[Jscheme-devel] new quasi-string was Re: [Jscheme-user] using JScheme ....

[Ken A. <kan...@bb...>]

Here are two proposals:

P1:  Use as the quasistring delimiter {{ also inside a quasistring expression {{ starts an escape to Scheme.  I think i found this approach in another web application and sent email to the group.

The advantage is
- you can keep the current syntax, if you only see { and use the new one if you see {
- Only one character #\{ becomes special.
- I'm guessing that "{{" is uncommon.

P2: Common Lisp has a very flexible reader controlled by a read-table.  (Once i sat down to work on a Lisp Machine that was reading in ALGOL syntax, boy was i suprised.)  One way to extend CL was to add reader-macros that had the form
#name where name was the name of a macro, typical one character, like #?. These are extensions of #t #f #().  Providing this facility would let anyone add a way of swithching syntax.  For example, Rahul could have solved his javascript problem by using #js{....}, say.

This proposal is just to add #... extension capability.

P3: I've been interested in rewriting the JScheme (read) in Scheme as a finite state machine, and compile it into Java.  This should be relatively easy because we only have a relatively small number of types and operations.  This could either implement P2 or the full read-table approach.

I guess i've vote for P1 as the easiest thing to do at this point.
k


At 07:12 PM 5/21/2004 -0400, Timothy John Hickey wrote:
>That shouldn't be too hard. What delimiters would you suggest?
>
>
>What would you think about some kind of general string delimiter say  
>like this
>
>       {{+ Here is "some" {javascript} or {CSS} or arrays A[x] or ...
>             and here is a Scheme escape +[(Date.)]+
>             hmmmm? +}}
>
>where the character following the
>      {{
>indicates the stop character for the string, in this case
>      +
>and
>    +[   ]+
>would delimit the quasi-string escapes.....
>
>So you could equivalently use a period
>
>       {{. Here is "some" {javascript} or {CSS} or arrays A[x] or ...
>             and here is a Scheme escape .[(Date.)].
>             hmmmm? .}}
>
>or a double quote
>
>       {{" Here is "some" {javascript} or {CSS} or arrays A[x] or ...
>             and here is a Scheme escape "[(Date.)]"
>             hmmmm? "}}
>
>and you could switch midway with each [...] providing an opportunity
>to switch delimiters. For example, here we switch from " to * to @
>
>
>       {{" Here is "some" {javascript} or {CSS} or arrays A[x] or ...
>             and here is a Scheme escape "[(Date.)]*
>             hmmmm?  here is a square bracket "["  see?
>             maybe just switch for fun *[]@   hmmmm.. @}}
>
>What do you think? Would this have helped make the code cleaner
>and the developers happy?
>
>What do other JSchemer's think of this notation?
>Any other ideas for handling the string delimiter problem?