conflicts: 2 shift/reduce












0















I'm trying to write a little interpreter with GNU bison.
I wanted to ask if anyone could explain the difference between the directive% right and% left and where my mistake is in the code below.



%token <flo> FLO
%token <name> NAME
%right '='
%left '+' '-'
%left '*' '/' '%'
%left '&' '|' 'x'
%left NEG NOT LOGIC_NOT
%left '^'
%left ARG

%type <flo> exp

%%

language: /* nothing */
| language statment

statment: 'n'
| exp
| error { yyerrok; }
;

exp: FLO { $$ = $1; }
| NAME '(' ')' { $$ = ycall($1); }
| NAME '(' exp ')' { $$ = ycall($1, $3); }
| NAME '(' exp ',' exp ')' { $$ = ycall($1, $3, $5); }
| NAME '=' exp { $$ = 1; ysetvar($1, $3); }
| NAME %prec VAR { $$ = ygetvar($1); }
| '_' exp %prec ARG { $$ = ygetarg($2, args); }
| '(' exp ')' { $$ = $2; }
/* 1 Operand */
| '-' exp %prec NEG { $$ = - $2; }
| '~' exp %prec NOT { $$ = ~ static_cast<int>($2); }
| '!' exp %prec LOGIC_NOT { $$ = ! static_cast<int>($2); }
/* 2 Operands */
| exp '+' exp { $$ = $1 + $3; }
| exp '-' exp { $$ = $1 - $3; }
| exp '*' exp { $$ = $1 * $3; }
| exp '/' exp { $$ = $1 / $3; }
| exp '%' exp { $$ = static_cast<int>($1) % static_cast<int>($3); }
| exp '^' exp { $$ = pow($1, $3); }
| exp '&' exp { $$ = static_cast<int>($1) & static_cast<int>($3); }
| exp '|' exp { $$ = static_cast<int>($1) | static_cast<int>($3); }
| exp 'x' exp { $$ = static_cast<int>($1) ^ static_cast<int>($3); }
;









share|improve this question

























  • There is no %left nor %right in your snippet and no explanation of why you think something is wrong with your program.

    – rici
    Jan 18 at 18:51











  • I forgot to share some of the code (flo is a double). I've corrected that now.

    – Marek
    Jan 18 at 18:54
















0















I'm trying to write a little interpreter with GNU bison.
I wanted to ask if anyone could explain the difference between the directive% right and% left and where my mistake is in the code below.



%token <flo> FLO
%token <name> NAME
%right '='
%left '+' '-'
%left '*' '/' '%'
%left '&' '|' 'x'
%left NEG NOT LOGIC_NOT
%left '^'
%left ARG

%type <flo> exp

%%

language: /* nothing */
| language statment

statment: 'n'
| exp
| error { yyerrok; }
;

exp: FLO { $$ = $1; }
| NAME '(' ')' { $$ = ycall($1); }
| NAME '(' exp ')' { $$ = ycall($1, $3); }
| NAME '(' exp ',' exp ')' { $$ = ycall($1, $3, $5); }
| NAME '=' exp { $$ = 1; ysetvar($1, $3); }
| NAME %prec VAR { $$ = ygetvar($1); }
| '_' exp %prec ARG { $$ = ygetarg($2, args); }
| '(' exp ')' { $$ = $2; }
/* 1 Operand */
| '-' exp %prec NEG { $$ = - $2; }
| '~' exp %prec NOT { $$ = ~ static_cast<int>($2); }
| '!' exp %prec LOGIC_NOT { $$ = ! static_cast<int>($2); }
/* 2 Operands */
| exp '+' exp { $$ = $1 + $3; }
| exp '-' exp { $$ = $1 - $3; }
| exp '*' exp { $$ = $1 * $3; }
| exp '/' exp { $$ = $1 / $3; }
| exp '%' exp { $$ = static_cast<int>($1) % static_cast<int>($3); }
| exp '^' exp { $$ = pow($1, $3); }
| exp '&' exp { $$ = static_cast<int>($1) & static_cast<int>($3); }
| exp '|' exp { $$ = static_cast<int>($1) | static_cast<int>($3); }
| exp 'x' exp { $$ = static_cast<int>($1) ^ static_cast<int>($3); }
;









share|improve this question

























  • There is no %left nor %right in your snippet and no explanation of why you think something is wrong with your program.

    – rici
    Jan 18 at 18:51











  • I forgot to share some of the code (flo is a double). I've corrected that now.

    – Marek
    Jan 18 at 18:54














0












0








0


1






I'm trying to write a little interpreter with GNU bison.
I wanted to ask if anyone could explain the difference between the directive% right and% left and where my mistake is in the code below.



