NAME

       frontend-spec - interface between jw and its frontends

DESCRIPTION

       jw(1)  calls  frontends like frontends/docbook to get the informations specific to a given
       input format. The frontend knows which information to return from the first  command  line
       parameter. It gets all necessary data via environment variables ready to use.

       This document describes that command line parameter and those environment variables.

       The  frontend  should  return  0 if there weren't any problem, and return a positive value
       otherwise.

VARIABLES

                 $1
              The command line parameter, specifying which information to return. It can take the
              following values:

              centralized-catalog
                     The   frontend  must  return  the  DTD-specific  centralized  catalog  name.
                     Centralized catalogs normally reside in /etc/sgml and provide  the  location
                     of  all  the  catalog files useful for handling this input type (the catalog
                     for the DTD, the catalog for the stylesheets, the catalog for the  entities,
                     ...)

              style-sheet
                     The frontend must return the filename of the style sheet to be used for this
                     document type and with the chosen backend.

                 SGML_CATALOGS_DIR
              The directory where the centralized catalogs reside. It is normally /etc/sgml.

              (This variable is valid only while determining the centralized catalog to use.)

                 SGML_BASE_DIR
              The base directory of the SGML system. It is normally /usr/share/sgml.

              (This variable is valid only while determining the style sheet to use.)

                 SGML_FILE
              The name of the file to convert.

              (This variable is valid only while determining the centralized catalog to use.)

                 SGML_TYPE
              The type of the backend to use, whether it produces output files  to  be  displayed
              online or to be printed out.  It can take the value html or print.

              (This variable is valid only while determining the style sheet to use).

                 SGML_STYLESHEETS
              The  desired custom stylesheet type, either none or default.  If none, the frontend
              must return the file name of the style sheet provided by  the  system  beneath  the
              docbook-utils.  If default, the frontend must return the custom stylesheet provided
              by the docbook-utils.

              (This variable is valid only while determining the style sheet to use).

                 SGML_XML
              The metalanguage of the file to convert, either sgml or xml.

              (This variable is valid only while determining the centralized catalog to use).

FILES

SEE ALSO

       backend-spec(7)

AUTHORS

       Jochem Huhmann <joh@revier.com>

                                         14 January 2022                         FRONTEND-SPEC(7)