74 files changed, 582 insertions, 327 deletions

diff --git a/ast/build.gradle.kts b/ast/build.gradle.kts
new file mode 100644
index 0000000..357e080
--- /dev/null
+++ b/ast/build.gradle.kts
@@ -0,0 +1,20 @@
+plugins {
+    java
+}
+
+dependencies {
+    implementation(project(":core"))
+    implementation(project(":utils"))
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_22
+    targetCompatibility = JavaVersion.VERSION_22
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(22)
+    }
+}
+
+tasks.withType<JavaCompile> {
+    options.compilerArgs.add("--enable-preview")
+}
\ No newline at end of file
diff --git a/ast/src/main/java/lv/enes/orang/ast/ArrayExpression.java b/ast/src/main/java/lv/enes/orang/ast/ArrayExpression.java
new file mode 100644
index 0000000..acd1a36
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/ArrayExpression.java
@@ -0,0 +1,12 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+import java.util.List;
+
+public record ArrayExpression(List<Expression> items) implements Expression {
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitArray(this);
+        }
+}
diff --git a/src/main/java/lv/enes/orang/ast/BinaryExpression.java b/ast/src/main/java/lv/enes/orang/ast/BinaryExpression.java
index c0b988c..fb8bac5 100644
--- a/src/main/java/lv/enes/orang/ast/BinaryExpression.java
+++ b/ast/src/main/java/lv/enes/orang/ast/BinaryExpression.java
@@ -1,8 +1,6 @@
 package lv.enes.orang.ast;
 
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.Value;
+import lv.enes.orang.core.OrangException;
 
 public record BinaryExpression(Operator operator, Expression lhs, Expression rhs) implements Expression {
         public enum Operator {
@@ -34,20 +32,7 @@ public record BinaryExpression(Operator operator, Expression lhs, Expression rhs
         }
 
