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cex: display shifts before reductions

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When reporting counterexamples for s/r conflicts, put the shift first.
This is more natural, and displays the default resolution first, which
is also what happens for r/r conflicts where the smallest rule number
is displayed first, and "wins".

* src/counterexample.c (counterexample): Add a shift_reduce member.
(new_counterexample): Adjust.
Swap the derivations when this is a s/r conflict.
(print_counterexample): For s/r conflicts, prefer "Shift derivation"
and "Reduce derivation" rather than "First/Second derivation".

* tests/conflicts.at, tests/counterexample.at, tests/report.at: Adjust.
* NEWS, doc/bison.texi: Ditto.
This commit is contained in:
Akim Demaille
2020-07-12 18:53:30 +02:00
parent 78f72a4516
commit 4f9ae5de07
7 changed files with 146 additions and 128 deletions
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14
NEWS
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@@ -2,6 +2,8 @@ GNU Bison NEWS
* Noteworthy changes in release ?.? (????-??-??) [?]
Changes in the display of counterexamples.
** Documentation
*** Examples
@@ -45,8 +47,8 @@ GNU Bison NEWS
conflict. For example:
Example exp '+' exp • '/' exp
First derivation exp → [ exp → [ exp '+' exp • ] '/' exp ]
Second derivation exp → [ exp '+' exp → [ exp • '/' exp ] ]
Shift derivation exp → [ exp '+' exp → [ exp • '/' exp ] ]
Reduce derivation exp → [ exp → [ exp '+' exp • ] '/' exp ]
When Bison is installed with text styling enabled, the example is actually
shown twice, with colors highlighting the ambiguity.
@@ -56,10 +58,10 @@ GNU Bison NEWS
bison cannot find an example that can be derived in two ways, it instead
generates two examples that are the same up until the dot:
First example expr • ID $end
First derivation $accept → [ s → [ a → [ expr • ] ID ] $end ]
Second example expr • ID ',' ID $end
Second derivation $accept → [ s → [ a → [ expr → [ expr • ID ',' ] ] ID ] $end ]
First example expr • ID ',' ID $end
Shift derivation $accept → [ s → [ a → [ expr → [ expr • ID ',' ] ] ID ] $end ]
Second example expr • ID $end
Reduce derivation $accept → [ s → [ a → [ expr • ] ID ] $end ]
In these cases, the parser usually doesn't have enough lookahead to
differentiate the two given examples.

42
doc/bison.texi
View File

@@ -9936,10 +9936,10 @@ output is actually in color)}:
@example
Shift/reduce conflict on token "else":
@group
Example @yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @yellow{"else" stmt}
First derivation @yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{]} @green{]} @yellow{"else" stmt ]}
Example @yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @blue{"else" stmt}
Second derivation @yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{"else" stmt ]} @green{]} @yellow{]}
Shift derivation @yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{"else" stmt ]} @green{]} @yellow{]}
Example @yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @yellow{"else" stmt}
Reduce derivation @yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{]} @green{]} @yellow{"else" stmt ]}
@end group
@end example
@end ifhtml
@@ -9947,14 +9947,14 @@ Shift/reduce conflict on token "else":
@smallexample
Shift/reduce conflict on token "else":
@group
Example
@yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @yellow{"else" stmt}
First derivation
@yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{]} @green{]} @yellow{"else" stmt ]}
Example
@yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @blue{"else" stmt}
Second derivation
Shift derivation
@yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{"else" stmt ]} @green{]} @yellow{]}
Example
@yellow{"if" expr "then"} @blue{"if" expr "then" stmt} @red{•} @yellow{"else" stmt}
Reduce derivation
@yellow{if_stmt @arrow{} [ "if" expr "then"} @green{stmt @arrow{} [} @blue{if_stmt @arrow{} [ "if" expr "then" stmt} @red{•} @blue{]} @green{]} @yellow{"else" stmt ]}
@end group
@end smallexample
@end ifnothtml
@@ -9987,10 +9987,10 @@ $ @kbd{bison -Wcex sequence.y}
sequence.y: @dwarning{warning}: 1 shift/reduce conflict [@dwarning{-Wconflicts-sr}]