%token <flo> FLO
%token <name> NAME
%right '='
%left '+' '-'
%left '*' '/' '%'
%left '&' '|' 'x'
%left NEG NOT LOGIC_NOT
%left '^'
%left ARG

%type <flo> exp

%%

language: /* nothing */
| language statment

statment: 'n'
| exp
| error { yyerrok; }
;

exp: FLO { $$ = $1; }
| NAME '(' ')' { $$ = ycall($1); }
| NAME '(' exp ')' { $$ = ycall($1, $3); }
| NAME '(' exp ',' exp ')' { $$ = ycall($1, $3, $5); }
| NAME '=' exp { $$ = 1; ysetvar($1, $3); }
| NAME %prec VAR { $$ = ygetvar($1); }
| '_' exp %prec ARG { $$ = ygetarg($2, args); }
| '(' exp ')' { $$ = $2; }
/* 1 Operand */
| '-' exp %prec NEG { $$ = - $2; }
| '~' exp %prec NOT { $$ = ~ static_cast<int>($2); }
| '!' exp %prec LOGIC_NOT { $$ = ! static_cast<int>($2); }
/* 2 Operands */
| exp '+' exp { $$ = $1 + $3; }
| exp '-' exp { $$ = $1 - $3; }
| exp '*' exp { $$ = $1 * $3; }
| exp '/' exp { $$ = $1 / $3; }
| exp '%' exp { $$ = static_cast<int>($1) % static_cast<int>($3); }
| exp '^' exp { $$ = pow($1, $3); }
| exp '&' exp { $$ = static_cast<int>($1) & static_cast<int>($3); }
| exp '|' exp { $$ = static_cast<int>($1) | static_cast<int>($3); }
| exp 'x' exp { $$ = static_cast<int>($1) ^ static_cast<int>($3); }
;









share|improve this question
















I'm trying to write a little interpreter with GNU bison.
I wanted to ask if anyone could explain the difference between the directive% right and% left and where my mistake is in the code below.



%token <flo> FLO
%token <name> NAME
%right '='
%left '+' '-'
%left '*' '/' '%'
%left '&' '|' 'x'
%left NEG NOT LOGIC_NOT
%left '^'
%left ARG

%type <flo> exp

%%

language: /* nothing */
| language statment

statment: 'n'
| exp
| error { yyerrok; }
;

exp: FLO { $$ = $1; }
| NAME '(' ')' { $$ = ycall($1); }
| NAME '(' exp ')' { $$ = ycall($1, $3); }
| NAME '(' exp ',' exp ')' { $$ = ycall($1, $3, $5); }
| NAME '=' exp { $$ = 1; ysetvar($1, $3); }
| NAME %prec VAR { $$ = ygetvar($1); }
| '_' exp %prec ARG { $$ = ygetarg($2, args); }
| '(' exp ')' { $$ = $2; }
/* 1 Operand */
| '-' exp %prec NEG { $$ = - $2; }
| '~' exp %prec NOT { $$ = ~ static_cast<int>($2); }
| '!' exp %prec LOGIC_NOT { $$ = ! static_cast<int>($2); }
/* 2 Operands */
| exp '+' exp { $$ = $1 + $3; }
| exp '-' exp { $$ = $1 - $3; }
| exp '*' exp { $$ = $1 * $3; }
| exp '/' exp { $$ = $1 / $3; }
| exp '%' exp { $$ = static_cast<int>($1) % static_cast<int>($3); }
| exp '^' exp { $$ = pow($1, $3); }
| exp '&' exp { $$ = static_cast<int>($1) & static_cast<int>($3); }
| exp '|' exp { $$ = static_cast<int>($1) | static_cast<int>($3); }
| exp 'x' exp { $$ = static_cast<int>($1) ^ static_cast<int>($3); }
;






parsing gnu bison yacc






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Jan 18 at 18:53







Marek

















asked Jan 18 at 17:19









MarekMarek

688




688













  • There is no %left nor %right in your snippet and no explanation of why you think something is wrong with your program.

    – rici
    Jan 18 at 18:51











  • I forgot to share some of the code (flo is a double). I've corrected that now.

    – Marek
    Jan 18 at 18:54



















  • There is no %left nor %right in your snippet and no explanation of why you think something is wrong with your program.

    – rici
    Jan 18 at 18:51











  • I forgot to share some of the code (flo is a double). I've corrected that now.

    – Marek
    Jan 18 at 18:54

















There is no %left nor %right in your snippet and no explanation of why you think something is wrong with your program.

– rici
Jan 18 at 18:51





There is no %left nor %right in your snippet and no explanation of why you think something is wrong with your program.

– rici
Jan 18 at 18:51













I forgot to share some of the code (flo is a double). I've corrected that now.

