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e969014232
This change was made by applying emacs' untabify function to nearly all files in Bison's repository. Required tabs in make files, ChangeLog, regexps, and test code were manually skipped. Other notable exceptions and changes are listed below. * bootstrap: Skip because we sync this with gnulib. * data/m4sugar/foreach.m4 * data/m4sugar/m4sugar.m4: Skip because we sync these with Autoconf. * djgpp: Skip because I don't know how to test djgpp properly, and this code appears to be unmaintained anyway. * README-hacking (Hacking): Specify that tabs should be avoided where not required.
34 lines
1.3 KiB
Plaintext
34 lines
1.3 KiB
Plaintext
From phr Tue Jul 8 10:36:19 1986
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Date: Tue, 8 Jul 86 00:52:24 EDT
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From: phr (Paul Rubin)
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To: riferguson%watmath.waterloo.edu@CSNET-RELAY.ARPA, tower
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Subject: Re: Bison documentation?
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The main difference between Bison and Yacc that I know of is that
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Bison supports the @N construction, which gives you access to
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the starting and ending line number and character number associated
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with any of the symbols in the current rule.
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Also, Bison supports the command `%expect N' which says not to mention
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the conflicts if there are N shift/reduce conflicts and no reduce/reduce
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conflicts.
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The differences in the algorithms stem mainly from the horrible
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kludges that Johnson had to perpetrate to make Yacc fit in a PDP-11.
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Also, Bison uses a faster but less space-efficient encoding for the
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parse tables (see Corbett's PhD thesis from Berkeley, "Static
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Semantics in Compiler Error Recovery", June 1985, Report No. UCB/CSD
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85/251), and more modern technique for generating the lookahead sets.
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(See Frank DeRemer and Thomas Pennello, "Efficient Computation of
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LALR(1) Look-Ahead Sets", ACM Transactions on Programming Languages
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and Systems (TOPLAS) 4, 4 (October 1982), 615-649. Their
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technique is the standard one now.)
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paul rubin
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free software foundation
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[DeRemer-Pennello reference corrected by Paul Eggert <eggert@cs.ucla.edu>,
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2004-06-21.]
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