If dtp is the heavyweight processor, not very easy to use, then dtplite is the easy to use little brother. It lives in tcllib under apps/, and is commonly installed with TclLib itself.

From the manpage:

dtplite was written with the following three use cases in mind:

  1. Validation of a single document, i.e. checking that it was written in valid doctools format. This mode can also be used to get a preliminary version of the formatted output for a single document, for display in a browser, nroff, etc., allowing proofreading of the formatting.
  2. Generation of the formatted documentation for a single package, i.e. all the manpages, plus a table of contents and an index of keywords.
  3. An extension of the previous mode of operation, a method for the easy generation of one documentation tree for several packages, and especially of a unified table of contents and keyword index.