Add diagnostics chaining

libraries/scripting/common/src/kotlin/script/experimental/api/errorHandling.kt

@@ -31,11 +31,27 @@ sealed class ResultWithDiagnostics<out R> {
     }
 }
 
+// call chaining
+
+suspend fun <R1, R2> ResultWithDiagnostics<R1>.onSuccess(body: suspend (R1) -> ResultWithDiagnostics<R2>): ResultWithDiagnostics<R2> = when (this) {
+    is ResultWithDiagnostics.Success -> this.reports + body(this.value)
+    is ResultWithDiagnostics.Failure -> this
+}
+
+suspend fun <R> ResultWithDiagnostics<R>.onFailure(body: suspend (ResultWithDiagnostics<R>) -> Unit): ResultWithDiagnostics<R> {
+    if (this is ResultWithDiagnostics.Failure) {
+        body(this)
+    }
+    return this
+}
+
 operator fun <R> List<ScriptDiagnostic>.plus(res: ResultWithDiagnostics<R>): ResultWithDiagnostics<R> = when (res) {
     is ResultWithDiagnostics.Success -> ResultWithDiagnostics.Success(res.value, this + res.reports)
     is ResultWithDiagnostics.Failure -> ResultWithDiagnostics.Failure(this + res.reports)
 }
 
+// results creation
+
 fun <R : Any> R.asSuccess(reports: List<ScriptDiagnostic> = listOf()): ResultWithDiagnostics.Success<R> =
     ResultWithDiagnostics.Success(this, reports)