v0.5 to v0.6 upgrade

v0.6.* (latest v0.6.0)

New features

• ORDER BY implementation in the evaluator

Deprecated items

• ExprNode deprecated in rest of code base including evaluator

Misc/bug fixes

• Upgrade Kotlin version to 1.4.322
• [fix] changed path ast node to sue its root node source location

Breaking changes

Breaking behavioral changes

Breaking API changes

1. Replace Environment with EvaluationSession for ExprFunctions

// ----- v0.5.* -----
class SomeExprFunction(): ExprFunction {
    override val signature = FunctionSignature(
        name = "some_expr_function",
        requiredParameters = listOf(StaticType.ANY),
        optionalParameter = StaticType.ANY,
        returnType = StaticType.ANY
    )

    // In v0.5.0, the `callWith*` functions' first argument was `Environment`
    override fun callWithRequired(env: Environment, required: List<ExprValue>): ExprValue {
        TODO("Implementation details without optional argument")
    }

    override fun callWithOptional(env: Environment, required: List<ExprValue>, opt: ExprValue): ExprValue {
        TODO("Implementation details with optional argument")
    }
}

// ----- v0.6.* -----
class SomeExprFunction(): ExprFunction {
    override val signature = FunctionSignature(
        name = "some_expr_function",
        requiredParameters = listOf(StaticType.ANY),
        optionalParameter = StaticType.ANY,
        returnType = StaticType.ANY
    )

    // Starting in v0.6.0, the `callWith*` functions' first argument is changed to `EvaluationSession`.
    // `Environment` has also been made private
    override fun callWithRequired(session: EvaluationSession, required: List<ExprValue>): ExprValue {
        TODO("Implementation details without optional argument")
    }

    override fun callWithOptional(session: EvaluationSession, required: List<ExprValue>, opt: ExprValue): ExprValue {
        TODO("Implementation details with optional argument")
    }
}

• v0.5.* example code
• v0.6.* example code

2. NaturalExprValueComparators fields have been renamed

• NULLS_FIRST → NULLS_FIRST_ASC
• NULLS_LAST → NULLS_FIRST_DESC

3. Migrate to PIG v0.5.0. This doesn't have any direct breaking changes. With PIG v0.5.0, the generated sources will now be in lang/domains/PartiqlAst.generated.kt rather than lang/domains/partiql-domains.kt.
4. Make a few APIs internal:

• Environment
• ExprAggregator
• ExprAggregatorFactory
• lang/eval’s Group class
• RegisterBank
• ThunkEnv
• ThunkExceptionHandlerForLegacyMode and ThunkExceptionHandlerForPermissiveMode
• DEFAULT_EXCEPTION_HANDLER_FOR_LEGACY_MODE and DEFAULT_EXCEPTION_HANDLER_FOR_PERMISSIVE_MODE