Ok so the functionality I was looking for was in readline(). I'll try that.
I was also wondering, is there a way to perform read() on strings? For example, if you read an entire something into a string, and then wanted to parse over that string, how would that be accomplished? It seems that the only way to take advantage of read()'s parsing capability is through the channels, which seem to require that they write/read to/from files. -Ian On Mon, Sep 14, 2015 at 8:57 AM, Brad Chamberlain <[email protected]> wrote: > I'd describe the rationale behind readln() as doing > its best to be the dual of writeln(). writeln() writes > out all of its arguments and then prints a newline. > readln() reads all of its arguments and then reads > thru the newline. > > In general, reading strings with read() is challenging > if those strings contain spaces (with or without the > -ln). This feels to me like something to make clear in > documentation though, not by making it an error. > > -Brad > > ________________________________________ > From: Michael Ferguson [[email protected]] > Sent: Monday, September 14, 2015 6:57 AM > To: Ian Bertolacci; [email protected] > Subject: Re: Bug: cannot use iostyle in read/readln > > Hi Ian - > > Thanks for pointing out this bug and its solution. Of course, > for this kind of thing, you are welcome to just create > a pull request yourself... > > I've created a bug fix patch here: > > https://github.com/chapel-lang/chapel/pull/2505 > > That bug fix patch includes a version of your test > case that I have adjusted to work correctly. See > > > https://github.com/mppf/chapel/blob/fix-read-style/test/io/ferguson/read-s > tyle.chpl > > This readln behavior is a common stumbling block. It is something > that Chapel has had for quite some time. The design is that > readln(a, b, c) reads a, b, c (whatever they are) and then reads > anything at all up to a newline. I believe that the motivation for this > design is that it enables easy skipping of input fields you don't want. > > Do you think that we should make readln(s) an error when s is a string? > In particular, readln(a,b,c) or readln(myInt) would still work as it does > now, but readln(myString) would cause a compilation error and suggest > using readline(myString) instead. > > In any case, the functionality you probably want is already implemented > in readline. We have implemented a two variants of readline - one > for a string argument and one for a []:uint(8) argument. I recommend using > these. See: > > > http://chapel.cray.com/docs/latest/modules/standard/IO.html#IO.channel.rea > dline > > > Thanks, > > -michael > > > On 9/13/15, 7:55 PM, "Ian Bertolacci" <[email protected]> wrote: > > >In the attached program, compilation results in: > > > > > >$CHPL_HOME/modules/standard/IO.chpl:3794: In function 'read': > > > >$CHPL_HOME/modules/standard/IO.chpl:3797: error: unresolved call > >'channel(false,dynamic,true).read(string, style=type iostyle, > >error=syserr)' > > > ><<< list of attempted function matches >>> > > > > > > > > > > > > > > > >Looking around IO.chpl:3797, I find the function declaration: > > > > > > > >pragma "no doc" > > > >proc channel.read(ref args ...?k, > > > > style:iostyle):bool { > > > > var e:syserr = ENOERR; > > > > this.read((...args), style=iostyle, error=e); // this is line 3797 > > > > if !e then return true; > > > > else if e == EEOF then return false; > > > > else { > > > > this._ch_ioerror(e, "in channel.read(" + > > > > _args_to_proto((...args), preArg="ref ") + > > > > "style:iostyle)"); > > > > return false; > > > > } > > > >} > > > > > > > > > > > > > > > >I believe that the call at 3797: > > > > > > > >this.read((...args), style=iostyle, error=e); // this is line 3797 > > > > > > > > > >is in error, since it passes iostyle (which is a type) to read, when it > >is expecting an instance of iostyle. > > > > > > > >I believe this to be incorrect behavior because the specification of > >readln > >( > http://chapel.cray.com/docs/latest/modules/standard/IO.html#IO.channel.re > >adln) > >shows that I should be able to pass an instance of an iostyle object to > >style: > > > > > > > >proc channel.readln(ref args ...?k, style: iostyle, out error: syserr): > >bool > > > > > > > > > >Changing line 3797 to be: > > > > > >this.read((...args), style=style, error=e); > > > > > >seems to solve this error. > > > > > >Also, is there a straight-forward way to read a full line from a channel > >into a variable? > >I cannot seem to form an iostyle that will read all bytes of a line. > > > > > >-Ian J. Bertolacci > > > > > > > > > > > > > > > > ------------------------------------------------------------------------------ > _______________________________________________ > Chapel-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/chapel-users >
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