Future/bison
1
0
Fork 0
mirror of https://git.savannah.gnu.org/git/bison.git synced 2026-03-12 05:43:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

symbol: use the first occurrence as an LHS as defining location

Browse Source 
Currently on the following grammar:

    %type <foo> foo
    %%
    start: foo | bar | "baz"
    foo: foo
    bar: bar

bison reports:

    warning: 2 nonterminals useless in grammar [-Wother]
    warning: 4 rules useless in grammar [-Wother]
    1.13-15: warning: nonterminal useless in grammar: foo [-Wother]
     %type <foo> foo
                 ^^^
    3.14-16: warning: nonterminal useless in grammar: bar [-Wother]
     start: foo | bar | "baz"
                  ^^^
    [...]

i.e., the location of the first occurrence of a symbol is taken as its
definition point.  In the case of nonterminals, the first occurrence
as a left-hand side of a rule makes more sense:

    warning: 2 nonterminals useless in grammar [-Wother]
    warning: 4 rules useless in grammar [-Wother]
    4.1-3: warning: nonterminal useless in grammar: foo [-Wother]
     foo: foo
     ^^^
    5.1-3: warning: nonterminal useless in grammar: bar [-Wother]
     bar: bar
     ^^^
    [...]

* src/symtab.h, src/symtab.c (symbol::location_of_lhs): New.
(symbol_location_as_lhs_set): New.
* src/parse-gram.y (current_lhs): Use it.
* tests/reduce.at: Update locations.
This commit is contained in:
Akim Demaille
2015-01-14 13:41:32 +01:00
parent 650af77812
commit 875ef1b90c
7 changed files with 46 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
tests/reduce.at
View File

@@ -254,9 +254,9 @@ not-reduced.y: warning: 3 rules useless in grammar [-Wother]
not-reduced.y:14.1-13: warning: nonterminal useless in grammar: not_reachable [-Wother]
not_reachable: useful { /* A not reachable action. */ }
^^^^^^^^^^^^^
not-reduced.y:11.6-19: warning: nonterminal useless in grammar: non_productive [-Wother]
| non_productive { /* A non productive action. */ }
^^^^^^^^^^^^^^
not-reduced.y:17.1-14: warning: nonterminal useless in grammar: non_productive [-Wother]
non_productive: non_productive useless_token
^^^^^^^^^^^^^^
not-reduced.y:11.6-57: warning: rule useless in grammar [-Wother]
| non_productive { /* A non productive action. */ }
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -330,12 +330,12 @@ indirection: underivable;
AT_BISON_CHECK([[-fcaret input.y]], 0, [],
[[input.y: warning: 2 nonterminals useless in grammar [-Wother]
input.y: warning: 3 rules useless in grammar [-Wother]
input.y:5.15-25: warning: nonterminal useless in grammar: underivable [-Wother]
exp: useful | underivable;
^^^^^^^^^^^
input.y:6.14-24: warning: nonterminal useless in grammar: indirection [-Wother]
input.y:6.1-11: warning: nonterminal useless in grammar: underivable [-Wother]
underivable: indirection;
^^^^^^^^^^^
^^^^^^^^^^^
input.y:7.1-11: warning: nonterminal useless in grammar: indirection [-Wother]
indirection: underivable;
^^^^^^^^^^^
input.y:5.15-25: warning: rule useless in grammar [-Wother]
exp: useful | underivable;
^^^^^^^^^^^