src/Pure/General/scan.scala
2011-10-22 ago class Lexicon as abstract datatype;
2011-07-07 ago explicit indication of type Symbol.Symbol;
2011-07-07 ago simplified Symbol based on lazy Symbol.Interpretation -- reduced odd "functorial style";
2011-06-17 ago unconditional recovery from bad context (e.g. Quoted with malformed quoted_body);
2011-06-16 ago partial scans of nested comments;
2011-06-16 ago some support for partial scans with explicit context;
2011-05-12 ago minor adaption for scala-2.9.0.final;
2011-04-21 ago more robust scanning of iterated comments, such as "(* (**) (**) *)";
2010-11-13 ago simplified/robustified treatment of malformed symbols, which are now fully internalized (total Symbol.explode etc.);
2010-10-30 ago support for floating-point tokens in outer syntax (coinciding with inner syntax version);
2010-08-12 ago more basic notion of unparsed input;
2010-05-17 ago renamed class Outer_Lex to Token and Token_Kind to Token.Kind;
2010-05-05 ago use IndexedSeq instead of deprecated RandomAccessSeq, which is merely an alias;
2010-03-29 ago replaced some deprecated methods;
2010-03-29 ago adapted to Scala 2.8.0 Beta1 -- with notable changes to scala.collection;
2010-01-11 ago clarified Symbol.is_plain/is_wellformed -- is_closed was rejecting plain backslashes;
2010-01-10 ago tuned;
2010-01-05 ago more accurate scanning of bad input;
2010-01-05 ago tuned;
2009-12-27 ago quoted_content: handle escapes;
2009-12-27 ago added byte_reader, which works without decoding and enables efficient length operation (for scala.util.parsing.input.Reader);
2009-12-22 ago explicit representation of Token_Kind -- cannot really depend on runtime types due to erasure;
2009-12-20 ago improve performance by reordering of parser combinators;
2009-12-20 ago added nested comments;
2009-12-20 ago simplified result of keyword and symbols parser;
2009-12-19 ago refined some Symbol operations/signatures;
2009-12-19 ago indicate final state of keywords;
2009-08-29 ago misc tuning;
2009-06-23 ago moved string utilities to completion.scala;
2009-06-23 ago more precise implementation of trait methods -- oddly this seems to require copy/paste for +, ++;
2009-06-22 ago Lexicon: removed unused max_entry;
2009-06-18 ago subSequence: bounds checking;
2009-06-18 ago added reverse CharSequence;
2009-06-16 ago added completions;
2009-06-16 ago reorganized and abstracted version, via Set trait;
2009-06-16 ago Efficient scanning of literals.