float()

[xXziroXx]

Can anyone tell me if this is supposed to happen and if so, why?

PHP Code:

float(123) = 123
float("123") = 123
float("str") = -1
float("str123") = -1
float("123str") = 123 


Note the very last one. If a string starts with numbers, the float() command thinks it's a number, and I find this very annoying and misleading. If it is indeed a bug with the engine, could it be fixed please?

[WhiteDragon]

This is known behavior, and I think intentional (would need to contact Stefan for reasoning). It shouldn't be hard to make your own float function which calls the internal float only in the case where all the characters of the string are integers (or decimal points). Not sure about scientific notation and how it handles that.

[xXziroXx]

Originally Posted by WhiteDragon

This is known behavior, and I think intentional (would need to contact Stefan for reasoning). It shouldn't be hard to make your own float function which calls the internal float only in the case where all the characters of the string are integers (or decimal points). Not sure about scientific notation and how it handles that.

I'd rather have the default float() function work like the way it, at least in my opinion, is supposed to work.

[WhiteDragon]

Originally Posted by xXziroXx

I'd rather have the default float() function work like the way it, at least in my opinion, is supposed to work.

It'd involve reworking literally all the string->number casting in GS which could introduce bugs. (Not saying that I disagree with your motive, it's just unrealistic.)

[xXziroXx]

Originally Posted by WhiteDragon

which could introduce bugs.

More like fix current bugs and have it work like supposed too after that. Maybe Stefan could even write something up that'll only affect how float() handles things.

[-Ramirez-]

Originally Posted by WhiteDragon

It'd involve reworking literally all the string->number casting

This is data conversion, not casting.

[fowlplay4]

Well this is just silly.

PHP Code:

echo("123str" + "123str"); // echos 246 


[fowlplay4]

int("123str") should really return -1 too

[xXziroXx]

Originally Posted by fowlplay4

int("123str") should really return -1 too

Definitely. Just because a string STARTS with numbers doesn't mean it's a number.

[Skyld]

Originally Posted by xXziroXx

Definitely. Just because a string STARTS with numbers doesn't mean it's a number.

This is intentional since it allows extra notation to be correctly parsed:

PHP Code:

echo(float("1.0e4")); // 10000
echo(float("0xBC"));  // 188 


GScript is behaving in this case completely as expected, and this is the same as in JavaScript and a lot of other dynamically/variantly typed languages, so no, it can't be changed without breaking it's intended functionality.

If this is a problem then you should validate your input before processing.

[MrOmega]

Call me stupid but what are some actual purpose of using float( "123str");

[Crow]

Originally Posted by MrOmega

Call me stupid but what are some actual purpose of using float( "123str");

Let's assume we have user input. We want a number. The user gives us a string instead of a number. Ideally, throwing it into the float()-bin will return -1 and tell us it's a string this way. When there are numbers at the beginning, it won't. Don't see an issue though. Of course, this is just an example. Might be a problem elsewhere. But that can be worked around.

[WhiteDragon]

Originally Posted by Skyld

This is intentional since it allows extra notation to be correctly parsed:

PHP Code:

echo(float("1.0e4")); // 10000
echo(float("0xBC"));  // 188 


It's not like it'd be impossible to make a parser which only accepts those variants when a letter is encountered.

I also don't think it matters that this is "how it usually works" in dynamically-typed languages, since a lot of other languages do dumb things.


But the important fact is that this behavior already exists and bugs may be introduced if it is changed.

[Admins]

This is the same behaviour as the various C functions for converting a string to integer or floating point value.

[xXziroXx]

Originally Posted by Stefan

This is the same behaviour as the various C functions for converting a string to integer or floating point value.

Perhaps, but it doesn't make any sense, you gotta agree on that much. At the very least could you add another function that doesn't think 123string49foobar equals the number 123?