std: sweeping changes.

- replace interfaces with classes
- replace : with then and do
- solidify memory management as rust-style ownership
- replace unsafe blocks with safe/unsafe attributes
- add magic and copy attributes
- switch Coerce impl from from to to

20 files changed, 509 insertions, 466 deletions

diff --git a/std/ast.pk b/std/ast.pk
index abc66ba..b069aa9 100644
--- a/std/ast.pk
+++ b/std/ast.pk
@@ -1,9 +1,13 @@
 ## std.ast: Exposes the AST for building and operating on with macros.
 
 pub type Expr = union
-  Ident(string), Number(int), Float(float), Char(chr), String(str)
-  Struct(list[tuple[field: str, value: Expr]])
-  Tuple(list[tuple[field: string?, value: Expr]])
+  Ident(string)
+  Number(int)
+  Float(float)
+  Char(chr)
+  String(str)
+  Struct(list[(field: str, value: Expr)])
+  Tuple(list[(field: str?, value: Expr)])
   List(list[Expr])
   Let(id: Pattern, kind: Type?, value: ref Expr)
   Var(id: Pattern, kind: Type?, value: ref Expr?)
@@ -13,51 +17,41 @@ pub type Expr = union
     generics: list[GenericParams],
     params: list[FunctionParams],
     kind: Type,
-    body: list[Expr]
-  )
+    body: list[Expr])
   TypeDecl(id: str, generics: list[str], alias: Type)
   Module(id: str, body: list[Expr])
   Use(path: str)
   Pub(Expr) # can easily generate incoherent statements. still desired?
   Call(id: str, params: list[Expr])
-  Cond(branches: list[CondBranch], else_body: list[Expr]?)
+  Cond(
+    branches: list[(cond: Expr, body: list[Expr])],
+    else_body: list[Expr]?)
   Try(
     try_body: list[Expr],
-    catches: list[TryBranch]
-    finally_body: list[Expr]?
-  )
+    catches: list[(exceptions: list[str], body: list[Expr])],
+    finally_body: list[Expr]?)
   Match(
     item: ref Expr,
-    branches: list[MatchBranch]
-  )
+    branches: list[(pattern: Pattern, guard: Expr?, body: list[Expr])])
   Block(id: str?, body: list[Expr])
   ConstBlock(body: list[Expr]),
   For(binding: Pattern, range: ref Expr, body: list[Expr])
   While(cond: ref Expr, body: list[Expr])
   Loop(body: list[Expr]),
 
-pub type CondBranch = tuple
-  cond: Expr
-  body: list[Expr]
-
-pub type TryBranch = tuple
-  exceptions: list[str]
-  body: list[Expr]
-
-pub type MatchBranch = tuple
-  pattern: Pattern
-  guard: Option[Expr]
-  body: list[Expr]
-
 pub type Type = ref union
-  Void, Never,
-  Integer, Float, String,
-  Func(from: Type, to: Type) # todo: multiple parameters
-  Struct(list[tuple[id: str, kind: Type]])
-  Tuple(list[tuple[id: str?, kind: Type]])
-  Union(list[tuple[id: str, kind: Type]])
-  Interface( # todo: generics
-    funcs: list[Signature]
+  Void
+  Never
+  Int(size: uint)
+  Dec(size: uint)
+  Float(size: uint)
+  String
+  Func(from: list[Type], to: Type)
+  Struct(list[(id: str, kind: Type)])
+  Tuple(list[(id: str?, kind: Type)])
+  Union(list[(id: str, kind: Type)])
+  Class( # todo: generics
+    funcs: list[(id: str, from: list[Type], to: Type?)]
     for_type: Type?
   )
   Array(size: uint, kind: Type)
@@ -65,17 +59,18 @@ pub type Type = ref union
   Slice(Type) # todo: plus ownership
   Alias(str) # todo: params?? huh?
   Static(Type)
-  Mutable(Type)
-  Reference(Type)
-  Pointer(Type)
-pub type Signature = struct # todo: generics
-  id: str
-  effect: Option[str]
-  params: list[Type]
-  kind: Option[Type]
+  Lent(Type)
+  Mut(Type)
+  Ref(Type)
+  Refc(Type)
+  Ptr(Type)
+
 pub type Pattern = union
   Ident(str)
   Number(int), Float(float), Char(chr), String(str)
   Struct(name: str, params: list[Pattern])
   Tuple(list[Pattern])
   List(list[Pattern])
+
+@[magic]
+pub func quote(body): Expr
diff --git a/std/async.pk b/std/async.pk
index 7c76076..f2ae3e0 100644
--- a/std/async.pk
+++ b/std/async.pk
@@ -1,5 +1,6 @@
 ## std.async: Zig-style colourless async/await.
 ## Future types, the async macro, and the await function.
+# reference: https://kristoff.it/blog/zig-colorblind-async-await/
 
 ## A standard Future type. Opaque.
 pub type Future[T] = struct
@@ -7,6 +8,9 @@ pub type Future[T] = struct
 
 ## The `async` macro transforms any function call into
 ## an asynchronous call returning a Future of some type.
+##
+## This does not "just work". Compiler magic is necessary to package up
+## *any* block into something independently callable.
 pub macro async[T](call: T): Future[T] =
   ...
 
@@ -14,6 +18,6 @@ pub macro async[T](call: T): Future[T] =
 pub func await[T](self: Future[T]): T =
   ...
 
-examples:
+examples
   std.net.connect()
   print 1.async.await
diff --git a/std/hashes.pk b/std/hashes.pk
index 911c9d2..6211a2e 100644
--- a/std/hashes.pk
+++ b/std/hashes.pk
@@ -1,4 +1,4 @@
 ## std.hashes: Hash functions on types.
 
-pub type Hash[H] = interface
+pub type Hash[H] = class
   hash[H](Self): H
diff --git a/std/prelude/arrays.pk b/std/prelude/arrays.pk
index 2e4a4d4..6f57865 100644
--- a/std/prelude/arrays.pk
+++ b/std/prelude/arrays.pk
@@ -1,20 +1,30 @@
-## std.arrays: The array[T, S] primitive and associated functions.
+## std.arrays: The array[T, size] primitive and associated functions.
 ## A stub module for documentation. Mostly compiler magic.
 
 ## Primitive fixed-size arrays. Their size is statically known at compile-time.
-pub type array[T, S: static[uint]]
+@[magic]
+pub type array[T, size: static uint]
 
 ## Array access. Returns None if i is out of range.
-pub func get[T, S: static[uint]](self: array[T, S], i: uint): T?
+@[magic]
+pub func get[T, size: static uint](self: lent array[T, size], i: uint): lent T?
+## Array access. Returns None if i is out of range.
+@[magic]
+pub func get[T, size: static uint](self: mut array[T, size], i: uint): mut T?
+
 ## Array mutation.
 # todo: how do we detect range errors?
-pub func set[T, S: static[uint]](self: mut array[T, S], i: uint, val: T): T?
+@[magic]
+pub func set[T, size: static uint](self: mut array[T, size], i: uint, val: T): Success[IndexOutOfBounds]
+
 ## A helper function to get the length of an array.
 ## Known to the compiler, and computed at compile-time.
-pub func len[T, S: static[uint]](self: array[T, S], i: uint): T?
+@[inline]
+pub func len[T, size: static uint](self: lent array[T, size]): uint = size
 
