Wish Detecting the + sign as attempting to concatenate strings in the B4A compiler

[Randy Younger]

I'm not sure how big of a deal this is to the community at large, but when I am translating code from a language like Swift that allows the + sign to be used to concatenate strings, the B4A compiler allows it, but then it blows up in runtime since the & character should be used. I tend to use a lot of string concatenation and so this is a big time waster for me that could be easily caught by the compiler (I think). Not a gotta have, but it would be nice...

 

[DonManfred]

B4X uses & to concatenate. + is for maths only.

 

[JordiCP]

It is not detected at compile time, because there are some cases, when the strings contain numeric expressions, annd they are casted as such.

    Dim d As Int = "123" + "321"           ' Here the strings are casted to numbers, added, and assigned to d
    Log(d)    '<--- 444
    Dim d2 As String= "123" + "321"     ' Here the strings are casted as numbers, added, and then again casted as a string to d2
    Log(d2)    '<--- 444
    Dim d3 As Int = "A23" + "321"        ' Runtime booom!

Perhaps a warning would make sense.

 

[Randy Younger]

Thank you for your replies. In Swift, "123" + "321" = "123321". I think most languages don't assume a + between literals means to cast those literals as integers. I get the convenience of this, and use it all of the time. Nevertheless, I am speaking of the specific case where I am translating large sections of code from Swift to B4A, and get hammered by the + sign as a concatenator a lot.

 

[Erel]

B4X goes a long way to convert types automatically:

Dim i As Int = EditText1.Text
i = Map.Get("a") + List.Get(12)

As mentioned above, there are many cases where the compiler will not be able to know whether you want to concatenate or to add.