sequence.y: @dwarning{warning}: 2 reduce/reduce conflicts [@dwarning{-Wconflicts-rr}]
Shift/reduce conflict on token "word":
Example @red{•} @yellow{"word"}
First derivation @yellow{sequence @arrow{} [} @green{sequence @arrow{} [} @red{•} @green{]} @yellow{"word" ]}
Example @red{•} @green{"word"}
Second derivation @yellow{sequence @arrow{} [} @green{maybeword @arrow{} [} @red{•} @green{"word" ]} @yellow{]}
Shift derivation @yellow{sequence @arrow{} [} @green{maybeword @arrow{} [} @red{•} @green{"word" ]} @yellow{]}
Example @red{•} @yellow{"word"}
Reduce derivation @yellow{sequence @arrow{} [} @green{sequence @arrow{} [} @red{•} @green{]} @yellow{"word" ]}
Reduce/reduce conflict on tokens $end, "word":
Example @red{•}
@@ -9999,10 +9999,10 @@ Reduce/reduce conflict on tokens $end, "word":
Second derivation @yellow{sequence @arrow{} [} @green{maybeword @arrow{} [} @red{•} @green{]} @yellow{]}
Shift/reduce conflict on token "word":
Example @red{•} @yellow{"word"}
First derivation @yellow{sequence @arrow{} [} @green{sequence @arrow{} [} @blue{maybeword @arrow{} [} @red{•} @blue{]} @green{]} @yellow{"word" ]}
Example @red{•} @green{"word"}
Second derivation @yellow{sequence @arrow{} [} @green{maybeword @arrow{} [} @red{•} @green{"word" ]} @yellow{]}
Shift derivation @yellow{sequence @arrow{} [} @green{maybeword @arrow{} [} @red{•} @green{"word" ]} @yellow{]}
Example @red{•} @yellow{"word"}
Reduce derivation @yellow{sequence @arrow{} [} @green{sequence @arrow{} [} @blue{maybeword @arrow{} [} @red{•} @blue{]} @green{]} @yellow{"word" ]}
sequence.y:8.3-45: @dwarning{warning}: rule useless in parser due to conflicts [@dwarning{-Wother}]
8 | @dwarning{%empty @{ printf ("empty maybeword\n"); @}}
@@ -10033,10 +10033,10 @@ expr: %empty | expr ID ','
@smallexample
Shift/reduce conflict on token ID:
First example @blue{expr} @red{•} @green{ID} @yellow{$end}
First derivation @yellow{$accept @arrow{} [} @green{s @arrow{} [} @blue{a @arrow{} [ expr} @red{•} @blue{]} @green{ID ]} @yellow{$end ]}
Second example @purple{expr} @red{•} @purple{ID ','} @green{ID} @yellow{$end}
Second derivation @yellow{$accept @arrow{} [} @green{s @arrow{} [} @blue{a @arrow{} [} @purple{expr @arrow{} [ expr} @red{•} @purple{ID ',' ]} @blue{]} @green{ID ]} @yellow{$end ]}
First example @purple{expr} @red{•} @purple{ID ','} @green{ID} @yellow{$end}
Shift derivation @yellow{$accept @arrow{} [} @green{s @arrow{} [} @blue{a @arrow{} [} @purple{expr @arrow{} [ expr} @red{•} @purple{ID ',' ]} @blue{]} @green{ID ]} @yellow{$end ]}
Second example @blue{expr} @red{•} @green{ID} @yellow{$end}
Reduce derivation @yellow{$accept @arrow{} [} @green{s @arrow{} [} @blue{a @arrow{} [ expr} @red{•} @blue{]} @green{ID ]} @yellow{$end ]}
@end smallexample
This conflict is caused by the parser not having enough information to know
@@ -10432,10 +10432,10 @@ counterexamples within the report, augmented with the corresponding items
Shift/reduce conflict on token '/':
1 exp: exp '+' exp •
4 exp: exp • '/' exp
Example @green{exp '+' exp} @red{•} @yellow{'/' exp}
First derivation @yellow{exp @arrow{} [} @green{exp @arrow{} [ exp '+' exp} @red{•} @green{]} @yellow{'/' exp ]}
Example @yellow{exp '+'} @green{exp} @red{•} @green{'/' exp}
Second derivation @yellow{exp @arrow{} [ exp '+'} @green{exp @arrow{} [ exp} @red{•} @green{'/' exp ]} @yellow{]}
Shift derivation @yellow{exp @arrow{} [ exp '+'} @green{exp @arrow{} [ exp} @red{•} @green{'/' exp ]} @yellow{]}
Example @green{exp '+' exp} @red{•} @yellow{'/' exp}
Reduce derivation @yellow{exp @arrow{} [} @green{exp @arrow{} [ exp '+' exp} @red{•} @green{]} @yellow{'/' exp ]}
@end example
This shows two separate derivations in the grammar for the same @code{exp}:

30
src/counterexample.c
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@@ -76,17 +76,29 @@ typedef struct
{
derivation *d1;
derivation *d2;
bool shift_reduce;
bool unifying;
bool timeout;
} counterexample;
static counterexample *
new_counterexample (derivation *d1, derivation *d2,
bool shift_reduce,
bool u, bool t)
{
counterexample *res = xmalloc (sizeof *res);
res->shift_reduce = shift_reduce;
if (shift_reduce)
{
// Display the shift first.
