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authormrshankly <mrshankly@riseup.net>2013-07-02 13:16:12 +0100
committermrshankly <mrshankly@riseup.net>2013-07-02 13:16:12 +0100
commitf68a80312b4bf56fd14b5f03d4644688d26710a0 (patch)
tree104f656a4fb50adac6c35b729d5c99eb5b8181fe /elixir.html.markdown
parenta86c8fe2c959b4ada383c748e4aae1525b8bf7c3 (diff)
Added section about functions, modules and records.
Diffstat (limited to 'elixir.html.markdown')
-rw-r--r--elixir.html.markdown116
1 files changed, 111 insertions, 5 deletions
diff --git a/elixir.html.markdown b/elixir.html.markdown
index 9343a683..a37d0f5e 100644
--- a/elixir.html.markdown
+++ b/elixir.html.markdown
@@ -68,9 +68,9 @@ tail # => [2,3]
## JOIN BINARIES AND LISTS
######################################################
-## --------------------
+## ---------------------------
## -- Operators
-## --------------------
+## ---------------------------
# Some math
1 + 1 # => 2
@@ -118,9 +118,9 @@ number < atom < reference < functions < port < pid < tuple < list < bit string
# To quote Joe Armstrong on this: "The actual order is not important,
# but that a total ordering is well defined is important."
-## --------------------
+## ---------------------------
## -- Control Flow
-## --------------------
+## ---------------------------
# `if` expression
if false do
@@ -199,6 +199,112 @@ end
## -- Modules and Functions
## ---------------------------
+###############################
+## EXPLAIN built-in functions?
+###############################
+
+# Anonymous functions (notice the dot)
+square = fn(x) -> x * x end
+square.(5) #=> 25
+
+# They also accept many clauses and guards
+f = fn
+ x, y when x > 0 -> x + y
+ x, y -> x * y
+end
+
+f.(1, 3) #=> 4
+f.(-1, 3) #=> -3
+
+# You can group several functions into a module. Inside a module use `def`
+# to define your functions.
+defmodule Math do
+ def sum(a, b) do
+ a + b
+ end
+
+ def square(x) do
+ x * x
+ end
+end
+
+Math.sum(1, 2) #=> 3
+Match.square(3) #=> 9
+
+# To compile our little Math module save it as `math.ex` and use `elixirc`
+elixirc math.ex
+
+# Inside a module we can define functions with `def` and
+# private functions with `defp`.
+#
+# A function defined with `def` is available to be invoked from other modules,
+# a private function can only be invoked locally.
+defmodule PrivateMath do
+ def sum(a, b) do
+ do_sum(a, b)
+ end
+
+ defp do_sum(a, b) do
+ a + b
+ end
+end
+
+PrivateMath.sum(1, 2) #=> 3
+PrivateMath.do_sum(1, 2) #=> ** (UndefinedFunctionError)
+
+# Function declarations also support guards and multiple clauses:
+defmodule Geometry do
+ def area({:rectangle, w, h}) do
+ w * h
+ end
+
+ def area({:circle, r}) when r > 0 do
+ 3.14 * r * r
+ end
+end
+
+Geometry.area({:rectangle, 2, 3}) #=> 6
+Geometry.area({:circle, 3}) #=> 28.25999999999999801048
+
+# Due to immutability, recursion is a big part of elixir
+defmodule Recursion do
+ def sum_list([head | tail], acc) do
+ sum_list(tail, acc + head)
+ end
+
+ def sum_list([], acc) do
+ acc
+ end
+end
+
+Recursion.sum_list([1,2,3], 0) #=> 6
+
+###############################
+## EXPLAIN module attributes
+###############################
+
+## ---------------------------
+## -- Records and Exceptions
+## ---------------------------
+
+# Records are basically structures that allow you to associate a name with
+# a particular value.
+defrecord Person, name: nil, age: 0, height: 0
+
+joe_info = Person.new(name: "Joe", age: 30, height: 180)
+#=> Person[name: "Joe", age: 30, height: 180]
+# Access the value of name
+joe_info.name #=> "Joe"
+
+# Update the value of age
+joe_info = joe_info.age(31) #=> Person[name: "Joe", age: 31, height: 180]
+
+## TODO: Exceptions
+
+## ---------------------------
+## -- Concurrency
+## ---------------------------
-``` \ No newline at end of file
+## TODO
+```