@item{Within this submodule, use @racket[define] to make a variable with the same name as the one in @racket[pollen/setup], but without the @racket[setup:] prefix.}
For instance, suppose you wanted the main export of every Pollen source file to be called @racket[van-halen] rather than @racket[doc], the extension of Pollen markup files to be @racket[.rock] rather than @racket[.pm], and the command character to be @litchar{🎸} instead of @litchar{◊}. Your @racket["pollen.rkt"] would look like this:
Every @racket[setup:]@racket[_name] function will resolve the current value of that variable: it will return the value from the @racket[setup] submodule (if @racket[_name] was defined there), otherwise it will return the default value (which is directly available from @racket[default-]@racket[_name]). For instance, @racket[default-command-char] will always be @litchar{◊}, but in the example above, @racket[(setup:command-char)] would return@litchar{🎸}.
@defoverridable[main-root-node symbol?]{Name of the root node in a decoded @racket[doc]. Initialized to @code{'root}.}
@defoverridable[block-tags (listof symbol?)]{Tags that are treated as blocks by @racket[block-txexpr?]. Initialized to the @link["https://developer.mozilla.org/en-US/docs/Web/HTML/Block-level_elements"]{block-level elements in HTML5}, namely:
@defoverridable[render-cache-active boolean?]{Whether the render cache, which speeds up interactive sessions by reusing rendered versions of Pollen output files, is active. Default is active (@racket[#t]).}
@defoverridable[compile-cache-active boolean?]{Whether the compile cache, which speeds up interactive sessions by saving compiled versions of Pollen source files, is active. Default is active (@racket[#t]).}
@defoverridable[unpublished-path? (path? . -> . boolean?)]{Predicate that determines whether a path is omitted from @secref{raco_pollen_publish} operations. If the predicate is @racket[#t], then the path is omitted. The default, therefore, is @racket[#f].}
@defoverridable[splicing-tag symbol?]{Key used to signal that an X-expression should be spliced into its containing X-expression. Default is @val[default-splicing-tag].}
@defoverridable[poly-source-ext symbol?]{Extension that indicates a source file can target multiple output types. Default is @racket['poly].}
@defoverridable[poly-targets (listof symbol?)]{List of symbols that denotes the possible targets of a @racket['poly] source file. Default is @racket['(html)].}
A parameter that reports the path to the directory of support files for the project server. Initialized to @racket[#f], but set to a proper value when the server runs.}