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The Purdue Compiler-Construction Tool Set
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Parr Research Corporation
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Minneapolis, Minnesota
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University of Minnesota
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Army High Performance Computing Research Center
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The PCCTS project began as a parser-generator project for a gra-
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duate course at Purdue University in the Fall of 1988 taught by Hank
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Dietz- translator-writing systems. Under the guidance of Professor
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Dietz, the parser generator, ANTLR (originally called YUCC), continued
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after the termination of the course and eventually became the subject
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of Terence Parr's Master's thesis. Originally, lexical analysis was
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performed via ALX which was soon replaced by Will Cohen's DLG in the
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Fall of 1989 (DFA-based lexical-analyzer generator, also an offshoot
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of the graduate translation course).
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The alpha version of ANTLR was totally rewritten resulting in
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1.00B. Version 1.00B was released via an internet newsgroup
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(comp.compilers) posting in February of 1990 and quickly gathered a
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large following. 1.00B generated only LL(1) parsers, but allowed the
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merged description of lexical and syntactic analysis. It had rudimen-
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tary attribute handling similar to that of YACC and did not incor-
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porate rule parameters or return values; downward inheritance was very
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awkward. 1.00B-generated parsers terminated upon the first syntax
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error. Lexical classes (modes) were not allowed and DLG did not have
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Upon starting his Ph.D. at Purdue in the Fall of 1990, Terence
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Parr began the second total rewrite of ANTLR. The method by which
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grammars may be practically analyzed to generate LL(k) lookahead
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information was discovered in August of 1990 just before his return.
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Version 1.00 incorporated this algorithm and included the AST mechan-
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ism, lexical classes, error classes, and automatic error recovery;
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code quality and portability were higher. In February of 1992 1.00
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was released via an article in SIGPLAN Notices. Peter Dahl, Ph.D.
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candidate, and Professor Matt O'Keefe (both at the University of Min-
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nesota) tested this version extensively. Dana Hoggatt (Micro Data
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Base Systems, Inc.) came up with the idea of error grouping (strings
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attached to non-terminals) and tested 1.00 heavily.
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Version 1.06 was released in December 1992 and represented a
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large feature enhancement over 1.00. For example, rudimentary seman-
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tic predicates were introduced, error messages were significantly
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improved for k>1 lookahead and ANTLR parsers could indicate that loo-
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kahead fetches were to occur only when necessary for the parse
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(normally, the lookahead "pipe" was constantly full). Russell Quong
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joined the project in the Spring of 1992 to aid in the semantic predi-
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cate design. Beginning and advanced tutorials were created and
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released as well. A makefile generator was included that sets up
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dependencies and such correctly for ANTLR and DLG. Very few 1.00
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incompatibilities were introduced (1.00 was quite different from 1.00B
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1.10 was released on August 31, 1993 and incorporated bug fixes,
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a few feature enhancements and a major new capability - an arbitrary
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lookahead operator (syntactic predicate), (alpha)?beta. This feature
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was co-designed with Professor Russell Quong also at Purdue. To sup-
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port infinite lookahead, a preprocessor flag, ZZINF_LOOK, was created
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that forced the ANTLR() macro to tokenize all input prior to parsing.
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Hence, at any moment, an action or predicate can see the entire input
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sentence. The predicate mechanism of 1.06 was extended to allow mul-
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tiple predicates to be hoisted; the syntactic context of a predicate
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was also moved along with the predicate.
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In February of 1994, SORCERER (a simple tree-parser generator)
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was released. This tool allows the user to parse child-sibling trees
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by specifying a grammar rather than building a recursive-descent tree
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walker by hand. Work towards a library of tree transformations is
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underway. Aaron Sawdey at The University of Minnesota became a second
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author of SORCERER after the initial release.
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On April 1, 1994, PCCTS 1.20 was released. This was the first
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version to actively support C++ output. It also included important
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fixes regarding semantic predicates and (..)+ subrules. This version
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also introduced token classes, the "not" operator, and token ranges.
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On June 19, 1994, SORCERER 1.00B9 was released. Gary Funck of
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Intrepid Technology joined the SORCERER team and provided very valu-
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able suggestions regarding the "transform" mode of SORCERER.
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On August 8, 1994, PCCTS 1.21 was released. It mainly cleaned up
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the C++ output and included a number of bug fixes.
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From the 1.21 release forward, the maintenance and support of all
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PCCTS tools will be primarily provided by Parr Research Corporation,
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Minneapolis MN---an organization founded on the principles of excel-
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lence in research and integrity in business; we are devoted to provid-
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ing really cool software tools. Please see file PCCTS.FUTURE for more
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information. All PCCTS tools currently in the public domain will con-
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tinue to be in the public domain.
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Looking towards the future, a graphical user-interface is in the
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design phase. This would allow users to view the syntax diagram
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representation of their grammars and would highlight nondeterministic
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productions. Parsing can be traced graphically as well. This system
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will be built using a multiplatform window library. We also antici-
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pate the introduction of a sophisticated error handling mechanism
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called "parser exception handling" in a near future release.
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Currently, PCCTS is used at over 1000 known academic, government,
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and commercial sites in 37 countries. Of course, the true number of
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users is unknown due to the large number of ftp sites.
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_____________________________________________________________________________
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_____________________________________________________________________________
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|ANTLR 1.00A Terence Parr Hank Dietz |
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|ALX Terence Parr Hank Dietz |
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|ANTLR 1.00B Terence Parr Hank Dietz, Will Cohen |
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|DLG 1.00B Will Cohen Terence Parr, Hank Dietz |
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|NFA Relabelling Will Cohen |
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|LL(k) analysis Terence Parr Hank Dietz |
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|ANTLR 1.00 Terence Parr Hank Dietz, Will Cohen |
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|DLG 1.00 Will Cohen Terence Parr, Hank Dietz |
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|ANTLR 1.06 Terence Parr Will Cohen, Russell Quong, Hank Dietz|
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|DLG 1.06 Will Cohen Terence Parr, Hank Dietz |
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|ANTLR 1.10 Terence Parr Will Cohen, Russell Quong |
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|ANTLR 1.20 Terence Parr Will Cohen, Russell Quong |
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|ANTLR 1.21 Terence Parr Russell Quong |
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|DLG 1.10 Will Cohen Terence Parr |
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|DLG 1.20 Will Cohen Terence Parr |
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|DLG 1.21 Terence Parr |
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|Semantic predicates Terence Parr Russell Quonq |
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|Syntactic predicates Terence Parr Russell Quonq |
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|SORCERER 1.00A Terence Parr |
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|SORCERER 1.00B Terence Parr Aaron Sawdey |
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|SORCERER 1.00B9 Terence Parr Aaron Sawdey, Gary Funck |
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|___________________________________________________________________________|
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pccts/history.txt
