reduce.at   [plain text]


# Exercising Bison Grammar Reduction.                      -*- Autotest -*-
# Copyright (C) 2001, 2002 Free Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.

AT_BANNER([[Grammar Reduction.]])


## ------------------- ##
## Useless Terminals.  ##
## ------------------- ##

AT_SETUP([Useless Terminals])

AT_DATA([[input.y]],
[[%verbose
%output="input.c"

%token useless1
%token useless2
%token useless3
%token useless4
%token useless5
%token useless6
%token useless7
%token useless8
%token useless9

%token useful
%%
exp: useful;
]])

AT_CHECK([[bison input.y]])

AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
[[Terminals which are not used
   useless1
   useless2
   useless3
   useless4
   useless5
   useless6
   useless7
   useless8
   useless9
]])

AT_CLEANUP



## ---------------------- ##
## Useless Nonterminals.  ##
## ---------------------- ##

AT_SETUP([Useless Nonterminals])

AT_DATA([[input.y]],
[[%verbose
%output="input.c"

%nterm useless1
%nterm useless2
%nterm useless3
%nterm useless4
%nterm useless5
%nterm useless6
%nterm useless7
%nterm useless8
%nterm useless9

%token useful
%%
exp: useful;
]])

AT_CHECK([[bison input.y]], 0, [],
[[input.y: warning: 9 useless nonterminals
input.y:4.8-15: warning: useless nonterminal: useless1
input.y:5.8-15: warning: useless nonterminal: useless2
input.y:6.8-15: warning: useless nonterminal: useless3
input.y:7.8-15: warning: useless nonterminal: useless4
input.y:8.8-15: warning: useless nonterminal: useless5
input.y:9.8-15: warning: useless nonterminal: useless6
input.y:10.8-15: warning: useless nonterminal: useless7
input.y:11.8-15: warning: useless nonterminal: useless8
input.y:12.8-15: warning: useless nonterminal: useless9
]])

AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
[[Useless nonterminals
   useless1
   useless2
   useless3
   useless4
   useless5
   useless6
   useless7
   useless8
   useless9
]])

AT_CLEANUP



## --------------- ##
## Useless Rules.  ##
## --------------- ##

AT_SETUP([Useless Rules])

AT_KEYWORDS([report])

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: warning: 9 useless nonterminals and 9 useless rules
input.y:6.1-8: warning: useless nonterminal: useless1
input.y:7.1-8: warning: useless nonterminal: useless2
input.y:8.1-8: warning: useless nonterminal: useless3
input.y:9.1-8: warning: useless nonterminal: useless4
input.y:10.1-8: warning: useless nonterminal: useless5
input.y:11.1-8: warning: useless nonterminal: useless6
input.y:12.1-8: warning: useless nonterminal: useless7
input.y:13.1-8: warning: useless nonterminal: useless8
input.y:14.1-8: warning: useless nonterminal: useless9
input.y:6.11-13: warning: useless rule: useless1: '1'
input.y:7.11-13: warning: useless rule: useless2: '2'
input.y:8.11-13: warning: useless rule: useless3: '3'
input.y:9.11-13: warning: useless rule: useless4: '4'
input.y:10.11-13: warning: useless rule: useless5: '5'
input.y:11.11-13: warning: useless rule: useless6: '6'
input.y:12.11-13: warning: useless rule: useless7: '7'
input.y:13.11-13: warning: useless rule: useless8: '8'
input.y:14.11-13: warning: useless rule: useless9: '9'
]])

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



## ------------------- ##
## Reduced Automaton.  ##
## ------------------- ##

# Check that the automaton is that as the for the grammar reduced by
# hand.

AT_SETUP([Reduced Automaton])

AT_KEYWORDS([report])

# The non reduced grammar.
# ------------------------
AT_DATA([[not-reduced.y]],
[[/* A useless token. */
%token useless_token
/* A useful one. */
%token useful
%verbose
%output="not-reduced.c"

%%

exp: useful            { /* A useful action. */ }
   | non_productive    { /* A non productive action. */ }
   ;

not_reachable: useful  { /* A not reachable action. */ }
             ;

non_productive: non_productive useless_token
                       { /* Another non productive action. */ }
              ;
%%
]])

AT_CHECK([[bison not-reduced.y]], 0, [],
[[not-reduced.y: warning: 2 useless nonterminals and 3 useless rules
not-reduced.y:14.1-13: warning: useless nonterminal: not_reachable
not-reduced.y:11.6-19: warning: useless nonterminal: non_productive
not-reduced.y:11.6-57: warning: useless rule: exp: non_productive
not-reduced.y:14.16-56: warning: useless rule: not_reachable: useful
not-reduced.y:17.17-18.63: warning: useless rule: non_productive: non_productive useless_token
]])

AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' not-reduced.output]], 0,
[[Useless nonterminals
   not_reachable
   non_productive
Terminals which are not used
   useless_token
Useless rules
    2 exp: non_productive
    3 not_reachable: useful
    4 non_productive: non_productive useless_token
]])

# The reduced grammar.
# --------------------
AT_DATA([[reduced.y]],
[[/* A useless token. */
%token useless_token
/* A useful one. */
%token useful
%verbose
%output="reduced.c"

%%

exp: useful            { /* A useful action. */ }
//   | non_productive    { /* A non productive action. */ } */
   ;

//not_reachable: useful  { /* A not reachable action. */ }
//             ;

//non_productive: non_productive useless_token
//                       { /* Another non productive action. */ }
//              ;
%%
]])

AT_CHECK([[bison reduced.y]])

# Comparing the parsers.
cp reduced.c expout
AT_CHECK([sed 's/not-reduced/reduced/g' not-reduced.c], 0, [expout])

AT_CLEANUP



## ------------------- ##
## Underivable Rules.  ##
## ------------------- ##

AT_SETUP([Underivable Rules])

AT_KEYWORDS([report])

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: warning: 2 useless nonterminals and 3 useless rules
input.y:5.15-25: warning: useless nonterminal: underivable
input.y:6.14-24: warning: useless nonterminal: indirection
input.y:5.15-25: warning: useless rule: exp: underivable
input.y:6.14-24: warning: useless rule: underivable: indirection
input.y:7.14-24: warning: useless rule: indirection: underivable
]])

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



## ---------------- ##
## Empty Language.  ##
## ---------------- ##

AT_SETUP([Empty Language])

AT_DATA([[input.y]],
[[%output="input.c"
%%
exp: exp;
]])

AT_CHECK([[bison input.y]], 1, [],
[[input.y: warning: 2 useless nonterminals and 2 useless rules
input.y:3.1-3: fatal error: start symbol exp does not derive any sentence
]])

AT_CLEANUP