diff --git a/ownlang-parser/src/main/java/com/annimon/ownlang/parser/ast/IncludeStatement.java b/ownlang-parser/src/main/java/com/annimon/ownlang/parser/ast/IncludeStatement.java
index 3b2c5de..8963de6 100644
--- a/ownlang-parser/src/main/java/com/annimon/ownlang/parser/ast/IncludeStatement.java
+++ b/ownlang-parser/src/main/java/com/annimon/ownlang/parser/ast/IncludeStatement.java
@@ -1,12 +1,11 @@
 package com.annimon.ownlang.parser.ast;
 
-import com.annimon.ownlang.parser.Lexer;
-import com.annimon.ownlang.parser.Parser;
-import com.annimon.ownlang.parser.SourceLoader;
-import com.annimon.ownlang.parser.Token;
-import com.annimon.ownlang.parser.visitors.FunctionAdder;
-import java.io.IOException;
-import java.util.List;
+import com.annimon.ownlang.exceptions.OwnLangParserException;
+import com.annimon.ownlang.exceptions.OwnLangRuntimeException;
+import com.annimon.ownlang.parser.error.ParseErrorsFormatterStage;
+import com.annimon.ownlang.stages.*;
+import com.annimon.ownlang.util.input.InputSourceFile;
+import com.annimon.ownlang.util.input.SourceLoaderStage;
 
 /**
  *
@@ -23,21 +22,21 @@ public final class IncludeStatement extends InterruptableNode implements Stateme
     @Override
     public void execute() {
         super.interruptionCheck();
-        try {
-            final Statement program = loadProgram(expression.eval().asString());
-            if (program != null) {
-                program.accept(new FunctionAdder());
-                program.execute();
-            }
-        } catch (Exception ex) {
-            throw new RuntimeException(ex);
-        }
-    }
 
-    public Statement loadProgram(String path) throws IOException {
-        final String input = SourceLoader.readSource(path);
-        final List<Token> tokens = Lexer.tokenize(input);
-        return Parser.parse(tokens);
+        final var stagesData = new StagesDataMap();
+        try {
+            final String path = expression.eval().asString();
+            new SourceLoaderStage()
+                    .then(new LexerStage())
+                    .then(new ParserStage())
+                    .then(new FunctionAddingStage())
+                    .then(new ExecutionStage())
+                    .perform(stagesData, new InputSourceFile(path));
+        } catch (OwnLangParserException ex) {
+            final var error = new ParseErrorsFormatterStage()
+                    .perform(stagesData, ex.getParseErrors());
+            throw new OwnLangRuntimeException(error, ex);
+        }
     }
     
     @Override
diff --git a/ownlang-parser/src/main/java/com/annimon/ownlang/parser/ast/UnaryExpression.java b/ownlang-parser/src/main/java/com/annimon/ownlang/parser/ast/UnaryExpression.java
index 551ba6a..20d35b1 100644
--- a/ownlang-parser/src/main/java/com/annimon/ownlang/parser/ast/UnaryExpression.java
+++ b/ownlang-parser/src/main/java/com/annimon/ownlang/parser/ast/UnaryExpression.java
@@ -53,27 +53,27 @@ public final class UnaryExpression implements Expression, Statement {
         final Value value = expr1.eval();
         switch (operation) {
             case INCREMENT_PREFIX: {
-                if (expr1 instanceof Accessible) {
-                    return ((Accessible) expr1).set(increment(value));
+                if (expr1 instanceof Accessible accessible) {
+                    return accessible.set(increment(value));
                 }
                 return increment(value);
             }
             case DECREMENT_PREFIX: {
-                if (expr1 instanceof Accessible) {
-                    return ((Accessible) expr1).set(decrement(value));
+                if (expr1 instanceof Accessible accessible) {
+                    return accessible.set(decrement(value));
                 }
                 return decrement(value);
             }
             case INCREMENT_POSTFIX: {
-                if (expr1 instanceof Accessible) {
-                    ((Accessible) expr1).set(increment(value));
+                if (expr1 instanceof Accessible accessible) {
+                    accessible.set(increment(value));
                     return value;
                 }
                 return increment(value);
             }
             case DECREMENT_POSTFIX: {
-                if (expr1 instanceof Accessible) {
-                    ((Accessible) expr1).set(decrement(value));
+                if (expr1 instanceof Accessible accessible) {
+                    accessible.set(decrement(value));
                     return value;
                 }
                 return decrement(value);
diff --git a/ownlang-parser/src/main/java/com/annimon/ownlang/parser/visitors/VisitorUtils.java b/ownlang-parser/src/main/java/com/annimon/ownlang/parser/visitors/VisitorUtils.java
index 1c593b8..007f764 100644
--- a/ownlang-parser/src/main/java/com/annimon/ownlang/parser/visitors/VisitorUtils.java
+++ b/ownlang-parser/src/main/java/com/annimon/ownlang/parser/visitors/VisitorUtils.java
@@ -3,6 +3,10 @@ package com.annimon.ownlang.parser.visitors;
 import com.annimon.ownlang.lib.NumberValue;
 import com.annimon.ownlang.lib.Types;
 import com.annimon.ownlang.lib.Value;
+import com.annimon.ownlang.parser.Lexer;
+import com.annimon.ownlang.parser.Parser;
+import com.annimon.ownlang.parser.SourceLoader;
+import com.annimon.ownlang.parser.Token;
 import com.annimon.ownlang.parser.ast.BinaryExpression;
 import com.annimon.ownlang.parser.ast.ConditionalExpression;
 import com.annimon.ownlang.parser.ast.IncludeStatement;
@@ -13,6 +17,7 @@ import com.annimon.ownlang.parser.ast.ValueExpression;
 import com.annimon.ownlang.parser.ast.VariableExpression;
 import java.io.IOException;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 
 public final class VisitorUtils {
@@ -28,9 +33,12 @@ public final class VisitorUtils {
     }
 
