New feature - inline casting

[aeric]

It is such a special thing that it would be even better to use square brackets (although typing these is more cumbersome).

[Buttons.Get(2) As B4XView].Text = "less boring"

I prefer

Buttons.Get(2).AsB4XView.Text = "More B4Xic"

 

[LucaMs]

I prefer

Buttons.Get(2).AsB4XView.Text = "More B4Xic"

That way you can't do it, mostly (but not only) because it wouldn't work with custom classes.

 

[Daestrum]

I have used similar code for a while (adapted to use Erels example)

    asB4XView(Buttons.Get(0)).Text = "hello"

...
Sub asB4XView(o As Object) As B4XView
    Return o
End Sub

 

[Heuristx]

(MyClass)lst.Get(i)

is C-like syntax. The charm and strength of B4X is that it shields us from weird c-like expressions.

 

[agraham]

(MyClass)lst.Get(i)

<pedant>it would be
(MyClass)(lst.Get(i)) in C,C# or Java
You want to cast the result of the Get and not the type of lst</pedant>

 

[alwaysbusy]

cast the result of the Get

You are correct! My example was wrong as I did indeed wanted to mimic the Java syntax

 

[Heuristx]

It doesn't matter. What's wrong with (something) is:
parentheses are there to GROUP, that is, bunch things together, like (x + 3). x + (3) does not make sense. When you cast a value to a type, you are connecting the type with the value. So logically both should be inside the parentheses. When you isolate one element like (string), you visually isolate the type from the rest of the expression. This is linguistically unmotivated and illogical. To me, just plain annoying.

 

[agraham]

and illogical

Very far from illogical. Language parsing is, by necessity extremely, nay ultimately, logical. Grouping is an often required order of execution indicator to the compiler.

 

[Heuristx]

That is your opinion, which you are entitled to. I like Erel's way much better and find it more logical.

 

[Erel]

Another example:

Dim j As String = $"{
    data: {
            key1: value1, 
            complex_key2: {key: value2}
    }, 
    items: [0, 1, 2]
}"$
Dim parser As JSONParser
parser.Initialize(j)
Dim m As Map = parser.NextObject
Dim value1 As String = m.Get As Map("data").Get("key1")
Dim value2 As String = m.Get As Map("data").Get As Map("complex_key2").Get("key")
Dim FirstItemInList As String = m.Get As List("items").Get(0)

For Each item As Int In m.Get As List("items")
    Log(item)
Next

 

[Erel]

BTW, this syntax is already used in the B4X language. Exactly here:

Sum(Array As Int(1, 2, 3, 4))
 
Sub Sum(values() As Int)
 ...

 

[alwaysbusy]

of course not needed because of the automatic casting, but this would compile too (As String at the end)?

Dim value2 As String = m.Get As Map("data").Get As Map("complex_key2").Get("key") As String

 

[Erel]

Almost. It should be:

Dim value2 As String = m.Get As Map("data").Get As Map("complex_key2").Get As String("key")

 

[agraham]

Sorry but I can't get my head around that syntax After half a century of coding separating the indexing from the object being indexed flummoxes my tiny mind.

 

[alwaysbusy]

Almost. It should be:

Right! One is going to get used to it, but I can see the power in it.

 

[Sandman]

Another example:

Dim j As String = $"{
    data: {
            key1: value1,
            complex_key2: {key: value2}
    },
    items: [0, 1, 2]
}"$
Dim parser As JSONParser
parser.Initialize(j)
Dim m As Map = parser.NextObject
Dim value1 As String = m.Get As Map("data").Get("key1")
Dim value2 As String = m.Get As Map("data").Get As Map("complex_key2").Get("key")
Dim FirstItemInList As String = m.Get As List("items").Get(0)

For Each item As Int In m.Get As List("items")
    Log(item)
Next

I 've stared at the code for ten minutes and I just can't parse it.

Can somebody please help me and convert it to the form that Jordi used (that we know isn't correct, but very simple to understand)? He did it like this:

buttons.Get(2).CastTo(B4XView).Text = "less boring"

 

[Erel]

Read it out loud: Get As Map = get something and treat it as a map

Dim value1 As String = m.<Get As Map>("data").Get("key1")

 

[Sandman]

If you turned this...

Dim value1 As String = m.Get As Map("data").Get("key1")

...to this, I would find it easier to understand

Dim value1 As String = (m.Get("data") As Map).Get("key1")

...or something like this

Dim value1 As String = ((Map) m.Get("data")).Get("key1")

...or something like this

Dim value1 As String = m.Get("data").CastTo(Map).Get("key1")

 

[alwaysbusy]

And this:

dim btn5 as B4XView = Buttons.Get(5)
dim btn2 as B4XView = Buttons.Get(2)
btn5.Text = btn2.Text
Buttons.Set(5,btn5) 'not really needed as btn5 already points to the instance in the list, but for arguments sake.

Would become this (first = Set):

Buttons.Set As B4XView(5).Text = Buttons.Get As B4XView(2).Text

Or this (first = Get)?

Buttons.Get As B4XView(5).Text = Buttons.Get As B4XView(2).Text

 

[AnandGupta]

Hmm.. Erel's implementation is simple and complex.

Once you get it, it becomes simple and will flow from your fingers. Till then it is complex to even read it.
The older members like me can use the older existing code flow, no problem there.

Let the new members see and behold the power of B4X !