Extension:PhpTags Functions/Functions/Variable handling

List of implemented functions

 * boolval — Get the boolean value of a variable
 * doubleval — Alias of floatval
 * floatval — Get float value of a variable
 * get_defined_vars — Returns an array of all defined variables
 * gettype — Get the type of a variable
 * intval — Get the integer value of a variable
 * is_array — Finds whether a variable is an array
 * is_bool — Finds out whether a variable is a boolean
 * is_double — Alias of is_float
 * is_float — Finds whether the type of a variable is float
 * is_int — Find whether the type of a variable is integer
 * is_integer — Alias of is_int
 * is_long — Alias of is_int
 * is_null — Finds whether a variable is NULL
 * is_numeric — Finds whether a variable is a number or a numeric string
 * is_object — Finds whether a variable is an object
 * is_real — Alias of is_float
 * is_scalar — Finds whether a variable is a scalar
 * is_string — Find whether the type of a variable is string
 * print_r — Prints human-readable information about a variable
 * settype — Set the type of a variable
 * strval — Get string value of a variable
 * var_dump — Dumps information about a variable
 * var_export — Outputs or returns a parsable string representation of a variable

The following functions are implemented in the Runtime of the extension PhpTags.
 * empty — Determine whether a variable is empty
 * isset — Determine if a variable is set and is not NULL
 * unset — Unset a given variable

Waiting for implementation
This function will be added after the implementation of the callback function in Runtime of Extension PhpTags.
 * is_callable — Verify that the contents of a variable can be called as a function

This functions can be added by request
 * debug_zval_dump — Dumps a string representation of an internal zend value to output
 * import_request_variables — Import GET/POST/Cookie variables into the global scope
 * serialize — Generates a storable representation of a value
 * unserialize — Creates a PHP value from a stored representation

Cannot be implemented
This functions are used the resources
 * get_resource_type — Returns the resource type
 * is_resource — Finds whether a variable is a resource