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