47 lines
2 KiB
Text
47 lines
2 KiB
Text
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The -r option has been implemented. The -r option tells Yacc to
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put the read-only tables in y.tab.c and the code and variables in
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y.code.c. Keith Bostic asked for this option so that :yyfix could be
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eliminated.
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The -l and -t options have been implemented. The -l option tells
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Yacc not to include #line directives in the code it produces. The -t
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option causes debugging code to be included in the compiled parser.
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The code for error recovery has been changed to implement the same
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algorithm as AT&T Yacc. There will still be differences in the way
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error recovery works because AT&T Yacc uses more default reductions
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than Berkeley Yacc.
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The environment variable TMPDIR determines the directory where
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temporary files will be created. If TMPDIR is defined, temporary files
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will be created in the directory whose pathname is the value of TMPDIR.
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By default, temporary files are created in /tmp.
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The keywords are now case-insensitive. For example, %nonassoc,
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%NONASSOC, %NonAssoc, and %nOnAsSoC are all equivalent.
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Commas and semicolons that are not part of C code are treated as
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commentary.
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Line-end comments, as in BCPL, are permitted. Line-end comments
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begin with // and end at the next end-of-line. Line-end comments are
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permitted in C code; they are converted to C comments on output.
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The form of y.output files has been changed to look more like
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those produced by AT&T Yacc.
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A new kind of declaration has been added. The form of the declaration
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is
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%ident string
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where string is a sequence of characters begining with a double quote
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and ending with either a double quote or the next end-of-line, whichever
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comes first. The declaration will cause a #ident directive to be written
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near the start of the output file.
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If a parser has been compiled with debugging code, that code can be
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enabled by setting an environment variable. If the environment variable
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YYDEBUG is set to 0, debugging output is suppressed. If it is set to 1,
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debugging output is written to standard output.
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