std: minor updates, consistently use Error and Err

4 files changed, 27 insertions, 13 deletions

diff --git a/README.md b/README.md
index e6b5cb1..44e7e3d 100644
--- a/README.md
+++ b/README.md
@@ -8,9 +8,9 @@ It aims to be clean and succinct while performant: inspired by the syntax and me
 ```nim
 import std/tables
 
-mod Ast:
+mod ast:
   pub type Value = interface
-    func repr(self: Self): string
+    repr(Self): string
   pub type Ident = string
   pub type Expr = ref union
     Literal: ref Value
@@ -20,19 +20,19 @@ mod Ast:
     Conditional: struct
       cond, then_branch, else_branch: Expr
 
-  pub func eval(expr: Expr, context: var HashTable[Ident, Value]): Result[Value]
+  pub func eval(expr: Expr, context: var HashTable[Ident, Value]): Result[Value, ref Err]
     match expr
     of Literal(value):
       Okay(value)
     of Variable(ident):
       context.get(ident)
-    of Application{body, arg}:
-      if body of Abstraction{param, body as inner_body}:
+    of Application(body, arg):
+      if body of Abstraction(param, body as inner_body):
         context.set(param, eval(arg))
         inner_body.eval(context)
       else:
         Error(InvalidExpr)
-    of Conditional{cond, then_branch, else_branch}:
+    of Conditional(cond, then_branch, else_branch):
       if eval(cond, context):
         then_case.eval(context)
       else:
@@ -40,7 +40,7 @@ mod Ast:
     of _:
       Error(InvalidExpr)
 
-Ast.eval("(λx.x) 413".parse(), HashTable.init())
+ast.eval("(λx.x) 413".parse(), HashTable.init())
 ```
 
 ## Why Puck?
diff --git a/std/default/format.pk b/std/default/format.pk
index ec573ef..ee8997d 100644
--- a/std/default/format.pk
+++ b/std/default/format.pk
@@ -7,13 +7,13 @@ pub type Display = interface
   str(Self): str
   dbg(Self): str
 
-## The Debug interface. Broadly implemented for every type with magic,
+## The Debug interface. Broadly implemented for every type with compiler magic,
 ## types can (and should) override the generic implementations.
 pub type Debug = interface
   dbg(Self): str
 
 ## Prints all of its arguments to the command line.
-pub proc print(params: varargs[Display]) =
+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.
diff --git a/std/default/options.pk b/std/default/options.pk
index bbe0d9c..397a8f3 100644
--- a/std/default/options.pk
+++ b/std/default/options.pk
@@ -3,14 +3,18 @@
 
 import std/format
 
+## The `Option` type.
+## A type that represents either the presence or absence of a value.
 pub type Option[T] = union
   Some: T
   None
 
+## Checks if a type is present within an `Option` type.
 pub func is_some[T](self: Option[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 =
-  not self.is_some
+  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] =
diff --git a/std/default/results.pk b/std/default/results.pk
index 4e4d27a..8faf0c0 100644
--- a/std/default/results.pk
+++ b/std/default/results.pk
@@ -3,20 +3,30 @@
 
 import std/[options, format]
 
+## The Result type.
+## A type that represents either success or failure.
 pub type Result[T, E] = union
   Okay: T
   Error: E
 
-pub type Error = interface
+## The Err interface. Useful for dynamically dispatching errors.
+pub type Err = interface
   str(Self): str
   dbg(Self): str
 
-pub type Result[T] = Result[T, ref Error]
+## A `Result` type that uses dynamically dispatched errors.
+## The `Error` may be any type implementing `Err`.
+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]
 
+## Checks if a `Result` type was successful.
 pub func is_ok[T, E](self: Result[T, E]): bool =
   self of Okay(_)
+## Checks if a `Result` type was not successful.
 pub func is_err[T, E](self: Result[T, E]): bool =
-  not self.is_ok
+  self of Error(_)
 
 ## Converts from a `Result[T, E]` to an `Option[T]`.
 pub func ok[T, E](self: Result[T, E]): Option[T] =