'a' and 'A' match each other.  (What constitutes a lowercase
+letter depends on the current locale settings.)
+On Unix, upper and lower case characters are different, i.e.,
+'foo' and 'FOO' are different filenames.
+
+Spaces and control characters are treated as normal characters.
+
+<b>Examples</b>
+
+The following patterns in the left column will match the filenames in
+the middle column and will not match filenames in the right column:
+<pre>
+    Pattern     Will Match                      Will Not Match
+    -------     ----------                      --------------
+    a           a (only)                        (anything else)
+    a.          a. (only)                       (anything else)
+    a?c         abc, acc, arc, a.c              a, ac, abbc
+    a*c         ac, abc, abbc, acc, a.c         a, ab, acb, bac
+    a*          a, ab, abb, a., a.b             b, ba
+    *           a, ab, abb, a., .foo, a.foo     (nothing)
+    *.          a., ab., abb., a.foo.           a, ab, a.foo, .foo
+    *.*         a., a.b, ah.bc.foo              a
+    ^Z          a, ab, abb                      a., .foo, a.foo
+    ^Z.         a., ab., abb.                   a, .foo, a.foo
+    ^Z.*        a, a., .foo, a.foo              ab, abb
+    *2.c        2.c, 12.c, foo2.c, foo.12.c     2x.c
+    a[b-z]c     abc, acc, azc (only)            (anything else)
+    [ab0-9]x    ax, bx, 0x, 9x                  zx
+    a[-.]b      a-b, a.b (only)                 (anything else)
+    a[!a-z]b    a0b, a.b, a@b                   aab, azb, aa0b
+    a[!-b]x     a0x, a+x, acx                   a-x, abx, axxx
+    a[-!b]x     a-x, a!x, abx (only)            (anything else)
+    a[`]]x      a]x (only)                      (anything else)
+    a``x        a`x (only)                      (anything else)
+    oh`!        oh! (only)                      (anything else)
+    is`?it      is?it (only)                    (anything else)
+    !a?c        a, ac, ab, abb, acb, a.foo      abc, a.c, azc
+</pre>