# Exercising Bison Grammar Sets. -*- Autotest -*- # Copyright (C) 2001-2002, 2005, 2007, 2009-2015, 2018-2019 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 3 of the License, 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, see . # AT_EXTRACT_SETS(INPUT, OUTPUT) # ------------------------------ # Extract the information about the grammar sets from a bison # trace output (INPUT), and save it in OUTPUT. # And remember, there is no alternation in portable sed. m4_define([AT_EXTRACT_SETS], [AT_DATA([extract.sed], [[#n /^NULLABLE$/ { :null p n /^ *$/ !b null } /^FIRSTS$/ { :firsts p n /^ *$/ !b firsts } /^FDERIVES$/ { :fderiv p n /^ *$/ !b fderiv } /^DERIVES$/ { :deriv p n /^ *$/ !b deriv } ]]) AT_CHECK([sed -f extract.sed $1], 0, [stdout]) AT_CHECK([mv stdout $2]) ]) 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_BISON_CHECK([[--trace=sets input.y]], [], [], [stderr]) AT_EXTRACT_SETS([stderr], [sets]) AT_CHECK([[cat sets]], [], [[DERIVES $accept derives 0 e $end e derives 1 'e' 2 %empty NULLABLE $accept: no e: yes FIRSTS $accept firsts $accept e e firsts e FDERIVES $accept derives 0 e $end 1 'e' 2 %empty e derives 1 'e' 2 %empty ]]) AT_CLEANUP ## ---------------- ## ## Broken Closure. ## ## ---------------- ## # TC was once broken during a massive 'simplification' of the code. # It resulted in bison dumping core on the following grammar (the # computation of FIRSTS uses TC). It managed to produce a pretty # exotic closure: # # TC: Input # # 01234567 # +--------+ # 0| 1 | # 1| 1 | # 2| 1 | # 3| 1 | # 4| 1 | # 5| 1 | # 6| 1| # 7| | # +--------+ # # TC: Output # # 01234567 # +--------+ # 0| 1 | # 1| 111 | # 2| 111 | # 3| 1111 | # 4| 111 1 | # 5| 111 1 | # 6| 111 1| # 7| 111 | # +--------+ # # instead of that below. AT_SETUP([Broken Closure]) AT_DATA([input.y], [[%% a: b; b: c; c: d; d: e; e: f; f: g; g: h; h: 'h'; ]]) AT_BISON_CHECK([[--trace=sets input.y]], [], [], [stderr]) AT_CHECK([[sed -n 's/[ ]*$//;/^RTC: Firsts Output BEGIN/,/^RTC: Firsts Output END/p' stderr]], [], [[RTC: Firsts Output BEGIN 012345678 .---------. 0|111111111| 1| 11111111| 2| 1111111| 3| 111111| 4| 11111| 5| 1111| 6| 111| 7| 11| 8| 1| `---------' RTC: Firsts Output END ]]) AT_CLEANUP ## -------- ## ## Firsts. ## ## -------- ## AT_SETUP([Firsts]) AT_DATA([input.y], [[%nonassoc '<' '>' %left '+' '-' %right '^' '=' %% exp: exp '<' exp | exp '>' exp | exp '+' exp | exp '-' exp | exp '^' exp | exp '=' exp | "exp" ; ]]) AT_BISON_CHECK([[--trace=sets input.y]], [], [], [stderr]) AT_EXTRACT_SETS([stderr], [sets]) AT_CHECK([[cat sets]], [], [[DERIVES $accept derives 0 exp $end exp derives 1 exp '<' exp 2 exp '>' exp 3 exp '+' exp 4 exp '-' exp 5 exp '^' exp 6 exp '=' exp 7 "exp" NULLABLE $accept: no exp: no FIRSTS $accept firsts $accept exp exp firsts exp FDERIVES $accept derives 0 exp $end 1 exp '<' exp 2 exp '>' exp 3 exp '+' exp 4 exp '-' exp 5 exp '^' exp 6 exp '=' exp 7 "exp" exp derives 1 exp '<' exp 2 exp '>' exp 3 exp '+' exp 4 exp '-' exp 5 exp '^' exp 6 exp '=' exp 7 "exp" ]]) AT_CLEANUP ## -------- ## ## Accept. ## ## -------- ## # In some weird cases Bison could compute an incorrect final state # number. This happens only if the $end token is used in the user # grammar, which is a very suspicious accidental feature introduced as # a side effect of allowing the user to name $end using '%token END 0 # "end of file"'. AT_SETUP([Accept]) AT_DATA([input.y], [[%token END 0 %% input: 'a' | '(' input ')' | '(' error END ; ]]) AT_BISON_CHECK([[-v -o input.c input.y]]) # Get the final state in the parser. AT_CHECK([[sed -n 's/.*define YYFINAL *\([0-9][0-9]*\)/final state \1/p' input.c]], 0, [stdout]) mv stdout expout # Get the final state in the report, from the "accept" action.. AT_CHECK([sed -n ' /^State \(.*\)/{ s//final state \1/ x } / accept/{ x p q } ' input.output], 0, [expout]) AT_CLEANUP ## ----------------- ## ## Reduced Grammar. ## ## ----------------- ## # Check information about the grammar, once reduced. AT_SETUP([Reduced Grammar]) AT_DATA([input.y], [[%% expr: expr "+" term | term term: term "*" fact | fact fact: "num" ]]) AT_BISON_CHECK([[--trace=grammar -o input.c input.y]], [], [], [[Reduced Grammar ntokens = 6, nvars = 4, nsyms = 10, nrules = 6, nritems = 17 Variables --------- Value Sprec Sassoc Tag 6 0 0 $accept 7 0 0 expr 8 0 0 term 9 0 0 fact Rules ----- Num (Num, Prec, Assoc, Useful, UselessChain, Ritem Range) Lhs -> Rhs (Ritem range) 0 ( 0, 0, 0, t, f, 0- 1) 6 -> 7 0 1 ( 1, 0, 0, t, f, 3- 5) 7 -> 7 3 8 2 ( 2, 0, 0, t, t, 7- 7) 7 -> 8 3 ( 3, 0, 0, t, f, 9-11) 8 -> 8 4 9 4 ( 4, 0, 0, t, t, 13-13) 8 -> 9 5 ( 5, 0, 0, t, t, 15-15) 9 -> 5 Rules interpreted ----------------- 0 $accept: expr $end 1 expr: expr "+" term 2 expr: term 3 term: term "*" fact 4 term: fact 5 fact: "num" reduced input.y defines 6 terminals, 4 nonterminals, and 6 productions. ]]) AT_CLEANUP