'''string wordstart''' ''string charIndex''

Returns the index of the first character in the word containing character ''charIndex'' of ''string''. ''charIndex'' may be specified as for the '''index''' method. 
A word is considered to be any contiguous range of alphanumeric ([Unicode] letters or decimal digits) or underscore (Unicode connector punctuation) characters, or any single character other than these.



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The point of '''word{start,stop}''' is to scan forward and backward for word boundaries.
Let's look at salient examples:
  % set s "abc defgh i jklmnop"
  abc defgh i jklmnop
  % string wordstart $s 2
  0
  % string wordstart $s 3
  3
  % string wordstart $s 4
  4
  % string wordstart $s 7
  4
  % string wordstart $s 13
  12

[Clif Flynt] usefully remarks that "... the idea is to match the behavior of
the [text] [widget] index list, where you know the location of a character in
a word (because a user clicked on it), and need to find the beginning and end."
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See also:

   * [string]
   * [string index]
   * [string wordend]


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[Tcl syntax help] -
[Category Command] -
[Category String Processing]