Super and Subscripts in a text widget

A usenet poster to news:comp.lang.tcl asked how to display text with super and subscripts. Kevin Kenny was kind enough to demonstrate two ways to do this:

1. text tags (only possible in text widgets, but there even before 8.1)
2. Unicoded superscripts (only possible if you have a font that contains these characters)

    font create normal -family times -size 12
    font create small  -family times -size 10

    grid [text .t -width 40 -height 5 -font normal] -columnspan 2

    .t tag configure subscript -font small -offset -5p ;# (1)
    .t insert 1.0 "Little Willy took a drink,\n" {}
    .t insert 2.0 "   But he will drink no more,\n" {}
    .t insert 3.0 "For what he thought was H" {} "2" subscript "O\n" {}
    .t insert 4.0 "   Was H" {} "2" subscript "SO" {} "4" subscript "!" {}

    button .b1 -text "H\u2082O"        -command { exit 0 } ;# (2)
    button .b2 -text "H\u2082SO\u2084" -command { exit 1 } ;# (2)

    grid .b1 .b2 -pady 5
    grid columnconfigure . { 0 1 } -weight 1

text - Arts and crafts of Tcl-Tk programming - Category GUI - Category String Processing