##
5.2.7 String conversions

A string conversion is an expression list enclosed in reverse (a.k.a. backward) quotes:

  string_conversion | ::= | "`" expression_list "`"

  Download entire grammar as text.

A string conversion evaluates the contained expression list and converts the resulting object into a string according to rules specific to its type.

If the object is a string, a number, `None`, or a tuple, list or dictionary containing only objects whose type is one of these, the resulting string is a valid Python expression which can be passed to the built-in function `eval()` to yield an expression with the same value (or an approximation, if floating point numbers are involved).

(In particular, converting a string adds quotes around it and converts ``funny'' characters to escape sequences that are safe to print.)

Recursive objects (for example, lists or dictionaries that contain a reference to themselves, directly or indirectly) use "`...`" to indicate a recursive reference, and the result cannot be passed to `eval()` to get an equal value (`SyntaxError` will be raised instead).

The built-in function `repr()` performs exactly the same conversion in its argument as enclosing it in parentheses and reverse quotes does. The built-in function `str()` performs a similar but more user-friendly conversion.