OK. Ambiguity is a property of the parse (grammar + input). Typically
you'll only check for it once the input is complete. So checking inside
the read()/resume() loop is not something you'll typically do, because
the interim values will be for the input so far -- not the input at the
point where you plan to actually do the parse. And the ambiguity with
the input you plan to parse will usually be what you are interested in.
(All this is assuming you're not up to some very advanced technique.)
Typically you'll
1.) Create the recognizer with new().
2.) Start reading the input with read().
3.) If you're doing event processing, loop, reading more input with
resume(), until you're done.
4.) HERE is the point where you'll usually check for ambiguity. Your
input is complete, and you've yet to call value(). The reason you'll
probably do it here is that depending on the result,
you may want to handle calling value() differently, or not do it at all.
5.) Call value.
You *can* call ambiguous() at any point after step 2. But it usually
won't make sense until step 4. After that, you can call it anywhere,
and get the same value. (Because ambiguity is about grammar+input and
after step 3 the input is complete.)
Your code looks like it is calling ambiguous() at all sorts of odd
locations and, accordingly, getting all sorts of odd answers.
Does this help? I answered after skimming the code, and if I've missed
the intent let me know and I'll look more closely.
-- jeffrey
On 09/30/2014 10:01 PM, Ron Savage wrote:
I've switched over to gists because they allow comments:
https://gist.github.com/ronsavage/a372ca2802f47808374b
As for desired behaviour, you'll note cases 0 & 4 print "Output: !->!
OK count: 2." This means the parse is correct, which is true. So why
don't all cases do that?
I accept there could be errors after calling value() [that's why I
always save the value], but I was expecting the above to be printed in
all cases, whether or not the parse is ambiguous.
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