On 07/22/2014 03:09 PM, orchidaceae phalaenopsis wrote:
Sorry to say but I could not continue to build my BBCode parser, I
added a new combinator:
fun choice [a] (p : parser a) (q : parser a) : parser a =
fn input => case p input of
Empty Failure => q input
| Empty ok => (case q input of
Empty _ => Empty ok
| consumed => consumed)
| consumed => consumed
and
val bbid : parser bbtag =
choice
(_<- char #"b" ; return B)
(_<- char #"u" ; return U)
triggers the anonymous function problem.
Can you point me to a full program demonstrating this problem? I added
your snippets to the version I sent before, in what seemed like the
natural way, and a simple test case worked fine.
Also to simulate lazy evaluation (which is essential in this parser),
I will need to change
datatype consumed a = Consumed of reply a
| Empty of reply a
to delay the replies
datatype consumed a = Consumed of unit -> reply a
| Empty of unit -> reply a
later on. These are higher order objects that I don't think could be
removed completely during compiling?
Yes, you won't be able to use that sort of parser type in server-side
code. It should work fine in client-side code, though, just as your
original example should work fine there, AFAIK.
Why do you want lazy evaluation? Can you give a minimal example
demonstrating the need?
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