documentation revisions and missing pieces

doc/site/classes.markdown

@@ -267,7 +267,7 @@ inside a method works like this:
 
 So, in the above example, we hit case #2 and it prints "Francis". Distinguishing
 self sends from outer variables based on the *case* of the first letter in the
-name probably seems crazy but it works surprisingly well. Method names are
+name probably seems weird but it works surprisingly well. Method names are
 lowercase in Wren. Class names are capitalized.
 
 Most of the time, when you're in a method and want to access a name from outside

doc/site/contributing.markdown

@@ -88,8 +88,7 @@ The basic process is simple:
     If there are no failures, you're good to go.
 
 2. **[Fork the repo][fork] so you can change it locally.** Please make your
-   changes in separate [feature branches][] to make things a little easier on
+   changes in separate [feature branches][] to make things a little easier.
-   me.
 
 3. **Change the code.** Please follow the style of the surrounding code. That
    basically means `camelCase` names, `{` on the next line, keep within 80
@@ -105,8 +104,7 @@ The basic process is simple:
 6. **Add your name and email to the [AUTHORS][] file if you haven't already.**
 
 7. **Send a [pull request][].** Pat yourself on the back for contributing to a
-   fun open source project! I'll take it from here and hopefully we'll get it
+   fun open source project! 
-   landed smoothly.
 
 ## Getting help
 

doc/site/control-flow.markdown

@@ -65,7 +65,7 @@ if (ready) {
 
 Unlike most other [operators][] in Wren which are just a special syntax for
 [method calls][], the `&&` and `||` operators are special. This is because they
-only conditionally evaluate right operand—they short-circuit.
+only conditionally evaluate the right operand—they short-circuit.
 
 [operators]: method-calls.html#operators
 [method calls]: method-calls.html
@@ -92,7 +92,7 @@ System.print(1 || 2)      //> 1
 
 Also known as the "ternary" operator since it takes three arguments, Wren has
 the little "if statement in the form of an expression" you know and love from C
-and its brethren.
+and similar languages.
 
 <pre class="snippet">
 System.print(1 != 2 ? "math is sane" : "math is not sane!")

doc/site/functions.markdown

@@ -1,129 +1,43 @@
 ^title Functions
 
-No self-respecting language today can get by without functions—first
+Like many languages today, functions in Wren are little bundles of code 
-class little bundles of code. Since Wren is object-oriented, most of your code
+you can store in a variable, or pass as an argument to a method. 
-will live in methods on classes, but free-floating functions are still
+
-eminently handy.
+Notice there's a difference between _function_ and _method_.
+
+Since Wren is object-oriented, most of your code will live in methods on
+classes, but free-floating functions are still eminently handy. 
 
 Functions are objects like everything else in Wren, instances of the `Fn`
 class.
 
-## Block arguments
+## Creating a function
 
-Most of the time you create a function just to pass it to some method. For
+To create a function, we call `Fn.new`, which takes a block to execute.
-example, if you want to filter a [list](lists.html) by some criteria, you'll
+To call the function, we use `.call()` on the function instance.
-call its `where` method, passing in a function that defines the predicate
-you're filtering on.
-
-Since that's the most common usage pattern, Wren's syntax optimizes for that.
-Taking a page from Ruby, a function is created by passing a *block argument* to
-a method. At its simplest, it looks like this:
 
 <pre class="snippet">
-blondie.callMe {
+var sayHello = Fn.new { System.print("hello") }
-  System.print("This is the body!")
+
-}
+sayHello.call() //> hello
 </pre>
 