– Marek
Jan 18 at 18:54





I forgot to share some of the code (flo is a double). I've corrected that now.

– Marek
Jan 18 at 18:54












1 Answer
1






active

oldest

votes


















1














Look at the y.output file produced by yacc or bison with the -v argument. The first conflict is in state 5:



State 5

7 exp: NAME . '(' ')'
8 | NAME . '(' exp ')'
9 | NAME . '(' exp ',' exp ')'
10 | NAME . '=' exp
11 | NAME .

'=' shift, and go to state 14
'(' shift, and go to state 15

'(' [reduce using rule 11 (exp)]
$default reduce using rule 11 (exp)


In this case the conflcit is when there's a '(' after a NAME -- this is an ambiguity in your grammar in which it might be a call expression, or it might be a simple NAME expression followed by a parenthesized expression, due to the fact that you have no separator between statements in your language.



The second conflict is:



State 13

4 statment: exp .
17 exp: exp . '+' exp
18 | exp . '-' exp
19 | exp . '*' exp
20 | exp . '/' exp
21 | exp . '%' exp
22 | exp . '^' exp
23 | exp . '&' exp
24 | exp . '|' exp
25 | exp . 'x' exp

'+' shift, and go to state 21
'-' shift, and go to state 22
'*' shift, and go to state 23
'/' shift, and go to state 24
'%' shift, and go to state 25
'&' shift, and go to state 26
'|' shift, and go to state 27
'x' shift, and go to state 28
'^' shift, and go to state 29

'-' [reduce using rule 4 (statment)]
$default reduce using rule 4 (statment)


which is essentially the same problem, this time with a '-' -- the input NAME - NAME might be a single binary subtract statements, or it might be two statements -- a NAME followed by a unary negate.



If you add a separator between statements (such as ;), both of these conflicts would go away.






share|improve this answer
























  • And how can I solve the conflict?

    – Marek
    Jan 18 at 19:52











Your Answer






StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f54258690%2fconflicts-2-shift-reduce%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









1














Look at the y.output file produced by yacc or bison with the -v argument. The first conflict is in state 5:



State 5

7 exp: NAME . '(' ')'
8 | NAME . '(' exp ')'
9 | NAME . '(' exp ',' exp ')'
10 | NAME . '=' exp
11 | NAME .

'=' shift, and go to state 14
'(' shift, and go to state 15

'(' [reduce using rule 11 (exp)]
$default reduce using rule 11 (exp)


In this case the conflcit is when there's a '(' after a NAME -- this is an ambiguity in your grammar in which it might be a call expression, or it might be a simple NAME expression followed by a parenthesized expression, due to the fact that you have no separator between statements in your language.



The second conflict is:



State 13

4 statment: exp .
17 exp: exp . '+' exp
18 | exp . '-' exp
19 | exp . '*' exp
20 | exp . '/' exp
21 | exp . '%' exp
22 | exp . '^' exp
23 | exp . '&' exp
24 | exp . '|' exp
25 | exp . 'x' exp

'+' shift, and go to state 21
'-' shift, and go to state 22
'*' shift, and go to state 23
'/' shift, and go to state 24
'%' shift, and go to state 25
'&' shift, and go to state 26
'|' shift, and go to state 27
'x' shift, and go to state 28
'^' shift, and go to state 29

'-' [reduce using rule 4 (statment)]
$default reduce using rule 4 (statment)


which is essentially the same problem, this time with a '-' -- the input NAME - NAME might be a single binary subtract statements, or it might be two statements -- a NAME followed by a unary negate.



If you add a separator between statements (such as ;), both of these conflicts would go away.






share|improve this answer
























  • And how can I solve the conflict?

    – Marek
    Jan 18 at 19:52
















1














Look at the y.output file produced by yacc or bison with the -v argument. The first conflict is in state 5:



State 5

7 exp: NAME . '(' ')'
8 | NAME . '(' exp ')'
9 | NAME . '(' exp ',' exp ')'
10 | NAME . '=' exp
11 | NAME .

'=' shift, and go to state 14
'(' shift, and go to state 15

'(' [reduce using rule 11 (exp)]
$default reduce using rule 11 (exp)


In this case the conflcit is when there's a '(' after a NAME -- this is an ambiguity in your grammar in which it might be a call expression, or it might be a simple NAME expression followed by a parenthesized expression, due to the fact that you have no separator between statements in your language.