         @Override
-        public Value evaluateExpression(Scope scope) throws OrangRuntimeException {
-                var lhs = lhs().evaluateExpression(scope);
-                var rhs = rhs().evaluateExpression(scope);
-                return switch (operator) {
-                        case EQUALS -> lhs.orangEquals(rhs);
-                        case NOT_EQUALS -> lhs.notEquals(rhs);
-                        case GT -> lhs.greaterThan(rhs);
-                        case GTE -> lhs.greaterThanOrEqual(rhs);
-                        case LT -> lhs.lessThan(rhs);
-                        case LTE -> lhs.lessThanOrEqual(rhs);
-                        case ADD -> lhs.add(rhs);
-                        case SUBTRACT -> lhs.subtract(rhs);
-                        case MULTIPLY -> lhs.multiply(rhs);
-                        case DIVIDE -> lhs.divide(rhs);
-                };
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitBinaryExpression(this);
         }
 }
diff --git a/ast/src/main/java/lv/enes/orang/ast/BooleanLiteral.java b/ast/src/main/java/lv/enes/orang/ast/BooleanLiteral.java
new file mode 100644
index 0000000..16bf176
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/BooleanLiteral.java
@@ -0,0 +1,10 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public record BooleanLiteral(boolean value) implements Expression {
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitBoolean(this);
+        }
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/CallExpression.java b/ast/src/main/java/lv/enes/orang/ast/CallExpression.java
new file mode 100644
index 0000000..38ff7bd
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/CallExpression.java
@@ -0,0 +1,10 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public record CallExpression(Expression callee, Expression arg) implements Expression {
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitCallExpression(this);
+        }
+}
diff --git a/src/main/java/lv/enes/orang/ast/DefSpec.java b/ast/src/main/java/lv/enes/orang/ast/DefSpec.java
index 2233d3f..2233d3f 100644
--- a/src/main/java/lv/enes/orang/ast/DefSpec.java
+++ b/ast/src/main/java/lv/enes/orang/ast/DefSpec.java
diff --git a/ast/src/main/java/lv/enes/orang/ast/Definition.java b/ast/src/main/java/lv/enes/orang/ast/Definition.java
new file mode 100644
index 0000000..b41cb1f
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/Definition.java
@@ -0,0 +1,10 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public record Definition(String name, Expression body) implements Statement {
+        @Override
+        public <R, E extends OrangException> R accept(StatementVisitor<R, E> visitor) throws E {
+                return visitor.visitDefinition(this);
+        }
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/DoExpression.java b/ast/src/main/java/lv/enes/orang/ast/DoExpression.java
new file mode 100644
index 0000000..47eaddd
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/DoExpression.java
@@ -0,0 +1,14 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+import java.util.List;
+
+public record DoExpression(List<Expression> body) implements Expression {
+        // assert body.!isEmpty()
+
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitDoExpression(this);
+        }
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/Expression.java b/ast/src/main/java/lv/enes/orang/ast/Expression.java
new file mode 100644
index 0000000..a3e2acc
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/Expression.java
@@ -0,0 +1,7 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public interface Expression {
+        <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E;
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/ExpressionStatement.java b/ast/src/main/java/lv/enes/orang/ast/ExpressionStatement.java
new file mode 100644
index 0000000..2a9dae1
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/ExpressionStatement.java
@@ -0,0 +1,10 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public record ExpressionStatement(Expression expr) implements Statement {
+        @Override
+        public <R, E extends OrangException> R accept(StatementVisitor<R, E> visitor) throws E {
+                return visitor.visitExpression(this);
+        }
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/ExpressionVisitor.java b/ast/src/main/java/lv/enes/orang/ast/ExpressionVisitor.java
new file mode 100644
index 0000000..ddb1157
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/ExpressionVisitor.java
@@ -0,0 +1,22 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public interface ExpressionVisitor<R, E extends OrangException> {
+        default R visit(Expression expression) throws E {
+                return expression.accept(this);
+        }
+
+        R visitArray(ArrayExpression array) throws E;
+        R visitBoolean(BooleanLiteral expr) throws E;
+        R visitBinaryExpression(BinaryExpression expr) throws E;
+        R visitCallExpression(CallExpression expr) throws E;
+        R visitDoExpression(DoExpression expr) throws E;
+        R visitFnExpression(FnExpression expr) throws E;
+        R visitIfElseExpression(IfElseExpression expr) throws E;
+        R visitIntLiteral(IntLiteral expr) throws E;
+        R visitLetInExpression(LetInExpression expr) throws E;
+        R visitStringLiteral(StringLiteral expr) throws E;
+        R visitUnaryExpression(UnaryExpression expr) throws E;
+        R visitVariable(VariableExpression expr) throws E;
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/FnExpression.java b/ast/src/main/java/lv/enes/orang/ast/FnExpression.java
new file mode 100644
index 0000000..68f43af
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/FnExpression.java
@@ -0,0 +1,11 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.utils.NonEmptyList;
+import lv.enes.orang.core.OrangException;
+
+public record FnExpression(NonEmptyList<String> args, Expression body) implements Expression {
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitFnExpression(this);
+        }
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/IfElseExpression.java b/ast/src/main/java/lv/enes/orang/ast/IfElseExpression.java
new file mode 100644
index 0000000..86e48d4
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/IfElseExpression.java
@@ -0,0 +1,10 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public record IfElseExpression(Expression condition, Expression trueBranch, Expression falseBranch) implements Expression {
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitIfElseExpression(this);
+        }
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/IntLiteral.java b/ast/src/main/java/lv/enes/orang/ast/IntLiteral.java
new file mode 100644
index 0000000..12333c9
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/IntLiteral.java
@@ -0,0 +1,10 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public record IntLiteral(int value) implements Expression {
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitIntLiteral(this);
+        }
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/LetInExpression.java b/ast/src/main/java/lv/enes/orang/ast/LetInExpression.java
new file mode 100644
index 0000000..b292f08
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/LetInExpression.java
@@ -0,0 +1,14 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+import java.util.List;
+
+public record LetInExpression(List<Binding> bindings, Expression body) implements Expression {
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitLetInExpression(this);
+        }
+
+        public record Binding(String name, Expression value) {}
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/Program.java b/ast/src/main/java/lv/enes/orang/ast/Program.java
new file mode 100644
index 0000000..9b38f3b
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/Program.java
@@ -0,0 +1,12 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+import java.util.List;
+
+public record Program(List<Statement> statements) implements Statement {
+        @Override
+        public <R, E extends OrangException> R accept(StatementVisitor<R, E> visitor) throws E {
+                return visitor.visitProgram(this);
+        }
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/Statement.java b/ast/src/main/java/lv/enes/orang/ast/Statement.java
new file mode 100644
index 0000000..283fd40
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/Statement.java
@@ -0,0 +1,7 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public interface Statement {
+        <R, E extends OrangException> R accept(StatementVisitor<R, E> visitor) throws E;
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/StatementVisitor.java b/ast/src/main/java/lv/enes/orang/ast/StatementVisitor.java
new file mode 100644
index 0000000..fa3b2f6
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/StatementVisitor.java
@@ -0,0 +1,13 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public interface StatementVisitor<R, E extends OrangException> {
+        default R visit(Statement stmt) throws E {
+                return stmt.accept(this);
+        }
+
+        R visitDefinition(Definition def) throws E;
+        R visitExpression(ExpressionStatement expr) throws E;
+        R visitProgram(Program program) throws E;
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/StringLiteral.java b/ast/src/main/java/lv/enes/orang/ast/StringLiteral.java
new file mode 100644
index 0000000..5c47b7e
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/StringLiteral.java
@@ -0,0 +1,10 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public record StringLiteral(String value) implements Expression {
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitStringLiteral(this);
+        }
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/UnaryExpression.java b/ast/src/main/java/lv/enes/orang/ast/UnaryExpression.java
new file mode 100644
index 0000000..d96ae6d
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/UnaryExpression.java
@@ -0,0 +1,16 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public record UnaryExpression(Operator operator, Expression child) implements Expression {
+        public enum Operator {
+                PLUS,
+                NEGATE,
+                NOT,
+        }
+
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitUnaryExpression(this);
+        }
+}
diff --git a/ast/src/main/java/lv/enes/orang/ast/VariableExpression.java b/ast/src/main/java/lv/enes/orang/ast/VariableExpression.java
new file mode 100644
index 0000000..615857b
--- /dev/null
+++ b/ast/src/main/java/lv/enes/orang/ast/VariableExpression.java
@@ -0,0 +1,10 @@
+package lv.enes.orang.ast;
+
+import lv.enes.orang.core.OrangException;
+
+public record VariableExpression(String name) implements Expression {
+        @Override
+        public <R, E extends OrangException> R accept(ExpressionVisitor<R, E> visitor) throws E {
+                return visitor.visitVariable(this);
+        }
+}
diff --git a/ast/src/main/java/module-info.java b/ast/src/main/java/module-info.java
new file mode 100644
index 0000000..7ebe37b
--- /dev/null
+++ b/ast/src/main/java/module-info.java
@@ -0,0 +1,6 @@
+module lv.enes.orang.ast {
+        exports lv.enes.orang.ast;
+
+        requires lv.enes.orang.core;
+        requires lv.enes.orang.utils;
+}
\ No newline at end of file
diff --git a/core/build.gradle.kts b/core/build.gradle.kts
new file mode 100644
index 0000000..19bbafc
--- /dev/null
+++ b/core/build.gradle.kts
@@ -0,0 +1,15 @@
+plugins {
+    java
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_22
+    targetCompatibility = JavaVersion.VERSION_22
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(22)
+    }
+}
+
+tasks.withType<JavaCompile> {
+    options.compilerArgs.add("--enable-preview")
+}
\ No newline at end of file
diff --git a/src/main/java/lv/enes/orang/OrangException.java b/core/src/main/java/lv/enes/orang/core/OrangException.java
index 9308643..d634fca 100644
--- a/src/main/java/lv/enes/orang/OrangException.java
+++ b/core/src/main/java/lv/enes/orang/core/OrangException.java
@@ -1,4 +1,4 @@
-package lv.enes.orang;
+package lv.enes.orang.core;
 
 public abstract class OrangException extends Exception {
         protected OrangException(String message) {
diff --git a/core/src/main/java/module-info.java b/core/src/main/java/module-info.java
new file mode 100644
index 0000000..b8b8703
--- /dev/null
+++ b/core/src/main/java/module-info.java
@@ -0,0 +1,3 @@
+module lv.enes.orang.core {
+        exports lv.enes.orang.core;
+}
\ No newline at end of file
diff --git a/grammar.bnf b/grammar.bnf
index 256e58a..7c18f8f 100644
--- a/grammar.bnf
+++ b/grammar.bnf
@@ -1,3 +1,5 @@
+// Comments are introduced by # and terminated by newline
+
 program ::= (statement ';'?)*;
 statement ::= definition | expression;
 definition ::= 'def' def-spec '=' expression;
diff --git a/build.gradle.kts b/orang/build.gradle.kts
index 212943a..f70609e 100644
--- a/build.gradle.kts
+++ b/orang/build.gradle.kts
@@ -5,6 +5,7 @@ plugins {
     id("org.beryx.jlink") version "3.0.1"
 }
 
