gistfile1.txt

assignment_expression:
        conditional_expression { $$ = $1; }
    |   coalesce_expression { $$ = $1; }
    |   unary_expression assignment_operator assignment_expression { $$ = ast_assignment($2, $1, $3); }
;

coalesce_expression:
        T_IDENTIFIER T_COALESCE scalar_value { $$ = ast_opr(T_COALESCE, 2, $1, $3); }
;