OpenEuphoria

Re: Thoughts on eval()

• Posted by Jason Gade <jaygade at yahoo.com> Dec 14, 2004
• 515 views

Hey, Matt.

Have you read my previous idea? http://www.listfilter.com/EUforum/m8646.html

I think if you have func(args, text) or proc(args, text) be functions that
return a routine_id().  The functions themselves, as you say, insert their text
into the normal Code[] space after being scanned and parsed.  Then you just call
your eval'ed function with call_func(id, {}) or whatever.

I think it would require a bit of re-wiring.  My original proposal was to
overload function and procedure like integer, atom, object, and sequence are. 
Looking further into keylist.e, though, I think it would be much easier to just
add func() and proc().  It would still be consistent with call_func() and
call_proc().

example:

integer a, b, c, rid
sequence args, text

args = "integer x, integer y"
text = "return x + y"

rid = func(args, text)

a = 2
b = 2

c = call_func(rid, {a, b}) -- c is now 4

Problem would be what happens when rid no longer refers to the function?  How is
it destroyed or is it just left lost in the Code[] space?

I notice that the interpreter does a quick scan of the symbol table to try and
match a literal.  I don't know if this is normal for interpreters or compilers
but I think that it is pretty cool.  One optimization should be that func() or
proc() would return the same routine_id for a function that was already defined.

Maybe the IL code could be stored in the variable space and added and removed
from the Code[] space as needed?

Also, I realize that this would not work with RDS official backend.  Shrouded,
bound, or translated programs would need to include the proper files from the
interpreter.  Hmm.  It could probably still work with RDS backend but you would
have to include the interpreter code just for the eval-type functions.

Okay, I'm done rambling.  I just like this idea and I think that it fits pretty
good with the rest of the language.

=====================================
Too many freaks, not enough circuses.

j.