-type ArrayIter[T, S: static[uint]] = struct
+type ArrayIter[T, size: static uint] = struct
+  ...
+pub func iter[T, size: static uint](self: array[T, size]): ArrayIter[T, S] =
   ...
-pub func iter[T, S: static[uint]](self: array[T, S]): ArrayIter[T, S]
 
 # todo: Eq, PartialEq, Ord, PartialOrd
diff --git a/std/prelude/booleans.pk b/std/prelude/booleans.pk
index bd81925..e92eac8 100644
--- a/std/prelude/booleans.pk
+++ b/std/prelude/booleans.pk
@@ -4,39 +4,26 @@
 pub type unit = union[sole]
 pub type bool = union[false, true]
 
-# note: puck could resolve kleene.false vs bool.false...
-# this is probably not worth it compared to improved type inference
-# pub type Kleene = union[False, Maybe, True]
-
 ## Boolean equality
-pub func ==(a: bool, b: bool): bool =
-  match a
-  of (true, true), (false, false): true
-  of (false, true), (true, false): false
+@[magic]
+pub func ==(a: bool, b: bool): bool
 
-pub func !=(a: bool, b: bool): bool =
-  not a == b
+## Boolean inequality
+@[magic]
+pub func !=(a: bool, b: bool): bool
 
 ## Boolean negation
-pub func not(a: bool): bool =
-  match a
-  of true: false
-  of false: true
+@[magic]
+pub func not(a: bool): bool
 
 ## Boolean conjunction
-pub func and(a: bool, b: bool): bool =
-  match (a, b)
-  of (true, true): true
-  of _: false
+@[magic]
+pub func and(a: bool, b: bool): bool
 
 ## Boolean disjunction
-pub func or(a: bool, b: bool): bool =
-  match (a, b)
-  of (false, false): false
-  of _: true
+@[magic]
+pub func or(a: bool, b: bool): bool
 
 ## Boolean exclusive disjunction
-pub func xor(a: bool, b: bool): bool =
-  match (a, b)
-  of (true, true), (false, false): false
-  of (true, false), (false, true): true
+@[magic]
+pub func xor(a: bool, b: bool): bool
diff --git a/std/prelude/clone.pk b/std/prelude/clone.pk
index 5b16b8b..5d11cdb 100644
--- a/std/prelude/clone.pk
+++ b/std/prelude/clone.pk
@@ -1,28 +1,36 @@
-## std.clone: Interfaces for explicitly Clonable types.
+## std.clone: Classes for explicitly Clonable types.
 ## This module is imported by default.
 
-## The Clone interface. Any type implementing Clone is cloneable.
+## The Clone class. Any type implementing Clone is cloneable.
 ## Data structures built with pointers and references are pretty much
 ## the only things that are *not* implicitly clonable.
-pub type Clone = interface
-  clone(lent Self): Self # todo
+pub type Clone = class
+  clone(lent Self): Self
 
 ## Generic implementation of `clone` for structs.
-pub func clone[T: struct](self: T): T =
+## fixme: this relies on no component of a struct being a ref or ptr
+## cloning an rc is fine??
+pub func clone[T: Clone](self: struct[T]): struct[T] =
   ...
 
 ## Generic implementation of `clone` for tuples.
-pub func clone[T: tuple](self: T): T =
+pub func clone[T: Clone](self: tuple[T]): tuple[T] =
   ...
 
 ## Implementation of `clone` for arrays of any size.
-pub func clone[T, S: static[uint]](self: array[T, S]): array[T, S] =
-  ...
+pub func clone[T: Clone, size: static[uint]](self: array[T, size]): array[T, size] =
+  var res: array[T, size]
+  for i in 0 .. size do
+    res.push(self.i.clone)
 
 ## Implementation of `clone` for lists.
-pub func clone[T](self: list[T]): list[T] =
-  ...
+pub func clone[T: Clone](self: list[T]): list[T] =
+  var res: list[T]
+  for elem in self do
+    res.push(elem.clone) # the explicit dependency on Clone gives us this
 
 ## Implementation of `clone` for strings.
 pub func clone(self: str): str =
-  ...
+  var res: str
+  for char in self do
+    res.push(char)
diff --git a/std/prelude/compare.pk b/std/prelude/compare.pk
index b506761..5f3ae74 100644
--- a/std/prelude/compare.pk
+++ b/std/prelude/compare.pk
@@ -1,30 +1,36 @@
-## std.compare: Interfaces for comparable types.
+## std.compare: Classes for comparable types.
 ## reference: https://doc.rust-lang.org/std/cmp
 
-## The Eq interface
-pub type Eq = interface
+## The Eq class. For types with some notion of equivalence.
+pub type Eq = class
   ==(Self, Self): bool
 
-## A possible Equivalence interface.
-# equality, equivalence, isomorphism, homomorphism, congruence
-# pub type Equiv = interface
-#   ...
+## A blanket implementation of a corresponding not-equal function.
+pub !=[T: Eq](a: T, b: T): bool =
+  not(a == b)
 
-pub type PartialOrd = interface
+## The Compare class. For a type comparable with itself.
+pub type Compare = class
   <(a: Self, b: Self): bool
 
-pub type Ord = interface
+## A blanket implementation of a corresponding greater-than function.
+## Note to self: do NOT inline!
+pub func >[T: Compare](a: T, b: T): bool =
+  b < a
+
+## The Ord class. For types with some notion of equivalence and comparision.
+##
+## Note: This is *not* a mathematical notion of an order!
+## No invariants on `<` nor `==` are guaranteed to hold, as classes
+## are implicitly implementable.
+pub type Ord = class
   <(a: Self, b: Self): bool
   ==(a: Self, b: Self): bool
 
-pub !=[T: Eq](a: T, b: T): bool =
-  not a == b
-
-pub func >[T: PartialOrd](a: T, b: T): bool =
-  b < a
-
+## A blanket implementation of a corresponding less-than-or-equal function.
 pub func <=[T: Ord](a: T, b: T): bool =
   a < b or a == b
 
+## A blanket implementation of a corresponding greater-than-or-equal function.
 pub func >=[T: Ord](a: T, b: T): bool =
   a > b or a == b
diff --git a/std/prelude/convert.pk b/std/prelude/convert.pk
index 6abf543..ec1a4a7 100644
--- a/std/prelude/convert.pk
+++ b/std/prelude/convert.pk
@@ -1,23 +1,19 @@
-## std.convert: Interfaces for type coersion and conversion.
+## std.convert: Classes for type coersion and conversion.
 ## This module is imported by default.
 
-## The Coerce interface is used for type conversion that will not fail.
+## The Coerce class is used for type conversion that will not fail.
 ## Its associated methods, `from` and `into`, are used internally
 ## by the compiler for implicit type conversion (coersion).
-pub type Coerce[T] = interface
-  from(T): Self
-  # into(Self): T
+pub type Coerce[T] = class
+  to(Self): T
+  # from(T): Self
 
-## The `into` function is automatically implemented for all types that
-## implement `from`: that is, all types U that are convertable to T.
-pub func into[T, U: Coerce[T]](self: T): U =
-  from(self)
+## The `from` function is automatically implemented for all types that
+## implement `to`: that is, all types T that are convertable to U.
+pub func from[T: Coerce[U], U](self: U): T =
+  to(self)
 
-## The Convert interface is used for type conversion that may fail.
+## The Convert class is used for type conversion that may fail.
 # We'll see what this breaks.
-pub type Convert[T] = interface
-  from(T): Self?!
-
-## A blanket implementation of a corresponding `into` function.
-pub func into[T, U: Convert[T]](self: T): U =
-  from(self)
+pub type Convert[T, E] = class
+  to(Self): Result[T, E]
diff --git a/std/prelude/debug.pk b/std/prelude/debug.pk
index 3af1def..92d31dd 100644
--- a/std/prelude/debug.pk
+++ b/std/prelude/debug.pk
@@ -1,27 +1,22 @@
 ## std.debug: Useful functions for debugging.
 ## This module is imported by default.
 
