# Exercising Bison Grammar Sets. -*- Autotest -*- # Copyright 2001 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., 59 Temple Place - Suite 330, Boston, MA # 02111-1307, USA. AT_BANNER([[Grammar Sets (Firsts etc.).]]) ## ---------- ## ## Nullable. ## ## ---------- ## AT_SETUP([Nullable]) # At some point, nullable had been smoking grass, and managed to say: # # Entering set_nullable # NULLABLE # 'e': yes # (null): no # ... AT_DATA([[input.y]], [[%% e: 'e' | /* Nothing */; ]]) AT_CHECK([[bison --trace input.y]], [], [], [[RITEM 'e' (rule 1) (rule 2) DERIVES e derives 1: 'e' (rule 1) 2: (rule 2) Entering set_nullable NULLABLE e: yes TC: Input BEGIN @&t@ 0 .-. 0| | `-' TC: Input END TC: Output BEGIN @&t@ 0 .-. 0| | `-' TC: Output END FIRSTS e firsts 4 (e) FDERIVES e derives 1: 'e' 2: Processing state 0 (reached by $) Closure: input Closure: output 0: . 'e' (rule 1) 2: . (rule 2) Entering new_itemsets, state = 0 Entering append_states, state = 0 Entering get_state, state = 0, symbol = 3 ('e') Entering new_state, state = 0, symbol = 3 ('e') Exiting get_state => 1 Processing state 1 (reached by 'e') Closure: input 1: . (rule 1) Closure: output 1: . (rule 1) Entering new_itemsets, state = 1 Entering append_states, state = 1 transpose: input 0: @&t@ transpose: output 0: @&t@ ]]) AT_CLEANUP ## ---------------- ## ## Broken Closure. ## ## ---------------- ## # TC was once broken during a massive `simplification' of the code. # It resulted in bison dumping core on the following grammar (the # computation of FIRSTS uses TC). It managed to produce a pretty # exotic closure: # # TC: Input # # 01234567 # +--------+ # 0| 1 | # 1| 1 | # 2| 1 | # 3| 1 | # 4| 1 | # 5| 1 | # 6| 1| # 7| | # +--------+ # # TC: Output # # 01234567 # +--------+ # 0| 1 | # 1| 111 | # 2| 111 | # 3| 1111 | # 4| 111 1 | # 5| 111 1 | # 6| 111 1| # 7| 111 | # +--------+ # # instead of that below. AT_SETUP([Broken Closure]) AT_DATA([input.y], [[%% a: b b: c c: d d: e e: f f: g g: h h: 'h' ]]) AT_CHECK([bison --trace input.y 2>&1 | sed -n '/^TC: Output BEGIN/,/^TC: Output END/p'], [0], [[TC: Output BEGIN @&t@ 01234567 .--------. 0| 1111111| 1| 111111| 2| 11111| 3| 1111| 4| 111| 5| 11| 6| 1| 7| | `--------' TC: Output END ]]) AT_CLEANUP