The datalog language tries to do this too. There's a repl-submit? predicate you can use and I have weird two-phase reading system to deal with the EOF issue:
https://github.com/plt/racket/blob/master/collects/datalog/lang/configure-runtime.rkt https://github.com/plt/racket/blob/master/collects/datalog/tool/submit.rkt Jay On Mon, Dec 10, 2012 at 8:04 AM, Matthew Flatt <[email protected]> wrote: > When you run plain `racket', the REPL is `read-eval-print-loop', which > uses `(current-prompt-read)', `(current-eval)', and `(current-print)'. > > Any line-editing capability is whatever the terminal does, which > normally means that input is sent to the reader when you hit Return. > Even if you load `readline' or `xrepl', a Return commits a line of > characters to be sent off to the reader. > > The delivery of an expression to the evaluator, however, is determined > by the reader. That is, if your reader sees a "fun" that should match > an "end", then it should keep reading input characters until it sees > the "end". When the reader returns a datum, then it's passed off to the > evaluator. > > (If an interactive EOF is needed to terminate a form for your reader, > that shouldn't necessarily make the REPL quit. The REPL should quit > only when the reader returns an EOF. So, a reader might consume an > interactive EOF as a terminator, and then it can continue reading the > next time around.) > > If I remember correctly, DrRacket is a little different. A Return in > DrRacket takes the text so far and implicitly adds an EOF to the end. > If the reader applied to that text raises `exn:fail:read:eof', then > DrRacket it as an indication that the expression isn't finished, and so > it lets the user keep editing on the next line. Meanwhile, an > `exn:fail:read' exception other than the subtype `exn:fail:read:eof' > means that the read error should be reported to the user. > > > At Sun, 9 Dec 2012 19:03:44 -0500, Daniel Patterson wrote: > > I'm working (with sk and jpolitz) on a non-sexp language built on top > > of racket. > > > > We have basic support for it in the repl inside DrRacket, but none at > > all from the racket commandline repl (which also means no support for > > embedding inside other editors) - and the former seems to be using > > s-exps to figure out when to send the input to our eval (I think - I > > haven't found documentation describing how this works). > > > > So my question is: > > > > Is there a way to specify how input is split before sending to eval, > > both so that DrRacket could follow our conventions (which might, for > > example, match a "fun" with matching "end"), and so that the > > commandline repl knows how to split input at all (as right now it just > > keeps waiting for input until EOF - and EOF also causes the repl to > > quit!) Is there something that read/read-syntax should signal, or another > > handler to use? > > > > Thanks! > > Daniel > > ____________________ > > Racket Users list: > > http://lists.racket-lang.org/users > ____________________ > Racket Users list: > http://lists.racket-lang.org/users > -- Jay McCarthy <[email protected]> Assistant Professor / Brigham Young University http://faculty.cs.byu.edu/~jay "The glory of God is Intelligence" - D&C 93
____________________ Racket Users list: http://lists.racket-lang.org/users
