Justkawal/complete new approach

[justkawal]

#Resolves Issue:

• Change polkadart-scale-codec approach to encode/decode #185

Description

• A complete new configurable re-design
• Easy to add functionality.
• Well documented

Why?

• More clean approach
• Less boilerplate code
• Short, clear and concised
• Less dependency on other libraries

How?

• By isolating the decode and encode functionality inside the basic type classes.
• Lesser intermediate cyclic conversion of types: forth and back.

Testing Plan

• Unit Test cases.
• Large Unit Testing
• Command: dart test

[Lohann]

The value is already of type int here

      output.pushByte(value << 2);
    } else if (value < 16384) {
      output
        ..pushByte((value & 0x3F) << 2 | 1)
        ..pushByte((value >> 6).toUnsigned(8));
    } else if (value < 1073741824) {
      output
        ..pushByte((value & 0x3F) << 2 | 2)
        ..pushByte((value >> 6).toUnsigned(8))
        ..pushByte((value >> 14).toUnsigned(8))
        ..pushByte((value >> 22).toUnsigned(8));

[Lohann]

Suggested change

	output.pushByte(value.toUnsigned(8).toInt());
	output.pushByte(value.toUnsigned(8));

[Lohann]

This should be an Map, because even simple enums can have sparse indexes, ex:

enum SomeEnum {
  #[index(0)]
  Value1,
  #[index(10)]
  Value2,
  #[index(30)]
  Value3,
}

[Lohann]

Same case here, where do you store the enum index?

[Lohann]

Unnecessary line break.

Suggested change

	output.pushByte(index);
	final codec = map[value.key];
	codec?.encodeTo(value.value, output);
	output.pushByte(index);
	final codec = map[value.key];
	codec?.encodeTo(value.value, output);

[Lohann]

We also need tests for OutOfBounds errors

[Lohann]

We also need tests for OutOfBounds errors

[Lohann]

We also need tests for OutOfBounds errors

[Lohann]

Nice

[Lohann]

We need tests for sparse indexes, I think in this case we can do this:

SimpleEnumCodec.sparse({
  'a': 0,
  'b': 10,
  'c': 20,
});

[Lohann]

Or the inverse (so we guarantee the index is unique):

SimpleEnumCodec.sparse({
  0: 'a',
  10: 'b',
  20: 'c',
});

[Lohann]

Suggested change

	class Option extends Equatable {
	final dynamic value;
	final bool _isSome; // Workaround for Option<int?>.some(null)
	class Option<T> extends Equatable {
	final T value;
	final bool _isSome; // Workaround for Option<int?>.some(null)