+val asmVersion = "9.7"
 val slf4jVersion = "2.0.13"
 val jakartaAnnotationVersion = "3.0.0"
 
@@ -16,9 +17,14 @@ repositories {
 }
 
 dependencies {
+    implementation("org.ow2.asm:asm:$asmVersion")
     implementation("jakarta.annotation:jakarta.annotation-api:$jakartaAnnotationVersion")
     implementation("org.slf4j:slf4j-api:$slf4jVersion")
     implementation("org.slf4j:slf4j-simple:$slf4jVersion")
+
+    implementation(project(":ast"))
+    implementation(project(":core"))
+    implementation(project(":utils"))
 }
 
 java {
diff --git a/src/main/java/lv/enes/orang/Builtins.java b/orang/src/main/java/lv/enes/orang/Builtins.java
index 0a76387..0a76387 100644
--- a/src/main/java/lv/enes/orang/Builtins.java
+++ b/orang/src/main/java/lv/enes/orang/Builtins.java
diff --git a/src/main/java/lv/enes/orang/Codepoint.java b/orang/src/main/java/lv/enes/orang/Codepoint.java
index 0dfaa2b..7157062 100644
--- a/src/main/java/lv/enes/orang/Codepoint.java
+++ b/orang/src/main/java/lv/enes/orang/Codepoint.java
@@ -14,6 +14,10 @@ public record Codepoint(int cp) {
                 return isIdentInitial() || Character.isDigit(cp);
         }
 
+        public boolean isNewline() {
+                return cp == '\n';
+        }
+
         public boolean isNumeral() {
                 return Character.isDigit(cp);
         }
diff --git a/orang/src/main/java/lv/enes/orang/Evaluator.java b/orang/src/main/java/lv/enes/orang/Evaluator.java
new file mode 100644
index 0000000..e2e96ff
--- /dev/null
+++ b/orang/src/main/java/lv/enes/orang/Evaluator.java
@@ -0,0 +1,144 @@
+package lv.enes.orang;
+
+import lv.enes.orang.ast.*;
+import lv.enes.orang.value.*;
+
+import java.util.ArrayList;
+import java.util.Collections;
+
+public record Evaluator(Scope scope, Value lastResult) implements ExpressionVisitor<Value, OrangRuntimeException>, StatementVisitor<Evaluator, OrangRuntimeException> {
+        public Evaluator() {
+                this(Scope.topLevel());
+        }
+
+        public Evaluator(Scope scope) {
+                this(scope, Undefined.INSTANCE);
+        }
+
+        @Override
+        public Value visitArray(ArrayExpression expr) throws OrangRuntimeException {
+                var values = new ArrayList<Value>(expr.items().size());
+                for (var item : expr.items()) {
+                        values.add(visit(item));
+                }
+                values.trimToSize();
+                return new Array(Collections.unmodifiableList(values));
+        }
+
+        @Override
+        public Value visitBinaryExpression(BinaryExpression expr) throws OrangRuntimeException {
+                var lhs = visit(expr.lhs());
+                var rhs = visit(expr.rhs());
+                return switch (expr.operator()) {
+                        case EQUALS -> lhs.orangEquals(rhs);
+                        case NOT_EQUALS -> lhs.notEquals(rhs);
+                        case GT -> lhs.greaterThan(rhs);
+                        case GTE -> lhs.greaterThanOrEqual(rhs);
+                        case LT -> lhs.lessThan(rhs);
+                        case LTE -> lhs.lessThanOrEqual(rhs);
+                        case ADD -> lhs.add(rhs);
+                        case SUBTRACT -> lhs.subtract(rhs);
+                        case MULTIPLY -> lhs.multiply(rhs);
+                        case DIVIDE -> lhs.divide(rhs);
+                };
+        }
+
+        @Override
+        public Value visitBoolean(BooleanLiteral expr) {
+                return OrangBoolean.of(expr.value());
+        }
+
+        @Override
+        public Value visitCallExpression(CallExpression expr) throws OrangRuntimeException {
+                var arg = visit(expr.arg());
+                return visit(expr.callee()).call(arg);
+        }
+
+        @Override
+        public Evaluator visitDefinition(Definition def) throws OrangRuntimeException {
+                var newScope = MutableScope.of(scope, def.name(), Undefined.INSTANCE);
+                var newEvaluator = new Evaluator(newScope);
+                newScope.setDefinition(def.name(), newEvaluator.visit(def.body()));
+                return newEvaluator;
+        }
+
+        @Override
+        public Value visitDoExpression(DoExpression expr) throws OrangRuntimeException {
+                Value value = Undefined.INSTANCE;
+                for (var child : expr.body()) {
+                        value = visit(child);
+                }
+                return value;
+        }
+
+        @Override
+        public Evaluator visitExpression(ExpressionStatement expr) throws OrangRuntimeException {
+                return new Evaluator(this.scope(), visit(expr.expr()));
+        }
+
+        @Override
+        public Value visitFnExpression(FnExpression expr) {
+                return new Function(this.scope, expr.args(), expr.body());
+        }
+
+        @Override
+        public Value visitIfElseExpression(IfElseExpression expr) throws OrangRuntimeException {
+                var cond = visit(expr.condition());
+                if (cond instanceof OrangBoolean value) {
+                        if (value.value()) {
+                                return visit(expr.trueBranch());
+                        } else {
+                                return visit(expr.falseBranch());
+                        }
+                } else {
+                        throw new OrangRuntimeException(STR."Condition in an if-else statement should be a boolean not a \{cond.typeName()}");
+                }
+        }
+
+        @Override
+        public Value visitIntLiteral(IntLiteral expr) {
+                return new OrangInteger(expr.value());
+        }
+
+        @Override
+        public Value visitLetInExpression(LetInExpression expr) throws OrangRuntimeException {
+                var newScope = MutableScope.of(scope);
+                for (var binding : expr.bindings()) {
+                        newScope.setDefinition(binding.name(), Undefined.INSTANCE);
+                }
+                var newEvaluator = new Evaluator(newScope);
+                for (var binding : expr.bindings()) {
+                        newScope.setDefinition(binding.name(), newEvaluator.visit(binding.value()));
+                }
+                return newEvaluator.visit(expr.body());
+        }
+
+        @Override
+        public Evaluator visitProgram(Program prog) throws OrangRuntimeException {
+                var evaluator = this;
+                for (var statement : prog.statements()) {
+                        evaluator = evaluator.visit(statement);
+                }
+                return evaluator;
+        }
+
+        @Override
+        public Value visitUnaryExpression(UnaryExpression expr) throws OrangRuntimeException {
+                var child = visit(expr.child());
+                return switch (expr.operator()) {
+                        case PLUS -> child.plus();
+                        case NEGATE -> child.negate();
+                        case NOT -> child.not();
+                };
+        }
+
+        @Override
+        public Value visitStringLiteral(StringLiteral expr) {
+                return new OrangString(expr.value());
+        }
+
+        @Override
+        public Value visitVariable(VariableExpression expr) throws OrangRuntimeException {
+                return scope.getDefinition(expr.name());
+        }
+}
diff --git a/orang/src/main/java/lv/enes/orang/ImmutableScope.java b/orang/src/main/java/lv/enes/orang/ImmutableScope.java
new file mode 100644
index 0000000..9cb6138
--- /dev/null
+++ b/orang/src/main/java/lv/enes/orang/ImmutableScope.java
@@ -0,0 +1,45 @@
+package lv.enes.orang;
+
+import lv.enes.orang.value.Value;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class ImmutableScope extends Scope {
+        public static ImmutableScope of(Scope parent) {
+                if (parent instanceof ImmutableScope imm) {
+                        return imm;
+                }
+                return ImmutableScope.of(parent, Map.of());
+        }
+
+        public static ImmutableScope of(Scope parent, String key, Value value) {
+                return ImmutableScope.of(parent, Map.of(key, value));
+        }
+
+        public static ImmutableScope of(Scope parent, Map<String, Value> definitions) {
+                return new ImmutableScope(parent, definitions).maybeFlattened();
+        }
+
+        protected ImmutableScope(Scope parent, Map<String, Value> definitions) {
+                super(parent, Map.copyOf(definitions));
+        }
+
+        public ImmutableScope maybeFlattened() {
+                if (depth > MAX_DEPTH) {
+                        return flattened();
+                }
+                return this;
+        }
+
+        private ImmutableScope flattened() {
+                if (parent instanceof ImmutableScope immParent) {
+                        var flatParent = immParent.flattened();
+                        var newDefs = new HashMap<>(flatParent.definitions);
+                        newDefs.putAll(definitions);
+                        return new ImmutableScope(flatParent.parent, newDefs);
+                }
+
+                return this;
+        }
+}
diff --git a/src/main/java/lv/enes/orang/Lexer.java b/orang/src/main/java/lv/enes/orang/Lexer.java
index 0ee2503..d4e1533 100644
--- a/src/main/java/lv/enes/orang/Lexer.java
+++ b/orang/src/main/java/lv/enes/orang/Lexer.java
@@ -163,6 +163,12 @@ public class Lexer implements Iterator<Token> {
         }
 