res->d1 = d2;
res->d2 = d1;
}
else
{
res->d1 = d1;
res->d2 = d2;
}
res->unifying = u;
res->timeout = t;
return res;
@@ -107,7 +119,7 @@ print_counterexample (counterexample *cex, FILE *out, const char *prefix)
prefix, cex->unifying ? _("Example") : _("First example"));
derivation_print_leaves (cex->d1, out, prefix);
fprintf (out, " %s%-20s ",
prefix, _("First derivation"));
prefix, cex->shift_reduce ? _("Shift derivation") : _("First derivation"));
derivation_print (cex->d1, out, prefix);
// If we output to the terminal (via stderr) and we have color
@@ -120,7 +132,7 @@ print_counterexample (counterexample *cex, FILE *out, const char *prefix)
derivation_print_leaves (cex->d2, out, prefix);
}
fprintf (out, " %s%-20s ",
prefix, _("Second derivation"));
prefix, cex->shift_reduce ? _("Reduce derivation") : _("Second derivation"));
derivation_print (cex->d2, out, prefix);
fputc ('\n', out);
@@ -506,7 +518,7 @@ example_from_path (bool shift_reduce,
: shortest_path_from_start (itm2, next_sym);
derivation *deriv2 = complete_diverging_example (next_sym, path_2, NULL);
gl_list_free (path_2);
return new_counterexample (deriv1, deriv2, false, true);
return new_counterexample (deriv1, deriv2, shift_reduce, false, true);
}
/*
@@ -619,7 +631,8 @@ ss_set_parse_state (search_state *ss, int idx, parse_state *ps)
*/
static counterexample *
complete_diverging_examples (search_state *ss,
symbol_number next_sym)
symbol_number next_sym,
bool shift_reduce)
{
derivation *new_derivs[2];
for (int i = 0; i < 2; ++i)
@@ -630,7 +643,8 @@ complete_diverging_examples (search_state *ss,
new_derivs[i] = complete_diverging_example (next_sym, sitems, derivs);
gl_list_free (sitems);
}
return new_counterexample (new_derivs[0], new_derivs[1], false, true);
return new_counterexample (new_derivs[0], new_derivs[1],
shift_reduce, false, true);
}
/*
@@ -1111,7 +1125,7 @@ unifying_example (state_item_number itm1,
{
// Once we have two derivations for the same symbol,
// we've found a unifying counterexample.
cex = new_counterexample (d1, d2, true, false);
cex = new_counterexample (d1, d2, shift_reduce, true, false);
derivation_retain (d1);
derivation_retain (d2);
goto cex_search_end;
@@ -1149,7 +1163,7 @@ cex_search_end:;
// If a search state from Stage 3 is available, use it
// to construct a more compact nonunifying counterexample.
if (stage3result)
cex = complete_diverging_examples (stage3result, next_sym);
cex = complete_diverging_examples (stage3result, next_sym, shift_reduce);
// Otherwise, construct a nonunifying counterexample that
// begins from the start state using the shortest
// lookahead-sensitive path to the reduce item.
@@ -1226,6 +1240,8 @@ counterexample_report (state_item_number itm1, state_item_number itm2,
free_counterexample (cex);
}
// ITM1 denotes a shift, ITM2 a reduce.
static void
counterexample_report_shift_reduce (state_item_number itm1, state_item_number itm2,
symbol_number next_sym,

20
tests/conflicts.at
View File

@@ -865,8 +865,8 @@ State 5
1 exp: exp OP exp .
