if 0 {Richard Suchenwirth 2006-02-12 - One of emacs's many features is that when you have, in the first five (or so) lines of a file, the string

 Time-stamp: "xxx"

the "xxx" part will be replaced by a time-stamp, every time you save the file. Of course one could also tell from file mtime, but if you have e.g. undated printouts, such time-stamps can help tell which is the newer. As Sunday is fun project time, I tried to emulate that feature "in 10 LOC or less". I needed 10, but here it is, usable for a text widget:}

 proc timestamp w {
    set token {Time-stamp: "}
    set pos [$w search $token 1.0 5.end]
    if {$pos eq ""} return
    set from [$w index $pos+[string length $token]c]
    set to [$w search \" $from 5.end]
    if {$to eq ""} return
    $w delete $from $to
    $w insert $from [clock format [clock sec] -format %Y-%m-%d,%H:%M:%S]
 }

#-- For testing, hit <F1> (in practice one would call timestamp before saving)

 pack [text .t]
 .t insert end "# Demo\n# Time-stamp: \"whatever\"\n# more text..."
 bind .t <F1> {timestamp %W}

Though stand-alone, this is part of e: a tiny editor plugin for eTcl, which again is part of Sepp.

---

Arts and crafts of Tcl-Tk programming