conflicts: 2 shift/reduce - parsing

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); }
;

Answer 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.