Move anselme code into its own directory

anselme/stdlib/boolean.lua

@@ -0,0 +1,42 @@
+local ast = require("anselme.ast")
+local Boolean, ArgumentTuple = ast.Boolean, ast.ArgumentTuple
+
+return {
+	{
+		"_==_", "(a, b)",
+		function(state, a, b)
+			if a.mutable ~= b.mutable then return Boolean:new(false)
+			elseif a.mutable then
+				return Boolean:new(a == b)
+			else
+				return Boolean:new(a:hash() == b:hash())
+			end
+		end
+	},
+	{
+		"!_", "(a)",
+		function(state, a)
+			return Boolean:new(not a:truthy())
+		end
+	},
+	{
+		"_&_", "(left, right)",
+		function(state, left, right)
+			if left:truthy() then
+				return right:call(state, ArgumentTuple:new())
+			else
+				return left
+			end
+		end
+	},
+	{
+		"_|_", "(left, right)",
+		function(state, left, right)
+			if left:truthy() then
+				return left
+			else
+				return right:call(state, ArgumentTuple:new())
+			end
+		end
+	},
+}