-Here we're invoking the `callMe` method on `blondie`. We're passing one
+Note that we'll see a shorthand syntax for creating a function below.
-argument, a function whose body is the
-following [block](syntax.html#blocks)&mdash;everything between that pair of
-curly braces.
-
-Methods that take a block argument receive it as a normal parameter. `callMe`
-could be defined like so:
-
-<pre class="snippet">
-class Blondie {
-  callMe(fn) {
-    // Call it...
-  }
-}
-
-var blondie = Blondie.new()
-</pre>
-
-A method can take other arguments in addition to the block. They appear before
-the block just like a regular argument list. For example:
-
-<pre class="snippet">
-blondie.callMeAt(867, 5309) {
-  System.print("This is the body!")
-}
-</pre>
-
-Of course, you don't *have* to use a block argument to pass a function to a
-method. If you already have a function object, you can pass it like a regular
-argument:
-
-<pre class="snippet">
-var someFn = // Get a function...
-blondie.callMe(someFn)
-</pre>
-
-Block arguments are purely sugar for creating a function and passing it in one
-little blob of syntax. There are some times when you want to create a function
-but *don't* need to pass it to a method. For that, you can call the `Fn`
-class's constructor:
-
-<pre class="snippet">
-var someFn = Fn.new {
-  System.print("Hi!")
-}
-</pre>
-
-As you can see it takes a block argument too! All the constructor does is
-return that argument, so this exists purely as a convenience method for you.
-
-## Calling functions
-
-Once you have a function, how do you invoke it? Like everything in Wren, you do
-so by calling a method on it:
-
-<pre class="snippet">
-class Blondie {
-  callMe(fn) {
-    fn.call()
-  }
-}
-</pre>
-
-Functions expose a `call()` method that executes the body of the function. This
-method is dynamically-dispatched like any other, so you can define your own
-"function-like" classes and pass them to methods that expect "real" functions.
-
-<pre class="snippet">
-class FakeFn {
-  call() {
-    System.print("I'm feeling functional!")
-  }
-}
-
-blondie.callMe(FakeFn.new())
-</pre>
 
 ## Function parameters
 
 Of course, functions aren't very useful if you can't pass values to them. The
-functions that we've seen so far take no arguments. To change that, you can
+function above takes no arguments. To change that, you can provide a parameter
-provide a parameter list surrounded by `|` immediately after the opening brace
+list surrounded by `|` immediately after the opening brace of the body.
-of the body, like so:
+
+To pass arguments to the function, pass them to the `call` method:
 
 <pre class="snippet">
-blondie.callMe {|first, last|
+var sayMessage {|recipient, message|
-  System.print("Hi, " + first + " " + last + "!")
+  System.print("message for %(recipient): %(message)")
 }
-</pre>
 
-Here we're passing a function to `callMe` that takes two parameters, `first` and
+sayMessage.call("Bob", "Good day!")
-`last`. They are passed to the function when it's called:
-
-<pre class="snippet">
-class Blondie {
-  callMe(fn) {
-    fn.call("Debbie", "Harry")
-  }
-}
 </pre>
 
 It's an error to call a function with fewer arguments than its parameter list
@@ -148,6 +62,14 @@ Fn.new {
 }
 </pre>
 
+The return value is handed back to you when using `call`:
+
+<pre class="snippet">
+var fn = Fn.new { "some value" }
+var result = fn.call()
+System.print(result) //> some value
+</pre>
+
 ## Closures
 
 As you expect, functions are closures&mdash;they can access variables defined
@@ -175,6 +97,149 @@ System.print(counter.call()) //> 2
 System.print(counter.call()) //> 3
 </pre>
 
