refs #22 try without catch but finally

docs/exceptions_handling.md

@@ -106,6 +106,22 @@ This way, in turn, can also be shortened, as it is overly popular:
 The trick, though, works with strings only, and always provide `Exception` instances, which is good for debugging but
 most often not enough.
 
+## finally block
+
+If `finally` block present, it will be executed after body (until first exception)
+and catch block, if any will match. finally statement is executed even if the
+exception will be thrown and not caught locally. It does not alter try/catch block result:
+
+    try {
+    }
+    finally {
+        println("called finally")
+    }
+    >>> called finally
+    >>> void
+
+- and yes, there could be try-finally block, no catching, but perform some guaranteed cleanup.
+
 # Custom error classes
 
 _this functionality is not yet released_

library/build.gradle.kts

@@ -5,7 +5,7 @@ import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
 import org.jetbrains.kotlin.gradle.dsl.JvmTarget
 
 group = "net.sergeych"
-version = "0.5.1-SNAPSHOT"
+version = "0.5.2-SNAPSHOT"
 
 buildscript {
     repositories {

library/src/commonMain/kotlin/net/sergeych/lyng/Compiler.kt

@@ -790,8 +790,6 @@ class Compiler(
                 t = cc.next()
             }
         }
-        if( catches.isEmpty() )
-            throw ScriptError(cc.currentPos(), "try block must have at least one catch clause")
         val finallyClause = if( t.value == "finally" ) {
             parseBlock(cc)
         } else {
@@ -799,6 +797,9 @@ class Compiler(
             null
         }
 
+        if( catches.isEmpty() && finallyClause == null )
+            throw ScriptError(cc.currentPos(), "try block must have either catch or finally clause or both")
+
         return statement {
             var result: Obj = ObjVoid
             try {