-## The special ... syntax is used to mark unimplemented parts of code.
-## Such code will compile, but panic upon being called at runtime.
-## It is usable almost anywhere, including in type declarations, thanks to compiler magic.
-pub func ...: never
-
 ## The `assert` macro checks that a provided assertation is true,
 ## and panics and dumps information if it is not.
-## Asserts remain in release builds. If not desired, see `debug_assert`
+## Asserts remain in release builds. If not desired, see `dbg_assert`
 pub macro assert(cond: bool) =
-  quote:
-    if not `cond`:
+  quote
+    if not `cond` then
       panic "assertation failed!\n {}".fmt(dbg(`cond`))
 
-## The `debug_assert` function provides an assert that is compiled out in release builds.
+## The `dbg_assert` function provides an assert that is compiled out in release builds.
 ## This is useful for debugging performance-critical code.
-pub macro debug_assert(cond: bool)
-  quote:
-    when debug: # fixme: where is this coming from?
+pub macro dbg_assert(cond: bool) =
+  quote
+    when debug then # fixme: where is this constant coming from?
       assert `cond`
 
-## The `discard` function consumes any type.
+## The `discard` function consumes an object of any type.
 ## Useful for throwing away the result of a computation.
 pub func discard[T](self: T) =
   return
@@ -30,3 +25,10 @@ pub func discard[T](self: T) =
 pub func panic(message: str): never =
   stderr.write(message, "\n")
   std.os.exit(1)
+
+## The special ... syntax is used to mark unimplemented parts of code.
+## Such code will compile, but panic upon being called at runtime.
+## It is usable almost anywhere, including in type declarations, thanks to compiler magic.
+@[magic]
+pub func ...: never =
+  panic("unimplemented")
diff --git a/std/prelude/format.pk b/std/prelude/format.pk
index 7cc1d81..6fc7c99 100644
--- a/std/prelude/format.pk
+++ b/std/prelude/format.pk
@@ -1,15 +1,15 @@
 ## std.format: Niceties around printing and debugging.
 ## This module is imported by default.
 
-## The Display interface. Any type implementing `str` is printable.
+## The Display class. Any type implementing `str` is printable.
 ## Any type that is Display must necessarily also implement Debug.
-pub type Display = interface
+pub type Display = class
   str(Self): str
   dbg(Self): str
 
-## The Debug interface. Broadly implemented for every type with compiler magic.
+## The Debug class. Broadly implemented for every type with compiler magic.
 ## Types can (and should) override the generic implementations.
-pub type Debug = interface
+pub type Debug = class
   dbg(Self): str
 
 ## Prints all of its arguments to the command line.
@@ -17,38 +17,42 @@ pub func print(params: varargs[Display]) =
   stdout.write(params.map(x => x.str).join(" "), "\n")
 
 ## Prints all of its arguments to the command line, in Debug form.
-## Note: this function is special! does not count as a side effect
+##
+## Note: this function is special! It does not count as a side effect.
+## This breaks effect tracking, of course: but `dbg` is for debugging.
+## It will produce a warning in code compiled for release.
+@[no_side_effect]
 pub func dbg(params: varargs[Debug]) =
   stdout.write(params.map(x => x.dbg).join(" "), "\n")
 
-## A dummy implementation of the Display interface for strings.
+## A dummy implementation of the Display class for strings.
 pub func str(self: str): str = self
-## An implementation of the Debug interface for strings.
+## An implementation of the Debug class for strings.
 pub func dbg(self: str): str = "\"" & self & "\""
 
-## An implementation of the Debug interface for all structs.
+## An implementation of the Debug class for all structs.
 ## Uses the special `struct` typeclass.
-pub func dbg(self: struct): str =
+pub func dbg[T: Debug](self: struct[T]): str =
   "{{}}".fmt(self.fields.map((key, val) => key & ":" & val.dbg))
 
-## An implementation of the Debug interface for all tuples.
+## An implementation of the Debug class for all tuples.
 ## Uses the special `tuple` typeclass.
-pub func dbg(self: tuple): str =
+pub func dbg[T: Debug](self: tuple[T]): str =
   "({})".fmt(self.fields.map((key, val) =>
     key.map(x => x & ":").get_or("") & val.dbg).join(", "))
 
-## An implementation of the Debug interface for all arrays and lists.
+## An implementation of the Debug class for all arrays and lists.
 pub func dbg[T: Debug](self: Iter[T]): str =
   "[{}]".fmt(self.map(x => x.dbg).join(", "))
 
 ## The fmt macro. Builds a formatted string from its arguments.
 pub macro fmt(self: static[str], args: varargs[Display]): str =
   let parts = self.split("{}")
-  if parts.len != args.len + 1:
+  if parts.len != args.len + 1 then
     macro_error("wrong number of arguments")
   use std.ast
   var res = parts.get(0)!
-  for i, arg in args:
+  for i, arg in args do
     res &= quote(`parts` & str(`arg`) &) # fixme
   res &= parts.last()!
   res
diff --git a/std/prelude/io.pk b/std/prelude/io.pk
index 002cc31..026d12a 100644
--- a/std/prelude/io.pk
+++ b/std/prelude/io.pk
@@ -4,7 +4,7 @@
 # reference: https://doc.rust-lang.org/stable/std/io/
 
 pub type File = ...
-pub type FileMode = union[Read, Write, ReadWrite, Append]
+pub type FileMode = enum[Read, Write, ReadWrite, Append]
 
 # todo: file destructors call `close`
 
diff --git a/std/prelude/iterators.pk b/std/prelude/iterators.pk
index 82137ee..1403b55 100644
--- a/std/prelude/iterators.pk
+++ b/std/prelude/iterators.pk
@@ -1,28 +1,28 @@
-## std.iterators: The Iter interface and associated functions.
+## std.iterators: The Iter class and associated functions.
 ## This module is imported by default.
 # reference: https://doc.rust-lang.org/std/iter/
 # reference: https://docs.rs/itertools/latest/itertools/
 
 use std.queue.ring
 
-## The Iter interface. Any type implementing `next()` is iterable.
-pub type Iter[T] = interface
+## The Iter class. Any type implementing `next()` is iterable.
+pub type Iter[T] = class
   next(mut Self): T? # should T be lent?
 
-## The IntoIter interface.
+## The IntoIter class.
 ## Any type implementing `iter()` may be converted to an iterable type.
-pub type IntoIter[T] = interface
+pub type IntoIter[T] = class
   iter(Self): Iter[T]
 
-## The Peek interface.
+## The Peek class.
 ## Any type implementing `Iter`, `peek`, and `peek_nth` is peekable.
-pub type Peek[T] = interface
+pub type Peek[T] = class
   next(mut Self): T?
   peek(mut Self): T?
   peek_nth(mut Self, int): T?
 
