1 The -r option has been implemented. The -r option tells Yacc to 2put the read-only tables in y.tab.c and the code and variables in 3y.code.c. Keith Bostic asked for this option so that :yyfix could be 4eliminated. 5 6 The -l and -t options have been implemented. The -l option tells 7Yacc not to include #line directives in the code it produces. The -t 8option causes debugging code to be included in the compiled parser. 9 10 The code for error recovery has been changed to implement the same 11algorithm as AT&T Yacc. There will still be differences in the way 12error recovery works because AT&T Yacc uses more default reductions 13than Berkeley Yacc. 14 15 The environment variable TMPDIR determines the directory where 16temporary files will be created. If TMPDIR is defined, temporary files 17will be created in the directory whose pathname is the value of TMPDIR. 18By default, temporary files are created in /tmp. 19 20 The keywords are now case-insensitive. For example, %nonassoc, 21%NONASSOC, %NonAssoc, and %nOnAsSoC are all equivalent. 22 23 Commas and semicolons that are not part of C code are treated as 24commentary. 25 26 Line-end comments, as in BCPL, are permitted. Line-end comments 27begin with // and end at the next end-of-line. Line-end comments are 28permitted in C code; they are converted to C comments on output. 29 30 The form of y.output files has been changed to look more like 31those produced by AT&T Yacc. 32 33 A new kind of declaration has been added. The form of the declaration 34is 35 36 %ident string 37 38where string is a sequence of characters begining with a double quote 39and ending with either a double quote or the next end-of-line, whichever 40comes first. The declaration will cause a #ident directive to be written 41near the start of the output file. 42 43 If a parser has been compiled with debugging code, that code can be 44enabled by setting an environment variable. If the environment variable 45YYDEBUG is set to 0, debugging output is suppressed. If it is set to 1, 46debugging output is written to standard output. 47