diff --git a/doc/batched_sequences.md b/doc/batched_sequences.md
index 7fbe109..d470a64 100644
--- a/doc/batched_sequences.md
+++ b/doc/batched_sequences.md
@@ -6,7 +6,8 @@ to drastically decrease the amount of single reads in the original source.
 
 Example:
 ```kt
-File("text.txt")  // File
+Path("text.txt")  // Path
+  .getFile()      // File
   .openRead()     // BatchSequence<Byte>
   .batched(64)    // BatchSequence<Byte>
 ```
@@ -21,6 +22,7 @@ Example:
 val data = myData  // Sequence<Byte>
   .asBatch()       // BatchSequence<Byte>
 
-File("text.txt")
+Path("text.txt")      // Path
+  .getOrCreateFile()  // File
   .write(data)
 ```
\ No newline at end of file
diff --git a/src/main/kotlin/blitz/Either.kt b/src/main/kotlin/blitz/Either.kt
index e4b3dc1..6ac1760 100644
--- a/src/main/kotlin/blitz/Either.kt
+++ b/src/main/kotlin/blitz/Either.kt
@@ -32,10 +32,10 @@ class Either<A, B> private constructor(
         if (isA) af(a!!.v) else bf(b!!.v)
 
     fun <RA> mapA(transform: (A) -> RA): Either<RA, B> =
-        Either(a.map(transform), b)
+        Either(a.mapNotNull(transform), b)
 
     fun <RB> mapB(transform: (B) -> RB): Either<A, RB> =
-        Either(a, b.map(transform))
+        Either(a, b.mapNotNull(transform))
 
     override fun toString(): String =
         if (isA) "Either<A>($a)"
diff --git a/src/main/kotlin/blitz/Fnp.kt b/src/main/kotlin/blitz/Fnp.kt
index f722d30..34fad06 100644
--- a/src/main/kotlin/blitz/Fnp.kt
+++ b/src/main/kotlin/blitz/Fnp.kt
@@ -1,5 +1,8 @@
 package blitz
 
+import blitz.func.*
+import blitz.func.io.*
+
 fun main(args: Array<String>) {
     // pureCat(args)
     //     .impure()
diff --git a/src/main/kotlin/blitz/ModifyException.kt b/src/main/kotlin/blitz/ModifyException.kt
new file mode 100644
index 0000000..0f3346d
--- /dev/null
+++ b/src/main/kotlin/blitz/ModifyException.kt
@@ -0,0 +1,8 @@
+package blitz
+
+fun <R> modifyException(new: Throwable, block: () -> R): R =
+    try {
+        block()
+    } catch (e: Throwable) {
+        throw new
+    }
\ No newline at end of file
diff --git a/src/main/kotlin/blitz/func/Multiples.kt b/src/main/kotlin/blitz/func/Multiples.kt
new file mode 100644
index 0000000..4c13675
--- /dev/null
+++ b/src/main/kotlin/blitz/func/Multiples.kt
@@ -0,0 +1,4 @@
+package blitz.func
+
+infix fun <A, B, C> Pair<A, B>.tri(c: C): Triple<A, B, C> =
+    Triple(first, second, c)
\ No newline at end of file
diff --git a/src/main/kotlin/blitz/func/Rewrap.kt b/src/main/kotlin/blitz/func/Rewrap.kt
index 85a5bc7..e168256 100644
--- a/src/main/kotlin/blitz/func/Rewrap.kt
+++ b/src/main/kotlin/blitz/func/Rewrap.kt
@@ -14,3 +14,19 @@ fun <T> Sequence<Monad<T>>.rewrap(): Monad<Sequence<T>> =
         val iter = this@rewrap.iterator()
         sequence { if (iter.hasNext()) yield(iter.next().impure()) }
     }
+
+fun <A, B> Monad<Pair<A, B>>.rewrap(): Pair<Monad<A>, Monad<B>> {
+    val v = lazy { impure() }
+    return Monad { v.value.first } to Monad { v.value.second }
+}
+
+fun <A, B> Pair<Monad<A>, Monad<B>>.rewrap(): Monad<Pair<A, B>> =
