Call this function to add another button to DrRacket’s toolbar. When buttons are added this way,
DrRacket monitors the #lang
line at the top of the file; when it changes DrRacket queries
the language to see if this button should be included.
These buttons are “opt out”, meaning that if the language doesn’t explicitly ask to not
have this button (or all such buttons), the button will appear. See
for more information.
Added in version 1.6 of package drracket.
The first two arguments name a procedure in a module that is loaded by
dynamic-require is specially designed separate place.
When DrRacket detects that
the editor has been modified, it sends the contents of the editor over to
that separate place, expands the program there, and then supplies
the fully expanded object to that first procedure. (The procedure is called
in the same context as the expansion process.)
If the expansion raises an exception, then that exception is supplied as the
first argument instead of the syntax object. If a non-exn? is raised,
or if the expansion process is terminated (e.g. via custodian-shutdown-all
called during expansion), then the expansion monitor is not notified.
The contract for that procedure is
There are three other arguments:
The path? argument is the path that was the current-directory
when the code was expanded. This directory should be used as the
current-directory when resolving module paths obtained from
the syntax object.
The third argument is the source object used in the syntax objects that
come from the definitions window in DrRacket. It may be a path (if the file
was saved), but it also might not be. Use equal? to compare it
with the syntax-source field of syntax objects to determine if
they come from the definitions window.
Note that the thread that calls this procedure may be
killed at any time: DrRacket may kill it when the user types in the buffer
(in order to start a new expansion), but bizarro code may also create a separate
thread during expansion that lurks around and then mutates arbitrary things.
Some code, however, should be longer running, surviving such custodian
shutdowns. To support this, the procedure called in the separate place is
supplied with a more powerful custodian that is not shut down.
The result of the procedure is expected to be something that can be sent
across a place-channel
, which is then sent back to the original
place where DrRacket itself is running and passed to the local-handler
argument. At this point, the only code running is trusted code (DrRacket itself
and other tools), but any long running computations may freeze DrRacket’s GUI,
since this procedure is invoked on DrRacket’s eventspace’s handler thread.
Registers a pair of procedures with DrRacket’s online expansion machinery.
the first two arguments name a procedure that is called in the separate place
designated for expansion.
The procedure is called before expansion starts and once it returns, expansion
begins. The procedure should match this contract:
The expectation is that this procedure creates a thread and monitors the
expansion process, sending back information to the main place while
expansion is progressing.
The local-handler procedure is called each time the
(-> any/c void?) procedure (described just above) is called.
It is also called each time an expansion starts; it receives a value
that returns #t from drracket:module-language-tools:start?
in that case.
To help with debugging, DrRacket logs progress and recovers from some
errors that happen when running the handler procedures. To monitor
its progress, monitor the 'debug
level of the
with the topic 'drracket-background-compilation
Registers func so that it is called while building the
preferences panel. The function is passed a panel that contains
other configuration controls for online expansion.
Used to inform a monitor-based handler that the online expansion has finished.