Grammar

ELENA uses LL(1) grammar. It is an analytical grammar, meaning that the role of the terminal token is defined by its position in the statement. As a result the grammar lacks the keywords ( instead user-defined attributes are used ) and there are no reserved words. For example, it is possible to write the code without attributes at all:

class
{
   field;

   method(param)
   {
   }
} 

where a class with a name class is declared. It has one field with a name field and one method - method[1]

But in most cases it is required to provide additional info. So the token role is defined by its position.

class class;

singleton Tester
{
    do(var class class)
    {        
    }
}

public program()
{
    var class class := new class();
        
    Tester.do(class);
}

where class is used as an attribute to declare a new class, as a identifier type and as an identifier.

Lexical grammar

input ::=
   { input-element* new-line }*

input-element ::=
    whitespace | comment | token

Line terminators

new-line ::=
   Carriage return character (U+000D) followed by line feed character (U+000A) 
   | Line feed character (U+000A)

White space

whitespace ::=
   whitespace-character+  

whitespace-character ::=
   Horizontal tab character (U+0009)
   | Space (U+0020)

Comments

comment ::=
   single-line-comment
   | delimited-comment

single-line-comment ::=
   "//" input-character*

input-character ::=
   Any Unicode character except a new-line-character

new-line-character ::=
   Carriage return character (U+000D)
   | Line feed character (U+000A)       

delimited-comment ::=
   "/*" delimited-comment-section* "*"+ "/"

delimited-comment-section ::=
   not-asterisk
   | "*"+ not-slash

not-asterisk ::=
   Any Unicode character except *

not-slash ::=
   Any Unicode character except /