PHP: rfc:zpp-conversion-rules

This is an old revision of the document!

Current :

	Zval type
ZPP type	IS_NULL	IS_FALSE	IS_TRUE	IS_LONG	IS_DOUBLE	IS_STRING
bool	Yes (-> false)	Native	Native	Yes (1)	Yes (1)	Yes (2)
long	Yes (-> 0)	Yes (-> 0)	Yes (-> 1)	Native	Yes	(3)
double	Yes (-> 0.0)	Yes (-> 0.0)	Yes (-> 1.0)	Yes	Native	(4)
string	Yes (-> “”)	Yes (-> “”)	Yes (-> “1”)	Yes	Yes	Native

(1) false if null, true if non null
(2) “” and “0” -> false, other values -> true
(3) Run string through is_numeric_str_function() and detect error. If double returned, convert it to long
(4) Run string through is_numeric_str_function() and detect error. If int returned, convert it to double

is_numeric_str_function() behavior :

Skip leading spaces
Stop conversion at first non digit character with no error

Proposed changes:

* error if non null fractional part * if string contains float, reject non null fractional part * 3/4 Accept trailing blanks, error if non-blank trailing chars

Result :

	Zval type
ZPP type	IS_NULL	IS_FALSE	IS_TRUE	IS_LONG	IS_DOUBLE	IS_STRING
null	Yes	No	No	No	No	No
bool	No	Native	Native	Yes (1)	Yes (1)	No
strict_bool	No	Native	Native	No	No	No
long	No	No	No	Native	(2)	(3)
strict_long	No	No	No	Native	No	No
double	No	No	No	Yes	Native	(4)
strict_double	No	No	No	No	Native	No
string	No	No	No	Yes	Yes	Native
strict_string	No	No	No	No	No	Native

(1) false if null, true if non null
(2) error if fractional part is non null
(3) Run string through is_numeric_str_function() and detect error. If double with null fractional part returned, convert to long, else error
(4) Run string through is_numeric_str_function() and detect error. If int returned, convert to double

is_numeric_str_function() behavior :

Skip leading spaces
Ignore trailing spaces
Error on non-blank trailing chars

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