The second conflict is:



State 13

4 statment: exp .
17 exp: exp . '+' exp
18 | exp . '-' exp
19 | exp . '*' exp
20 | exp . '/' exp
21 | exp . '%' exp
22 | exp . '^' exp
23 | exp . '&' exp
24 | exp . '|' exp
25 | exp . 'x' exp

'+' shift, and go to state 21
'-' shift, and go to state 22
'*' shift, and go to state 23
'/' shift, and go to state 24
'%' shift, and go to state 25
'&' shift, and go to state 26
'|' shift, and go to state 27
'x' shift, and go to state 28
'^' shift, and go to state 29

'-' [reduce using rule 4 (statment)]
$default reduce using rule 4 (statment)


which is essentially the same problem, this time with a '-' -- the input NAME - NAME might be a single binary subtract statements, or it might be two statements -- a NAME followed by a unary negate.



If you add a separator between statements (such as ;), both of these conflicts would go away.






share|improve this answer
























  • And how can I solve the conflict?

    – Marek
    Jan 18 at 19:52














1












1








1







Look at the y.output file produced by yacc or bison with the -v argument. The first conflict is in state 5:



State 5

7 exp: NAME . '(' ')'
8 | NAME . '(' exp ')'
9 | NAME . '(' exp ',' exp ')'
10 | NAME . '=' exp
11 | NAME .

'=' shift, and go to state 14
'(' shift, and go to state 15

'(' [reduce using rule 11 (exp)]
$default reduce using rule 11 (exp)


In this case the conflcit is when there's a '(' after a NAME -- this is an ambiguity in your grammar in which it might be a call expression, or it might be a simple NAME expression followed by a parenthesized expression, due to the fact that you have no separator between statements in your language.



The second conflict is:



State 13

4 statment: exp .
17 exp: exp . '+' exp
18 | exp . '-' exp
19 | exp . '*' exp
20 | exp . '/' exp
21 | exp . '%' exp
22 | exp . '^' exp
23 | exp . '&' exp
24 | exp . '|' exp
25 | exp . 'x' exp

'+' shift, and go to state 21
'-' shift, and go to state 22
'*' shift, and go to state 23
'/' shift, and go to state 24
'%' shift, and go to state 25
'&' shift, and go to state 26
'|' shift, and go to state 27
'x' shift, and go to state 28
'^' shift, and go to state 29

'-' [reduce using rule 4 (statment)]
$default reduce using rule 4 (statment)


which is essentially the same problem, this time with a '-' -- the input NAME - NAME might be a single binary subtract statements, or it might be two statements -- a NAME followed by a unary negate.



If you add a separator between statements (such as ;), both of these conflicts would go away.






share|improve this answer













Look at the y.output file produced by yacc or bison with the -v argument. The first conflict is in state 5:



State 5

7 exp: NAME . '(' ')'
8 | NAME . '(' exp ')'
9 | NAME . '(' exp ',' exp ')'
10 | NAME . '=' exp
11 | NAME .

'=' shift, and go to state 14
'(' shift, and go to state 15

'(' [reduce using rule 11 (exp)]
$default reduce using rule 11 (exp)


In this case the conflcit is when there's a '(' after a NAME -- this is an ambiguity in your grammar in which it might be a call expression, or it might be a simple NAME expression followed by a parenthesized expression, due to the fact that you have no separator between statements in your language.



The second conflict is:



State 13

4 statment: exp .
17 exp: exp . '+' exp
18 | exp . '-' exp
19 | exp . '*' exp
20 | exp . '/' exp
21 | exp . '%' exp
22 | exp . '^' exp
23 | exp . '&' exp
24 | exp . '|' exp
25 | exp . 'x' exp

'+' shift, and go to state 21
'-' shift, and go to state 22
'*' shift, and go to state 23
'/' shift, and go to state 24
'%' shift, and go to state 25
'&' shift, and go to state 26
'|' shift, and go to state 27
'x' shift, and go to state 28
'^' shift, and go to state 29

'-' [reduce using rule 4 (statment)]
$default reduce using rule 4 (statment)


which is essentially the same problem, this time with a '-' -- the input NAME - NAME might be a single binary subtract statements, or it might be two statements -- a NAME followed by a unary negate.



If you add a separator between statements (such as ;), both of these conflicts would go away.







share|improve this answer












share|improve this answer



share|improve this answer










answered Jan 18 at 19:47









Chris DoddChris Dodd

80.8k680160




80.8k680160













  • And how can I solve the conflict?

    – Marek
    Jan 18 at 19:52



















  • And how can I solve the conflict?

    – Marek
    Jan 18 at 19:52

















And how can I solve the conflict?

– Marek
Jan 18 at 19:52





And how can I solve the conflict?

– Marek
Jan 18 at 19:52


















draft saved

draft discarded




















































Thanks for contributing an answer to Stack Overflow!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f54258690%2fconflicts-2-shift-reduce%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Homophylophilia

Updating UILabel text programmatically using a function

Cloud Functions - OpenCV Videocapture Read method fails for larger files from cloud storage