         private void skipWhitespace() {
-                skipWhile(Codepoint::isWhitespace);
+                while (true) {
+                        skipWhile(Codepoint::isWhitespace);
+                        if (input.peek().cp() != '#') {
+                                return;
+                        }
+                        skipWhile(cp -> !cp.isNewline());
+                }
         }
 }
diff --git a/src/main/java/lv/enes/orang/Main.java b/orang/src/main/java/lv/enes/orang/Main.java
index 9a607ed..7ca14a1 100644
--- a/src/main/java/lv/enes/orang/Main.java
+++ b/orang/src/main/java/lv/enes/orang/Main.java
@@ -1,5 +1,7 @@
 package lv.enes.orang;
 
+import lv.enes.orang.core.OrangException;
+
 import java.io.FileReader;
 import java.io.IOException;
 
@@ -14,11 +16,11 @@ public class Main {
         }
 
         private static void repl() throws IOException {
-                var scope = new Scope();
+                var evaluator = new Evaluator();
 
                 try (var stream = Main.class.getResourceAsStream("prelude.orang")) {
                         var prog = Parser.parseProgram(stream);
-                        scope = prog.runStatement(scope);
+                        evaluator = evaluator.visitProgram(prog);
                 } catch (OrangException ex) {
                         STDOUT.println(STR."While evaluating prelude: \{ex}");
                         throw new RuntimeException(ex);
@@ -48,7 +50,7 @@ public class Main {
                                                 var filename = line.substring(2).trim();
                                                 try (var reader = new FileReader((filename))) {
                                                         var prog = Parser.parseProgram(reader);
-                                                        scope = prog.runStatement(scope);
+                                                        evaluator = evaluator.visitProgram(prog);
                                                 } catch (IOException | OrangException ex) {
                                                         STDOUT.println(ex);
                                                 }
@@ -64,10 +66,10 @@ public class Main {
 
