mirror of
https://git.savannah.gnu.org/git/bison.git
synced 2026-03-09 12:23:04 +00:00
dee8fbbc1e
It seems that not many people read these logs: the error was
introduced in 2001 (3067fbef53),
* src/gram.c (grammar_dump): Fix the headers of the table: remove
duplicate display of "Ritem Range".
While at it, remove duplicate display of the rule number (and remove
an incorrect comment about it: these numbers _are_ equal).
* tests/sets.at (Reduced Grammar): Use useless rule, nterm and token
in the example.
369 lines
6.6 KiB
Plaintext
369 lines
6.6 KiB
Plaintext
# Exercising Bison Grammar Sets. -*- Autotest -*-
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# Copyright (C) 2001-2002, 2005, 2007, 2009-2015, 2018-2019 Free
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# Software Foundation, Inc.
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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# AT_EXTRACT_SETS(INPUT, OUTPUT)
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# ------------------------------
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# Extract the information about the grammar sets from a bison
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# trace output (INPUT), and save it in OUTPUT.
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# And remember, there is no alternation in portable sed.
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m4_define([AT_EXTRACT_SETS],
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[AT_DATA([extract.sed],
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[[#n
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/^NULLABLE$/ {
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:null
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p
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n
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/^ *$/ !b null
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}
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/^FIRSTS$/ {
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:firsts
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p
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n
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/^ *$/ !b firsts
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}
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/^FDERIVES$/ {
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:fderiv
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p
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n
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/^ *$/ !b fderiv
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}
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/^DERIVES$/ {
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:deriv
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p
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n
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/^ *$/ !b deriv
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}
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]])
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AT_CHECK([sed -f extract.sed $1], 0, [stdout])
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AT_CHECK([mv stdout $2])
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])
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AT_BANNER([[Grammar Sets (Firsts etc.).]])
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## ---------- ##
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## Nullable. ##
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## ---------- ##
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AT_SETUP([Nullable])
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# At some point, nullable had been smoking grass, and managed to say:
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#
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# Entering set_nullable
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# NULLABLE
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# 'e': yes
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# (null): no
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# ...
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AT_DATA([[input.y]],
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[[%%
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e: 'e' | /* Nothing */;
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]])
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AT_BISON_CHECK([[--trace=sets input.y]], [], [], [stderr])
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AT_EXTRACT_SETS([stderr], [sets])
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AT_CHECK([[cat sets]], [],
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[[DERIVES
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$accept derives
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0 e $end
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e derives
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1 'e'
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2 %empty
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NULLABLE
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$accept: no
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e: yes
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FIRSTS
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$accept firsts
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$accept
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e
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e firsts
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e
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FDERIVES
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$accept derives
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0 e $end
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1 'e'
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2 %empty
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e derives
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1 'e'
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2 %empty
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]])
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AT_CLEANUP
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## ---------------- ##
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## Broken Closure. ##
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## ---------------- ##
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# TC was once broken during a massive 'simplification' of the code.
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# It resulted in bison dumping core on the following grammar (the
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# computation of FIRSTS uses TC). It managed to produce a pretty
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# exotic closure:
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#
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# TC: Input
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#
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# 01234567
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# +--------+
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# 0| 1 |
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# 1| 1 |
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# 2| 1 |
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# 3| 1 |
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# 4| 1 |
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# 5| 1 |
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# 6| 1|
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# 7| |
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# +--------+
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#
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# TC: Output
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#
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# 01234567
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# +--------+
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# 0| 1 |
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# 1| 111 |
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# 2| 111 |
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# 3| 1111 |
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# 4| 111 1 |
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# 5| 111 1 |
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# 6| 111 1|
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# 7| 111 |
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# +--------+
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#
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# instead of that below.
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AT_SETUP([Broken Closure])
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AT_DATA([input.y],
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[[%%
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a: b;
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b: c;
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c: d;
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d: e;
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e: f;
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f: g;
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g: h;
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h: 'h';
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]])
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AT_BISON_CHECK([[--trace=sets input.y]], [], [], [stderr])
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AT_CHECK([[sed -n 's/[ ]*$//;/^RTC: Firsts Output BEGIN/,/^RTC: Firsts Output END/p' stderr]], [],
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[[RTC: Firsts Output BEGIN
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012345678
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.---------.
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0|111111111|
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1| 11111111|
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2| 1111111|
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3| 111111|
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4| 11111|
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5| 1111|
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6| 111|
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7| 11|
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8| 1|
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`---------'
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RTC: Firsts Output END
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]])
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AT_CLEANUP
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## -------- ##
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## Firsts. ##
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## -------- ##
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AT_SETUP([Firsts])
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AT_DATA([input.y],
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[[%nonassoc '<' '>'
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%left '+' '-'
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%right '^' '='
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%%
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exp:
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exp '<' exp
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| exp '>' exp
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| exp '+' exp
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| exp '-' exp
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| exp '^' exp
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| exp '=' exp
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| "exp"
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;
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]])
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AT_BISON_CHECK([[--trace=sets input.y]], [], [], [stderr])
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AT_EXTRACT_SETS([stderr], [sets])
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AT_CHECK([[cat sets]], [],
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[[DERIVES
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$accept derives
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0 exp $end
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exp derives
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1 exp '<' exp
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2 exp '>' exp
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3 exp '+' exp
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4 exp '-' exp
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5 exp '^' exp
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6 exp '=' exp
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7 "exp"
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NULLABLE
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$accept: no
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exp: no
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FIRSTS
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$accept firsts
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$accept
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exp
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exp firsts
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exp
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FDERIVES
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$accept derives
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0 exp $end
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1 exp '<' exp
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2 exp '>' exp
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3 exp '+' exp
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4 exp '-' exp
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5 exp '^' exp
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6 exp '=' exp
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7 "exp"
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exp derives
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1 exp '<' exp
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2 exp '>' exp
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3 exp '+' exp
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4 exp '-' exp
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5 exp '^' exp
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6 exp '=' exp
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7 "exp"
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]])
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AT_CLEANUP
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## -------- ##
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## Accept. ##
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## -------- ##
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# In some weird cases Bison could compute an incorrect final state
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# number. This happens only if the $end token is used in the user
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# grammar, which is a very suspicious accidental feature introduced as
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# a side effect of allowing the user to name $end using '%token END 0
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# "end of file"'.
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AT_SETUP([Accept])
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AT_DATA([input.y],
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[[%token END 0
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%%
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input:
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'a'
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| '(' input ')'
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| '(' error END
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;
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]])
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AT_BISON_CHECK([[-v -o input.c input.y]])
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# Get the final state in the parser.
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AT_CHECK([[sed -n 's/.*define YYFINAL *\([0-9][0-9]*\)/final state \1/p' input.c]],
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0, [stdout])
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mv stdout expout
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# Get the final state in the report, from the "accept" action..
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AT_CHECK([sed -n '
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/^State \(.*\)/{
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s//final state \1/
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x
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}
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/ accept/{
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x
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p
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q
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}
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' input.output],
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0, [expout])
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AT_CLEANUP
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## ----------------- ##
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## Reduced Grammar. ##
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## ----------------- ##
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# Check information about the grammar, once reduced.
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AT_SETUP([Reduced Grammar])
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AT_DATA([input.y],
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[[%%
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expr: expr "+" term | term
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term: term "*" fact | fact
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useless: "useless"
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fact: "num"
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]])
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AT_BISON_CHECK([[--trace=grammar -o input.c input.y]], [], [],
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[[input.y: warning: 1 nonterminal useless in grammar [-Wother]
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input.y: warning: 1 rule useless in grammar [-Wother]
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input.y:4.1-7: warning: nonterminal useless in grammar: useless [-Wother]
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Reduced Grammar
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ntokens = 7, nvars = 4, nsyms = 11, nrules = 6, nritems = 17
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Variables
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---------
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Value Sprec Sassoc Tag
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7 0 0 $accept
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8 0 0 expr
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9 0 0 term
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10 0 0 fact
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Rules
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-----
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Num (Prec, Assoc, Useful, UselessChain) Lhs -> (Ritem Range) Rhs
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0 ( 0, 0, t, f) 7 -> ( 0- 1) 8 0
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1 ( 0, 0, t, f) 8 -> ( 3- 5) 8 3 9
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2 ( 0, 0, t, t) 8 -> ( 7- 7) 9
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3 ( 0, 0, t, f) 9 -> ( 9-11) 9 4 10
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4 ( 0, 0, t, t) 9 -> (13-13) 10
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5 ( 0, 0, t, t) 10 -> (17-17) 6
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6 ( 0, 0, f, t) 11 -> (15-15) 5
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Rules interpreted
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-----------------
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0 $accept: expr $end
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1 expr: expr "+" term
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2 expr: term
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3 term: term "*" fact
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4 term: fact
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5 fact: "num"
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6 useless: "useless"
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reduced input.y defines 7 terminals, 4 nonterminals, and 6 productions.
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]])
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AT_CLEANUP
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