Undeclared Variable Detect?

[Scantech]

Undeclared variable gets compiled successfully? I was not aware of it. Can we turn this feature off? Option Explicit perhaps?

I do not want to make a mistake like this.

Dim TypeRequest as int
RequestType = 1

It will compile ok. Funny thing is I just noticed it today. I need to double check my spelling.

 

[Erel]

This is planned for the next version.

 

[vndnguyen]

I have also the problem with variable.

According to B4A, the global variables (declared in Process_Globals) can be accessed from all modules. But in fact I cannot access them from other Activity.

Any help?

 

[Erel]

Please start a new thread for this question.

 

[DemoFreak]

This is planned for the next version.

In V1.8 this code still compiles successfully.

Dim L As Label
Dim GetIP As InputDialog

L = Sender
s = GetType(L.Tag)
If s = "android.widget.TextView" Then L = L.Tag

i = L.Tag

s and i are undeclared.

 

[klaus]

But you should see s and i in red showing that these variables are not declared.

Best regards.

 

[DemoFreak]

But you should see s and i in red showing that these variables are not declared.

Yes, of course.

I'm asking just out of curiosity. I hadn't expected this behaviour at all, and stumbled over it when I tried your ScrollView example this morning (and wondered why it is operating well despite some red colored variables).

 

[DemoFreak]

But you should see s and i in red showing that these variables are not declared.

And just I've noticed, that FOR does an implicit DIM, or the syntax coloring has a tiny glitch:

Sub Activity_Create(FirstTime As Boolean)
Dim top As Int
For i = 0 To 15
   Dim ID, IP As Label
   ID.Initialize("Device")
   IP.Initialize("Device")
   ID.tag = IP
   IP.tag = i
   ID.TextSize = 29
   IP.TextSize = 29
   top = i * 30dip
'...
Next

Here the i isn't colored in red. But, when I comment out the FOR line, the i gets colored instantly.

 

[Erel]

'For' keyword implicitly declares the variable if needed. Basic4android allows you to use undeclared variables which are treated as string variables.
The red color should help you avoid unintentional use of such variables.

 

[DemoFreak]

Basic4android allows you to use undeclared variables which are treated as string variables.

Thanks for that hint.

I was bitten by that just now, as I read back a map with File.Readmap.

The map consists of a byte-type key and some user-defined type value.

Dim mapIPAdresses As Map
mapIPAdresses.Initialize

' populate map with already known IP addresses from global DSPs map
For i = 0 To Main.DSPs.Size - 1
   Dim x As typeDSP
' [some other code]
' Gettype(Main.DSPs.GetKeyAt(i)) results in "java.lang.byte"
   mapIPAdresses.Put(Main.DSPs.GetKeyAt(i), x.IP)
Next

' write IP configuration to file
File.WriteMap(File.DirInternal, "devices.map", mapIPAdresses)

When I read back that map, I stumbled over my assumption, that the key type of the read map is byte, as it was written as byte.

Dim DeviceMap As Map
DeviceMap = File.ReadMap(File.DirInternal, "devices.map")
For i = 0 To DeviceMap.Size - 1
   Dim DSPData As typeDSP
   DSPData.IP = DeviceMap.GetValueAt(i)

   Log(GetType(DeviceMap.GetKeyAt(i)))
   ' results in "java.lang.String"

   Dim tempByte As Byte
   tempByte = DeviceMap.GetKeyAt(i)
   Log(GetType(tempByte))
   ' results in "java.lang.Byte"

   DSPs.Put(tempByte, DSPData)

   ' the following line leads to some confusion as the keys that
   ' was read in was of type "String" and other (further added) keys
   ' was of type "Byte" as desired, so some key comparison failed
   ' and I've got a map with two keys "0" and "0", one of type "Byte"
   ' and the other one of type "String"
   ' DSPs.Put(DeviceMap.GetKeyAt(i), DSPData)
Next

Now, as I explicitely cast the key to byte, all works as expected.