# PadWalker

📦 std

Reach into another subroutine’s `my` and `our` variables — read them, change them, find out their names — from anywhere on the call stack. `PadWalker` is the tool of choice for debuggers, introspection utilities, and any code that needs to look at variables it did not declare. It is what Perl’s own built-in debugger uses, and it is the modern replacement for `Devel::LexAlias` when you want to alias or substitute a lexical in a caller’s pad. Every function that walks the stack takes a `$level` argument interpreted just like the argument to `caller`: - `0` — the current scope. - `1` — the scope of whoever called the current sub. - `2` — two frames up, and so on. File scope is a valid destination: asking for a `$level` deeper than the call stack supports raises `Not nested deeply enough`. Returned hashes key on the variable name *including* its sigil — so `$x` appears under the key `'$x'`, `@items` under `'@items'`. Values are always references to the live variable, so assigning through the reference updates the original. ## Functions ### Lexical inspection #### [`peek_my`](PadWalker/peek_my.md) Return every `my` variable in scope at a given call-stack depth as a hash of name-to-reference pairs. #### [`peek_our`](PadWalker/peek_our.md) Return every `our` variable in scope at a given call-stack depth as a hash of name-to-reference pairs. #### [`peek_sub`](PadWalker/peek_sub.md) Return the `my` variables declared inside a given subroutine, whether or not the sub is currently on the call stack. #### [`closed_over`](PadWalker/closed_over.md) Return the lexicals that a subroutine closes over — the variables it references but did not itself declare. #### [`var_name`](PadWalker/var_name.md) Given a reference to a variable, return the name that variable has in a specified subroutine’s pad — or `undef` if it is not there. ### Lexical modification #### [`set_closed_over`](PadWalker/set_closed_over.md) Replace the lexicals that a subroutine closes over with a new set of references.