                         try {
                                 var prog = Parser.parseProgram(line);
-                                scope = prog.runStatement(scope);
-                                if (scope.getLastResult() != null) {
+                                evaluator = evaluator.visitProgram(prog);
+                                if (evaluator.lastResult() != null) {
                                         STDOUT.print("-> ");
-                                        STDOUT.println(scope.getLastResult().stringify());
+                                        STDOUT.println(evaluator.lastResult().stringify());
                                 }
                         } catch (OrangException ex) {
                                 STDOUT.println(ex);
diff --git a/orang/src/main/java/lv/enes/orang/MutableScope.java b/orang/src/main/java/lv/enes/orang/MutableScope.java
new file mode 100644
index 0000000..8d900a4
--- /dev/null
+++ b/orang/src/main/java/lv/enes/orang/MutableScope.java
@@ -0,0 +1,24 @@
+package lv.enes.orang;
+
+import lv.enes.orang.value.Value;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class MutableScope extends Scope {
+        public static MutableScope of(Scope parent) {
+                return new MutableScope(parent, Map.of());
+        }
+
+        public static MutableScope of(Scope parent, String name, Value value) {
+                return new MutableScope(parent, Map.of(name, value));
+        }
+
+        protected MutableScope(Scope parent, Map<String, Value> definitions) {
+                super(parent, new HashMap<>(definitions));
+        }
+
+        public void setDefinition(String key, Value value) {
+                definitions.put(key, value);
+        }
+}
diff --git a/src/main/java/lv/enes/orang/OrangRuntimeException.java b/orang/src/main/java/lv/enes/orang/OrangRuntimeException.java
index 9648c30..8a7d575 100644
--- a/src/main/java/lv/enes/orang/OrangRuntimeException.java
+++ b/orang/src/main/java/lv/enes/orang/OrangRuntimeException.java
@@ -1,5 +1,7 @@
 package lv.enes.orang;
 
+import lv.enes.orang.core.OrangException;
+
 public class OrangRuntimeException extends OrangException {
         public OrangRuntimeException(String message) {
                 super(message);
diff --git a/src/main/java/lv/enes/orang/Parser.java b/orang/src/main/java/lv/enes/orang/Parser.java
index fd4b9bb..4011bd7 100644
--- a/src/main/java/lv/enes/orang/Parser.java
+++ b/orang/src/main/java/lv/enes/orang/Parser.java
@@ -3,6 +3,7 @@ package lv.enes.orang;
 import lv.enes.orang.ast.*;
 import lv.enes.orang.ast.IfElseExpression;
 import lv.enes.orang.ast.Statement;
+import lv.enes.orang.utils.NonEmptyList;
 
 import java.io.InputStream;
 import java.io.Reader;
@@ -253,7 +254,7 @@ public class Parser {
                 if (input.peek().type() == TokenType.DEF) {
                         return parseDefinition();
                 } else {
-                        return parseExpression();
+                        return new ExpressionStatement(parseExpression());
                 }
         }
 
diff --git a/src/main/java/lv/enes/orang/ParserException.java b/orang/src/main/java/lv/enes/orang/ParserException.java
index 9000a93..bd65e7a 100644
--- a/src/main/java/lv/enes/orang/ParserException.java
+++ b/orang/src/main/java/lv/enes/orang/ParserException.java
@@ -1,5 +1,7 @@
 package lv.enes.orang;
 
+import lv.enes.orang.core.OrangException;
+
 public class ParserException extends OrangException {
         public ParserException(String message) {
                 super(message);
diff --git a/src/main/java/lv/enes/orang/PeekableStream.java b/orang/src/main/java/lv/enes/orang/PeekableStream.java
index b77bab1..b77bab1 100644
--- a/src/main/java/lv/enes/orang/PeekableStream.java
+++ b/orang/src/main/java/lv/enes/orang/PeekableStream.java
diff --git a/orang/src/main/java/lv/enes/orang/Scope.java b/orang/src/main/java/lv/enes/orang/Scope.java
new file mode 100644
index 0000000..7fe57c7
--- /dev/null
+++ b/orang/src/main/java/lv/enes/orang/Scope.java
@@ -0,0 +1,34 @@
+package lv.enes.orang;
+
+import lv.enes.orang.value.Value;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public abstract class Scope {
+        public static final int MAX_DEPTH = 4;
+
+        protected final Scope parent;
+        protected final Map<String, Value> definitions;
+        protected final int depth;
+
+        public static MutableScope topLevel() {
+                return new MutableScope(null, new HashMap<>(Builtins.BUILTINS));
+        }
+
+        protected Scope(Scope parent, Map<String, Value> definitions) {
+                this.parent = parent;
+                this.definitions = definitions;
+                this.depth = parent == null ? 0 : parent.depth + 1;
+        }
+
+        public Value getDefinition(String name) throws OrangRuntimeException {
+                if (definitions.containsKey(name)) {
+                        return definitions.get(name);
+                } else if (parent != null) {
+                        return parent.getDefinition(name);
+                } else {
+                        throw new OrangRuntimeException(STR."Value named \{name} is not defined!");
+                }
+        }
+}
diff --git a/src/main/java/lv/enes/orang/State.java b/orang/src/main/java/lv/enes/orang/State.java
index 46b115b..46b115b 100644
--- a/src/main/java/lv/enes/orang/State.java
+++ b/orang/src/main/java/lv/enes/orang/State.java
diff --git a/src/main/java/lv/enes/orang/Token.java b/orang/src/main/java/lv/enes/orang/Token.java
index 4456b8f..4456b8f 100644
--- a/src/main/java/lv/enes/orang/Token.java
+++ b/orang/src/main/java/lv/enes/orang/Token.java
diff --git a/src/main/java/lv/enes/orang/TokenType.java b/orang/src/main/java/lv/enes/orang/TokenType.java
index 960435e..960435e 100644
--- a/src/main/java/lv/enes/orang/TokenType.java
+++ b/orang/src/main/java/lv/enes/orang/TokenType.java
diff --git a/src/main/java/lv/enes/orang/value/Array.java b/orang/src/main/java/lv/enes/orang/value/Array.java
index c3b645d..c3b645d 100644
--- a/src/main/java/lv/enes/orang/value/Array.java
+++ b/orang/src/main/java/lv/enes/orang/value/Array.java
diff --git a/src/main/java/lv/enes/orang/value/BuiltinFunction.java b/orang/src/main/java/lv/enes/orang/value/BuiltinFunction.java
index 92ccc2e..92ccc2e 100644
--- a/src/main/java/lv/enes/orang/value/BuiltinFunction.java
+++ b/orang/src/main/java/lv/enes/orang/value/BuiltinFunction.java
diff --git a/src/main/java/lv/enes/orang/value/Function.java b/orang/src/main/java/lv/enes/orang/value/Function.java
index 1f288c6..901776e 100644
--- a/src/main/java/lv/enes/orang/value/Function.java
+++ b/orang/src/main/java/lv/enes/orang/value/Function.java
@@ -1,5 +1,7 @@
 package lv.enes.orang.value;
 
+import lv.enes.orang.Evaluator;
+import lv.enes.orang.ImmutableScope;
 import lv.enes.orang.OrangRuntimeException;
 import lv.enes.orang.Scope;
 import lv.enes.orang.ast.Expression;
@@ -20,7 +22,8 @@ public record Function(Scope scope, List<String> args, Expression body) implemen
         @Override
         public Value call(Value param) throws OrangRuntimeException {
                 if (args.size() == 1) {
-                        return body.evaluateExpression(scope.withDefinition(args.getFirst(), param));
+                        var eval = new Evaluator(ImmutableScope.of(scope, args.getFirst(), param));
+                        return eval.visit(body);
                 } else {
                         return new PartialFunction(scope, args, List.of(param), body);
                 }
diff --git a/src/main/java/lv/enes/orang/value/OrangBoolean.java b/orang/src/main/java/lv/enes/orang/value/OrangBoolean.java
index 8a4776c..8a4776c 100644
--- a/src/main/java/lv/enes/orang/value/OrangBoolean.java
+++ b/orang/src/main/java/lv/enes/orang/value/OrangBoolean.java
diff --git a/src/main/java/lv/enes/orang/value/OrangInteger.java b/orang/src/main/java/lv/enes/orang/value/OrangInteger.java
index 9b8d505..9b8d505 100644
--- a/src/main/java/lv/enes/orang/value/OrangInteger.java
+++ b/orang/src/main/java/lv/enes/orang/value/OrangInteger.java
diff --git a/src/main/java/lv/enes/orang/value/OrangString.java b/orang/src/main/java/lv/enes/orang/value/OrangString.java
index c03f7ac..c03f7ac 100644
--- a/src/main/java/lv/enes/orang/value/OrangString.java
+++ b/orang/src/main/java/lv/enes/orang/value/OrangString.java
diff --git a/src/main/java/lv/enes/orang/value/PartialBuiltinFunction.java b/orang/src/main/java/lv/enes/orang/value/PartialBuiltinFunction.java
index 37278a4..37278a4 100644
--- a/src/main/java/lv/enes/orang/value/PartialBuiltinFunction.java
+++ b/orang/src/main/java/lv/enes/orang/value/PartialBuiltinFunction.java
diff --git a/src/main/java/lv/enes/orang/value/PartialFunction.java b/orang/src/main/java/lv/enes/orang/value/PartialFunction.java
index 59e1466..0dbf530 100644
--- a/src/main/java/lv/enes/orang/value/PartialFunction.java
+++ b/orang/src/main/java/lv/enes/orang/value/PartialFunction.java
@@ -1,5 +1,7 @@
 package lv.enes.orang.value;
 
+import lv.enes.orang.Evaluator;
+import lv.enes.orang.ImmutableScope;
 import lv.enes.orang.OrangRuntimeException;
 import lv.enes.orang.Scope;
 import lv.enes.orang.ast.Expression;
@@ -29,7 +31,8 @@ public record PartialFunction(Scope scope, List<String> args, List<Value> params
                         for (var i = 0; i < args.size(); i++) {
                                 newDefs.put(args.get(i), newParams.get(i));
                         }
-                        return body.evaluateExpression(scope.withDefinitions(newDefs));
+                        var eval = new Evaluator(ImmutableScope.of(scope, newDefs));
+                        return eval.visit(body);
                 }
 
                 return new PartialFunction(scope, args, Collections.unmodifiableList(newParams), body);
diff --git a/src/main/java/lv/enes/orang/value/Undefined.java b/orang/src/main/java/lv/enes/orang/value/Undefined.java
index a341ee8..a341ee8 100644
--- a/src/main/java/lv/enes/orang/value/Undefined.java
+++ b/orang/src/main/java/lv/enes/orang/value/Undefined.java
diff --git a/src/main/java/lv/enes/orang/value/Value.java b/orang/src/main/java/lv/enes/orang/value/Value.java
index fa8275c..fa8275c 100644
--- a/src/main/java/lv/enes/orang/value/Value.java
+++ b/orang/src/main/java/lv/enes/orang/value/Value.java
diff --git a/src/main/java/module-info.java b/orang/src/main/java/module-info.java
index a4bdb66..060657f 100644
--- a/src/main/java/module-info.java
+++ b/orang/src/main/java/module-info.java
@@ -1,5 +1,10 @@
 module lv.enes.orang {
         exports lv.enes.orang;
+        exports lv.enes.orang.value;
+
+        requires lv.enes.orang.ast;
+        requires lv.enes.orang.core;
+        requires lv.enes.orang.utils;
 
         requires static jakarta.annotation;
         requires static lombok;
diff --git a/src/main/resources/lv/enes/orang/prelude.orang b/orang/src/main/resources/lv/enes/orang/prelude.orang
index 36bf197..d29eef3 100644
--- a/src/main/resources/lv/enes/orang/prelude.orang
+++ b/orang/src/main/resources/lv/enes/orang/prelude.orang
@@ -1,12 +1,16 @@
+# builtins
 def isRepl = __builtin_isRepl ()
 def len arrayOrString = __builtin_len arrayOrString
 def parseInt stringOrInt = __builtin_parseInt stringOrInt
 def print anything = __builtin_print anything
-def printLn x = do print x; print "\n"; x end
 def randInt min max = __builtin_randInt min max
-def readInt _ = parseInt (readLn ())
 def readLn _ = __builtin_readLn ()
 
+# standard library
+def readInt _ = parseInt (readLn ())
+def printLn x = do print x; print "\n"; x end
+
+# repl intro :)
 def _ =
   if isRepl then do
     printLn "Hello! This is the Orang Programming Language!";
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 4c4ac7d..fc692fa 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -1,2 +1,3 @@
 rootProject.name = "orang"
 
