diff --git a/README.md b/README.md
index 0fc6396..f884c4a 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ repositories {
 }
 
 dependencies {
-    implementation("me.alex_s168:blitz:0.14")
+    implementation("me.alex_s168:blitz:0.15")
 }
 ```
 
diff --git a/build.gradle.kts b/build.gradle.kts
index cd3e3f7..1290dbb 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -5,7 +5,7 @@ plugins {
 }
 
 group = "me.alex_s168"
-version = "0.14"
+version = "0.15"
 
 repositories {
     mavenCentral()
diff --git a/src/main/kotlin/blitz/Either.kt b/src/main/kotlin/blitz/Either.kt
index 56d27b1..dbe9b8c 100644
--- a/src/main/kotlin/blitz/Either.kt
+++ b/src/main/kotlin/blitz/Either.kt
@@ -4,6 +4,9 @@ class Either<A, B> private constructor(
     private val a: Obj<A>?,
     private val b: Obj<B>?
 ) {
+    override fun equals(other: Any?): Boolean =
+        other is Either<*, *> && other.a == a && other.b == b
+
     fun getAOrNull(): A? =
         a?.v
 
@@ -41,6 +44,12 @@ class Either<A, B> private constructor(
         if (isA) "Either<A>(${a!!.v})"
         else "Either<B>(${b!!.v})"
 
+    override fun hashCode(): Int {
+        var result = a?.hashCode() ?: 0
+        result = 31 * result + (b?.hashCode() ?: 0)
+        return result
+    }
+
     companion object {
         fun <A, B> ofA(a: A): Either<A, B> =
             Either(Obj.of(a), null)
@@ -51,4 +60,28 @@ class Either<A, B> private constructor(
 }
 
 fun <A, B, R> Either<A, B>.flatten(): R where A: R, B: R =
-    getAOrNull() ?: getB()
\ No newline at end of file
+    getAOrNull() ?: getB()
+
+fun <A, BA, BB, BAN> Either<A, Either<BA, BB>>.mapBA(fn: (BA) -> BAN): Either<A, Either<BAN, BB>> =
+    mapB { it.mapA(fn) }
+
+fun <A, BA, BB, BBN> Either<A, Either<BA, BB>>.mapBB(fn: (BB) -> BBN): Either<A, Either<BA, BBN>> =
+    mapB { it.mapB(fn) }
+
+fun <AA, AB, B, AAN> Either<Either<AA, AB>, B>.mapAA(fn: (AA) -> AAN): Either<Either<AAN, AB>, B> =
+    mapA { it.mapA(fn) }
+
+fun <AA, AB, B, ABN> Either<Either<AA, AB>, B>.mapAB(fn: (AB) -> ABN): Either<Either<AA, ABN>, B> =
+    mapA { it.mapB(fn) }
+
+fun <AA, AB, B> Either<Either<AA, AB>, B>.getAAOrNull(): AA? =
+    getAOrNull()?.getAOrNull()
+
+fun <AA, AB, B> Either<Either<AA, AB>, B>.getABOrNull(): AB? =
+    getAOrNull()?.getBOrNull()
+
+fun <A, BA, BB> Either<A, Either<BA, BB>>.getBAOrNull(): BA? =
+    getBOrNull()?.getAOrNull()
+
+fun <A, BA, BB> Either<A, Either<BA, BB>>.getBBOrNull(): BB? =
+    getBOrNull()?.getBOrNull()
\ No newline at end of file
diff --git a/src/main/kotlin/blitz/Obj.kt b/src/main/kotlin/blitz/Obj.kt
index d4dea17..425e742 100644
--- a/src/main/kotlin/blitz/Obj.kt
+++ b/src/main/kotlin/blitz/Obj.kt
@@ -12,6 +12,11 @@ interface Obj<T> {
 
                 override fun toString(): String =
                     "Obj($v)"
+
+                override fun equals(other: Any?): Boolean =
+                    (other is Obj<*>) && v == other.v
+
+                override fun hashCode(): Int = v.hashCode()
             }
     }
 }
@@ -32,6 +37,11 @@ interface MutObj<T> {
 
                 override fun toString(): String =
                     "MutObj($v)"
+
+                override fun equals(other: Any?): Boolean =
+                    (other is Obj<*>) && v == other.v
+
+                override fun hashCode(): Int = v.hashCode()
             }
 
         fun <T> mutex(v: T): MutObj<T> =
@@ -43,6 +53,11 @@ interface MutObj<T> {
 
                 override fun toString(): String =
                     "MutMutexObj($v)"
+
+                override fun equals(other: Any?): Boolean =
+                    (other is Obj<*>) && v == other.v
+
+                override fun hashCode(): Int = v.hashCode()
             }
     }
 }
\ No newline at end of file
diff --git a/src/main/kotlin/blitz/collections/ListOps.kt b/src/main/kotlin/blitz/collections/ListOps.kt
index 6cd58dd..376d792 100644
--- a/src/main/kotlin/blitz/collections/ListOps.kt
+++ b/src/main/kotlin/blitz/collections/ListOps.kt
@@ -24,4 +24,7 @@ fun <T> MutableList<T>.removeLastInto(count: Int, dest: MutableList<T> = mutable
         dest.add(removeLast())
     }
     return dest
-}
\ No newline at end of file
+}
+
+fun <T> MutableList<T>.addFront(value: T) =
+    add(0, value)
\ No newline at end of file
diff --git a/src/main/kotlin/blitz/str/Escape.kt b/src/main/kotlin/blitz/str/Escape.kt
new file mode 100644
index 0000000..f4ca7b1
--- /dev/null
+++ b/src/main/kotlin/blitz/str/Escape.kt
@@ -0,0 +1,28 @@
+package blitz.str
+
+fun unescape(str: String): String {
+    val out = StringBuilder()
+    var escaped = false
+
+    for (char in str) {
+        if (escaped) {
+            escaped = false
+            val e = when (char) {
+                'n' -> '\n'
+                'r' -> '\r'
+                't' -> '\t'
+                '\\' -> '\\'
+                '"' -> '"'
+                '\'' -> '\''
+                else -> error("Unexpected character '$char'")
+            }
+            out.append(e)
+        } else if (char == '\\') {
+            escaped = true
+        } else {
+            out.append(char)
+        }
+    }
+
+    return out.toString()
+}
\ No newline at end of file