Update project use gradle.

.gitattributes

@@ -1,2 +1,6 @@
-# Auto detect text files and perform LF normalization
-* text=auto
+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# These are explicitly windows files and should use crlf
+*.bat           text eol=crlf
+

.gitignore

@@ -1,2 +1,13 @@
 
 .DS_Store
+
+# Ignore Gradle project-specific cache directory
+.gradle
+
+# Ignore Gradle build output directory
+build
+
+# Ignore config folder.
+.idea
+
+

app/build.gradle

@@ -0,0 +1,27 @@
+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * This generated file contains a sample Java application project to get you started.
+ * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
+ * User Manual available at https://docs.gradle.org/7.4.2/userguide/building_java_projects.html
+ */
+
+plugins {
+    // Apply the application plugin to add support for building a CLI application in Java.
+    id 'application'
+}
+
+repositories {
+    // Use Maven Central for resolving dependencies.
+    mavenCentral()
+}
+
+dependencies {
+    // Use JUnit test framework.
+    testImplementation 'junit:junit:4.13.2'
+}
+
+application {
+    // Define the main class for the application.
+    mainClass = 'MathParser.App'
+}

app/src/test/java/com/aghajari/MathParserTest.java

@@ -0,0 +1,44 @@
+package com.aghajari;
+
+import com.aghajari.math.MathParser;
+import org.junit.Test;
+
+/**
+ * test code from README.md
+ */
+public class MathParserTest {
+    @Test
+    public void test(){
+        MathParser parser = MathParser.create();
+        try {
+            System.out.println(parser.parse("2 + 2"));                       // 4.0
+            System.out.println(parser.parse("5^2 * (2 + 3 * 4) + 5!/4"));    // 380.0
+
+            parser.addExpression("f(x, y) = 2(x + y)");                      // addFunction
+            parser.addExpression("x0 = 1 + 2 ^ 2");                          // addVariable
+            parser.addExpression("y0 = 2x0");                                // addVariable
+            System.out.println(parser.parse("1 + 2f(x0, y0)/3"));            // 21.0
+
+            System.out.println(parser.parse("sin(3pi/2) + tan(45°)"));
+
+            System.out.println(parser.parse("2 ∫(x, (x^3)/(x+1), 5, 10)"));  // 517.121062
+            System.out.println(parser.parse("derivative(x, x^3, 2)"));       // 12.0
+            System.out.println(parser.parse("lim(x->2, x^(x + 2)) / 2"));    // 8.0
+            System.out.println(parser.parse("Σ(i, 2i^2, 1, 5)"));            // 220.0
+
+            System.out.println(parser.parse("5!/4"));                        // 30.0
+            System.out.println(parser.parse("(0b100)!"));                    // 4! = 24.0
+            System.out.println(parser.parse("log2((0xFF) + 1)"));            // log2(256) = 8.0
+            System.out.println(parser.parse("(0o777)"));                     // 511.0
+
+            System.out.println(parser.parse("2 + if(2^5 >= 5!, 1, 0)"));     // 2.0
+
+            parser.addExpression("gcd(x, y) = if(y = 0, x, gcd(y, x % y))"); // GCD Recursive
+            System.out.println(parser.parse("gcd(8, 20)"));                  // 4.0
+
+            System.out.println(parser.parse("gcd(8, 20, 100, 150)"));        // 2.0
+        } catch (Exception e){
+            e.printStackTrace();
+        }
+    }
+}

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.4.2-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists