grammarrule comparison add

src/main/java/parser/grammar/GrammarRule.java

@@ -1,13 +1,15 @@
 package parser.grammar;
 
+import java.util.Objects;
+
 public class GrammarRule {
 
     private final String leftside;
     private final String rightside;
 
     public GrammarRule(String leftside, String... rightside) {
-        this.leftside = leftside;
+        this.leftside = leftside.trim();
-        this.rightside = String.join(" ", rightside);
+        this.rightside = String.join(" ", rightside).trim();
     }
 
     public String getLeftside() {
@@ -17,4 +19,24 @@ public class GrammarRule {
     public String getRightside() {
         return this.rightside;
     }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof GrammarRule) {
+            return this.leftside.equals(((GrammarRule) obj).leftside)
+                   && this.rightside.equals(((GrammarRule) obj).rightside);
+        }
+
+        return false;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.leftside, this.rightside);
+    }
+
+    @Override
+    public String toString() {
+        return this.leftside + " -> " + this.rightside;
+    }
 }