+    Monad { first.impure() to second.impure() }
+
+fun <A, B, C> Monad<Triple<A, B, C>>.rewrap(): Triple<Monad<A>, Monad<B>, Monad<C>> {
+    val v = lazy { impure() }
+    return Monad { v.value.first } to Monad { v.value.second } tri Monad { v.value.third }
+}
+
+fun <A, B, C> Triple<Monad<A>, Monad<B>, Monad<C>>.rewrap(): Monad<Triple<A, B, C>> =
+    Monad { first.impure() to second.impure() tri third.impure() }
\ No newline at end of file
diff --git a/src/main/kotlin/blitz/func/io/File.kt b/src/main/kotlin/blitz/func/io/File.kt
index d13b880..69c8d02 100644
--- a/src/main/kotlin/blitz/func/io/File.kt
+++ b/src/main/kotlin/blitz/func/io/File.kt
@@ -1,13 +1,32 @@
 package blitz.func.io
 
-import blitz.func.Monad
-import blitz.func.bind
-import blitz.io.readerSequence
-import kotlinx.io.files.Path
-import kotlinx.io.files.SystemFileSystem
+import blitz.*
+import blitz.func.*
+import blitz.io.*
 
-fun Monad<String>.asPath() =
-    bind { Path(it) }
+fun Monad<String>.asPath(): Monad<Path> =
+    bind { Path.of(it) }
 
-fun Monad<Path>.read() =
-    bind { p -> { SystemFileSystem.source(p) }.readerSequence() }
\ No newline at end of file
+fun Monad<Path>.read(): Monad<ByteBatchSequence> =
+    bind { it.getFile().read() }
+
+fun Monad<Path>.write(seq: Monad<ByteBatchSequence>): Monad<Unit> =
+    bind { it.getFile().write(seq.impure()) }
+
+fun Monad<Path>.append(seq: Monad<ByteBatchSequence>): Monad<Unit> =
+    bind { it.getFile().append(seq.impure()) }
+
+fun Monad<ByteBatchSequence>.writeTo(path: Monad<Path>): Monad<Unit> =
+    path.write(this)
+
+fun Monad<ByteBatchSequence>.appendTo(path: Monad<Path>): Monad<Unit> =
+    path.append(this)
+
+fun Monad<Path>.exists(): Monad<Boolean> =
+    bind { it.exists() }
+
+fun Monad<Path>.isDir(): Monad<Boolean> =
+    bind { it.isDir() }
+
+fun Monad<Path>.isFile(): Monad<Boolean> =
+    bind { it.isFile() }
\ No newline at end of file
diff --git a/src/main/kotlin/blitz/io/Dir.kt b/src/main/kotlin/blitz/io/Dir.kt
new file mode 100644
index 0000000..83853c2
--- /dev/null
+++ b/src/main/kotlin/blitz/io/Dir.kt
@@ -0,0 +1,6 @@
+package blitz.io
+
+@JvmInline
+value class Dir internal constructor(
+    val path: Path
+)
\ No newline at end of file
diff --git a/src/main/kotlin/blitz/io/File.kt b/src/main/kotlin/blitz/io/File.kt
new file mode 100644
index 0000000..dfbddd8
--- /dev/null
+++ b/src/main/kotlin/blitz/io/File.kt
@@ -0,0 +1,34 @@
+package blitz.io
+
+import blitz.ByteBatchSequence
+import kotlinx.io.Buffer
+import kotlinx.io.files.SystemFileSystem
+
+@JvmInline
+value class File internal constructor(
+    val path: Path
+)
+
+fun File.read(): ByteBatchSequence =
+    path.toKotlinxPath().let {
+        { SystemFileSystem.source(it) }
+    }.readerSequence()
+
+private fun File.writeAppendFrom(seq: ByteBatchSequence, append: Boolean) {
+    val path = path.toKotlinxPath()
+    SystemFileSystem.sink(path, append).use { sink ->
+        val iter = seq.iterator()
+        while (iter.hasNext()) {
+            val batch = iter.nextBytes(8192)
+            val buff = Buffer()