+include("ast", "core", "orang", "utils")
\ No newline at end of file
diff --git a/src/main/java/lv/enes/orang/Scope.java b/src/main/java/lv/enes/orang/Scope.java
deleted file mode 100644
index 3625c69..0000000
--- a/src/main/java/lv/enes/orang/Scope.java
+++ /dev/null
@@ -1,54 +0,0 @@
-package lv.enes.orang;
-
-import jakarta.annotation.Nullable;
-import lv.enes.orang.value.Value;
-
-import java.util.HashMap;
-import java.util.Map;
-
-public class Scope {
-        private final Map<String, Value> definitions;
-
-        private final Value lastResult;
-
-        public Scope() {
-                this(new HashMap<>(Builtins.BUILTINS), null);
-        }
-
-        private Scope(Map<String, Value> definitions, Value lastResult) {
-                this.definitions = definitions;
-                this.lastResult = lastResult;
-        }
-
-        public Value getDefinition(String name) throws OrangRuntimeException {
-                if (definitions.containsKey(name)) {
-                        return definitions.get(name);
-                }
-                throw new OrangRuntimeException(STR."Value named \{name} is not defined!");
-        }
-
-        @Nullable
-        public Value getLastResult() {
-                return lastResult;
-        }
-
-        public Scope withDefinition(String key, Value value) {
-                var newDefs = new HashMap<>(definitions);
-                newDefs.put(key, value);
-                return new Scope(newDefs, null);
-        }
-
-        public Scope withDefinitions(Map<String, Value> definitions) {
-                var newDefs = new HashMap<>(this.definitions);
-                newDefs.putAll(definitions);
-                return new Scope(newDefs, null);
-        }
-
-        public void setDefinition(String key, Value value) {
-                definitions.put(key, value);
-        }
-
-        public Scope withLastResult(Value value) {
-                return new Scope(definitions, value);
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/ArrayExpression.java b/src/main/java/lv/enes/orang/ast/ArrayExpression.java
deleted file mode 100644
index d2437cf..0000000
--- a/src/main/java/lv/enes/orang/ast/ArrayExpression.java
+++ /dev/null
@@ -1,21 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.Array;
-import lv.enes.orang.value.Value;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-
-public record ArrayExpression(List<Expression> items) implements Expression {
-        @Override
-        public Value evaluateExpression(Scope scope) throws OrangRuntimeException {
-                var values = new ArrayList<Value>();
-                for (var item : items) {
-                        values.add(item.evaluateExpression(scope));
-                }
-                return new Array(Collections.unmodifiableList(values));
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/BooleanLiteral.java b/src/main/java/lv/enes/orang/ast/BooleanLiteral.java
deleted file mode 100644
index 9110f67..0000000
--- a/src/main/java/lv/enes/orang/ast/BooleanLiteral.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.OrangBoolean;
-import lv.enes.orang.value.Value;
-
-public record BooleanLiteral(boolean value) implements Expression {
-        @Override
-        public Value evaluateExpression(Scope scope) {
-                return OrangBoolean.of(value);
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/CallExpression.java b/src/main/java/lv/enes/orang/ast/CallExpression.java
deleted file mode 100644
index 8f05496..0000000
--- a/src/main/java/lv/enes/orang/ast/CallExpression.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.Value;
-
-public record CallExpression(Expression callee, Expression arg) implements Expression {
-        @Override
-        public Value evaluateExpression(Scope scope) throws OrangRuntimeException {
-                return callee.evaluateExpression(scope).call(arg.evaluateExpression(scope));
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/Definition.java b/src/main/java/lv/enes/orang/ast/Definition.java
deleted file mode 100644
index 715daae..0000000
--- a/src/main/java/lv/enes/orang/ast/Definition.java
+++ /dev/null
@@ -1,15 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.Undefined;
-
-public record Definition(String name, Expression body) implements Statement {
-        @Override
-        public Scope runStatement(Scope scope) throws OrangRuntimeException {
-                scope.setDefinition(name, Undefined.INSTANCE);
-                var value = body.evaluateExpression(scope);
-                scope.setDefinition(name, value);
-                return scope;
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/DoExpression.java b/src/main/java/lv/enes/orang/ast/DoExpression.java
deleted file mode 100644
index 9d69a3e..0000000
--- a/src/main/java/lv/enes/orang/ast/DoExpression.java
+++ /dev/null
@@ -1,19 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.Value;
-
-import java.util.List;
-
-public record DoExpression(List<Expression> body) implements Expression {
-        // assert body.!isEmpty()
-
-        @Override
-        public Value evaluateExpression(Scope scope) throws OrangRuntimeException {
-                for (var i = 0; i < body.size() - 1; i++) {
-                        body.get(i).evaluateExpression(scope);
-                }
-                return body.getLast().evaluateExpression(scope);
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/Expression.java b/src/main/java/lv/enes/orang/ast/Expression.java
deleted file mode 100644
index a0fc3af..0000000
--- a/src/main/java/lv/enes/orang/ast/Expression.java
+++ /dev/null
@@ -1,14 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.Value;
-
-public interface Expression extends Statement {
-        Value evaluateExpression(Scope scope) throws OrangRuntimeException;
-
-        @Override
-        default Scope runStatement(Scope scope) throws OrangRuntimeException {
-                return scope.withLastResult(evaluateExpression(scope));
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/FnExpression.java b/src/main/java/lv/enes/orang/ast/FnExpression.java
deleted file mode 100644
index 3c3522f..0000000
--- a/src/main/java/lv/enes/orang/ast/FnExpression.java
+++ /dev/null
@@ -1,14 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.NonEmptyList;
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.Function;
-import lv.enes.orang.value.Value;
-
-public record FnExpression(NonEmptyList<String> args, Expression body) implements Expression {
-        @Override
-        public Value evaluateExpression(Scope scope) throws OrangRuntimeException {
-                return new Function(scope, args, body);
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/IfElseExpression.java b/src/main/java/lv/enes/orang/ast/IfElseExpression.java
deleted file mode 100644
index 9b52cc5..0000000
--- a/src/main/java/lv/enes/orang/ast/IfElseExpression.java
+++ /dev/null
@@ -1,22 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.OrangBoolean;
-import lv.enes.orang.value.Value;
-
