Re: [Caml-list] Re: Toplevel function question

[Cedric Auger <Cedric.Auger@lri.fr>]

And one last thing in your title, avoid using "toplevel" term as it 
often refers to the program runned by typing "ocaml", that is the 
interactive system, so it is a bit confusing.

Cedric Auger a écrit :
> Joel Christner a écrit :
>> Simpler representation - tried compiling this and got the same syntax 
>> error - at a line number that was after the EOF.  Thanks in advance 
>> for any help!!
>>
>> let add_text variablelist text =
>>   variablelist.contents <- text::variablelist.contents
>>
>> let originalprogramcontents = ref [""]
>>
>> let _ =
>>   let lexbuf = Lexing.from_channel stdin in
>>   let rec storeoriginalprogram =
>>     let expr = lexbuf in
>>     match expr with
>>     | EOF   -> ()
>>     | _     -> (add_text originalprogramcontents expr); 
>> storeoriginalprogram
>>   in let parseprogram = List.iter
>>     (fun n -> print_string n; print_string "\n";) 
>> originalprogramcontents
>>
>> $ ocamlc -c toplevel.ml <http://toplevel.ml>
>> File "toplevel.ml <http://toplevel.ml>", line 17, characters 1-1:
>> Syntax error
>>
> Why do you use ( and ) delimiting "add_text originalprogramcontents 
> expr"?
> in (fun n -> print_string n; print_string "\n";), last ";" is useless
> as Benjamin said your "let" is missing its "in"
> eventually I assume you didn't intended to write "expr = lexbuf", but 
> rather "expr = parse lexbuf", where parse is a function you must 
> define, probably the "Parser.expr Scanner.token" of your first mail, 
> so I think that the following would be better:
>
> let add_text variablelist text =
>  variablelist := text::!variablelist
>
> let originalprogramcontents = ref [""]
>
> let _ =
>  let lexbuf = Lexing.from_channel stdin in
>  let rec storeoriginalprogram =
>    let expr = Parser.expr Scanner.token lexbuf in
>    match expr with
>    | EOF   -> ()
>    | _     -> add_text originalprogramcontents expr; storeoriginalprogram
>  in
>  List.iter
>     (fun n -> print_string n; print_string "\n")
>     originalprogramcontents
>
> And I don't think "let _ =" is mandatory
> Note that a list can be empty and you can write
> let originalprogramcontents = ref []
> if you want an empty list at beginning (I don't know if you need an 
> empty list or a list containing an empty string), caml will guess its 
> type since you used add_text on this list.
> If you don't use the list or want to restrict a type you also can 
> "cast" it:
> let (originalprogramcontents : (string list) ref) = ref []
>
>
>>   
>>
>> On Wed, May 13, 2009 at 4:43 PM, Joel Christner 
>> <joel.christner@gmail.com <mailto:joel.christner@gmail.com>> wrote:
>>
>>     Hello,
>>
>>     I hope you guys don't mind another beginner's question, I'm
>>     waiting on approval from the Yahoo! group moderator for the
>>     beginner's section.
>>
>>     I'm trying to implement a toplevel function that will accept input
>>     from stdin (someone running the program will do ./programname <
>>     someinputfile), store it to a ref string list, and then once
>>     stored, iteratively evaluate each item in the list individually.
>>
>>     What I've put together is:
>>
>>     let _ =
>>       let lexbuf = Lexing.from_channel stdin in
>>       let rec storeoriginalprogram =
>>         let expr = Parser.expr Scanner.token lexbuf in
>>         match expr with
>>         | EOF   -> ()
>>         | _     -> add_text originalprogramcontents expr;
>>     storeoriginalprogram
>>       in let parseprogram = List.iter
>>         (fun n -> eval expr) originalprogramcontents
>>
>>     where...
>>     - Parser and Scanner are already built and working great
>>     - When a line of text comes in, it calls 'add_text' which adds the
>>     expr into the 'originalprogramcontents' ref string list, and then
>>     recursively calls itself to get the next line
>>        - let originalprogramcontents = ref [""]
>>        - let add_text variablelist text = variablelist.contents <-
>>     text::variablelist.contents
>>     - Then when finished reading from stdin, iteratively executes
>>     'eval' against each line in the ref string list called
>>     'originalprogramcontents'
>>
>>     For some reason (probably a stupid mistake on my part) it's giving
>>     me a syntax error and pointing to a line of code that is AFTER the
>>     end of my program:
>>
>>     $ make
>>     ocamlc -c program.ml <http://program.ml>
>>     File "program.ml <http://program.ml>", line 203, characters 2-2:
>>     Syntax error
>>     make: *** [program.cmo] Error 2
>>
>>     But my program is only 202 lines long.
>>
>>     Any ideas on how I might go about making this work?
>>
>>     Thanks
>>     Joel
>>
>>
>> ------------------------------------------------------------------------
>>
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>>   
>
>


-- 
Cédric AUGER

Univ Paris-Sud, Laboratoire LRI, UMR 8623, F-91405, Orsay