1 exp: exp . OP exp
Example exp OP exp . OP exp
First derivation exp -> [ exp -> [ exp OP exp . ] OP exp ]
Second derivation exp -> [ exp OP exp -> [ exp . OP exp ] ]
Shift derivation exp -> [ exp OP exp -> [ exp . OP exp ] ]
Reduce derivation exp -> [ exp -> [ exp OP exp . ] OP exp ]
]])
@@ -1753,18 +1753,18 @@ State 4
Shift/reduce conflict on token 'a':
10 reported_conflicts: . %empty
8 reported_conflicts: . 'a'
First example resolved_conflict . 'a'
First derivation start -> [ resolved_conflict reported_conflicts -> [ . ] 'a' ]
Second example resolved_conflict . 'a' 'a'
Second derivation start -> [ resolved_conflict reported_conflicts -> [ . 'a' ] 'a' ]
First example resolved_conflict . 'a' 'a'
Shift derivation start -> [ resolved_conflict reported_conflicts -> [ . 'a' ] 'a' ]
Second example resolved_conflict . 'a'
Reduce derivation start -> [ resolved_conflict reported_conflicts -> [ . ] 'a' ]
Shift/reduce conflict on token 'a':
10 reported_conflicts: . %empty
9 reported_conflicts: . 'a'
First example resolved_conflict . 'a'
First derivation start -> [ resolved_conflict reported_conflicts -> [ . ] 'a' ]
Second example resolved_conflict . 'a' 'a'
Second derivation start -> [ resolved_conflict reported_conflicts -> [ . 'a' ] 'a' ]
First example resolved_conflict . 'a' 'a'
Shift derivation start -> [ resolved_conflict reported_conflicts -> [ . 'a' ] 'a' ]
Second example resolved_conflict . 'a'
Reduce derivation start -> [ resolved_conflict reported_conflicts -> [ . ] 'a' ]

100
tests/counterexample.at
View File

@@ -47,8 +47,8 @@ AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
Shift/reduce conflict on token B:
Example A . B C
First derivation s -> [ a -> [ A . ] x -> [ B C ] ]
Second derivation s -> [ y -> [ A . B ] c -> [ C ] ]
Shift derivation s -> [ y -> [ A . B ] c -> [ C ] ]
Reduce derivation s -> [ a -> [ A . ] x -> [ B C ] ]
input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]
]])
@@ -76,13 +76,13 @@ AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
Shift/reduce conflict on token B:
Example A . B C
First derivation s -> [ a -> [ A . ] bc -> [ B C ] ]
Second derivation s -> [ ac -> [ A ac -> [ b -> [ . B ] ] C ] ]
Shift derivation s -> [ ac -> [ A ac -> [ b -> [ . B ] ] C ] ]
Reduce derivation s -> [ a -> [ A . ] bc -> [ B C ] ]
Shift/reduce conflict on token B:
Example A A . B B C C
First derivation s -> [ a -> [ A a -> [ A . ] ] bc -> [ B bc -> [ B C ] C ] ]
Second derivation s -> [ ac -> [ A ac -> [ A ac -> [ b -> [ . b -> [ B B ] ] ] C ] C ] ]
Shift derivation s -> [ ac -> [ A ac -> [ A ac -> [ b -> [ . b -> [ B B ] ] ] C ] C ] ]
Reduce derivation s -> [ a -> [ A a -> [ A . ] ] bc -> [ B bc -> [ B C ] C ] ]
input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
]])
@@ -111,14 +111,14 @@ AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
Shift/reduce conflict on token B:
Example A . B
First derivation s -> [ ax -> [ A x -> [ . ] ] by -> [ B y -> [ ] ] ]
Second derivation s -> [ A xby -> [ . B ] ]
Shift derivation s -> [ A xby -> [ . B ] ]
Reduce derivation s -> [ ax -> [ A x -> [ . ] ] by -> [ B y -> [ ] ] ]
Shift/reduce conflict on token B:
First example A X . B y $end
First derivation $accept -> [ s -> [ ax -> [ A x -> [ X x -> [ . ] ] ] by -> [ B y ] ] $end ]
Second example A X . B Y $end
Second derivation $accept -> [ s -> [ A xby -> [ X xby -> [ . B ] Y ] ] $end ]
First example A X . B Y $end
Shift derivation $accept -> [ s -> [ A xby -> [ X xby -> [ . B ] Y ] ] $end ]