     public static Statement includeProgram(IncludeStatement s) {
-        if (!isValue(s)) return null;
+        if (!isValue(s.expression)) return null;
         try {
-            return s.loadProgram(s.expression.eval().asString());
+            final String path = s.expression.eval().asString();
+            final String input = SourceLoader.readSource(path);
+            final List<Token> tokens = Lexer.tokenize(input);
+            return Parser.parse(tokens);
         } catch (IOException ex) {
             return null;
         }
diff --git a/ownlang-parser/src/test/resources/modules/yaml/yamldecode.own b/ownlang-parser/src/test/resources/modules/yaml/yamldecode.own
index 7906f2e..4deea1a 100644
--- a/ownlang-parser/src/test/resources/modules/yaml/yamldecode.own
+++ b/ownlang-parser/src/test/resources/modules/yaml/yamldecode.own
@@ -1,4 +1,4 @@
-use std, yaml, ounit
+use std, yaml
 
 x = yamldecode("
   name: \"std\"
@@ -23,9 +23,9 @@ x = yamldecode("
         print typeof([]) // 3 (ARRAY)
 ")
 
-assertEquals("std", x.name)
-assertEquals("both", x.scope)
-assertEquals(0, length(x.constants))
-assertEquals(2, length(x.functions))
-assertEquals("arrayCombine", x.functions[0].name)
-assertEquals("возвращает тип переданного значения", x.functions[1].desc_ru)
\ No newline at end of file
+  assertEquals("std", x.name)
+  assertEquals("both", x.scope)
+  assertEquals(0, x.constants.length)
+  assertEquals(2, x.functions.length)
+  assertEquals("arrayCombine", x.functions[0].name)
+  assertEquals("возвращает тип переданного значения", x.functions[1].desc_ru)
diff --git a/ownlang-parser/src/test/resources/modules/yaml/yamlencode.own b/ownlang-parser/src/test/resources/modules/yaml/yamlencode.own
index 77e2e3b..7ee5609 100644
--- a/ownlang-parser/src/test/resources/modules/yaml/yamlencode.own
+++ b/ownlang-parser/src/test/resources/modules/yaml/yamlencode.own
@@ -1,20 +1,20 @@
-use std, yaml, ounit
+use std, yaml
 
 yml = yamlencode({
-  "name": "Yaml Example",
-  "version": 1,
-  "arrayData": [
-     1, 2, 3, 4
-  ],
-  "objectData": {
-    "key": "value",
-    10: "1000"
-  }
-})
-obj = yamldecode(yml)
+    "name": "Yaml Example",
+    "version": 1,
+    "arrayData": [
+       1, 2, 3, 4
+    ],
+    "objectData": {
+      "key": "value",
+      10: "1000"
+    }
+  })
+  obj = yamldecode(yml)
 
-assertEquals("Yaml Example", obj.name)
-assertEquals(1, obj.version)
-assertEquals(4, length(obj.arrayData))
-assertEquals("value", obj.objectData.key)
-assertEquals("1000", obj.objectData["10"])
\ No newline at end of file
+  assertEquals("Yaml Example", obj.name)
+  assertEquals(1, obj.version)
+  assertEquals(4, length(obj.arrayData))
+  assertEquals("value", obj.objectData.key)
+  assertEquals("1000", obj.objectData["10"])
\ No newline at end of file