The following table provides a brief reference for how documents are summarized depending on their type. These actions can be customized, as discussed in Section 4.4.4. Some summarizers are implemented as UNIX programs while others are expressed as regular expressions; see Section 4.4.4 or Appendix C.4 for more information about how to write a summarizer.
Type Summarizer Function -------------------------------------------------------------------- Audio Extract file name Bibliographic Extract author and titles Binary Extract meaningful strings and manual page summary C, CHeader Extract procedure names, included file names, and comments Dvi Invoke the Text summarizer on extracted ASCII text FAQ, FullText, README Extract all words in file Framemaker Up-convert to SGML and pass through SGML summarizer Font Extract comments HTML Extract anchors, hypertext links, and selected fields (see SGML) LaTex Parse selected LaTex fields (author, title, etc.) Mail Extract certain header fields Makefile Extract comments and target names ManPage Extract synopsis, author, title, etc., based on ``-man'' macros News Extract certain header fields Object Extract symbol table Patch Extract patched file names Perl Extract procedure names and comments PostScript Extract text in word processor-specific fashion, and pass through Text summarizer. RCS, SCCS Extract revision control summary RTF Up-convert to SGML and pass through SGML summarizer SGML Extract fields named in extraction table (see Section~\ref{sec:sgml}) ShellScript Extract comments SourceDistribution Extract full text of README file and comments from Makefile and source code files, and summarize any manual pages SymbolicLink Extract file name, owner, and date created Tex Invoke the Text summarizer on extracted ASCII text Text Extract first 100 lines plus first sentence of each remaining paragraph Troff Extract author, title, etc., based on ``-man'', ``-ms'', ``-me'' macro packages, or extract section headers and topic sentences. Unrecognized Extract file name, owner, and date created.