 ## A concrete Peekable structure formed from a generic Iter type.
-## Implements the Peek interface. Can be formed with `.peekable()`
+## Implements the Peek class. Can be formed with `.peekable()`
 type PeekImpl = struct
   iter: ref Iter[T] # this is probably bad... heap allocated...
   buf: Queue[T]
@@ -34,26 +34,26 @@ pub func peekable[T](iter: owned Iter[T]): PeekImpl[T] =
 
 pub func next[T](self: mut PeekImpl[T]): T? =
   match self.buf.pop()
-  of None:
+  of None then
     self.iter.next()
-  of Some(val):
+  of Some(val) then
     val
 pub func peek[T](self: mut PeekImpl[T]): T? =
   match self.buf.peek()
-  of None:
+  of None then
     self.buf.push(self.iter.next())
     self.buf.peek()
-  of Some(val):
+  of Some(val) then
     val
 pub func peek_nth[T](self: mut PeekImpl[T], i: uint): T? =
-  if self.buf.len > i:
+  if self.buf.len > i then
     self.buf.get(i)!
-  else:
-    for _ in self.buf.len .. i: # fixme
+  else
+    for _ in self.buf.len .. i do # fixme
       match self.buf.next()
-      of None:
+      of None then
         return None
-      of Some(val):
+      of Some(val) then
         self.buf.push(val)
     self.buf.peek()
 
@@ -61,26 +61,23 @@ pub func peek_nth[T](self: mut PeekImpl[T], i: uint): T? =
 # https://doc.rust-lang.org/std/iter/trait.Iterator.html#provided-methods
 
 func advance_by[T](self: Iter[T], n: uint) =
-  for i in 0 .. n:
-    if self.next().is_none():
-      return
+  for i in 0 .. n do
+    if self.next().is_none() then return
 
-pub func get[T](self: Iter[T], at: uint): Option[T]
+pub func get[T](self: Iter[T], at: uint): T?
   self.advance_by(at-1).ok? # fixme
   self.next()
 
 ## Returns true if every element in an Iter fulfills the conditional.
 pub func all[T](self: Iter[T], cond: T -> bool): bool =
-  for elem in self:
-    if not cond(elem):
-      return false
+  for elem in self do
+    if not cond(elem) then return false
   true
 
 ## Returns true if any element in an Iter fulfills the conditional.
 pub func any[T](self: Iter[T], cond: T -> bool): bool =
-  for elem in self:
-    if cond(elem):
-      return true
+  for elem in self do
+    if cond(elem) then return true
   false
 
 ## Returns true if an Iter contains the given element.
@@ -89,52 +86,48 @@ pub func contains[T](self: Iter[T], val: T): bool =
 
 ## Returns the first element matching a condition, if it exists.
 pub func find[T](self: Iter[T], cond: T -> bool): T? =
-  for elem in self:
-    if cond(elem):
-      return Some(elem)
+  for elem in self do
+    if cond(elem) then return Some(elem)
   None
 
 ## Returns the position of the first element matching a condition, if it exists.
 pub func position[T](self: Iter[T], cond: T -> bool): T? =
   var i = 0
-  for elem in self:
-    if cond(elem):
-      return Some(i)
+  for elem in self do
+    if cond(elem) then return Some(i)
     i += 1
   None
 
+@[inline]
 pub func fold[T, U](self: Iter[T], init: U, op: (U, T) -> U) =
   var res = init
-  for elem in self:
+  for elem in self do
     res = res.op(elem)
   res
 
 pub func reduce[T, U](self: Iter[T], op: (U, T) -> U): U? =
   match self.next()
-  of None:
-    None
-  of Some(val):
+  of None then None
+  of Some(val) then
     var res = val
-    for elem in self:
-      res = op(res, elem)
+    for elem in self do res = op(res, elem)
     Some(res)
 
 pub func count[T](self: Iter[T], element: T): uint =
-  self.fold(0, (elem, acc) => if elem == element: acc + 1 else: acc)
+  self.fold(0, (elem, acc) => if elem == element then acc + 1 else acc)
 
 pub func count[T](self: Iter[T]): uint =
   self.fold(0, (elem, acc) => acc + 1)
 
 pub func last[T](self: Iter[T]): T =
   var res = None
-  for elem in self:
-    res = elem
+  for elem in self do res = elem
   res
 
 pub func ==[T](first: Iter[T], second: Iter[T]): bool =
-  for (a, b) in :
-    if a != b:
-      return false
+  if first.len != second.len then return false
+  for (a, b) in zip(first, second) do
+    if a != b then return false
   true
 
 type LazyIter = struct
@@ -165,16 +158,16 @@ pub func zip[T, U](first: Iter[T], second: Iter[U]): Iter[(T, U)]
 pub func unzip[T, U](self: Iter[(T, U)]): (Iter[T], Iter[U])
 
 # equivalent of collect. useful for type conversion
-pub func from[T](self: LazyIter[T]): list[T]
-pub func from(self: LazyIter[chr]): str
+pub func to[T](self: LazyIter[T]): list[T]
+pub func to(self: LazyIter[chr]): str
 
-pub type BoundIter[T] = interface
+pub type BoundIter[T] = class
   next(mut Self): T?
   pop(mut Self): T?
 
 pub func rev[T](self: BoundIter[T]): BoundIter[T]
 
-pub type SizedIter[T] = interface
+pub type SizedIter[T] = class
   next(mut Self): T?
   pop(mut Self): T?
   len(Self): uint
diff --git a/std/prelude/lists.pk b/std/prelude/lists.pk
index 1e8dee5..57de91b 100644
--- a/std/prelude/lists.pk
+++ b/std/prelude/lists.pk
@@ -2,105 +2,113 @@
 ## This module is imported by default.
 # reference: https://doc.rust-lang.org/nomicon/vec/vec.html
 
-use std.pointers
-
-## The list type.
-type list[T] = struct
-  data: unique[T] # hrm
+## The fundamental list type. Heap-allocated.
+## Equivalent to Vec<T> in other languages.
+@[unsafe] # unsafe on a struct tells us raw field access breaks invariants.
+pub type list[T] = struct
+  data: ptr T
   capacity: int
   length: int
 
+## A transparent, common alias for a list of bytes.
+pub type bytes = list[byte]
+
 ## Initialize and return an empty list with inner type T.
-pub func init[T](): list[T] =
-  ... # malloc? idk
-  let (data, )
-  { data: , capacity: 0, length: 0 }
+pub func init[T]: list[T] =
+  { data = nil, capacity = 0, length = 0 } # fixme: nil!!!!!
 