Second example A X . B y $end
Reduce derivation $accept -> [ s -> [ ax -> [ A x -> [ X x -> [ . ] ] ] by -> [ B y ] ] $end ]
input.y:5.4-9: warning: rule useless in parser due to conflicts [-Wother]
]])
@@ -146,10 +146,10 @@ bc: B C;
AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
Shift/reduce conflict on token C:
First example B . C D $end
First derivation $accept -> [ g -> [ x -> [ b -> [ B . ] cd -> [ C D ] ] ] $end ]
Second example B . C $end
Second derivation $accept -> [ g -> [ x -> [ bc -> [ B . C ] ] ] $end ]
First example B . C $end
Shift derivation $accept -> [ g -> [ x -> [ bc -> [ B . C ] ] ] $end ]
Second example B . C D $end
Reduce derivation $accept -> [ g -> [ x -> [ b -> [ B . ] cd -> [ C D ] ] ] $end ]
input.y:6.4: warning: rule useless in parser due to conflicts [-Wother]
]])
@@ -175,10 +175,10 @@ y: A A B;
AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
Shift/reduce conflict on token A:
First example A . A $end
First derivation $accept -> [ s -> [ s -> [ t -> [ x -> [ A . ] ] ] t -> [ x -> [ A ] ] ] $end ]
Second example A . A B $end
Second derivation $accept -> [ s -> [ t -> [ y -> [ A . A B ] ] ] $end ]
First example A . A B $end
Shift derivation $accept -> [ s -> [ t -> [ y -> [ A . A B ] ] ] $end ]
Second example A . A $end
Reduce derivation $accept -> [ s -> [ s -> [ t -> [ x -> [ A . ] ] ] t -> [ x -> [ A ] ] ] $end ]
]])
@@ -209,14 +209,14 @@ AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
Shift/reduce conflict on token A:
Example b . A X X Y
First derivation a -> [ r -> [ b . ] t -> [ A x -> [ X ] xy -> [ X Y ] ] ]
Second derivation a -> [ s -> [ b . xx -> [ A X X ] y -> [ Y ] ] ]
Shift derivation a -> [ s -> [ b . xx -> [ A X X ] y -> [ Y ] ] ]
Reduce derivation a -> [ r -> [ b . ] t -> [ A x -> [ X ] xy -> [ X Y ] ] ]
Shift/reduce conflict on token X:
First example X . X xy
First derivation a -> [ x -> [ X . ] t -> [ X xy ] ]
Second example A X . X
Second derivation a -> [ t -> [ A xx -> [ X . X ] ] ]
First example A X . X
Shift derivation a -> [ t -> [ A xx -> [ X . X ] ] ]
Second example X . X xy
Reduce derivation a -> [ x -> [ X . ] t -> [ X xy ] ]
input.y:4.4: warning: rule useless in parser due to conflicts [-Wother]
input.y:8.4: warning: rule useless in parser due to conflicts [-Wother]
@@ -297,10 +297,10 @@ AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
Shift/reduce conflict on token J:
time limit exceeded: XXX
First example H i . J $end
First derivation $accept -> [ s -> [ a -> [ H i . ] J ] $end ]
Second example H i . J K $end
Second derivation $accept -> [ a -> [ H i -> [ i . J K ] ] $end ]
First example H i . J K $end
Shift derivation $accept -> [ a -> [ H i -> [ i . J K ] ] $end ]
Second example H i . J $end
Reduce derivation $accept -> [ s -> [ a -> [ H i . ] J ] $end ]
input.y:4.4-6: warning: rule useless in parser due to conflicts [-Wother]
]])
@@ -330,13 +330,13 @@ AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
Shift/reduce conflict on token B:
Example N A . B C
First derivation s -> [ n -> [ N a -> [ A . ] B ] C ]
Second derivation s -> [ n -> [ N b -> [ A . B C ] ] ]
Shift derivation s -> [ n -> [ N b -> [ A . B C ] ] ]
Reduce derivation s -> [ n -> [ N a -> [ A . ] B ] C ]
Shift/reduce conflict on token B:
Example N N A . B D C
First derivation s -> [ n -> [ N n -> [ N a -> [ A . ] B ] D ] C ]
Second derivation s -> [ n -> [ N n -> [ N b -> [ A . B D ] ] C ] ]
