O2 quirks

Code: [Select]

#unique on
enum
   x = 1
   y
end enum

If you use enum without an identifier, and the #unique on directive, the reported error message is that "sys" is already defined.

Without #unique on, it says that "x" is not defined.

Also, why enum requires an identifier if later isn't used for anything?

I can't do

Code: [Select]

enum x
   a = 10
   b
   c
end enum

enum x2
   a = 1
   b
   c
end enum

print x.a

They should work like namespaces if an identifier, e.g. "explicit", is specified, e.g.

Code: [Select]

enum x explicit
   a = 10
   b
   c
end enum

enum x2 explicit
   a = 1
   b
   c
end enum

print x.a
print x2.a

Currently, they're working as if I was using an anonymous enum.

Code: [Select]

namespace aa
   type t
      int x
      int y
   end type
end namespace

aa::t.x = 11
print aa::t.x

"print aa::t.x" throws and "unexpected end of program" error.

I know that i must use

Code: [Select]

namespace aa
   type t
      int x
      int y
   end type
end namespace

dim tt as aa::t
tt.x = 11
print tt.x

but why aa::t.x = 11 compiles?

Looks like O2 needs much improvement regarding error checking.

In other languages, the using directive allows all the names in a namespace to be used without the namespace-name as an explicit qualifier. In O2 seems to be yet another alias for "use" and "uses".

Other languages also allow an alias for the identifier of a namespace to avoid conflicts with other libraries using the same namespace identifier, e.g.

namespace foo alias "MyFoo"

[José Roca]

Nested namespaces.

Code: [Select]

namespace aa
   int i = 10
   int x = 22
   print bb::i   ' prints 10 instead of 11, or give an error
   namespace bb
      int i = 11
      int x = 33
   end namespace
end namespace


Does :: have more uses besides working with namespaces?

In C++ can be used to access variables outside a namespace from inside a namespace, e.g.

Code: [Select]

int i = 12345

namespace aa
   int i = 10
   int x = 22
   namespace bb
      int i = 11
      int x = 33
   end namespace
   print ::i   ' access the global i variable
end namespace

In O2 it compiles, but does not work.

How can we access the global variable i from inside a namespace?

[Charles Pegge]

Attempts to assign to  a type will now be trapped!

Code: [Select]

   type t
      int x
      int y
   end type
   t.x=9 'trapped


[José Roca]

Funny, this works!

Code: [Select]

int i = 12345

namespace aa
   int i = 10
   int x = 22
   namespace bb
      int i = 11
      int x = 33
   end namespace
   print std::i   ' access the global i variable
end namespace

Looks like I have to learn C++ to understand O2

So the global namespace is called "std"...

[Charles Pegge]

I could make namespaces nestable.

If you used nested scopes instead, would this be a viable alternative?

Anything that you consider that can be useful. I'm just trying to learn the language.

I looked at namespaces and found a line of code that uses the "::" operator.

Then I tried to use ::i to access the global i variable, but did not work.

Then I looked at the C++ documentation for "::" and I saw that they also used std::, so I tried std::i and it works.

Above all, error trapping is fundamental to me.

[Charles Pegge]

This works by accident

Code: [Select]

namespace aa
   int i = 10
   int x = 22
   print std::i   ' access the global i variable
end namespace

It could be global::i

No problem: I will use "global".

Discovered by mistake:

Code: [Select]

print print "ok"

First prints "ok" and then a number.

This also compiles:

Code: [Select]

print print print print "ok"


[Charles Pegge]

This is legit, strange as it may seem.

Code: [Select]

print print print print "ok"

The compiler sees it like this:

Code: [Select]

print print( print ( print( "ok") ) )


[José Roca]

But this does not work.

Code: [Select]

int i = 12345

namespace aa
   int i = 10
   int x = 22
   print global::i
end namespace

It prints 10 instead of 12345.

[José Roca]

This is legit, strange as it may seem.

Code: [Select]

print print print print "ok"

The compiler sees it like this:

Code: [Select]

print print( print ( print( "ok") ) )


Do you mean that print is a function instead of an statement?

[Charles Pegge]

Yes, print is an overrideable core procedure, not a statement.