 ## Gets the length of a list.
-pub func len[T](self: list[T]): uint =
+@[inline] # idk what to do with attributes
+pub func len[T](self: lent list[T]): uint =
   self.length
 
-pub func empty[T](self: list[T]): bool =
+pub func empty[T](self: lent list[T]): bool =
   self.length == 0
 
 ## Gets the internal capacity of a list.
-func cap[T](self: list[T]): uint =
+func cap[T](self: lent list[T]): uint =
   self.capacity
 
 ## Expands the capacity of a list.
+@[safe]
 func grow[T](self: mut list[T]) =
-  ...
+  self.capacity = max(self.length + 1, self.capacity * 2)
+  self.data = self.data.realloc(self.capacity * sizeof(T))
 
 ## Pushes a new element to the end of a list.
-pub func push[T](self: mut list[T], val: owned T) =
-  if self.length == self.capacity:
-    self.grow()
-  unsafe: # todo: do we want unsafe blocks, as they are in rust?
-    self.data.raw_set(self.length, val) # fixme
-    # unsafe { ptr::write(self.ptr().add(self.length), val); }
-    self.length += 1
+@[safe]
+pub func push[T](self: mut list[T], val: T) =
+  if self.capacity == self.length then self.grow()
+  self.data.set(val, offset = self.length)
+  self.length += 1
 
 ## Takes ownership of and pushes all the values of a list into another list.
-pub func push[T](self: mut list[T], val: owned list[T]) =
-  ...
+pub func push[T](self: mut list[T], values: list[T]) =
+  for val in values do
+    self.push(val)
 
 ## Removes & returns an element from the end of a list, if it exists.
+@[safe]
 pub func pop[T](self: mut list[T]): T? =
-  if self.length == 0:
+  if self.length == 0 then
     None
-  unsafe:
+  else
     self.length -= 1
-    Some(self.data.raw_get[T](self.length)) # fixme
-    # unsafe { Some(ptr::read(self.ptr().add(self.length))) }
+    Some(self.data.get(offset = self.length))
 
 ## Returns a reference to an element of a list, if in range.
-pub func get[T](self: list[T], i: uint): lent T? =
-  ...
+@[safe]
+pub func get[T](self: lent list[T], i: uint): lent T? =
+  if i > self.length then
+    None
+  else # fixme: interior mutability
+    Some(lent self.data.get(offset = i))
+## Returns a mutable reference to an element of a list, if in range.
+@[safe]
+pub func get[T](self: mut list[T], i: uint): mut T? =
+  if i > self.length then
+    None
+  else # fixme: interior mutability
+    Some(mut self.data.get(offset = i))
 
-## Sets the element of a list to a value. todo: when is `val` owned?
-## todo: how do we deal with having the wrong offset?
-pub func set[T](self: mut list[T], i: uint, val: owned T) =
-  ...
+## Sets the element of a list to a value.
+@[safe]
+pub func set[T](self: mut list[T], i: uint, val: T) =
+  assert i <= self.length, "index out of bounds"
+  Okay(self.data.set(offset = i, val))
 
 ## Inserts a value at a location and shifts elements of the list accordingly.
+@[safe]
 pub func insert[T](self: mut list[T], i: uint, val: T) =
   assert i <= self.length, "index out of bounds"
-  if self.cap == self.len:
-    self.grow()
-  ...
-  # unsafe {
-  #     ptr::copy(
-  #         self.ptr().add(index),
-  #         self.ptr().add(index + 1),
-  #         self.len - index,
-  #     );
-  #     ptr::write(self.ptr().add(index), elem);
-  #     self.len += 1;
-  # }
+  if self.capacity == self.length then self.grow()
+  self.data.offset(i).copy(self.data.offset(i + 1), self.length - i)
+  self.data.set(i, val)
+  self.length += 1
+## Inserts a list of values at a location and shifts elements of the list accordingly.
+pub func insert[T](self: mut list[T], i: uint, vals: list[T]) =
+  for val in vals.rev: # inserting backwards avoids counting
+    self.insert(val, i)
 
 ## Removes a value at a location and shifts elements of the list accordingly.
-pub func remove[T](self: mut list[T], i: uint): T =
-  assert index < self.length, "index out of bounds"
-  unsafe:
+@[safe]
+pub func remove[T](self: mut list[T], i: uint): T? =
+  if index < self.length then None
+  else
     self.length -= 1
-    result = ...
-  # unsafe {
-  #     self.len -= 1;
-  #     let result = ptr::read(self.ptr().add(index));
-  #     ptr::copy(
-  #         self.ptr().add(index + 1),
-  #         self.ptr().add(index),
-  #         self.len - index,
-  #     );
-  #     result
-  # }
+    let res = self.data.get(i)
+    self.data.offset(i + 1).copy(self.data.offset(i), self.length - i)
+    res
 
 ## Gets the last element of a list, if it exists.
-pub func last[T](self: list[T]): lent T? =
+pub func last[T](self: lent list[T]): lent T? =
+  self.get(self.len - 1)
+## Gets the last element of a list mutably, if it exists.
+pub func last[T](self: mut list[T]): mut T? =
   self.get(self.len - 1)
 
 # todo: many questions. owned? how does it not free?
-pub func iter[T](self: owned list[T]): ListIter[T] =
+pub func iter[T](self: list[T]): ListIter[T] =
   ...
 
 # todo: iteration...
diff --git a/std/prelude/mem.pk b/std/prelude/mem.pk
index 79c524b..5ad3c7a 100644
--- a/std/prelude/mem.pk
+++ b/std/prelude/mem.pk
@@ -1,35 +1,58 @@
 ## std.mem: Unsafe functions for working with raw memory.
+## This module is imported by default.
 
 ## Raw pointers. Extremely unsafe.
 ## While they are removed from the memory model by default (and hence can
-## cause undefined behavior), pointers must know what *type* they point at.
+## cause memory errors), pointers must know what *type* they point at.
 ## This cuts down on errors somewhat - not much, but somewhat.
+@[magic]
 pub type ptr[T] =
   addr: uint
 ## Heap-allocated, memory-safe references.
+@[magic]
 pub type ref[T]
-pub type unique[T]
+## Heap-allocated, reference-counted references.
+## These are a special type - rather than anything handled by the type system
+## alone - because there are significant optimizations the compiler can make.
+@[magic]
+pub type refc[T]
+
+## Tells the compiler to interpret data of one type directly as data of another.
+## Extremely unsafe. Take caution to memory representations when using.
+## Compiler magic. The type signature is left here for documentation purposes.
+@[unsafe, magic]
+pub func cast[T, U](self: T): U
 
 ## Sets the sizeof(T) bytes following data + offset * sizeof(T) to T.
 ## Extremely unsafe.
-pub func raw_set[T](data: ptr[T], val: T, offset: uint = 0) =
+@[unsafe]
+pub func set[T](data: ptr T, val: T, offset: uint = 0) =
   ...
 
 ## Gets the value at data + offset * sizeof(T), and interprets it as type T.
 ## Extremely unsafe.
-pub func raw_get[T](data: ptr[T], offset: uint = 0) =
+@[unsafe]
+pub func get[T](data: ptr T, offset: uint = 0) =
   ...
 
 ## Returns a pointer offset by offset * sizeof(T).
 ## Extremely unsafe.
-pub func raw_offset[T](data: ptr[T], offset: uint): ptr[T] =
+@[unsafe]
+pub func offset[T](data: ptr T, offset: uint): ptr T =
+  ...
+
+@[unsafe]
+pub func malloc[T](size: uint = sizeof(T)): ptr T =
   ...
 
-pub func malloc[T](size: uint = sizeof(T)): ptr[T] =
+@[unsafe]
+pub func calloc[T](size: uint = sizeof(T)): ptr T =
   ...
 
-pub func calloc[T](size: uint = sizeof(T)): ptr[T] =
+@[unsafe]
+pub func realloc[T](data: ptr T): ptr T =
   ...
 
