10 files changed, 126 insertions, 134 deletions
diff --git a/std/ast.pk b/std/ast.pk
new file mode 100644
index 0000000..abc66ba
--- /dev/null
+++ b/std/ast.pk
@@ -0,0 +1,81 @@
+## 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]])
+  List(list[Expr])
+  Let(id: Pattern, kind: Type?, value: ref Expr)
+  Var(id: Pattern, kind: Type?, value: ref Expr?)
+  Const(id: Pattern, kind: Type?, value: ref Expr)
+  FuncDecl( # effects?
+    id: str,
+    generics: list[GenericParams],
+    params: list[FunctionParams],
+    kind: Type,
+    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]?)
+  Try(
+    try_body: list[Expr],
+    catches: list[TryBranch]
+    finally_body: list[Expr]?
+  )
+  Match(
+    item: ref Expr,
+    branches: list[MatchBranch]
+  )
+  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]
+    for_type: Type?
+  )
+  Array(size: uint, kind: Type)
+  List(Type)
+  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]
+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])
diff --git a/std/async.pk b/std/async.pk
new file mode 100644
index 0000000..7c76076
--- /dev/null
+++ b/std/async.pk
@@ -0,0 +1,19 @@
+## std.async: Zig-style colourless async/await.
+## Future types, the async macro, and the await function.
+
+## A standard Future type. Opaque.
+pub type Future[T] = struct
+  ...
+
+## The `async` macro transforms any function call into
+## an asynchronous call returning a Future of some type.
+pub macro async[T](call: T): Future[T] =
+  ...
+
+## The `await` function blocks on a Future[T] call until it returns a value.
+pub func await[T](self: Future[T]): T =
+  ...
+
+examples:
+  std.net.connect()
+  print 1.async.await
diff --git a/std/fundamental/ast.pk b/std/fundamental/ast.pk
deleted file mode 100644
index 0529cbd..0000000
--- a/std/fundamental/ast.pk
+++ /dev/null
@@ -1,113 +0,0 @@
-## std/ast: Exposes the AST for building and operating on with macros.
-
-pub type Ident = string
-pub type Number = int
-pub type Float = float
-pub type Char = char
-pub type String = str
-pub type Struct = list[struct[field: str, value: Expr]]
-pub type Tuple = list[struct[field: Option[string], value: Expr]]
-pub type List = list[Expr]
-
-pub type Let = struct
-  id: Pattern
-  kind: Option[Type]
-  value: ref Expr
-pub type Var = struct
-  id: Pattern
-  kind: Option[Type]
-  value: Option[ref Expr] # variable bindings can be delayed
-pub type Const = struct
-  id: Pattern
-  kind: Option[Type]
-  value = ref Expr
-pub type FuncDecl = struct
-  public: bool
-  effect: Option[str]
-  id: str
-  generics: list[struct[id: str, kind: Option[Type]]]
-  params: list[struct[id: str, kind: Type]]
-  kind: Type
-  body: list[Expr]
-pub type TypeDecl = struct
-  id: str
-  generics: list[str]
-  alias: Type
-pub type Import = struct
-  mod_from: Option[string]
-  imports: list[str]
-  alias: Option[str]
-pub type Module = struct
-  id: str
-  body: list[Expr]
-
-pub type Call = struct
-  id: str
-  params: list[Expr]
-pub type Cond = struct
-  branches: list[struct[cond: Expr, body: list[Expr]]]
-  else_body: Option[list[Expr]]
-pub type Try = struct
-  body: list[Expr]
-  catches: list[struct[exceptions: list[str], body: list[Expr]]]
-  finally_body: Option[list[Expr]]
-pub type Match = struct
-  item: ref Expr
-  branches: list[struct[pattern: Pattern, guard: Option[Expr], body: list[Expr]]]
-pub type Block = struct
-  id: Option[str]
-  body: list[Expr]
-pub type Static = struct
-  body: list[Expr]
-pub type For = struct
-  binding: Pattern
-  range: ref Expr
-  body: list[Expr]
-pub type While = struct
-  cond: ref Expr
-  body: list[Expr]
-pub type Loop = struct
-  body: list[Expr]
-
-# the first style of union. naming anonymous types.
-pub type Type = union
-  Void, Never,
-  Integer, Float, String,
-  Func: struct[from, to: ref Type] # todo: multiple parameters
-  Struct: list[struct[id: str, kind: Type]]
-  Tuple: list[struct[id: Option[str], kind: Type]]
-  Union: list[struct[id: str, kind: Type]]
-  Interface: struct # todo: generics
-    funcs: list[Signature]
-    for_type: Option[ref Type]
-  Array: struct[size: uint, kind: ref Type]
-  List: ref Type
-  Slice: ref Type # todo: plus ownership
-  Alias: str # todo: params?? huh?
-  Static: ref Type
-  Mutable: ref Type
-  Reference: ref Type
-pub type Signature = struct # todo: generics
-  id: str
-  effect: Option[str]
-  params: list[Type]
-  kind: Option[Type]
-pub type Pattern = union
-  Ident: str
-  Number: int, Float: float, Char: char, String: str
-  Struct: struct[name: str, params: list[Pattern]]
-  Tuple: list[Pattern]
-  List: list[Pattern]
-
-# the second style of union. A union of literal types, no names.
-pub type Expr = union
-  Ident, Number, Float, Char, String, Struct, Tuple, List,
-  Let, Var, Const, FuncDecl, TypeDecl, Import, Module,
-  Call, Cond, Try, Match, Block, Static, For, While, Loop,
-
-# todo: decide on a style of union
-
-# anonymous struct objects can be constructed with {}
-# anonymous tuple objects can be constructed with ()
-# anonymous list objects can be constructed with []
-# anonymous union *types* can be constructed with | (in parameters)
diff --git a/std/fundamental/logs.pk b/std/fundamental/logs.pk
deleted file mode 100644
index 7a0060f..0000000
--- a/std/fundamental/logs.pk
+++ /dev/null
@@ -1 +0,0 @@
-## std/logs: Utility macros and functions for logging.
diff --git a/std/logs.pk b/std/logs.pk
new file mode 100644
index 0000000..98042b0
--- /dev/null
+++ b/std/logs.pk
@@ -0,0 +1 @@
+## std.logs: Utility macros and functions for logging.
diff --git a/std/default/format.pk b/std/prelude/format.pk
index b117632..3adb68b 100644
--- a/std/default/format.pk
+++ b/std/prelude/format.pk
@@ -1,8 +1,8 @@
-## std/format: Niceties around printing and debugging.
+## std.format: Niceties around printing and debugging.
 ## This module is imported by default.
 
