Implement visitor: NamedExpr

[namannimmo10]

Reference code:

def test_namedexpr():
    a: i32
    x: i32
    y: i32

    # check 1
    x = (y := 0)

    # check 2
    if a := ord('3'):
        x = 1

    # check 3
    while a := 1:
        y = 1

ASR:

(TranslationUnit
   (SymbolTable
      1
      {
         test_namedexpr:
            (Subroutine
               (SymbolTable
                  2
                  {
                     a:
                        (Variable
                           2
                           a
                           Local () ()
                           Default
                           (Integer 4 [])
                           Source
                           Public
                           Required .false.),
                     x:
                        (Variable
                           2
                           x
                           Local () ()
                           Default
                           (Integer 4 [])
                           Source
                           Public
                           Required .false.),
                     y:
                        (Variable
                           2
                           y
                           Local () ()
                           Default
                           (Integer 4 [])
                           Source
                           Public
                           Required .false.)
                  })
               test_namedexpr [] [
               (=
                  (Var 2 x)
                  (NamedExpr
                     (Var 2 y) (ConstantInteger 0
                     (Integer 4 []))
                     (Integer 4 [])) ())
               (If
                  (NamedExpr
                     (Var 2 a) (ConstantInteger 51
                     (Integer 4 []))
                     (Integer 4 [])) [
                  (=
                     (Var 2 x) (ConstantInteger 1
                     (Integer 4 [])) ())] [])
               (WhileLoop
                  (NamedExpr
                     (Var 2 a) (ConstantInteger 1
                     (Integer 4 []))
                     (Integer 4 [])) [
                  (=
                     (Var 2 y) (ConstantInteger 1
                     (Integer 4 [])) ())])]
               Source
               Public
               Implementation () .false. .false.)
      })
   [])

[certik]

I guess just rerunning the tests does not fix them (apparently the CI tests are not running on a merge commit?). But rebasing on top of the latest main should fix this, so I did that.

[certik]

Ok, so the CI failure is real, the C++ backend does not support this yet. I think we have to separate the C++ backend tests from new improvements in ASR.

[namannimmo10]

Ok, so the CI failure is real, the C++ backend does not support this yet. I think we have to separate the C++ backend tests from new improvements in ASR.

I'm working on it.

[certik]

I pushed in the fix, now it should work.

[namannimmo10]

Awesome, thanks!

[certik]

I think it works now. After the CI passes, you can merge it.