# A problem with understanding handles

This is the definition of a handle:

1.A “handle” of a string is a substring that matches the RHS of a production.

And

2.Whose reduction to the non-terminal (on the LHS of the production) represents one step along the reverse of a rightmost derivation toward reducing to the start symbol.

I don't understand the second condition, it's confusing. Can someone clarify it please. Thank you/

• Could you give more context? Where did you find this definition? The term "handle" is used in many different ways. – David Richerby Jul 25 '18 at 12:11
• Is this helpful? cs.stackexchange.com/questions/7587/what-are-handles-in-parsing – Yuval Filmus Jul 25 '18 at 12:27
• @YuvalFilmus I read that page before, didn't find it helpful. – John Sall Jul 25 '18 at 19:27
• @DavidRicherby of course, the handle mentioned here is the one used in LR parsers. If there's a string that matches the RHS of a production rule then we call that string a handle. – John Sall Jul 25 '18 at 19:28