1 files changed, 29 insertions, 0 deletions
diff --git a/plotter/view/puzzletree/nodes/composition.py b/plotter/view/puzzletree/nodes/composition.py
new file mode 100755
index 0000000..120318f
--- /dev/null
+++ b/plotter/view/puzzletree/nodes/composition.py
@@ -0,0 +1,29 @@
+# coding=utf-8
+
+from .node import Node
+from .binaryoperator import BinaryOperator
+from gettext import gettext as _
+
+
+class Composition(BinaryOperator):
+    """Composition: left compose right function."""
+
+    CLASS = "composition"
+    background = BinaryOperator.loadbackground("composition.svg")
+    title = _("Function Composition")
+    description = _(u"Combines two functions by applying the result of the "
+        u"right function to the left.\n"
+        u"For example, (x ** 2) ∘ (x + 1) = (x + 1) ** 2.")
+
+    def __call__(self, x):
+        """Returns self's leftchild(rightchild(x))."""
+        return self.children[0](self.children[1](x))
+
+
+    def get_equation_string(self, variable):
+        """Returns a string representing the current equation."""
+
+        # result from right will be new variable in left
+        variable = Node.get_equation_string(self.children[1], variable)
+        return Node.get_equation_string(self.children[0], variable)
+