Shift derivation s -> [ n -> [ N n -> [ N b -> [ A . B D ] ] C ] ]
Reduce derivation s -> [ n -> [ N n -> [ N a -> [ A . ] B ] D ] C ]
input.y:5.4: warning: rule useless in parser due to conflicts [-Wother]
]])
@@ -420,10 +420,10 @@ time limit exceeded: XXX
Shift/reduce conflict on token A:
time limit exceeded: XXX
First example b c . c A A $end
First derivation $accept -> [ a -> [ b d -> [ a -> [ c d -> [ a -> [ b -> [ . ] d -> [ c A A ] ] ] ] ] ] $end ]
Second example b c . A
Second derivation a -> [ b d -> [ c . A ] ]
First example b c . A
Shift derivation a -> [ b d -> [ c . A ] ]
Second example b c . c A A $end
Reduce derivation $accept -> [ a -> [ b d -> [ a -> [ c d -> [ a -> [ b -> [ . ] d -> [ c A A ] ] ] ] ] ] $end ]
Reduce/reduce conflict on token A:
First example b c . c A A $end
@@ -432,10 +432,10 @@ Reduce/reduce conflict on token A:
Second derivation $accept -> [ a -> [ b d -> [ a -> [ c d -> [ c -> [ . ] A ] ] ] ] $end ]
Shift/reduce conflict on token A:
First example b c . A $end
First derivation $accept -> [ a -> [ b d -> [ a -> [ c d -> [ c -> [ . ] A ] ] ] ] $end ]
Second example b c . A
Second derivation a -> [ b d -> [ c . A ] ]
First example b c . A
Shift derivation a -> [ b d -> [ c . A ] ]
Second example b c . A $end
Reduce derivation $accept -> [ a -> [ b d -> [ a -> [ c d -> [ c -> [ . ] A ] ] ] ] $end ]
Reduce/reduce conflict on token $end:
Example b d .
@@ -475,8 +475,8 @@ AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
Shift/reduce conflict on token J:
Example H i J . J J
First derivation s -> [ a -> [ H i -> [ i J . ] J J ] ]
Second derivation s -> [ a -> [ H i J . J ] J ]
Shift derivation s -> [ a -> [ H i J . J ] J ]
Reduce derivation s -> [ a -> [ H i -> [ i J . ] J J ] ]
input.y:5.13-15: warning: rule useless in parser due to conflicts [-Wother]
]])
@@ -507,8 +507,8 @@ AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
Shift/reduce conflict on token D:
Example A a . D
First derivation s -> [ A a a -> [ b -> [ c -> [ . ] ] ] d -> [ D ] ]
Second derivation s -> [ A a d -> [ . D ] ]
Shift derivation s -> [ A a d -> [ . D ] ]
Reduce derivation s -> [ A a a -> [ b -> [ c -> [ . ] ] ] d -> [ D ] ]
]])
@@ -536,10 +536,10 @@ d: D;
AT_BISON_CHECK_CEX([input.y], [], [],
[[input.y: warning: 1 shift/reduce conflict [-Wconflicts-sr]
Shift/reduce conflict on token D:
First example A a . D E $end
First derivation $accept -> [ s -> [ A a a -> [ b -> [ c -> [ . ] ] ] d -> [ D ] E ] $end ]
Second example A a . D $end
Second derivation $accept -> [ s -> [ A a d -> [ . D ] ] $end ]
First example A a . D $end
Shift derivation $accept -> [ s -> [ A a d -> [ . D ] ] $end ]
Second example A a . D E $end
Reduce derivation $accept -> [ s -> [ A a a -> [ b -> [ c -> [ . ] ] ] d -> [ D ] E ] $end ]
]])

24
tests/diagnostics.at
View File

@@ -534,28 +534,28 @@ exp
| "num"
]],
[1],
[[input.y: <error>error:</error> shift/reduce conflicts: 4 found, 0 expected
Shift/reduce conflict on token "+":
[[input.y: <error>error:</error> shift/reduce conflicts: 4 found, 0 expected
First derivation <cex-0><cex-step>exp → [ </cex-step><cex-1><cex-step>exp → [ </cex-step><cex-leaf>exp</cex-leaf> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot><cex-step> ]</cex-step></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-0>
Shift/reduce conflict on token "+":
Example <cex-0><cex-leaf>exp</cex-leaf> <cex-leaf>"+"</cex-leaf><cex-1> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
