A parameter that holds the root directory of the current project (e.g., the directory where you launched @code{raco pollen start}).}
@defparam[world:current-server-extras-path dir path?]{
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.}
A parameter that determines whether the @racket[world:directory-require] file is checked for changes on every pass through @racket[render]. (Can be faster to turn this off if you don't need it.) Initialized to @racket[#t].}
These values can be changed by overriding them in your @racket["directory-require.rkt"] source file. Within this file, @seclink["submodules" #:doc '(lib "scribblings/guide/guide.scrbl")]{create a submodule} called @racket[config]. Then within this submodule, use @racket[define] to make a variable with the same name as the one in @racket[pollen/world], but without the @racket[world:] prefix. Assign it whatever value you like. Repeat as needed. When Pollen runs, these definitions will supersede those in @racket[pollen/world].
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["directory-require.rkt"] would look like this:
Though any of the values below can be overridden, it may not always be wise to do so. For instance, if you redefined @racket[world:fallback-template-prefix], you would simply break the fallback-template mechanism, because it would look for files that don't exist. But we don't live in a nanny state, so you are entrusted to say what you mean and accept the consequences.
Of course, you can restore the defaults simply by deleting these defined values from @racket["directory-require.rkt"].
These settable values are each equipped with a corresponding @racket[world:current-]@racket[_settable-value] function that will return the value loaded from the @racket[config] submodule (if @racket[_settable-value] was defined there), otherwise the default given by @racket[world:]@racket[_settable-value]. For instance, @racket[world:command-char] will always be @litchar{◊}, but in the example above, @racket[world:current-command-char] would return @litchar{🎸}.
@defoverridable[directory-require string?]{File implicitly required into every Pollen source file from its directory. Initialized to @filepath{directory-require.rkt}.}
@defoverridable[pagetree-root-node symbol?]{Name of the root node in a decoded pagetree. It's ignored by the code, so its only role is to clue you in that you're looking at something that came out of the pagetree decoder. Initialized to @code{'pagetree-root}.}
@defoverridable[fallback-template-prefix string?]{Used to generate the name of the fallback template (i.e., the template used to render a Pollen markup file when no other template can be found). Prefix is combined with the output suffix of the source file. Initialized to @code{"fallback"}.}
@defoverridable[paths-excluded-from-dashboard (listof path?)]{Paths not shown in the Pollen dashboard.}
@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[compile-cache-max-size exact-positive-integer?]{Maximum size of the compile cache. Default is 10 megabytes.}
@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].}
