Prepare scripting infrastructure for REPL:

- refactor script compiler to simplify extending it for repl
- add repl snippet compilation functions to the new scripting compiler
- extract util functions into appropriate files
- extract repl part into separate class
- extract bridge definition and related definitions into separate file

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

@@ -161,3 +161,11 @@ fun <R> ResultWithDiagnostics<R>.resultOrNull(): R? = when (this) {
     is ResultWithDiagnostics.Success<R> -> value
     else -> null
 }
+
+/**
+ * Extracts the result value from the receiver wrapper or run non-returning lambda if receiver represents a Failure
+ */
+inline fun <R> ResultWithDiagnostics<R>.resultOr(body: (ResultWithDiagnostics.Failure) -> Nothing): R = when (this) {
+    is ResultWithDiagnostics.Success<R> -> value
+    else -> body(this as ResultWithDiagnostics.Failure)
+}

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

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.script.experimental.api
+
+import java.io.Serializable
+
+const val REPL_SNIPPET_FIRST_NO = 1
+const val REPL_Snippet_FIRST_GEN = 1
+
+interface ReplSnippetId : Serializable, Comparable<ReplSnippetId> {
+    val no: Int
+    val generation: Int
+}
+
+data class ReplSnippetIdImpl(override val no: Int, override val generation: Int, private val codeHash: Int) : ReplSnippetId, Serializable {
+
+    constructor(no: Int, generation: Int, code: SourceCode) : this(no, generation, code.text.hashCode())
+
+    override fun compareTo(other: ReplSnippetId): Int = (other as? ReplSnippetIdImpl)?.let { otherId ->
+        no.compareTo(otherId.no).takeIf { it != 0 }
+            ?: generation.compareTo(otherId.generation).takeIf { it != 0 }
+            ?: codeHash.compareTo(otherId.codeHash)
+    } ?: -1
+
+    companion object {
+        private val serialVersionUID: Long = 1L
+    }
+}