At Sun, 05 Aug 2018 11:40:25 -0400, Christopher Lemmer Webber wrote: > Eventually I would like to write a multiplayer game in Racket where > users can write and execute code safely [...] > > In a sense, it would sound as if Racket's #lang support would be perfect > for this. But in fact there is a problem with the #lang approach here: > while a #lang, once selected, can constrain the language features > available, the fact that one can select a #lang itself indicates that > doing "#lang w7" is not the right approach.
The `get-info` function of `setup/getinfo` may be a useful model of how to make a constrained `#lang` work for your purposes. An "info.rkt" for collection or package info must be written in `#lang info` to constrain the things that an "info.rkt" file can do. The requirement to use `#lang info` is enforced by not loading the modules directly, but by using `get-info`, which checks the module's language before doing anything interesting (such as expanding the module). The implementation has two main parts: * Set `current-reader-guard` to ensure that no readers are used other than the intended language's reader. * Check the result of `read-syntax` to make sure it's a module that uses the right language. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
