Re: [Chicken-users] need idea for read-syntax

[Category 5]

felix wrote:

> Hi, all!
>
> I would like to add a read-syntax for embedding C code into
> expressions (as opposed to embedding it into the program itself, like
> "#> ... <#").  It must be possible to specify C code, with an optional
> type specification.
>
> So far I have just come up with something like:
>
> #>"doSomeInitStuff();" ; embed statement (no type given)
>
> (print #>"my_version_string" : c-string) ; embed expression (type given)

Hmmn!  Interesting challenge.  I played with this for a while and the
most promising syntax I was able to come up with was:

  statement:         #[ doSomeInitStuff(); ]#
  typed expression:  #[[c-string] my_version_string]#

I think the significance of C embedding justifies the use of #[...] and
most other syntax overloads or overcomplicates.  From a parsing point of
view you always know that #[ starts some inline C and it's easy to then
check for the #[[ to tell a typed expression from a statement.  It's
also helpful for expression readability to see the type first.

I'm a bit unclear on the statement case, though; what's the return value
of an inline C statement?  Do you intend to allow for just one statement
or a sequence of them?  If sequences of statements are allowed, this
seems pretty similar to #>...<#, apart from program context.

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