Shift derivation <cex-0><cex-step>exp → [ </cex-step><cex-leaf>exp</cex-leaf> <cex-leaf>"+"</cex-leaf><cex-1> <cex-step>exp → [ </cex-step><cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-1><cex-step> ]</cex-step></cex-0>
Example <cex-0><cex-1><cex-leaf>exp</cex-leaf> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
Reduce derivation <cex-0><cex-step>exp → [ </cex-step><cex-1><cex-step>exp → [ </cex-step><cex-leaf>exp</cex-leaf> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot><cex-step> ]</cex-step></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-0>
Shift/reduce conflict on token "else":
First derivation <cex-0><cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot><cex-step> ]</cex-step></cex-1> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-0>
Shift/reduce conflict on token "else":
Example <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
Shift derivation <cex-0><cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-1><cex-step> ]</cex-step></cex-0>
Example <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
Reduce derivation <cex-0><cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot><cex-step> ]</cex-step></cex-1> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-0>
Shift/reduce conflict on token "+":
First derivation <cex-0><cex-step>exp → [ </cex-step><cex-1><cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot><cex-step> ]</cex-step></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-0>
Shift/reduce conflict on token "+":
Example <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
Shift derivation <cex-0><cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf><cex-1> <cex-step>exp → [ </cex-step><cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-1><cex-step> ]</cex-step></cex-0>
Example <cex-0><cex-1><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
Reduce derivation <cex-0><cex-step>exp → [ </cex-step><cex-1><cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot><cex-step> ]</cex-step></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-0>
Shift/reduce conflict on token "+":
First derivation <cex-0><cex-step>exp → [ </cex-step><cex-1><cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot><cex-step> ]</cex-step></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-0>
Shift/reduce conflict on token "+":
Example <cex-0><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"else"</cex-leaf><cex-1> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-1></cex-0>
Shift derivation <cex-0><cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"else"</cex-leaf><cex-1> <cex-step>exp → [ </cex-step><cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-1><cex-step> ]</cex-step></cex-0>
Example <cex-0><cex-1><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf></cex-0>
Reduce derivation <cex-0><cex-step>exp → [ </cex-step><cex-1><cex-step>exp → [ </cex-step><cex-leaf>"if"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"then"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-leaf>"else"</cex-leaf> <cex-leaf>exp</cex-leaf> <cex-dot>•</cex-dot><cex-step> ]</cex-step></cex-1> <cex-leaf>"+"</cex-leaf> <cex-leaf>exp</cex-leaf><cex-step> ]</cex-step></cex-0>

40
tests/report.at
View File

@@ -1539,8 +1539,8 @@ AT_CHECK([LC_ALL="$locale" bison -fno-caret -o input.cc -rall -Wcex --graph=inpu
input.y: warning: 3 reduce/reduce conflicts [-Wconflicts-rr]
Shift/reduce conflict on token "⊕":
Example exp "+" exp • "⊕" exp
