bison grammar,access returned variables

Question

block:
    "{" { //push scope;}
    multi_stmt
    "}" {
        //pop scope
        $$=new ASTNode_Block($2,..........)
     }

I'm trying to implement block structures in bison. However, I am having troubles here to access $2 (returned value from multi_stmt)

ps: It's intended to not using "|" to separate them, thus i can have them executed in orders.

Answer 1

Mid-rule actions also have numbers (but not, by default, return types). So the value of multi_stmt is $3 , not $2 .

$1 is the open brace (which I think should be '{' , not "{" -- in bison, they are different --), $2 is the mid-rule action, $3 is multi_stmt and $4 is the close brace.

Answer 2

Try with removing second { in line "{" { . If I understand correctly you intend to define a grammar rule { multi_stmt } , so the second { is a mistake here.