title  Regexp ref.
author GPL(C) Mohsin Ahmed, http://www.cs.albany.edu/~mosh

section REGEXP Emacs/Perl/Vim /*
moshtag=regexp,vim,emacs
{

    .           Any char except newline,
    ?           zero or one,
    *           zero or more,
    +           one or more, \+ in vim.
    \           quote, match next char literally,
    \Number     of match of left open paren,
    [a-z]       in char-class,
    [^a-z]      not in char class,

        ---------------------------------------------------------
        Emacs           Perl            Vim
        ---------------------------------------------------------
        \|              |               |       Alternative.
        \< \>           \b              \< \>   Word begin/end.
        ^  $            ^  $            ^ $     Line begin/end.
        \` \'           \A \Z                   Buffer begin/end.
        \sw \Sw         \w \W           \w \W   Word char, not a word char.
        [0-9]           \d \D           \d \D   Digit, not a digit.
        \s- \S-         \s \S           \s \S   Space, not a space.
                        [a-zA-Z]        \a \A   Alphabetic
                        [a-z]           \l \L   Lower, not.
                        [A-Z]           \u \U   Upper, not.
        +               +               \+      One or more.
                                        \{n,m}  m..n (greedy).
        \( \)           ( )             \( \)   Grouping.
        \1              $1              \1      Group 1 that matched.
        \&              $&              &       Whole match for re.
                                        ~       Last subst.
                                        :set magic
                                        :help regexp for non-eager.
        ---------------------------------------------------------

    Vim6 Regexp
        ---------------------------------------------------------
        \?                     0 or 1 (greedy).
        \=                     0 or 1 (greedy).
        \{n,m} \{-n,m}         m..n   (greedy,non-greedy).
        \{n}   \{-n}           n      (greedy,non-greedy).
        \{,m}  \{-,m}          0..m   (greedy,non-greedy).
        *      \{-}            0..more (greedy,non-greedy).
        \_.                    [.\n]
        \%^ \^# \%$            bof, cursor/point, eof.
        \%23l \%23c \23v       line 23, column 23, vcolumn 23.
        \L \l \U \u \D \d      alphabets (not)lower,(not)upper,(not)digit.
        \p                     printable.
    Directives
        \c \C \M \m \V \v      (no)case,(no)magic,(no)very-magic-perl.
        ---------------------------------------------------------

    Emacs Syntax table.
        ---------------------------------------------------------
        \sC \SC             In Class C, not in Class C.
        '\s ' or \s-        whitespace, eg. [space,tab,newline,formfeed,..]
            (\S-)         Not a space char.
        \sw  (\Sw)         word, eg. [a-zA-Z0-9]. (not a word char)
        \s_  (\S_)         symbol, in C '_', in lisp `$&*+-_<>'. ' Not a symbol.
        \s.                punctuation.
        \s( and \s)        parenthesis eg. ()[]{}.
        \s"                string quote, do not nest ".
        \s\                escape, eg. backslash. See words-include-escapes.
        \s/                character quote.
        \s$                paired delimiter, as in TeX.
        \s'                expression prefix, eg 'x in elisp.
        \s< \s>            comment start/end.
        \s@                inherit.
        \=                 Point

        Eg. for syntax class of backslash do: (char-to-string (char-syntax ?\\ ))
        To change the syntax class of _ to word: (modify-syntax-entry ?_ "w"   )
        ---------------------------------------------------------

    ksh patterns
    ---------------------------------------------------------
    ?                Matches one file char except / and a . at the beginning of a file name.
    *                Matches >= 0, same restrictions as ?.
    ?(pattern-list)  Matches 0,1 of pattern-list.
    *(pattern-list)  Matches zero or more of pattern-list.
    +(pattern-list)  Matches >= 1, of pattern-list.
    @(pattern-list)  Matches == 1, of pattern-list.
    !(pattern-list)  Matches any string that does not match pattern-list.
    ---------------------------------------------------------


    MSDEV:        VC++, MSDN isn't clear, please verify.
    ---------------------------------------------------------
        Usual:      ^ | $ [a-z] [^] () \N . + \quotedchar

        OnlyVC:     Usual notation
        { }         \( \)
        #           +
        @           *
        ..~X..      Not X
        X^N         X{N,N}
        :a          [a-zA-Z0-9]
        :c          [a-zA-Z]
        :d          [0-9]
        :h          [0-9a-fA-F]+
        :I          [a-zA-Z_$][a-zA-Z0-9_$]*
        :n          \d+.\d*|\d*.\d+|\d+
        :q          "[^"]*' | '[^']'
        :w          [a-zA-Z]+
        :z          \d+
        \t          tab
        \x#### \u####   Unicode char in 4 hex numbers.
    ---------------------------------------------------------
    */
}

============================================================