Functions for performing conversion from PHPSessionValue objects to Haskell types while using a subset of the implicit PHP type coercion behaviour. Some of the differences from the implicit type conversion found in PHP are noted:

• Conversions that are documented as undefined behaviour in the PHP manual will throw definite exceptions with these functions.
• A significant difference from PHP's conversion rules is that NULL cannot be directly converted to any data type except to Bool, otherwise NULL has to be handled by using the type Maybe a to capture nullable values.
• Objects that implement Serializable are not convertible to any other type at all as their value systems are not directly interpretable in a meaningful manner.
• Numbers can be converted to strings, but only strings that satisfy reads str = [(value, "")] can be converted back to numbers.
• Arrays and objects to string conversions which would normally be coerced to the simple strings "Array" and "Object" in PHP, are simply considered errors with these conversion functions.