refactor: move condition to IfArtifact

Author: BFergerson

common/src/main/kotlin/spp/jetbrains/artifact/model/ControlStructureArtifact.kt

@@ -16,7 +16,13 @@
  */
 package spp.jetbrains.artifact.model
 
+/**
+ * A control structure artifact refers to things that control the flow of a program:
+ * - conditionals (i.e. if/elif/else)
+ * - for-loops, while-loops, do-while loops
+ * - try-catch-finally
+ * - switch statements
+ */
 interface ControlStructureArtifact {
-    val condition: ArtifactElement?
     val childArtifacts: List<ArtifactElement>
 }

common/src/main/kotlin/spp/jetbrains/artifact/model/IfArtifact.kt

@@ -18,9 +18,12 @@ package spp.jetbrains.artifact.model
 
 import com.intellij.psi.PsiElement
 
+/**
+ * Represents if/elif/else control structures.
+ */
 abstract class IfArtifact(psiElement: PsiElement) : ArtifactElement(psiElement), ControlStructureArtifact {
 
-    abstract override val condition: ArtifactElement?
+    abstract val condition: ArtifactElement?
     abstract val thenBranch: ArtifactElement?
     abstract val elseBranch: ArtifactElement?