 ## The Display interface. Any type implementing `str` is printable.
-## Any type that is Display must also implement Debug.
+## Any type that is Display must necessarily also implement Debug.
 pub type Display = interface
   str(Self): str
   dbg(Self): str
@@ -29,24 +29,25 @@ pub func dbg(self: str): str = "\"" & self & "\""
 ## An implementation of the Debug interface for all structs.
 ## Uses the special `struct` typeclass.
 pub func dbg(self: struct): str =
-  "{" & self.fields.map(field => field.id & field.value.dbg) & "}"
+  "{{}}".fmt(self.fields.map((key, val) => key & ":" & val.dbg))
 
 ## An implementation of the Debug interface for all tuples.
 ## Uses the special `tuple` typeclass.
 pub func dbg(self: tuple): str =
-  result &= "("
-  for i, field in self.fields.enumerate():
-    result &= field.id.map(id => id & " = ").get_or("")
-    if i != self.fields.len:
-      result &= ", "
-  result &= ")"
+  "({})".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.
-pub func dbg(self: Iter[Debug]): str =
-  "[" & self.map(x => x.str).join(", ") & "]"
+pub func dbg[T: Debug](self: Iter[T]): str =
+  "[{}]".fmt(self.map(x => x.str).join(", "))
 
 ## The fmt macro. Builds a formatted string from its arguments.
-pub macro fmt(formatted: static[str], args: varargs[Display]) =
-  # if not formatted of String:
-  #   macro_error("fmt must take a static string parameter!")
-  ...
+pub macro fmt(self: static[str], args: varargs[Display]): str =
+  let parts = self.split("{}")
+  if parts.len != args.len + 1:
+    macro_error("wrong number of arguments")
+  use std.ast
+  result = parts.get(0)!
+  for i, arg in args:
+    result &= quote(`parts` & str(`arg`) &) # fixme
+  result &= parts.last()!
diff --git a/std/default/iterators.pk b/std/prelude/iterators.pk
index f7e4972..224460f 100644
--- a/std/default/iterators.pk
+++ b/std/prelude/iterators.pk
@@ -1,4 +1,4 @@
-## std/iterators: The Iter interface and associated functions.
+## std.iterators: The Iter interface and associated functions.
 ## This module is imported by default.
 
 ## The Iter interface. Any type implementing `next()` is iterable.
diff --git a/std/default/options.pk b/std/prelude/options.pk
index fb696ba..4f6cef2 100644
--- a/std/default/options.pk
+++ b/std/prelude/options.pk
@@ -1,4 +1,4 @@
-## std/options: Optional types.
+## std.options: Optional types.
 ## This module is imported by default.
 
 use std.format
@@ -54,10 +54,14 @@ pub func flatten[T](self: Option[Option[T]]): Option[T] =
 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 Exception # todo: syntax??
+  else: raise EmptyType
 
 ## Indirect access. Propagates `None`.
 ## Parsed by compiler magic.
diff --git a/std/default/results.pk b/std/prelude/results.pk
index 8e21234..1209b40 100644
--- a/std/default/results.pk
+++ b/std/prelude/results.pk
@@ -1,4 +1,4 @@
-## std/results: Result types.
+## std.results: Result types.
 ## This module is imported by default.
 
 use std[options, format]
diff --git a/std/fundamental/tests.pk b/std/tests.pk
index 7eb00a8..8d13a4e 100644
--- a/std/fundamental/tests.pk
+++ b/std/tests.pk
@@ -1,4 +1,4 @@
-## std/tests: Utility macros and functions for testing.
+## std.tests: Utility macros and functions for testing.
 
 ## A macro for runnable examples. Runs them on compilation.
 pub macro examples(body) =