disperse the old FST TODO file

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1457549 13f79535-47bb-0310-9956-ffa450edef68

lucene/core/src/java/org/apache/lucene/util/fst/Builder.java

@@ -25,6 +25,9 @@ import org.apache.lucene.util.RamUsageEstimator;
 import org.apache.lucene.util.fst.FST.INPUT_TYPE; // javadoc
 import org.apache.lucene.util.packed.PackedInts;
 
+// TODO: could we somehow stream an FST to disk while we
+// build it?
+
 /**
  * Builds a minimal FST (maps an IntsRef term to an arbitrary
  * output) from pre-sorted terms with outputs.  The FST

lucene/core/src/java/org/apache/lucene/util/fst/FST.java

@@ -1093,6 +1093,9 @@ public final class FST<T> {
     return arc;
   }
 
+  // TODO: could we somehow [partially] tableize arc lookups
+  // look automaton?
+
   /** Finds an arc leaving the incoming arc, replacing the arc in place.
    *  This returns null if the arc was not found, else the incoming arc. */
   public Arc<T> findTargetArc(int labelToMatch, Arc<T> follow, Arc<T> arc, BytesReader in) throws IOException {

lucene/core/src/java/org/apache/lucene/util/fst/TODO

@@ -1,39 +0,0 @@
-is threadlocal.get costly?  if so maybe make an FSTReader?  would hold this "relative" pos, and each thread'd use it for reading, instead of PosRef
-
-maybe changed Outputs class to "reuse" stuff?  eg this new BytesRef in ByteSequenceOutputs..
-
-do i even "need" both non_final_end_state and final_end_state?
-
-hmm -- can I get weights working here?
-
-can FST be used to index all internal substrings, mapping to term?
-  - maybe put back ability to add multiple outputs per input...?
-
-make this work w/ char...?
-  - then FSTCharFilter/FSTTokenFilter
-  - syn filter?
-
-experiment: try reversing terms before compressing -- how much smaller?
-
-maybe seprate out a 'writable/growing fst' from a read-only one?
-
-can we somehow [partially] tableize lookups like oal.util.automaton?
-
-make an FST terms index option for codecs...?
-
-make an FSTCharsMap?
-
-need a benchmark testing FST traversal -- just fix the static main to rewind & visit all terms
-
-thread state
-
-when writing FST to disk:
-- Sequentially writing (would save memory in codec during indexing). We are now using DataOutput, which could also go directly to disk
-- problem: size of BytesRef must be known before
-
-later
-  - maybe don't require FSTEnum.advance to be forward only?
-  - should i make a posIntOutputs separate from posLongOutputs?
-  - mv randomAccpetedWord / run / etc. from test into FST?
-  - hmm get multi-outputs working again?  do we ever need this?
-

lucene/core/src/test/org/apache/lucene/util/fst/TestFSTs.java

@@ -587,6 +587,12 @@ public class TestFSTs extends LuceneTestCase {
     }
   }
 
+  // TODO: try experiment: reverse terms before
+  // compressing -- how much smaller?
+
+  // TODO: can FST be used to index all internal substrings,
+  // mapping to term?
+
   // java -cp ../build/codecs/classes/java:../test-framework/lib/randomizedtesting-runner-2.0.8.jar:../build/core/classes/test:../build/core/classes/test-framework:../build/core/classes/java:../build/test-framework/classes/java:../test-framework/lib/junit-4.10.jar org.apache.lucene.util.fst.TestFSTs /xold/tmp/allTerms3.txt out
   public static void main(String[] args) throws IOException {
     int prune = 0;