1 _____________________________________________________________________________
4 - Sequence extends Element (?) -> then add Union.add(element)
5 - Parameterize Sequence/Union/Atom <Tok,Result>
6 - Make sure we never use raw types
7 - do Forest/Tree still need a Region?
9 - More topology untangling
11 - tib: use the lexer only for indentation increases/decreases
13 - grammar highlighting?
19 ______________________________________________________________________________
22 - Forest needs a "manual access" API
23 - the unwrap bit in Forest makes it really hard to expose an API for forests
25 - evil problems with (x y? z /ws)
28 ______________________________________________________________________________
31 - finalize metagrammar and rdp-op's
36 - RFC2822 (email message/headers)
37 - clean up the whole Walk situation (?)
40 ______________________________________________________________________________
43 - serialization of parse tables
45 - "ambiguity modulo dropped fragments"?
46 - can this be checked statically?
47 - eliminated statically?
49 - substring parsing for better error messages
52 - "Regular Right Part" grammars (NP Chapman, etc)
53 - Attribute unification
55 - inference of rejections for literals
56 - "prefer whitespace higher up" (?)
58 - Labeled edges on trees (associate a label with each slot in the
59 child array in Forest.Body? might make equality tough) --
60 equivalent to Feature Structures. Colon-labeling.
62 ______________________________________________________________________________
65 - Partly-Linear-PATR? (O(n^6) unification grammar)
67 - Implement a k-token peek buffer (for each state, see if it "dead
68 ends" during the next k Phases based solely on state -- ignoring
71 - Arrange for the SPPF corresponding to dropped subtrees to never be
72 generated (or merged, etc)
74 - Is there any way we can avoid creating a GSS.Node instance for
75 nodes which are transient in the sense that they have only one
78 - Re-read Rekers, particularly the stuff on optimal sharing
80 - Isolate the Element objects from Parse.Table/GSS so we can move
83 - consider allowing a Forest.Body to represent some other Tree whose
84 Body's should be [recursively] considered part of this Forest.
86 - perhaps not: right now we have a nice situation where
87 Forest.Ref instances become immutable once iterator()ed. This
88 also gives us a strong place to to culling with the certainty
89 that we won't throw out a Body which would later be salvaged
90 by some yet-to-be-added dependency.
92 - Figure out if there is a way to:
94 - allow unwrapping of children other than the very last one.
96 - fold repetitions into an array form in Forest, before
97 conversion to Tree. The major problem here is that multiple
98 tree-arrays are possible, all of different lengths. Worse,
99 even if they're all the same length, not all elements belong
100 in the same "possibility vector" as all others. You
101 essentially need a GSS to represent the array, which perhaps
102 is what the unfolded form was in the first place.
104 - Wikipedia grammar (needs to be both lexerless and boolean)
107 => Ordered Choice (";" operator)
109 - bring back in parse-table phase resolution of precedence (just
110 like associativity). This can be inferred from the use of ">"
111 when the rules are in one of these special forms:
122 where "_" is anything and "E" is the defining nonterminal.
123 Essentially what we're looking for is the situation where the
124 leftmost portion of one rule produces another rule, and the
125 rightmost portion of the latter produces the former.
127 I'm not 100% certain that this is as "strong" as the prefer/avoid
128 form (try to prove this, you probably can), but it's "what people
129 intend" most of the time.
131 - implement Johnstone's algorithm for "reduced, resolved LR
132 tables" to eliminate superfluous reductions on
135 ______________________________________________________________________________
138 - Rekers & Koorn note that GLR Substring Parsing can be used to do
139 really elegant and generalized "autocompletion".
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145 - Incremental parse table construction
146 - "lazy GLR" and "lazy trees" -> language with first-class CF matching
147 - perhaps linear boolean grammars instead? (linear time, quad space)
148 - Forest parsing => chained parsers
149 - unification parsing, attributes, etc
151 - Take another stab at maximal-match? Nonterminal not-followed-by is
153 - Error recovery based on substring parsing