[racket] repl parsing question

Different Scheme variants vary in whether `#t' and `#f' must be
followed by a delimiter. R6RS, for example, requires a delimiter.

Prior to version 5.0.2, Racket did not require a delimiter, but now it
does (while `#true' and `#false' are also allowed as booleans).

At Tue, 1 Feb 2011 08:59:04 -0600, qld3303 wrote:
> Hello,
> I'm a beginner trying to write a simple Scheme interpreter to help
> understand Racket better.  I try to mimic the results from the repl as best
> possible however in some cases I'm not sure how to reproduce them, this
> being one such case.  It seems to imply that an identifier or something
> other than a boolean could begin with #t but I'm not sure.  I tried this
> using Guile and got the opposite results:
> guile> (+ 3 1)#t+
> 4
> #t
> #<primitive-generic +>
> guile> (+ 3 1)#\t+
> 4
> ERROR: In procedure scm_lreadr:
> ERROR: #<unknown port>:2:1: unknown character name t+
> ABORT: (read-error)
> 
> Currently, my naive repl will work for both characters and booleans but
> perhaps it shouldn't?
> 
> Thanks
> 
> On Mon, Jan 31, 2011 at 9:13 PM, qld3303 <qld3303 at gmail.com> wrote:
> 
> > I'm not clear as to why the following occurs:
> >
> > > (+ 3 1)#t+
> > 4
> > readline-input::183: read: bad syntax `#t+'
> >
> > > (+ 3 1)#\t+
> > 4
> > #\t
> > #<procedure:+>
> >
> > Why doesn't it recognize that #t is a boolean value?
> >
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