From fe0efadeca2d8bc875dfa3cc152a75dad48c88b2 Mon Sep 17 00:00:00 2001
From: Hahnbee Lee <hl985@cornell.edu>
Date: Tue, 23 Nov 2021 20:59:27 -0500
Subject: [PATCH] lambda expressions

---
 A1/submission/part1.py | 56 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/A1/submission/part1.py b/A1/submission/part1.py
index ba67446..c52853b 100644
--- a/A1/submission/part1.py
+++ b/A1/submission/part1.py
@@ -32,6 +32,62 @@ def minimum_cost_member_of_extension(self):
     def version_space_size(self):
         assert False, "implement as part of homework"
 
+# Lambda calculus
+class Application(Expression):
+    def __init__(self, exp1, exp2):
+        self.exp1 = exp1
+        self.exp2 = exp2
+
+    def pretty_print(self, indent, bool_ind, bool_nln):
+        ret_string = ""
+        if bool_ind:
+            for x in range(indent):
+                ret_string += tab
+        ret_string += "(" + self.exp1.pretty_print(indent, False, False) + ") " + self.exp2.pretty_print(indent, False, True)
+        if bool_nln:
+            ret_string += "\n"
+        return ret_string
+
+    def evaluate(self, environment):
+        assert False, "not implemented"
+
+class Lambda(Expression):
+    def __init__(self, var, exp):
+        self.var = var # type: NumberVariable
+        self.exp = exp # type: Expression
+
+    def pretty_print(self, indent, bool_ind, bool_nln):
+        ret_string = ""
+        if bool_ind:
+            for x in range(indent):
+                ret_string += tab
+        ret_string += "lambda " +  self.var.pretty_print(indent, False, False) + " = " + self.exp1.pretty_print(indent, False, False) + " in\n" + self.exp2.pretty_print(indent + 1, True, True)
+        if bool_nln:
+            ret_string += "\n"
+        return ret_string
+
+    def evaluate(self, environment):
+        assert False, "not implemented"
+class Let(Expression):
+    def __init__(self, var, exp1, exp2):
+        self.var = var
+        self.exp1 = exp1
+        self.exp2 = exp2
+
+    def pretty_print(self, indent, bool_ind, bool_nln):
+        ret_string = ""
+        if bool_ind:
+            for x in range(indent):
+                ret_string += tab
+        ret_string += "let " +  self.var.pretty_print(indent, False, False) + " = " + self.exp1.pretty_print(indent, False, False) + " in\n" + self.exp2.pretty_print(indent + 1, True, True)
+        if bool_nln:
+            ret_string += "\n"
+        return ret_string
+
+    def evaluate(self, environment):
+        assert False, "not implemented"
+
+
 class FALSE(Expression):
     return_type = "bool"
     argument_types = []