-public record IfElseExpression(Expression condition, Expression trueBranch, Expression falseBranch) implements Expression {
-        @Override
-        public Value evaluateExpression(Scope scope) throws OrangRuntimeException {
-                var condValue = condition.evaluateExpression(scope);
-                if (condValue instanceof OrangBoolean value) {
-                        if (value.value()) {
-                                return trueBranch.evaluateExpression(scope);
-                        } else {
-                                return falseBranch.evaluateExpression(scope);
-                        }
-                } else {
-                        throw new OrangRuntimeException(STR."Condition in an if should be a Boolean not a \{condValue.typeName()}");
-                }
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/IntLiteral.java b/src/main/java/lv/enes/orang/ast/IntLiteral.java
deleted file mode 100644
index 339ba3b..0000000
--- a/src/main/java/lv/enes/orang/ast/IntLiteral.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.OrangInteger;
-import lv.enes.orang.value.Value;
-
-public record IntLiteral(int value) implements Expression {
-        @Override
-        public Value evaluateExpression(Scope scope) {
-                return new OrangInteger(value);
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/LetInExpression.java b/src/main/java/lv/enes/orang/ast/LetInExpression.java
deleted file mode 100644
index 2379902..0000000
--- a/src/main/java/lv/enes/orang/ast/LetInExpression.java
+++ /dev/null
@@ -1,27 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.Undefined;
-import lv.enes.orang.value.Value;
-
-import java.util.HashMap;
-import java.util.List;
-
-public record LetInExpression(List<Binding> bindings, Expression body) implements Expression {
-        @Override
-        public Value evaluateExpression(Scope scope) throws OrangRuntimeException {
-                var newDefs = new HashMap<String, Value>();
-                for (var binding : bindings) {
-                        newDefs.put(binding.name, Undefined.INSTANCE);
-                }
-                var newState = scope.withDefinitions(newDefs);
-                for (var binding : bindings) {
-                        var value = binding.value.evaluateExpression(newState);
-                        newState.setDefinition(binding.name, value);
-                }
-                return body.evaluateExpression(newState);
-        }
-
-        public record Binding(String name, Expression value) {}
-}
diff --git a/src/main/java/lv/enes/orang/ast/Program.java b/src/main/java/lv/enes/orang/ast/Program.java
deleted file mode 100644
index ae5d31e..0000000
--- a/src/main/java/lv/enes/orang/ast/Program.java
+++ /dev/null
@@ -1,17 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-
-import java.util.List;
-
-public record Program(List<Statement> statements) implements Statement {
-        @Override
-        public Scope runStatement(Scope inScope) throws OrangRuntimeException {
-                var state = inScope;
-                for (var statement : statements) {
-                        state = statement.runStatement(state);
-                }
-                return state;
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/Statement.java b/src/main/java/lv/enes/orang/ast/Statement.java
deleted file mode 100644
index 0f52fc3..0000000
--- a/src/main/java/lv/enes/orang/ast/Statement.java
+++ /dev/null
@@ -1,8 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-
-public interface Statement {
-        Scope runStatement(Scope scope) throws OrangRuntimeException;
-}
diff --git a/src/main/java/lv/enes/orang/ast/StringLiteral.java b/src/main/java/lv/enes/orang/ast/StringLiteral.java
deleted file mode 100644
index 367dff5..0000000
--- a/src/main/java/lv/enes/orang/ast/StringLiteral.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.OrangString;
-import lv.enes.orang.value.Value;
-
-public record StringLiteral(String value) implements Expression {
-        @Override
-        public Value evaluateExpression(Scope scope) throws OrangRuntimeException {
-                return new OrangString(value);
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/UnaryExpression.java b/src/main/java/lv/enes/orang/ast/UnaryExpression.java
deleted file mode 100644
index a0f565b..0000000
--- a/src/main/java/lv/enes/orang/ast/UnaryExpression.java
+++ /dev/null
@@ -1,23 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.Value;
-
-public record UnaryExpression(Operator operator, Expression child) implements Expression {
-        public enum Operator {
-                PLUS,
-                NEGATE,
-                NOT,
-        }
-
-        @Override
-        public Value evaluateExpression(Scope scope) throws OrangRuntimeException {
-                var child = child().evaluateExpression(scope);
-                return switch (operator) {
-                        case PLUS -> child.plus();
-                        case NEGATE -> child.negate();
-                        case NOT -> child.not();
-                };
-        }
-}
diff --git a/src/main/java/lv/enes/orang/ast/VariableExpression.java b/src/main/java/lv/enes/orang/ast/VariableExpression.java
deleted file mode 100644
index 1f5334d..0000000
--- a/src/main/java/lv/enes/orang/ast/VariableExpression.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package lv.enes.orang.ast;
-
-import lv.enes.orang.OrangRuntimeException;
-import lv.enes.orang.Scope;
-import lv.enes.orang.value.Value;
-
-public record VariableExpression(String name) implements Expression {
-        @Override
-        public Value evaluateExpression(Scope scope) throws OrangRuntimeException {
-                return scope.getDefinition(name);
-        }
-}
diff --git a/utils/build.gradle.kts b/utils/build.gradle.kts
new file mode 100644
index 0000000..04cda43
--- /dev/null
+++ b/utils/build.gradle.kts
@@ -0,0 +1,20 @@
+plugins {
+    java
+    id("io.freefair.lombok") version "8.6"
+}
+
+repositories {
+    mavenCentral()
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_22
+    targetCompatibility = JavaVersion.VERSION_22
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(22)
+    }
+}
+
+tasks.withType<JavaCompile> {
+    options.compilerArgs.add("--enable-preview")
+}
\ No newline at end of file
diff --git a/src/main/java/lv/enes/orang/NonEmptyList.java b/utils/src/main/java/lv/enes/orang/utils/NonEmptyList.java
index 860db28..197491f 100644
--- a/src/main/java/lv/enes/orang/NonEmptyList.java
+++ b/utils/src/main/java/lv/enes/orang/utils/NonEmptyList.java
@@ -1,4 +1,4 @@
-package lv.enes.orang;
+package lv.enes.orang.utils;
 
 import lombok.EqualsAndHashCode;
 
diff --git a/utils/src/main/java/module-info.java b/utils/src/main/java/module-info.java
new file mode 100644
index 0000000..47e37e0
--- /dev/null
+++ b/utils/src/main/java/module-info.java
@@ -0,0 +1,5 @@
+module lv.enes.orang.utils {
+        exports lv.enes.orang.utils;
+
+        requires static lombok;
+}
\ No newline at end of file