+## Callable classes
+
+Because `Fn` is a class, and responds to `call()`, any class can respond to 
+`call()` and be used in place of a function. This is particularly handy when 
+the function is passed to a method to be called, like a callback or event.
+
+<pre class="snippet">
+class Callable {
+  construct new() {}
+  call(name, version) {
+    System.print("called %(name) with version %(version)")
+  }
+}
+
+var fn = Callable.new()
+fn.call("wren", "0.4.0")
+</pre>
+
+## Block arguments
+
+Very frequently, functions are passed to methods to be called. There are 
+countless examples of this in Wren, like [list](lists.html) can be filtered
+using a method `where` which accepts a function:
+
+<pre class="snippet">
+var list = [1, 2, 3, 4, 5]
+var filtered = list.where(Fn.new {|value| value > 3 }) 
+System.print(filtered.toList) //> [4, 5]
+</pre>
+
+This syntax is a bit less fun to read and write, so Wren implements the 
+_block argument_ concept. When a function is being passed to a method, 
+and is the last argument to the method, it can use a shorter syntax: 
+_just the block part_.
+
+Let's use a block argument for `list.where`, it's the last (only) argument:
+
+<pre class="snippet">
+var list = [1, 2, 3, 4, 5]
+var filtered = list.where {|value| value > 3 } 
+System.print(filtered.toList) //> [4, 5]
+</pre>
+
+We've seen this before in a previous page using `map` and `where`:
+
+<pre class="snippet">
+numbers.map {|n| n * 2 }.where {|n| n < 100 }
+</pre>
+
+## Block argument example
+
+Let's look at a complete example, so we can see both ends.
+
+This may be a bit of a spoiler for [classes](classes.html), so feel free
+to read that page first and come back.
+
+Here's a fictional class for something that will call a function
+when a click event is sent to it. It allows us to pass just a 
+function and assume the left mouse button, or to pass a button and a function.
+
+<pre class="snippet">
+class Clickable {
+  construct new() {
+    _fn = null
+    _button = 0
+  }
+  
+  onClick(fn) {
+    _fn = fn
+  }
+
+  onClick(button, fn) {
+    _button = button
+    _fn = fn
+  }
+
+  fireEvent(button) {
+    if(_fn && button == _button) {
+      _fn.call(button)
+    }
+  }
+}
+</pre>
+
+Now that we've got the clickable class, let's use it.
+We'll start by using the method that accepts just a function
+because we're fine with it just being the default left mouse button.
+
+<pre class="snippet">
+var link = Clickable.new()
+
+link.onClick {|button|
+  System.print("I was clicked by button %(button)")
+}
+
+// send a left mouse click
+// normally this would happen from elsewhere
+
+link.fireEvent(0)  //> I was clicked by button 0
+</pre>
+
+Now let's try with the extra button argument:
+
+<pre class="snippet">
+var contextMenu = Clickable.new()
+
+contextMenu.onClick(1) {|button|
+  System.print("I was right-clicked")
+}
+
+link.fireEvent(0)  //> (nothing happened)
+link.fireEvent(1)  //> I was right-clicked
+</pre>
+
+Notice that we still pass the other arguments normally, 
+it's only the last argument that is special.
+
+**Just a regular function**   
+
+Block arguments are purely syntax sugar for creating a function and passing it
+in one little blob of syntax. These two are equivalent:
+
+<pre class="snippet">
+onClick(Fn.new { System.print("clicked") })
+onClick { System.print("clicked") }
+</pre>
+
+And this is just as valid:
+
+<pre class="snippet">
+var onEvent = Fn.new {|button|
+  System.print("clicked by button %(button)")
+}
+
+onClick(onEvent)
+onClick(1, onEvent)
+</pre>
+
+**Fn.new**   
+As you may have noticed by now, `Fn` accepts a block argument for the `Fn.new`.
+All the constructor does is return that argument right back to you!
+
+
 <br><hr>
 <a class="right" href="classes.html">Classes &rarr;</a>
 <a href="variables.html">&larr; Variables</a>

doc/site/lists.markdown

@@ -20,23 +20,23 @@ element you want. Like most languages, indexes start at zero:
 [subscript operator]: method-calls.html#subscripts
 
 <pre class="snippet">
-var hirsute = ["sideburns", "porkchops", "'stache", "goatee"]
+var trees = ["cedar", "birch", "oak", "willow"]
-System.print(hirsute[0]) //> sideburns
+System.print(trees[0]) //> cedar
-System.print(hirsute[1]) //> porkchops
+System.print(trees[1]) //> birch
 </pre>
 
 Negative indices counts backwards from the end:
 
 <pre class="snippet">
-System.print(hirsute[-1]) //> goatee
+System.print(trees[-1]) //> willow
-System.print(hirsute[-2]) //> 'stache
+System.print(trees[-2]) //> oak
 </pre>
 
 It's a runtime error to pass an index outside of the bounds of the list. If you
 don't know what those bounds are, you can find out using count:
 
 <pre class="snippet">
-System.print(hirsute.count) //> 4
+System.print(trees.count) //> 4
 </pre>
 
 ## Slices and ranges
@@ -45,7 +45,7 @@ Sometimes you want to copy a chunk of elements from a list. You can do that by
 passing a [range](values.html#ranges) to the subscript operator, like so:
 
 <pre class="snippet">
-System.print(hirsute[1..2]) //> [porkchops, 'stache]
+System.print(trees[1..2]) //> [birch, oak]
 </pre>
 
 This returns a new list containing the elements of the original list whose
@@ -56,7 +56,7 @@ Negative bounds also work like they do when passing a single number, so to copy
 a list, you can just do:
 
