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gram: correct token numbering in precedence declarations
In a precedence declaration, when tokens are declared with a litteral character (e.g., 'a') or with a identifier (e.g., B), Bison behaved differently: the litteral tokens would be numbered first, and then the other ones, leading to the following grammar: %right A B 'c' 'd' being numbered as such: 'c' 'd' A B. * src/parse-gram.y (symbol.prec): Set the symbol number when reading the symbols. * tests/conflicts.at (Token declaration order: literals vs. identifiers): New. Signed-off-by: Akim Demaille <akim@lrde.epita.fr>
This commit is contained in:
Valentin Tolmer
committed by
Akim Demaille
Akim Demaille
parent
02879b4e81
commit
5202b6ac1d
24
NEWS
24
NEWS
@@ -284,11 +284,27 @@ GNU Bison NEWS
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It used to be an error only if used in non GLR mode, _and_ if there are
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reduce/reduce conflicts.
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** Token numbering has changed to preserve the user-defined order
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** Tokens are numbered in their order of appearance
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When declaring %token A B, the numbering for A is inferior to B. Up to now,
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when declaring associativity at the same time, with %left (or %right,
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%precedence, %nonassoc), B was inferior to A.
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Contributed by Valentin Tolmer.
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With '%token A B', A had a number less than the one of B. However,
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precedence declarations used to generate a reversed order. This is now
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fixed, and introducing tokens with any of %token, %left, %right,
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%precedence, or %nonassoc yields the same result.
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When mixing declarations of tokens with a litteral character (e.g., 'a')
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or with an identifier (e.g., B) in a precedence declaration, Bison
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numbered the litteral characters first. For example
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%right A B 'c' 'd'
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would lead to the tokens declared in this order: 'c' 'd' A B. Again, the
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input order is now preserved.
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These changes were made so that one can remove useless precedence and
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associativity declarations (i.e., map %nonassoc, %left or %right to
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%precedence, or to %token) and get exactly the same output.
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** Useless precedence and associativity
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@@ -503,8 +503,17 @@ symbols.prec:
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;
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symbol.prec:
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symbol { $$ = $1; }
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| symbol INT { $$ = $1; symbol_user_token_number_set ($1, $2, @2); }
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symbol
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{
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$$ = $1;
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symbol_class_set ($1, token_sym, @1, false);
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}
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| symbol INT
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{
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$$ = $1;
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symbol_user_token_number_set ($1, $2, @2);
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symbol_class_set ($1, token_sym, @1, false);
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}
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;
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/* One or more symbols to be %typed. */
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@@ -87,6 +87,92 @@ AT_BISON_OPTION_POPDEFS
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AT_CLEANUP
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## --------------------------------------------------- ##
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## Token declaration order: literals vs. identifiers. ##
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## --------------------------------------------------- ##
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# This test checks that when several tokens are declared by the same keyword,
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# some of them defined as a character ('a'), others as simple textual reference
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# (A), they are declared correctly left to right.
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# Previously, the following test would declare the states in the order 'o' 'p'
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# M N, instead of M N 'o' 'p'.
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AT_SETUP([Token declaration order: literals vs. identifiers])
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AT_DATA_GRAMMAR([[input.y]],
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[[%token 'a' 'b' C D
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%token E F 'g' 'h'
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%right 'i' 'j' K L
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%right M N 'o' 'p'
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%%
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exp: 'a'
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| 'b'
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| C
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| D
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| E
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| F
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| 'g'
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| 'h'
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| 'i'
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| 'j'
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| K
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| L
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| M
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| N
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| 'o'
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| 'p'
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;
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%%
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]])
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AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore])
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AT_CHECK([[cat input.output | sed -n '/^State 0$/,/^State 1$/p']], 0,
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[[State 0
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0 $accept: . exp $end
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1 exp: . 'a'
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2 | . 'b'
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3 | . C
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4 | . D
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5 | . E
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6 | . F
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7 | . 'g'
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8 | . 'h'
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9 | . 'i'
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10 | . 'j'
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11 | . K
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12 | . L
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13 | . M
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14 | . N
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15 | . 'o'
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16 | . 'p'
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'a' shift, and go to state 1
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'b' shift, and go to state 2
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C shift, and go to state 3
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D shift, and go to state 4
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E shift, and go to state 5
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F shift, and go to state 6
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'g' shift, and go to state 7
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'h' shift, and go to state 8
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'i' shift, and go to state 9
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'j' shift, and go to state 10
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K shift, and go to state 11
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L shift, and go to state 12
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M shift, and go to state 13
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N shift, and go to state 14
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'o' shift, and go to state 15
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'p' shift, and go to state 16
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exp go to state 17
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State 1
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]])
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AT_CLEANUP
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## ------------------------------- ##
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## Useless associativity warning. ##
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## ------------------------------- ##
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