-pub func realloc[T](data: ptr[T]): ptr[T] =
+@[unsafe]
+pub func copy[T](from: ptr T, to: ptr T, length: uint) =
   ...
diff --git a/std/prelude/numbers.pk b/std/prelude/numbers.pk
index 7857d34..801591a 100644
--- a/std/prelude/numbers.pk
+++ b/std/prelude/numbers.pk
@@ -3,53 +3,73 @@
 # reference: https://en.wikipedia.org/wiki/IEEE_754
 
 ## The default integer type. Size depends on architecture.
+@[copy, magic]
 pub type int
 ## A signed 8-bit integer.
+@[copy, magic]
 pub type i8
 ## A signed 16-bit integer.
+@[copy, magic]
 pub type i16
 ## A signed 32-bit integer.
+@[copy, magic]
 pub type i32
 ## A signed 64-bit integer.
+@[copy, magic]
 pub type i64
 ## A signed 128-bit integer.
+@[copy, magic]
 pub type i128
 
 ## The default unsigned integer type. Size depends on architecture.
+@[copy, magic]
 pub type uint
 ## An unsigned 8-bit integer.
+@[copy, magic]
 pub type u8
 ## An unsigned 16-bit integer.
+@[copy, magic]
 pub type u16
 ## An unsigned 32-bit integer.
+@[copy, magic]
 pub type u32
 ## An unsigned 64-bit integer.
+@[copy, magic]
 pub type u64
 ## An unsigned 128-bit integer.
+@[copy, magic]
 pub type u128
 
 ## A floating-point type. Takes up 64 bits by default.
 pub type float = f64
 ## A 32-bit floating point type. Single precision.
+@[copy, magic]
 pub type f32
 ## A 64-bit floating point type. Double precision.
+@[copy, magic]
 pub type f64
 ## A 128-bit floating point type. Quadruple precision.
+@[copy, magic]
 pub type f128
 
 ## A decimal type, according to IEEE 754. Takes up 64 bits by default.
 pub type decimal = dec64
 ## A 64-bit decimal type.
+@[copy, magic]
 pub type dec64
 ## A 128-bit decimal type.
+@[copy, magic]
 pub type dec128
 
-## 8-bit bytes.
+## A primitive byte type. 8 bits wide.
 pub type byte = u8
-## 4-byte chars. These represent distinct Unicode characters.
-pub type char = distinct u32
-## An alias to `char`, to match with `str`.
-pub type chr = char
+## A primitive char type. 4 bytes wide.
+## These represent distinct Unicode characters, and are useful with `str`.
+pub type chr = u32
+
+## Get the underlying length of a char, in bytes. 1-4.
+pub func len(self: chr): uint =
+  ...
 
 ## The IEEE floating point value of *Not a Number*.
 pub const NaN: f64 = 0x7FF7FFFFFFFFFFFF
@@ -60,18 +80,31 @@ pub const NegInf: f64 = 0xFFF0000000000000
 
 # todo: type conversions
 
+# fixme: types are all wrong
+@[magic]
 pub func +[T](a: T, b: T): T
+@[magic]
 pub func -[T](a: T, b: T): T
+@[magic]
 pub func *[T](a: T, b: T): T
+@[magic]
 pub func /[T](a: T, b: T): float
-pub func ^[T](a: T, b: T): T # todo: should be exp?
 
+@[magic]
+pub func exp[T](a: T, b: T = eulers_number): T
+@[magic]
+pub func log[T](a: T, b: T = eulers_number): T
+@[magic]
+pub func abs[T](a: T): T
+
+@[magic]
 pub func div[T](a: T, b: T): T
-pub func mod[T](a: T, b: T): T # fixme
+@[magic]
+pub func mod[T](a: T, b: T): T
+@[magic]
 pub func rem[T](a: T, b: T): T
 
+@[magic]
 pub func shl[T](a: T): T
+@[magic]
 pub func shr[T](a: T): T
-
-pub func abs[T](a: T): T
-pub func neg[T](a: T): bool
diff --git a/std/prelude/options.pk b/std/prelude/options.pk
index 4f6cef2..d5cfb9d 100644
--- a/std/prelude/options.pk
+++ b/std/prelude/options.pk
@@ -9,91 +9,84 @@ pub type Option[T] = union
   Some(T)
   None
 
+## Syntactic sugar for optional type declarations.
+pub macro ?(T: type) =
+  quote Option[`T`]
+
+## Directly accesses the inner value. Throws an exception if None.
+pub func ![T](self: T?): T =
+  if self of Some(x) then x
+  else raise "empty"
+
+## Indirect access. Propagates `None`.
+pub macro ?[T](self: T?) =
+  quote
+    match `self`
+    of Some(x) then x
+    of None then return None
+
 ## Checks if a type is present within an `Option` type.
-pub func is_some[T](self: Option[T]): bool =
+pub func is_some[T](self: T?): bool =
   self of Some(_)
 ## Checks if a type is not present within an `Option` type.
-pub func is_none[T](self: Option[T]): bool =
+pub func is_none[T](self: T?): bool =
   self of None
 
 ## Converts an `Option[T]` to a `Result[T, E]` given a user-provided error.
-pub func err[T, E](self: Option[T], error: E): Result[T, E] =
-  if self of Some(x):
+pub func err[T, E](self: T?, error: E): Result[T, E] =
+  if self of Some(x) then
     Okay(x)
-  else:
+  else
     Error(error)
 
 ## Applies a function to `T`, if it exists.
-pub func map[T, U](self: Option[T], fn: T -> U): Option[U] =
-  if self of Some(x):
+pub func map[T, U](self: T?, fn: T -> U): U? =
+  if self of Some(x) then
     Some(fn(x))
-  else:
+  else
     None
 ## Converts `T` to a `None`, if `fn` returns false and it exists.
-pub func filter[T](self: Option[T], fn: T -> bool): Option[T] =
-  if self of Some(x) and fn(x):
+pub func filter[T](self: T?, fn: T -> bool): T? =
+  if self of Some(x) and fn(x) then
     Some(x)
-  else:
+  else
     None
 
 ## Applies a function to T, if it exists. Equivalent to `self.map(fn).flatten`.
-pub func flatmap[T, U](self: Option[T], fn: T -> Option[U]): Option[U] =
-  if self of Some(x):
+pub func flatmap[T, U](self: T?, fn: T -> U?): U? =
+  if self of Some(x) then
     fn(x)
-  else:
+  else
     None
 ## Converts from Option[Option[T]] to Option[T].
-pub func flatten[T](self: Option[Option[T]]): Option[T] =
-  match self
-  of Some(Some(x)):
+pub func flatten[T](self: T??): T? =
+  if self of Some(Some(x)) then
     Some(x)
-  of _:
+  else
     None
 
 ## Returns the inner value or a default.
-pub func get_or[T](self: Option[T], default: T): T =
-  if self of Some(x): x
-  else: default
-
-## A dummy type signalling the empty value
-type EmptyType = distinct unit
-
-## Directly accesses the inner value. Throws an exception if None.
-pub func ![T](self: Option[T]): T =
-  if self of Some(x): x
-  else: raise EmptyType
-
-## Indirect access. Propagates `None`.
-## Parsed by compiler magic.
-pub macro ?[T](self: Option[T]) =
-  quote:
-    match `self`
-    of Some(x): x
-    of None: return None
-
-## Syntactic sugar for optional type declarations.
-pub macro ?(T: type) =
-  quote:
-    Option[`T`]
+pub func get_or[T](self: T?, default: T): T =
+  if self of Some(x) then x
+  else default
 
 ## Overloads the `==` operation for use on Options.
-pub func ==[T](a, b: Option[T]): bool =
-  match (a, b)
-  of (Some(x), Some(y)):
+pub func ==[T](a, b: T?): bool =
+  if (a, b) of (Some(x), Some(y)) then
     x == y
-  of _:
+  else
     false
 
