public Class DecisionProbe

Took too long to analyze a DFA

return set of states w/o emanating edges and w/o resolving sem preds. These states come about because the analysis algorithm had to terminate early to avoid infinite recursion for example (due to left recursion perhaps).

Return a string like "3:22: ( A {;} | B )" that describes this decision.

Return all DFA states in this DFA that have NFA configurations that conflict. You must report a problem for each state in this set because each state represents a different input sequence.

Which alts were specifically turned off to resolve nondeterminisms? This is different than the unreachable alts. Disabled doesn't mean that the alternative is totally unreachable necessarily, it just means that for this DFA state, that alt is disabled. There may be other accept states for that alt that make an alt reachable.

Return a list of alts whose predicate context was insufficient to resolve a nondeterminism for state d.

Given List<Label>, return a String with a useful representation of the associated input string. One could show something different for lexers and parsers, for example.

Given an alternative associated with a nondeterministic DFA state, find the path of NFA states associated with the labels sequence. Useful tracing where in the NFA, a single input sequence can be matched. For different alts, you should get different NFA paths. The first NFA state for all NFA paths will be the same: the starting NFA state of the first nondeterministic alt. Imagine (A|B|A|A): 5->9-A->o | 6->10-B->o | 7->11-A->o | 8->12-A->o There are 3 nondeterministic alts. The paths should be: 5 9 ... 5 6 7 11 ... 5 6 7 8 12 ... The NFA path matching the sample input sequence (labels) is computed using states 9, 11, and 12 rather than 5, 7, 8 because state 5, for example can get to all ambig paths. Must isolate for each alt (hence, the extra state beginning each alt in my NFA structures). Here, firstAlt=1.

Return the sorted list of alts that conflict within a single state. Note that predicates may resolve the conflict.

How many states does the DFA predictor have?

Return a List<Label> indicating an input sequence that can be matched from the start state of the DFA to the targetState (which is known to have a problem).

Each state in the DFA represents a different input sequence for an alt of the decision. Given a DFA state, what is the semantic predicate context for a particular alt.

From an alt number associated with artificial Tokens rule, return the name of the token that is associated with that alt.

Get a list of all unreachable alternatives for this decision. There may be multiple alternatives with ambiguous input sequences, but this is the overall list of unreachable alternatives (either due to conflict resolution or alts w/o accept states).

At least one alt refs a sem or syn pred

If no states are dead-ends, no alts are unreachable, there are no nondeterminisms unresolved by syn preds, all is ok with decision.

Found recursion in > 1 alt

If a recursion overflow is resolve with predicates, then we need to shut off the warning that would be generated.

Report the list of predicates found for each alternative; copy the list because this set gets altered later by the method tryToResolveWithSemanticPredicates() while flagging NFA configurations in d as resolved.

Report the fact that DFA state d is not a state resolved with predicates and yet it has no emanating edges. Usually this is a result of the closure/reach operations being unable to proceed

Currently the analysis reports issues between token definitions, but we don't print out warnings in favor of just picking the first token definition found in the grammar ala lex/flex.

Report that at least 2 alts have recursive constructs. There is no way to build a DFA so we terminated.