 <pre class="snippet">
-hirsute[0..-1]
+trees[0..-1]
 </pre>
 
 ## Adding elements
@@ -65,22 +65,22 @@ Lists are *mutable*, meaning their contents can be changed. You can swap out an
 existing element in the list using the subscript setter:
 
 <pre class="snippet">
-hirsute[1] = "muttonchops"
+trees[1] = "spruce"
-System.print(hirsute[1]) //> muttonchops
+System.print(trees[1]) //> spruce
 </pre>
 
 It's an error to set an element that's out of bounds. To grow a list, you can
 use `add` to append a single item to the end:
 
 <pre class="snippet">
-hirsute.add("goatee")
+trees.add("maple")
-System.print(hirsute.count) //> 5
+System.print(trees.count) //> 5
 </pre>
 
 You can insert a new element at a specific position using `insert`:
 
 <pre class="snippet">
-hirsute.insert(2, "soul patch")
+trees.insert(2, "hickory")
 </pre>
 
 The first argument is the index to insert at, and the second is the value to
@@ -143,8 +143,8 @@ System.print(letters.remove("not found")) //> null
 If you want to remove everything from the list, you can clear it:
 
 <pre class="snippet">
-hirsute.clear()
+trees.clear()
-System.print(hirsute) //> []
+System.print(trees) //> []
 </pre>
 
 <br><hr>

doc/site/maps.markdown

@@ -9,22 +9,26 @@ curly braces. Each entry is a key and a value separated by a colon:
 
 <pre class="snippet">
 {
-  "George": "Harrison",
+  "maple":  "Sugar Maple (Acer Saccharum)",
-  "John":   "Lennon",
+  "larch":  "Alpine Larch (Larix Lyallii)",
-  "Paul":   "McCartney",
+  "oak":    "Red Oak (Quercus Rubra)",
-  "Ringo":  "Starr"
+  "fir":    "Fraser Fir (Abies Fraseri)"
 }
 </pre>
 
-This creates a map that associates the first name of each Beatle with his last
+This creates a map that associates a type of tree (key) to a specific 
-name. Syntactically, in a map literal, keys can be any literal, a variable
+tree within that family (value). Syntactically, in a map literal, keys 
-name, or a parenthesized expression. Values can be any expression. Here, we're
+can be any literal, a variable name, or a parenthesized expression. 
-using string literals for both keys and values.
+Values can be any expression. Here, we're using string literals for both keys 
+and values.
 
 *Semantically*, values can be any object, and multiple keys may map to the same
-value. Keys have a few limitations. They must be one of the immutable built-in
+value. 
+
+Keys have a few limitations. They must be one of the immutable built-in
 [value types][] in Wren. That means a number, string, range, bool, or `null`.
-You can also use a [class object][] as a key.
+You can also use a [class object][] as a key (not an instance of that class, 
+the actual class itself).
 
 [value types]: values.html
 [class object]: classes.html
@@ -67,12 +71,12 @@ doesn't necessarily mean the key wasn't found.
 To tell definitively if a key exists, you can call `containsKey()`:
 
 <pre class="snippet">
-var belief = {"nihilism": null}
+var capitals = {"Georgia": null}
 
-System.print(belief["nihilism"]) //> null (though key exists)
+System.print(capitals["Georgia"]) //> null (though key exists)
-System.print(belief["solipsism"]) //> null
+System.print(capitals["Idaho"])   //> null 
-System.print(belief.containsKey("nihilism")) //> true
+System.print(capitals.containsKey("Georgia")) //> true
-System.print(belief.containsKey("solipsism")) //> false
+System.print(capitals.containsKey("Idaho"))   //> false
 </pre>
 
 You can see how many entries a map contains using `count`:
@@ -113,16 +117,38 @@ System.print(capitals.count) //> 0
 
 The subscript operator works well for finding values when you know the key
 you're looking for, but sometimes you want to see everything that's in the map.
-For that, map exposes two methods: `keys` and `values`.
+You can use a regular for loop to iterate the contents, and map exposes two 
+additional methods to access the contents: `keys` and `values`. 
 
