pydocspec.genericvisitor.When

This enumeration contains the different times an extension is used.

Attributes:

BEFORE: For each node, before calling the visit() method on the customizable visitor.

..note:: The depart() method will be called AFTER calling depart() on

the customizable visitor. Outer scope.

AFTER: For each node, before calling the visit(), and before the children gets visited.

..note:: The depart() method will be called after the children have been visited,

and BEFORE calling depart() on the customizable visitor. Inner scope.

Example:

Considering that the customizable visitor MainVisitor is set up with two extension visitors: one that runs BEFORE and one that runs AFTER, all 3 visitors simply print the name of the visitor class and the call beeing made.

Running the MainVisitor on the following tree:

:0 - Module: a
| :1 - Indirection: Union

Will generate the following output:

Before              .visit(a)
MainVistor          .visit(a)
After               .visit(a)
Before              .visit(a.Union)
MainVistor          .visit(a.Union)
After               .visit(a.Union)
After               .depart(a.Union)
MainVistor          .depart(a.Union)
Before              .depart(a.Union)
After               .depart(a)
MainVistor          .depart(a)
Before              .depart(a)