+            buff.write(batch)
+            sink.write(buff, buff.size)
+        }
+    }
+}
+
+fun File.write(seq: ByteBatchSequence) =
+    writeAppendFrom(seq, false)
+
+fun File.append(seq: ByteBatchSequence) =
+    writeAppendFrom(seq, true)
\ No newline at end of file
diff --git a/src/main/kotlin/blitz/io/Path.kt b/src/main/kotlin/blitz/io/Path.kt
new file mode 100644
index 0000000..c034cc5
--- /dev/null
+++ b/src/main/kotlin/blitz/io/Path.kt
@@ -0,0 +1,91 @@
+package blitz.io
+
+import blitz.modifyException
+import kotlinx.io.files.SystemFileSystem
+import kotlinx.io.files.SystemPathSeparator
+
+/**
+ * Every instance of this class represents an absolute path in a file system.
+ */
+@JvmInline
+value class Path(
+    val parts: Array<String>
+) {
+    val full: String
+        get() = parts.joinToString(separator.toString())
+
+    val name: String
+        get() = parts.last()
+
+    fun parent(): Path? =
+        if (parts.isEmpty()) null
+        else Path(parts.dropLast(1).toTypedArray())
+
+    // TODO: remove "." and ".." from the path
+    fun child(vararg paths: String): Path =
+        modifyException(Exception("children in Path.child() can not contain path separator!")) {
+            Path(parts + paths.onEach { assert(separator !in it) })
+        }
+
+    fun exists(): Boolean =
+         SystemFileSystem.exists(toKotlinxPath())
+
+    internal fun toKotlinxPath() =
+        kotlinx.io.files.Path("", *parts)
+
+    private fun kotlinxMeta() =
+        SystemFileSystem.metadataOrNull(toKotlinxPath())
+
+    fun isDir() =
+        kotlinxMeta()?.isDirectory ?: false
+
+    fun isFile() =
+        kotlinxMeta()?.isRegularFile ?: false
+
+    fun getDir(): Dir {
+        if (!exists()) throw Exception("Path does not exist!")
+        return Dir(this)
+    }
+
+    fun getOrCreateDir(): Dir {
+        if (!exists()) SystemFileSystem.createDirectories(toKotlinxPath())
+        return Dir(this)
+    }
+
+    fun getFile(): File {
+        if (!exists()) throw Exception("Path does not exist!")
+        return File(this)
+    }
+
+    fun getOrCreateFile(): File {
+        if (!exists()) SystemFileSystem.sink(toKotlinxPath()).flush()
+        return File(this)
+    }
+
+    fun deleteFileOrDir() {
+        if (!exists()) throw Exception("Path does not exist!")
+        SystemFileSystem.delete(toKotlinxPath())
+    }
+
+    fun tryDeleteFileOrDir() {
+        try {
+            if (exists())
+                SystemFileSystem.delete(toKotlinxPath())
+        } catch (_: Exception) {}
+    }
+
+    companion object {
+        val separator: Char = SystemPathSeparator
+
+        /**
+         * Creates a path from a relative or absolute path string.
+         */
+        fun of(path: String): Path {
+            if (path.isEmpty()) return Path(emptyArray())
+            val kx = kotlinx.io.files.Path(path)
+            if (kx.isAbsolute)
+                return Path(path.substring(1).split(separator).toTypedArray())
+            return of(SystemFileSystem.resolve(kx).toString())
+        }
+    }
+}
\ No newline at end of file