Method lfun::_sprintf()

Method _sprintf

string _sprintf(int conversion_type, mapping(string:int)|void params)

Description

Sprintf callback.

This method is called by sprintf() to print objects. If it is not present, printing of the object will not be supported for any conversion-type except for the %O-conversion-type, which will output "object".

Parameter conversion_type

One of:

'b'	Signed binary integer.
'd'	Signed decimal integer.
'u'	Unsigned decimal integer.
'o'	Signed octal integer.
'x'	Lowercase signed hexadecimal integer.
'X'	Uppercase signed hexadecimal integer.
'c'	Character. If a fieldsize has been specified this will output the low-order bytes of the integer in network byte order.
'f'	Float.
'g'	Heuristically chosen representation of float.
'G'	Like %g, but uses uppercase E for exponent.
'e'	Exponential notation float.
'E'	Like %e, but uses uppercase E for exponent.
's'	String.
'O'	Any value (debug style).
't'	Type of the argument.

Parameter params

Conversion parameters. The following parameters may be supplied:

"precision" : int	Precision.
"width" : int	Field width.
"flag_left" : int(1..1)	Indicates that the output should be left-aligned.
"indent" : int	Indentation level in %O-mode.

Returns

Is expected to return a string describing the object formatted according to conversion_type.

Note

_sprintf() is currently not called for the following conversion-types:

'F'	Binary IEEE representation of float (%4F gives single precision, %8F gives double precision.)

Note

This function might be called at odd times, e.g. before lfun::create has been called or when an error has occurred. The reason is typically that it gets called when a backtrace is being formatted to report an error. It should therefore be very robust and not make any assumptions about its own internal state, at least not when conversion_type is 'O'.

Note

It's assumed that this function is side-effect free.

See also

sprintf()