if 0 {[Richard Suchenwirth] 2004-08-20 - "Small Caps" is a typesetting
style in which each letter is set with an uppercase glyph, but the logical
"lowercases" are in a smaller point size, like 60..80 % of the logical
"uppercase" letters. Here's my take to implement them for [Tk]'s [text]
widget. You specify the widget, the position where to insert (I often
use "end" there), the text itself, and optionally a font, and a
smallness percentage (defaults to 67%).

[http://mini.net/files/smallcaps.png]

I noticed that on Win95 with Tcl 8.4.5, the default font for text widgets
{{MS Sans Serif]} 8} is not rendered smaller to 5 pt, even if specified.
So better give an explicit font if the smallcapping doesn't seem to
work...

#(1): (Couldn't you use [[[[:upper:]]]] in place of [[A-Z]]?  ISTR that 
character classes handle umlauts etc. (in a locale specific way?) - I 
would test in a tkcon here, but I don't actually know how to persuade 
my keyboard to produce an umlauted char! --[MNO] - [RS]: Oh yes, [[[[:upper:]]]]
works indeed well in my 8.4.5. I just didn't read man re_syntax too carefully... Thanks, fixed!)
}
 proc smallcaps {w index text {font ""} {smallness 67}} {
    if {$font eq ""} {set font [$w cget -font]}
    set bigtag [string map {" " _ \{ _ \} _} $font]
    $w tag configure $bigtag -font $font
    
    set bigsize   [lindex $font 1]
    set smallsize [expr {round($bigsize*$smallness/100.)}]
    set smallfont [lreplace $font 1 1 $smallsize]
    set smalltag  [string map {" " _ \{ _ \} _} $smallfont]
    $w tag configure $smalltag -font $smallfont

    set cmd [list $w insert $index]
    #set re {([A-Z]*)([^A-Z]*)} ;# (1)
    set re {([[:upper:]]*)([^[:upper:]]*)}
    foreach {- big small} [regexp -all -inline $re $text] {
        lappend cmd $big $bigtag [string toupper $small] $smalltag
    }
    eval $cmd
 }
#-- Testing:
 pack [text .t]
 smallcaps .t end "Testing SmallCaps..\n\n" {Times 12}
 .t insert end "This is normal text, in comparison"

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[Arts and crafts of Tcl-Tk programming]