-The first returns a [Sequence][] that [iterates][] over all of the keys in the
+The `keys` method on a map returns a [Sequence][] that [iterates][] over all of
-map, and the second returns one that iterates over the values.
+the keys in the map, and the `values` method returns one that iterates over the values.
 
 [sequence]: modules/core/sequence.html
 [iterates]: control-flow.html#the-iterator-protocol
 
-If you want to see all of the key-value pairs in a map, the easiest way is to
+Regardless of how you iterate, the *order* that things are iterated in 
-iterate over the keys and use each to look up its value:
+isn't defined. Wren makes no promises about what order keys and values are 
+iterated. All it promises is that every entry will appear exactly once.
+
+**Iterating with for(entry in map)**   
+When you iterate a map with `for`, you'll be handed an _entry_, which contains
+a `key` and a `value` field. That gives you the info for each element in the map.
+
+<pre class="snippet">
+var birds = {
+  "Arizona": "Cactus wren",
+  "Hawaii": "Nēnē",
+  "Ohio": "Northern Cardinal"
+}
+
+for (bird in birds) {
+  System.print("The state bird of %(bird.key) is %(bird.value)")
+}
+</pre>
+
+**Iterating using the keys**   
+
+You can also iterate over the keys and use each to look up its value:
 
 <pre class="snippet">
 var birds = {
@@ -132,15 +158,10 @@ var birds = {
 }
 
 for (state in birds.keys) {
-  System.print("The state bird of " + state + " is " + birds[state])
+  System.print("The state bird of %(state) is " + birds[state])
 }
 </pre>
 
-This program prints the three states and their birds. However, the *order*
-that they are printed isn't defined. Wren makes no promises about what order
-keys and values are iterated in when you use these methods. All it promises is
-that every entry will appear exactly once.
-
 <br><hr>
 <a class="right" href="method-calls.html">Method Calls &rarr;</a>
 <a href="lists.html">&larr; Lists</a>

doc/site/method-calls.markdown

@@ -52,7 +52,9 @@ In a language like Python or JavaScript, these would both call a single `int()`
 method, which has some kind of "optional" parameter. The body of the method
 figures out how many arguments were passed and uses control flow to handle the
 two different behaviors. That means first parameter represents "max unless
-another parameter was passed, in which case it's min". Kind of gross.
+another parameter was passed, in which case it's min". 
+
+This type of 'variadic' code isn't ideal, so Wren doesn't encourage it.
 
 In Wren, these are calls to two entirely separate methods, `int(_,_)` and
 `int(_)`. This makes it easier to define "overloads" like this since you don't
@@ -163,7 +165,7 @@ like mocks or proxies where you want an object to masquerade as a certain class.
 
 ## Subscripts
 
-Another familiar syntax from math class is *subscripting* using square brackets
+Another familiar syntax from math is *subscripting* using square brackets
 (`[]`). It's handy for working with collection-like objects. For example:
 
 <pre class="snippet">

doc/site/syntax.markdown

@@ -149,7 +149,7 @@ put a newline in there:
 </pre>
 
 Using an initial newline after the `{` does feel a little weird or magical, but
-newlines are already significant in Wren, so it's not totally crazy. The nice
+newlines are already significant in Wren, so it's not totally unreasonable. The nice
 thing about this syntax as opposed to something like `=>` is that the *end* of
 the block has an explicit delimiter. That helps when chaining:
 

doc/site/values.markdown

@@ -199,12 +199,16 @@ This creates a range from four to six *not* including six itself. Ranges are
 commonly used for [iterating](control-flow.html#for-statements) over a
 sequences of numbers, but are useful in other places too. You can pass them to
 a [list](lists.html)'s subscript operator to return a subset of the list, for
-example:
+example, or on a String, the substring in that range:
 
 <pre class="snippet">
 var list = ["a", "b", "c", "d", "e"]
 var slice = list[1..3]
 System.print(slice) //> [b, c, d]
+
+var string = "hello wren"
+var wren = string[-4..-1]
+System.print(wren) //> wren
 </pre>
 
 Their class is [Range][].

doc/site/variables.markdown

@@ -54,7 +54,7 @@ var a = "again" //! "a" is already declared.
 
 ## Assignment
 
-After a variable has been declared, you can assign to it using `=`:
+After a variable has been declared, you can assign to it using `=`
 
 <pre class="snippet">
 var a = 123