Re: [Chicken-users] [1.89] The symbol .

[felix winkelmann]

On 25 Apr 2005 15:25:26 +0200, Nicolas Pelletier
<address@hidden> wrote:
> Hello,
> 
> I would like to represent "the symbol .". This works fine:
> 
> #;1> (list 'a (string->symbol ".") 'b)
> (a |.| b)
> 
> But this does not:
> 
> #;2> (list 'a '|.| 'b)
> Error: invalid use of '.'
> #;2> b
> #;3> (a)

The above expression would be read in as

(list (quote a) (quote .) (quote b))

which is invalid syntax. The second item is still treated as an (invalid)
dotted pair.

> 
> I expected the same behaviour as with "the symbol )":
> 
> #;4> (list 'a (string->symbol ")") 'b)
> (a |\)| b)
> #;5> (list 'a '|\)| 'b)
> (a |\)| b)

Here the reader specifically scans the input stream for a list
terminator, and so the quoted paren is not recognized as the
delimiter.

> 
> Is there a way to input the dot as a symbol literal ?
> 

Hm, in fact I can't think of a decent solution right now. It certainly
is somewhat inconsistent. Perhaps I can find a way around this.


cheers,
felix