lecture 05

lectures/05/notes.ex

@@ -0,0 +1,23 @@
+# see abstract syntax tree (ast)
+quote do: 1 + 2
+# {:+, [context: Elixir, imports: [{1, Kernel}, {2, Kernel}]], [1, 2]}
+#
+#	   +
+#	  / \
+#	 1	 2
+#
+
+alias String, as: S
+# {:__aliases__, [alias: String], [:S]}
+
+### Abstract literal
+quote do: 1 # -> 1
+quote do: "hello" # -> "hello"
+quote do: [1, 2, 3] # -> [1, 2, 3] # a list of ast literals is an ast literal
+quote do: {1, 2} # -> {1, 2} # doubles are ast literals but not triples
+
+
+### Macro - something that takes an AST and returns an AST
+x = 2
+quote do: x # -> {:x, [], Elixir} # doesnt evaluate it, just ast of expression
+quote do: unquote(x) # -> 2