Skip to content

New feature: For-comprehensions for Eithers and Validations #3063

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 3 commits into
base: main
Choose a base branch
from
Open

New feature: For-comprehensions for Eithers and Validations #3063

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
6337759
New feature: For-comprehensions for Eithers and Validations
adamkopec Aug 6, 2025
9fcac58
Merge branch 'main' into feature/For-comprehensions
adamkopec Aug 6, 2025
1b92e8e
Merge branch 'main' into feature/For-comprehensions
adamkopec Aug 7, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
43 changes: 29 additions & 14 deletions vavr/generator/Generator.scala
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -98,7 +98,8 @@ def generateMainClasses(): Unit = {
val PredicateType = im.getType("java.util.function.Predicate")
val SupplierType = im.getType("java.util.function.Supplier")

val monadicTypesFor = List("Iterable", OptionType, FutureType, TryType, ListType)
val monadicTypesFor = List("Iterable", OptionType, FutureType, TryType, ListType, EitherType, ValidationType)
val monadicTypesThatNeedParameter = List(EitherType, ValidationType)

def genTraversableAliases(traversableType: String, returnType: String, name: String) = xs"""
// -- $name
Expand Down Expand Up @@ -772,12 +773,15 @@ def generateMainClasses(): Unit = {

${monadicTypesFor.gen(mtype => (1 to N).gen(i => {
val forClassName = if (mtype == "Iterable") { s"For$i" } else { s"For$i$mtype" }
val generics = (1 to i).gen(j => s"T$j")(", ")
val params = (1 to i).gen(j => s"$mtype<T$j> ts$j")(", ")
val isComplex = monadicTypesThatNeedParameter.contains(mtype)
val parameterInset = (if (isComplex) {"L, "} else "")
val generics = parameterInset + (1 to i).gen(j => s"T$j")(", ")
val params = (1 to i).gen(j => s"$mtype<${parameterInset}T$j> ts$j")(", ")
xs"""
/$javadoc
* Creates a {@code For}-comprehension of ${i.numerus(mtype)}.
${(0 to i).gen(j => if (j == 0) "*" else s"* @param ts$j the ${j.ordinal} $mtype")("\n")}
${if (isComplex) s"* @param <L> left-hand type of all ${mtype}s\n" else ""}
${(1 to i).gen(j => s"* @param <T$j> component type of the ${j.ordinal} $mtype")("\n")}
* @return a new {@code For}-comprehension of arity $i
*/
Expand All @@ -792,7 +796,8 @@ def generateMainClasses(): Unit = {
val rtype = if (mtype == "Iterable") { IteratorType } else { mtype }
val cons: String => String = if (mtype == "Iterable") { m => s"$IteratorType.ofAll($m)" } else { m => m }
val forClassName = if (mtype == "Iterable") { s"For$i" } else { s"For$i$mtype" }
val generics = (1 to i).gen(j => s"T$j")(", ")
val parameterInset = (if (monadicTypesThatNeedParameter.contains(mtype)) { "L, " } else "")
val generics = parameterInset + (1 to i).gen(j => s"T$j")(", ")
val functionType = i match {
case 1 => FunctionType
case 2 => BiFunctionType
Expand All @@ -805,20 +810,20 @@ def generateMainClasses(): Unit = {
*/
public static class $forClassName<$generics> {

${(1 to i).gen(j => xs"""private final $mtype<T$j> ts$j;""")("\n")}
${(1 to i).gen(j => xs"""private final $mtype<${parameterInset}T$j> ts$j;""")("\n")}

private $forClassName(${(1 to i).gen(j => s"$mtype<T$j> ts$j")(", ")}) {
private $forClassName(${(1 to i).gen(j => s"$mtype<${parameterInset}T$j> ts$j")(", ")}) {
${(1 to i).gen(j => xs"""this.ts$j = ts$j;""")("\n")}
}

/$javadoc
* Yields a result for elements of the cross product of the underlying ${i.plural(mtype)}.
* Yields a result for elements of the cross-product of the underlying ${i.plural(mtype)}.
*
* @param f a function that maps an element of the cross product to a result
* @param f a function that maps an element of the cross-product to a result
* @param <R> type of the resulting {@code $rtype} elements
* @return an {@code $rtype} of mapped results
*/
public <R> $rtype<R> yield($functionType<$args, ? extends R> f) {
public <R> $rtype<${parameterInset}R> yield($functionType<$args, ? extends R> f) {
$Objects.requireNonNull(f, "f is null");
${if (i == 1) xs"""
return ${cons("ts1")}.map(f);
Expand All @@ -835,7 +840,7 @@ def generateMainClasses(): Unit = {
*
* @return an {@code Iterator} of mapped results
*/
public $rtype<T1> yield() {
public $rtype<${parameterInset}T1> yield() {
return this.yield(Function.identity());
}
""")}
Expand Down Expand Up @@ -2657,13 +2662,20 @@ def generateTestClasses(): Unit = {
val SeqType = im.getType("io.vavr.collection.Seq")
val MapType = im.getType("io.vavr.collection.Map")
val OptionType = im.getType("io.vavr.control.Option")
val EitherType = im.getType("io.vavr.control.Either")
val ValidationType = im.getType("io.vavr.control.Validation")
val FutureType = im.getType("io.vavr.concurrent.Future")
val ExecutorsType = im.getType("java.util.concurrent.Executors")
val ExecutorService = s"$ExecutorsType.newSingleThreadExecutor()"
val TryType = im.getType("io.vavr.control.Try")
val JavaComparatorType = im.getType("java.util.Comparator")

val monadicTypesFor = List(OptionType)
val monadicTypesFor = List(OptionType, EitherType, ValidationType)
val monadicTypeMetadataFor = Map(
(OptionType -> ("", "of")),
(EitherType -> ("Object, ", "right")),
(ValidationType -> ("Object, ", "valid"))
)
val monadicFunctionTypesFor = List(FutureType, TryType)

val d = "$"
Expand Down Expand Up @@ -2952,11 +2964,14 @@ def generateTestClasses(): Unit = {
}
""")("\n\n")}

${monadicTypesFor.gen(mtype => (1 to N).gen(i => { xs"""
${monadicTypesFor.gen(mtype => (1 to N).gen(i =>
val (parameterInset, builderName) = monadicTypeMetadataFor(mtype);
{ xs"""

@$test
public void shouldIterateFor$mtype$i() {
final $mtype<Integer> result = For(
${(1 to i).gen(j => s"$mtype.of($j)")(",\n")}
final $mtype<${parameterInset}Integer> result = For(
${(1 to i).gen(j => s"$mtype.${builderName}($j)")(",\n")}
).yield(${(i > 1).gen("(")}${(1 to i).gen(j => s"i$j")(", ")}${(i > 1).gen(")")} -> ${(1 to i).gen(j => s"i$j")(" + ")});
$assertThat(result.get()).isEqualTo(${(1 to i).sum});
}
Expand Down
Loading
Loading