Extended statement templates

[arakov]

Is your feature request related to a problem? Please describe.
Expression patterns should be introduced

[arakov]

Several basic expression patterns can be introduced, allowing to make the operation pattern more readable:

if:is pattern :

import extensions;

class Proxy
{
   field _o;

   constructor(o)
   {
      _o := o
   }

   int cast()
      => _o;
}

guessWho(o)
{
   if (o :is int val)
   {
      console.printLine(o," can be converted to int=", val);
   };
}

public program()
{
   guessWho(2);
   guessWho(new Proxy(2));
}

foreach:in pattern:

foreach(char ch :in "abc")
{
    console.printLine(ch)
}

[arakov]

The issue is implemented in ELENA 6.0.7