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Instead of mapping the LHS of unused rules to -1, keep the LHS

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valid, but flag the rules as invalid.
* src/gram.h (rule_t): `useful' is a new member.
* src/print.c (print_grammar): Adjust.
* src/derives.c (set_derives): Likewise.
* src/reader.c (packgram, reduce_output): Likewise.
* src/reduce.c (reduce_grammar_tables): Likewise.
* tests/reduce.at (Underivable Rules, Useless Rules): New.
This commit is contained in:
Akim Demaille
2001-11-30 10:46:08 +00:00
parent d287d66a69
commit d39a6b7ca9
7 changed files with 131 additions and 30 deletions
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98
tests/reduce.at
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@@ -106,3 +106,101 @@ AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
]])
AT_CLEANUP
## --------------- ##
## Useless Rules. ##
## --------------- ##
AT_SETUP([Useless Rules])
AT_DATA([[input.y]],
[[%verbose
%output="input.c"
%token useful
%%
exp: useful;
useless1: '1';
useless2: '2';
useless3: '3';
useless4: '4';
useless5: '5';
useless6: '6';
useless7: '7';
useless8: '8';
useless9: '9';
]])
AT_CHECK([[bison input.y]], 0, [],
[[input.y contains 9 useless nonterminals and 9 useless rules
]])
AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
[[Useless nonterminals:
useless1
useless2
useless3
useless4
useless5
useless6
useless7
useless8
useless9
Terminals which are not used:
'1'
'2'
'3'
'4'
'5'
'6'
'7'
'8'
'9'
Useless rules:
#2 useless1: '1';
#3 useless2: '2';
#4 useless3: '3';
#5 useless4: '4';
#6 useless5: '5';
#7 useless6: '6';
#8 useless7: '7';
#9 useless8: '8';
#10 useless9: '9';
]])
AT_CLEANUP
## ------------------- ##
## Underivable Rules. ##
## ------------------- ##
AT_SETUP([Underivable Rules])
AT_DATA([[input.y]],
[[%verbose
%output="input.c"
%token useful
%%
exp: useful | underivable;
underivable: indirection;
indirection: underivable;
]])
AT_CHECK([[bison input.y]], 0, [],
[[input.y contains 2 useless nonterminals and 3 useless rules
]])
AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
[[Useless nonterminals:
underivable
indirection
Useless rules:
#2 exp: underivable;
#3 underivable: indirection;
#4 indirection: underivable;
]])
AT_CLEANUP