Commit 56cb6485 authored by Léo Grange's avatar Léo Grange
Browse files

fix shift/reduce conflicts with very simple rule 

All binary operators have the same precedance due to a "feature" of yacc
that makes difficult to write something better without some
duplications.
parent 74aab7d4

node.cpp

+1 −0
Original line number Diff line number Diff line
@@ -124,6 +124,7 @@ void NBinaryOperator::printNode(std::ostream &o) { 


void NUnaryOperator::printNode(std::ostream &o) {

	o << tokenToString(op) << " ";

	exp->printNode(o);

}

parser.y

+25 −5
Original line number Diff line number Diff line
@@ -81,11 +81,30 @@ std::unique_ptr<T> UNIQUE(T *ptr) { return std::unique_ptr<T>(ptr); } 
%type <cond> cond





%type <token> unop

%type <token> binop

/*%type <token> unop

%type <token> binop*/

%type <token> compop





/* precedence to solve shift/reduce conflicts explicitly */

%precedence TOK_THEN

%precedence TOK_ELSE





/* operator associativity to avoid shift/reduce conflicts */

/*

%left TOK_OR

%left TOK_AND

%left TOK_LSHIFT TOK_RSHIFT

%left TOK_PLUS TOK_MINUS

%left TOK_MUL TOK_DIV

*/

%left TOK_OR TOK_AND TOK_LSHIFT TOK_RSHIFT TOK_PLUS TOK_MINUS TOK_MUL TOK_DIV ANY_BINOP

%type <token> binop

%type <token> unop



%right UNARY_MINUS





%start program
@@ -160,7 +179,8 @@ ident : TOK_ID { $$ = new NIdentifier(*$1); delete $1; } 
literal : TOK_INT { $$ = new NInteger(*$1); delete $1; }

		;



binop : TOK_PLUS | TOK_MINUS | TOK_MUL | TOK_DIV | TOK_AND | TOK_OR ;

binop : TOK_PLUS | TOK_MINUS | TOK_MUL | TOK_DIV | TOK_AND | TOK_OR

	  | TOK_LSHIFT | TOK_RSHIFT;



compop : TOK_EQ | TOK_NE | TOK_GT | TOK_GE | TOK_LT | TOK_LE ;
@@ -175,8 +195,8 @@ variable : ident { $$ = new NBitfieldVariable(UNIQUE($1)); } 


expr : variable { $$ = $1; }

	 | literal { $$ = $1; }

	 | unop expr { $$ = new NUnaryOperator($1, UNIQUE($2)); }

	 | expr binop expr { $$ = new NBinaryOperator($2, UNIQUE($1), UNIQUE($3)); }

	 | unop expr %prec UNARY_MINUS { $$ = new NUnaryOperator($1, UNIQUE($2)); }

	 | expr binop expr %prec ANY_BINOP { $$ = new NBinaryOperator($2, UNIQUE($1), UNIQUE($3)); }

	 | TOK_LPAR expr TOK_RPAR { $$ = $2; }

	 ;