I don't think I need to. The DrRacket EOF insertion isn't (or wasn't) documented, so I just hacked and experimented until I got it working. There's probably a better way to do it (which is what my comment on the code says.)
On Mon, Dec 10, 2012 at 10:09 AM, Robby Findler <[email protected] > wrote: > Why do you need a weird two-phase reading system to deal with the EOF > issue? > > Robby > > > On Monday, December 10, 2012, Jay McCarthy wrote: > >> 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 >> > -- Jay McCarthy <[email protected]> Assistant Professor / Brigham Young University http://faculty.cs.byu.edu/~jay "The glory of God is Intelligence" - D&C 93
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