Design of Tuple type

[ramakotareddy]

Design proposal Tuple type #172

[ramakotareddy]

Similar to Record type and Array type, we can model the Tuple Type object in the Rust side in the runtime and use opaque pointer on the LLVM codegen. Similar to Array and Record, we have to implement Operations like store and load and pass the required information from Codegen side to Rust side.

Same as Array type, we have to implement init function for this Tuple Type. We need to pass Tuple type information as parameters like Tuple field order.
First we need to store Tuple field types order into vector and pass to Rust runtime. (correct me if i am wrong)
based on the vector fields(Tuple fields type order) we have to initialize the Tuple with fields.

We have to implement Load and Store API's like Array and we have to call these runtime rust functions from LLVM codegen side with required information.

Please give your suggestions.

[ramakotareddy]

@ayonam, Can you please add if i miss anything.

[KavinduZoysa]

@ramakotareddy, I think the tuple type is a bit different from the array type or map type. I like to point you to a couple of features of tuple type, which need to be considered when designing. Please consider the below example.

[int, string] a = [10, "John"];
int aint;    
string astr;
[aint, astr] = a;

1. When considering defining tuple variable([int, string] a = [10, "John"];) we need to think, how to model the type([int, string])
2. We need to design how the destructuring part happens ([aint, astr] = a).

For more examples please read https://ballerina.io/learn/by-example/tuple-type.html

[ramakotareddy]

@KavinduZoysa, Thanks.

[ramakotareddy]

simple tuple test case:

public function main() {
[int, string] a = [10, "John"];
int aint;
string astr;
[aint, astr] = a;
}

BIR:

public main function() -> () {
%0(RETURN) ();
%0(RETURN) ();
%1(LOCAL) (int, string);
%3(TEMP) int;
%4(TEMP) any;
%5(TEMP) int;
%6(TEMP) any;
%7(TEMP) string;
%8(LOCAL) int;
%9(LOCAL) string;
%10(LOCAL) any[];
%14(TEMP) int;
%15(TEMP) any;
%18(TEMP) int;
%19(TEMP) any;

bb0 {
    %3 = ConstLoad 2;
    %5 = ConstLoad 10;
    %4 = <any> %5;
    %7 = ConstLoad John;
    %6 = <any> %7;
    %1 = newArray (int, string)[%3];
    %10 = %1;
    %14 = ConstLoad 0;
    %15 = %10[%14];
    %8 = <int> %15;
    %18 = ConstLoad 1;
    %19 = %10[%18];
    %9 = <string> %19;
    %0 = ConstLoad 0;
    GOTO bb2;
}
bb1 {
    GOTO bb2;
}
bb2 {
    return;
}

}

-> Here, "%1 = newArray (int, string)[%3];" initializing as a array.