struct/module/class concept

[ppaulweber]

• add new grammar syntax for the struct/module/class concept
• provide unit test cases to the TC repository
• implement IR representation
• add proper run-time implementation and AST execution etc.

As already discussed 2 years ago, please add the struct/module/class concept to the CASM language. Inspired by the RUST language and the "traits" concept, we define the following syntax and semantics of our struct~~/module/class~~ concept and call the trait a feature:

structure ::= 'structure' identifier '=' '{' functionDefinitions '}'

feature ::= 'feature' identifier '=' '{' ( declaration | definition )+ '}'

declaration ::= kind identifier ':' typeRelation

implements ::= 'implements' [ identifier 'for' ] identifier '=' '{' definitions '}'

Furthermore, we also need a new keyword this to reference in implementations the correct overlapping structure attributes etc.

example struct/module/class definition Counter.casm:

CASM init foo 

// definition of the structure, traits and the implementation of it
structure Counter =
{
    function value : -> Integer
}

feature Incrementor =
{
    rule increment : -> Void
    derived next : -> Integer
}

implements Counter =
{
    derived value -> String = asString( this.value )
}

implements Incrementor for Counter =
{
    rule increment =
    {
        this.value := this.next()
    }
    derived next -> Integer = this.value + 1
}

function c : -> Counter

rule foo = 
{
    call c.increment()
    println( c.value() )
}

[ppaulweber]

• casm-lang/libcasm-fe@6997e6d
• casm-lang/libcasm-fe@fce06e4
• casm-lang/libcasm-fe@452957a