 ## Overloads the `str()` function for use on Options.
-pub func str[T](self: Option[T]): str =
-  if self of Some(x):
-    fmt("Some({})", x.str)
-  else:
+pub func str[T: Display](self: T?): str =
+  if self of Some(x) then
+    "Some({})".fmt(x.str)
+  else
     "None"
 
-examples:
+examples
   let x = Some(42)
-  if x of Some(y):
+  if x of Some(y) then
     assert x! == y
 
 # references:
diff --git a/std/prelude/ranges.pk b/std/prelude/ranges.pk
index e3af8a4..8410c5e 100644
--- a/std/prelude/ranges.pk
+++ b/std/prelude/ranges.pk
@@ -5,7 +5,7 @@ type Range[T] = struct
   start: T
   end: T
 
-type RangeInclusive[T] = struct
+type RangeIncl[T] = struct
   start: T
   end: T
   done: bool
@@ -17,49 +17,48 @@ pub func ..(from: int, to: int): Range[int] =
 
 ## Inclusive ranges. Useful for ranges.
 ## Includes `from` and `to`.
-pub func ..=(from: int, to: int): RangeInclusive[int] =
+pub func ..=(from: int, to: int): RangeIncl[int] =
   { from, to, done: false }
 
 # todo: implement for all types that can increment or smth idk
 pub func next[T: int](self: mut Range[T]): T? =
-  if self.start < self.end:
-    result = Some(self.start)
+  if self.start < self.end then
     self.start += 1
-  else:
-    result = None
+    Some(self.start - 1)
+  else
+    None
 
 # todo: We don't need a mutable Range here to peek.
-# How does this interact with interfaces?
+# How does this interact with classes?
 pub func peek[T: int](self: mut Range[T]): T? =
   self.peek_nth(0)
 
 pub func peek_nth[T: int](self: mut Range[T], i: uint): T? =
   let res = self.start + i
-  if res < self.end:
+  if res < self.end then
     return Some(res)
-  else:
+  else
     return None
 
-pub func next[T: int](self: mut RangeInclusive[T]): T? =
-  if self.done:
-    return None
-  elif self.start < self.end:
+pub func next[T: int](self: mut RangeIncl[T]): T? =
+  if self.done then
+    None
+  elif self.start < self.end then
     let res = self.start
     self.start += 1
-    return Some(res)
-  elif self.start == self.end:
+    Some(res)
+  elif self.start == self.end then
     self.done = true
-    return Some(self.start)
-  else:
+    Some(self.start)
+  else
     self.done = true
-    return None
+    None
 
-pub func peek[T: int](self: mut RangeInclusive[T]): T? =
+pub func peek[T: int](self: mut RangeIncl[T]): T? =
   self.peek_nth(0)
 
-pub func peek_nth[T: int](self: mut RangeInclusive[T], i: uint): T? =
+pub func peek_nth[T: int](self: mut RangeIncl[T], i: uint): T? =
   let res = self.start + i
-  if res <= self.end:
-    return Some(res)
-  else:
-    return None
+  if res <= self.end
+  then Some(res)
+  else None
diff --git a/std/prelude/results.pk b/std/prelude/results.pk
index 81bccf0..61b0c8a 100644
--- a/std/prelude/results.pk
+++ b/std/prelude/results.pk
@@ -8,8 +8,8 @@ pub type Result[T, E] = union
   Okay(T)
   Error(E)
 
-## The Err interface. Useful for dynamically dispatching errors.
-pub type Err = interface
+## The Err class. Useful for dynamically dispatching errors.
+pub type Err = class
   str(Self): str
   dbg(Self): str
 
@@ -18,7 +18,21 @@ pub type Err = interface
 pub type Result[T] = Result[T, ref Err]
 ## A `Result` type that only checks for success.
 ## Does not contain a value.
-pub type Success[E] = Result[Unit, E]
+# pub type Success[E] = Result[void, E]
+## A `Result` type that only checks for success.
+## Does not contain a value. Dynamically dispatched.
+# pub type Success = Result[void]
+
+## Syntactic sugar for dynamic result type declarations.
+pub macro !(T: type) =
+  quote Result[`T`]
+
+## Indirect access. Propagates `Error`.
+pub macro ?[T, E](self: Result[T, E]) =
+  quote
+    match `self`
+    of Okay(x) then x
+    of Error(e) then return Error(e)
 
 ## Checks if a `Result` type was successful.
 pub func is_ok[T, E](self: Result[T, E]): bool =
@@ -28,110 +42,94 @@ pub func is_err[T, E](self: Result[T, E]): bool =
   self of Error(_)
 
 ## Converts from a `Result[T, E]` to an `Option[T]`.
-pub func ok[T, E](self: Result[T, E]): Option[T] =
-  if self of Okay(x):
+pub func ok[T, E](self: Result[T, E]): T? =
+  if self of Okay(x) then
     Some(x)
-  else:
-    None()
+  else
+    None
 ## Converts from a `Result[T, E]` to an `Option[E]`.
-pub func err[T, E](self: Result[T, E]): Option[E] =
-  if self of Error(x):
+pub func err[T, E](self: Result[T, E]): E? =
+  if self of Error(x) then
     Some(x)
-  else:
-    None()
+  else
+    None
 
 ## Applies a function to `T`, if self is `Okay`.
 pub func map[T, E, U](self: Result[T, E], fn: T -> U): Result[U, E] =
   match self
-  of Okay(x):
+  of Okay(x) then
     Okay(fn(x))
-  of Error(e):
+  of Error(e) then
     Error(e)
 ## Applies a function to `E`, if self is `Error`.
 pub func map_err[T, E, F](self: Result[T, E], fn: E -> F): Result[T, F] =
   match self
-  of Error(e):
+  of Error(e) then
     Error(fn(e))
-  of Okay(x):
+  of Okay(x) then
     Okay(x)
 
 ## Applies a function to `T`, if it exists. Equivalent to `self.map(fn).flatten`.
 pub func flatmap[T, E, U](self: Result[T, E], fn: T -> Result[U, E]): Result[U, E] =
   match self
-  of Okay(x):
+  of Okay(x) then
     fn(x)
-  of Error(e):
+  of Error(e) then
     Error(e)
 ## Converts from a `Result[Result[T, E], E]` to a `Result[T, E]`.
 pub func flatten[T, E](self: Result[Result[T, E], E]): Result[T, E] =
   match self
-  of Okay(Okay(x)):
+  of Okay(Okay(x)) then
     Okay(x)
-  of Okay(Error(e)), Error(e):
+  of Okay(Error(e)), Error(e) then
     Error(e)
 
 ## Transposes a `Result[Option[T], E]` to an `Option[Result[T, E]]`.
-pub func transpose[T, E](self: Result[Option[T], E]): Option[Result[T, E]] =
+pub func transpose[T, E](self: Result[T?, E]): Result[T, E]? =
   match self
-  of Okay(Some(x)):
+  of Okay(Some(x)) then
     Some(Okay(x))
-  of Okay(None()), Error(_):
-    None()
+  of Okay(None), Error(_) then
+    None
 ## Transposes an `Option[Result[T, E]]` to a `Result[Option[T], E]`. Takes a default error.
-pub func transpose[T, E](self: Option[Result[T, E]], error: E): Result[Option[T], E] =
+pub func transpose[T, E](self: Result[T, E]?, error: E): Result[T?, E] =
   match self
-  of Some(Okay(x)):
-    Okay(Some(x))
-  of Some(Error(e)):
-    Error(e)
-  of None():
-    Error(error)
+  of Some(Okay(x)) then Okay(Some(x))
+  of Some(Error(e)) then Error(e)
+  of None then Error(error)
 
