Re: Digit separators for numeric literals

Rasmus Lerdorf wrote: > On 02/18/2015 11:21 PM, Rick Widmer wrote: > >> how about: >> >> my_func( '1,000.04' ); //if you want to use separators there. > > The problem with that is that the world is split. The other half, or > actually more than half, would write that as '1.000,04'. There is no way > we would want to take sides on that one. And we have support for > locale-based number formatting and parsing via numfmt_format() and > numfmt_parse(). If we were going to add a separator for literals, the > only real low-ascii choice is _ which is also used by Ada, D, Java, Perl > and Ruby. I agree that _ is most reasonable, mainly because it is used by other languages also. > I was 90% kidding about using a Unicode character, but if you think > about it a bit, most people are using IDEs or at least smart scriptable > editors, it wouldn't be that much of a stretch to picture your editor > pretty-printing 1234567890 as 1·234·567·890 or 1˙234˙567˙890 (U+02D9). > It would be easy to make the parser ignore that character in numeric > literals. Much easier than working out the various issues with _ anyway. Which issues do you see? IMHO it doesn't make much sense to use a digit separator in a trailing or leading position, because that wouldn't improve readability. So PHP could make the same restrictions as Java with regard to integer and float literals[1] (basically that the underscore is allowed only between actual digits), in which case I don't see any syntactic ambiguity. Ignoring the _ in the scanner (IMHO there is no need to obtain it in the token) doesn't seem to be harder than ignoring any other character. [1] <http://docs.oracle.com/javase/specs/jls/se8/html/jls-3.html#jls-3.10> -- Christoph M. Becker