First derivation exp → [ exp → [ exp "+" exp • ] "⊕" exp ]
Second derivation exp → [ exp "+" exp → [ exp • "⊕" exp ] ]
Shift derivation exp → [ exp "+" exp → [ exp • "⊕" exp ] ]
Reduce derivation exp → [ exp → [ exp "+" exp • ] "⊕" exp ]
Reduce/reduce conflict on tokens $end, "+", "⊕":
Example exp "+" exp •
@@ -1549,23 +1549,23 @@ Reduce/reduce conflict on tokens $end, "+", "⊕":
Shift/reduce conflict on token "⊕":
Example exp "+" exp • "⊕" exp
First derivation exp → [ exp → [ exp "+" exp • ] "⊕" exp ]
Second derivation exp → [ exp "+" exp → [ exp • "⊕" exp ] ]
Shift derivation exp → [ exp "+" exp → [ exp • "⊕" exp ] ]
Reduce derivation exp → [ exp → [ exp "+" exp • ] "⊕" exp ]
Shift/reduce conflict on token "⊕":
Example exp "⊕" exp • "⊕" exp
First derivation exp → [ exp → [ exp "⊕" exp • ] "⊕" exp ]
Second derivation exp → [ exp "⊕" exp → [ exp • "⊕" exp ] ]
Shift derivation exp → [ exp "⊕" exp → [ exp • "⊕" exp ] ]
Reduce derivation exp → [ exp → [ exp "⊕" exp • ] "⊕" exp ]
Shift/reduce conflict on token "+":
Example exp "⊕" exp • "+" exp
First derivation exp → [ exp → [ exp "⊕" exp • ] "+" exp ]
Second derivation exp → [ exp "⊕" exp → [ exp • "+" exp ] ]
Shift derivation exp → [ exp "⊕" exp → [ exp • "+" exp ] ]
Reduce derivation exp → [ exp → [ exp "⊕" exp • ] "+" exp ]
Shift/reduce conflict on token "+":
Example exp "⊕" exp • "+" exp
First derivation exp → [ exp → [ exp "⊕" exp • ] "+" exp ]
Second derivation exp → [ exp "⊕" exp → [ exp • "+" exp ] ]
Shift derivation exp → [ exp "⊕" exp → [ exp • "+" exp ] ]
Reduce derivation exp → [ exp → [ exp "⊕" exp • ] "+" exp ]
input.y:6.3-13: warning: rule useless in parser due to conflicts [-Wother]
]])
@@ -1714,8 +1714,8 @@ State 7
2 exp: exp "+" exp •
1 exp: exp • "⊕" exp
Example exp "+" exp • "⊕" exp
First derivation exp → [ exp → [ exp "+" exp • ] "⊕" exp ]
Second derivation exp → [ exp "+" exp → [ exp • "⊕" exp ] ]
Shift derivation exp → [ exp "+" exp → [ exp • "⊕" exp ] ]
Reduce derivation exp → [ exp → [ exp "+" exp • ] "⊕" exp ]
Reduce/reduce conflict on tokens $end, "+", "⊕":
2 exp: exp "+" exp •
@@ -1728,8 +1728,8 @@ State 7
3 exp: exp "+" exp •
1 exp: exp • "⊕" exp
Example exp "+" exp • "⊕" exp
First derivation exp → [ exp → [ exp "+" exp • ] "⊕" exp ]
Second derivation exp → [ exp "+" exp → [ exp • "⊕" exp ] ]
Shift derivation exp → [ exp "+" exp → [ exp • "⊕" exp ] ]
Reduce derivation exp → [ exp → [ exp "+" exp • ] "⊕" exp ]
@@ -1751,22 +1751,22 @@ State 8
1 exp: exp "⊕" exp •
1 exp: exp • "⊕" exp
Example exp "⊕" exp • "⊕" exp
First derivation exp → [ exp → [ exp "⊕" exp • ] "⊕" exp ]
Second derivation exp → [ exp "⊕" exp → [ exp • "⊕" exp ] ]
Shift derivation exp → [ exp "⊕" exp → [ exp • "⊕" exp ] ]
Reduce derivation exp → [ exp → [ exp "⊕" exp • ] "⊕" exp ]
Shift/reduce conflict on token "+":
1 exp: exp "⊕" exp •
2 exp: exp • "+" exp
Example exp "⊕" exp • "+" exp
First derivation exp → [ exp → [ exp "⊕" exp • ] "+" exp ]
Second derivation exp → [ exp "⊕" exp → [ exp • "+" exp ] ]
Shift derivation exp → [ exp "⊕" exp → [ exp • "+" exp ] ]
Reduce derivation exp → [ exp → [ exp "⊕" exp • ] "+" exp ]
Shift/reduce conflict on token "+":
1 exp: exp "⊕" exp •
3 exp: exp • "+" exp
Example exp "⊕" exp • "+" exp
First derivation exp → [ exp → [ exp "⊕" exp • ] "+" exp ]
Second derivation exp → [ exp "⊕" exp → [ exp • "+" exp ] ]
Shift derivation exp → [ exp "⊕" exp → [ exp • "+" exp ] ]
Reduce derivation exp → [ exp → [ exp "⊕" exp • ] "+" exp ]
]])