 ## Returns the inner value or a default.
 pub func get_or[T, E](self: Result[T, E], default: T): T =
-  if self of Okay(x): x
-  else: default
+  if self of Okay(x) then x
+  else default
 
 ## Directly accesses the inner value. Throws an exception if `Error`.
 pub func ![T, E](self: Result[T, E]): T =
   match self
-  of Okay(x): x
-  of Error(e): raise e
+  of Okay(x) then x
+  of Error(e) then raise e
 ## Directly accesses the inner error. Throws an exception of type T if `Okay`.
 pub func get_err[T, E](self: Result[T, E]): E =
   match self
-  of Error(e): e
-  of Okay(x): raise x
-
-## Indirect access. Propagates `Error`.
-pub macro ?[T, E](self: Result[T, E]) =
-  quote:
-    match `self`
-    of Okay(x): x
-    of Error(e): return Error(e)
-
-## Syntactic sugar for dynamic `Result` type declarations.
-pub macro ?!(T: type) =
-  quote:
-    Result[`T`]
+  of Error(e) then e
+  of Okay(x) then raise x
 
 ## Overloads the `==` operation for use on Results.
 pub func ==[T, E, F](a: Result[T, E], b: Result[T, F]): bool =
-  match (a, b)
-  of (Okay(x), Okay(y)):
+  if (a, b) of (Okay(x), Okay(y)) then
     x == y
-  of _:
+  else
     false
 
 ## Overloads the `str()` function for use on Results.
-pub func str[T, E](self: Result[T, E]): str =
+pub func str[T: Display, E: Display](self: Result[T, E]): str =
   match self
-  of Some(x):
-    fmt("Okay({})", x.str)
-  of Error(e):
-    fmt("Error({})", e.str)
+  of Some(x) then
+    "Okay({})".fmt(x.str)
+  of Error(e) then
+    "Error({})".fmt(e.str)
 
-examples:
+examples
   let x: Error("fuck") = Okay(42)
   func idk: Result[int, string]
 
diff --git a/std/prelude/strings.pk b/std/prelude/strings.pk
index 2f48b67..e86d520 100644
--- a/std/prelude/strings.pk
+++ b/std/prelude/strings.pk
@@ -2,100 +2,82 @@
 ## This module is imported by default.
 # reference: https://doc.rust-lang.org/std/string/struct.String.html
 
-use std.pointers
-
-# possible approaches: list[byte], distinct list[byte], this
-# should *really* just rely on lists, i don't want to duplicate slicing logic, but... maybe...
-type str = struct
-  data: ptr[byte]
-  length: uint
-  capacity: uint
+## A primitive string type.
+##
+## We do not want methods defined on `list[byte]` to carry over,
+## so we define `str` as a newtype.
+pub type str = struct
+  data: list[byte]
 
 ## Initialize and return an empty string.
-pub func init(): str =
-  ...
+pub func init: str = { data = [] }
 
 ## Gets the length of a string.
-pub func len(self: str): uint =
-  self.length
-
-pub func empty(self: str): bool =
-  self.length == 0
-
-## Gets the internal capacity of a string.
-func cap(self: str): uint =
-  self.capacity
-
-## Expands the capacity of a string.
-func grow(self: mut str) =
-  ...
+## This is an O(n) operation, due to UTF-8 encoding.
+pub func len(self: lent str): uint =
+  var res: uint
+  for _ in self do
+    res += 1
+  res
 
 ## Pushes a character to the end of a mutable string.
-pub func push(self: mut str, val: chr) = # todo: `add` alias?
-  ...
+pub func push(self: mut str, val: chr) =
+  self.data.push(val.byte) # todo: obsolete by from/to conversion??
 
 ## Pushes an owned string to the end of a mutable string.
 pub func push(self: mut str, val: str) =
-  ...
+  self.data.push(val.bytes) # todo: obsolete by from/to conversion??
 
 ## Removes and returns the last character of a string, if it exists.
+##
+## SAFETY: We return early upon an empty string.
+## And decrement by one char for a non-empty string.
+@[safe]
 pub func pop(self: mut str): chr? =
-  ...
+  let char = self.chars.rev.next?
+  self.data.set_len(self.len - char.len) # this is normally unsafe.
+  Some(char)
 
 ## Returns the character at the provided index, if it exists.
 pub func get(self: str, i: uint): chr? =
   ...
 
 ## Sets the character at the provided index, if it exists.
-## todo: what if it does not exist?
+## As strings are packed, this may call str.grow and reallocate.
+## oh fuck we have to insert + remove anyway
 pub func set(self: mut str, i: uint, val: chr) =
   ...
 
 ## Inserts a character at an arbitrary position within a string.
-## Error handling: todo
+## Panics on failure. (todo: can we do better?)
 pub func insert(self: mut str, i: uint, val: chr) =
   ...
 
 ## Removes and returns a character at an arbitrary position within a string.
-## Panics on failure.
+## Panics on failure. (todo: can we do better?)
 pub func remove(self: mut str, i: uint): chr =
   ...
 
-## Returns the *byte* at an arbitrary position within a string.
-## Explicitly distinct from `get` as this breaks safety conventions idk
-pub func get_byte(self: str): byte =
-  ...
-
-## Sets a byte at the provided index, if it exists. Do we want this?
-pub func set_byte(self: mut str, i: uint, val: byte) =
-  ...
-
-## Inserts a byte into a string. Breaks string convention. Do we want this?
-pub func insert_byte(self: mut str, i: uint, val: byte) =
-  ...
-
-## Removes a byte at a given offset from a string. Do we want this?
-pub func remove_byte(self: mut str, i: uint): byte? =
-  ...
-
-## Converts a given string to a list of bytes for iteration purposes.
-pub func bytes(self: str): list[byte] =
-  ... # many performance considerations
-
-## Converts a given string to a list of chars for iteration purposes.
-pub func chars(self: str): list[chr] # todo: useful?
-
-## The concatenation operator.
-pub func &(a: str, b: str): str =
-  ...
-
 ## Syntactic sugar for string appending.
-pub func &=(a: mut str, b: owned str) =
+pub func &=(a: mut str, b: str) =
   a.push(b)
 
-# todo: many things
+## The concatenation operator. Consumes two strings.
+pub func &(a: str, b: str): str =
+  a.push(b)
+  a
+
+## Conversion from a string to a list of bytes. Zero-cost.
+pub func to(self: str): list[byte] = self.data
+## Conversion from a str to a list[chr]. Reallocates.
+pub func to(self: str): list[chr] =
+  var res: list[chr]
+  for char in self do res.push(char)
+  res
+## Conversion from a char to an array of bytes. Zero-cost.
+@[safe] # possibly unsafe?? depends on repr of arrays
+pub func to(self: chr): array[byte, 4] = self.cast[array[byte, 4]]
 
-# pub func iter(self: str): StrIter
 # pub func next(self: mut StrIter)
 # pub func peek(self: mut StrIter)
 # pub func peek_nth(self: mut StrIter, i: uint)
diff --git a/std/threads.pk b/std/threads.pk
index 2b1e98f..fcb65d4 100644
--- a/std/threads.pk
+++ b/std/threads.pk
@@ -1 +1,3 @@
 ## std.threads: Primitives for threads and thread-safe code.
+## These are system threads, not greenthreads. Does not include a threadpool.
+# reference: https://github.com/mratsim/weave