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 <[email protected]> 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? > > > _________________________________________________ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/users _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
