2 files changed, 18 insertions, 0 deletions
diff --git a/core/src/main/kotlin/model/CompositeSourceSetID.kt b/core/src/main/kotlin/model/CompositeSourceSetID.kt
index 5eb106bf..3c1cf7de 100644
--- a/core/src/main/kotlin/model/CompositeSourceSetID.kt
+++ b/core/src/main/kotlin/model/CompositeSourceSetID.kt
@@ -27,4 +27,12 @@ data class CompositeSourceSetID(
     operator fun contains(sourceSet: DokkaConfiguration.DokkaSourceSet): Boolean {
         return sourceSet.sourceSetID in this
     }
+
+    operator fun plus(other: DokkaSourceSetID): CompositeSourceSetID {
+        return copy(children = children + other)
+    }
+}
+
+operator fun DokkaSourceSetID.plus(other: DokkaSourceSetID): CompositeSourceSetID {
+    return CompositeSourceSetID(listOf(this, other))
 }
diff --git a/core/src/test/kotlin/model/CompositeSourceSetIDTest.kt b/core/src/test/kotlin/model/CompositeSourceSetIDTest.kt
index ab9a2ab1..472581e7 100644
--- a/core/src/test/kotlin/model/CompositeSourceSetIDTest.kt
+++ b/core/src/test/kotlin/model/CompositeSourceSetIDTest.kt
@@ -2,6 +2,7 @@ package model
 
 import org.jetbrains.dokka.DokkaSourceSetID
 import org.jetbrains.dokka.model.CompositeSourceSetID
+import org.jetbrains.dokka.model.plus
 import kotlin.test.*
 
 class CompositeSourceSetIDTest {
@@ -55,4 +56,13 @@ class CompositeSourceSetIDTest {
             "Expected merged source set id being contained in composite"
         )
     }
+
+    @Test
+    fun `plus operator`() {
+        val composite = DokkaSourceSetID("m1", "s1") + DokkaSourceSetID("m2", "s2") + DokkaSourceSetID("m3", "s3")
+        assertEquals(
+            DokkaSourceSetID("m1+m2+m3", "s1+s2+s3"), composite.merged,
+            "Expected all three source sets being merged in order"
+        )
+    }
 }