[plt-scheme] Specifics on how display works..

From: Richard Cleis (rcleis at mac.com)
Date: Sun Apr 24 02:04:22 EDT 2005

 From the R5RS manual:
* [ ] { } |   Left and right square brackets and curly braces and 
vertical bar are reserved for possible future extensions to the 

Language: Textual (MzScheme, includes R5RS) is apparently includes some 
'future' extensions; it runs your second example.  Apparently PLT is 
accommodating enough to run the first one, too.


"You tend to think that all fish have fins, and then you pull up an 
octopus." --- Timoth Brown, NCAR

On Apr 23, 2005, at 11:38 PM, Jim Witte wrote:

> Hi,
> The following display statement will run, display a complicated list 
> like I want (a representation of an FSM in a program I'm writing"
> (display '(["Stop at a B" "AB" 2]
>            [('first [('A 'first 'right)
>                      ('B 'second 'right)])
>             ('second [('A ("Found a B"))
>                       ('B ("Found a B"))])]) )
> but this will not, treating part of it as a procedure application, not 
> a list:
> (display '[["Stop at a B" "ABC" 2]
>            [('first [('A 'first 'right)
>                      ('B 'second 'right)])
>             ('second [('A ("Found a B"))
>                       ('B ("Found a B"))])]] )
>   I thought that the '(; and '[' characters were identical as 
> list-delimiters as far as RSR5 was concerned?  Or is '['  a way to do 
> an application, even within a list structure (similar to an unquote in 
> a backquoted list?)
> Jim

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