did first 9 qs of project scheme

projects/scheme/.ok_messages

@@ -0,0 +1 @@
+�]�.

projects/scheme/scheme_classes.py

@@ -26,13 +26,16 @@ def __repr__(self):
     def define(self, symbol, value):
         """Define Scheme SYMBOL to have VALUE."""
         # BEGIN PROBLEM 1
-        "*** YOUR CODE HERE ***"
+        self.bindings[symbol] = value
         # END PROBLEM 1
 
     def lookup(self, symbol):
         """Return the value bound to SYMBOL. Errors if SYMBOL is not found."""
         # BEGIN PROBLEM 1
-        "*** YOUR CODE HERE ***"
+        if symbol in self.bindings:
+            return self.bindings[symbol]
+        if self.parent:
+            return self.parent.lookup(symbol)
         # END PROBLEM 1
         raise SchemeError('unknown identifier: {0}'.format(symbol))
 
@@ -51,7 +54,12 @@ def make_child_frame(self, formals, vals):
         if len(formals) != len(vals):
             raise SchemeError('Incorrect number of arguments to function call')
         # BEGIN PROBLEM 8
-        "*** YOUR CODE HERE ***"
+        child_frame = Frame(self)
+        while formals is not nil:
+            child_frame.bindings[formals.first] = vals.first
+            formals = formals.rest
+            vals = vals.rest
+        return child_frame
         # END PROBLEM 8
 
 ##############

projects/scheme/scheme_eval_apply.py

@@ -33,7 +33,9 @@ def scheme_eval(expr, env, _=None): # Optional third argument is ignored
         return scheme_forms.SPECIAL_FORMS[first](rest, env)
     else:
         # BEGIN PROBLEM 3
-        "*** YOUR CODE HERE ***"
+        operator = scheme_eval(expr.first, env)
+        operands = expr.rest.map(lambda x: scheme_eval(x, env))
+        return scheme_apply(operator, operands, env)
         # END PROBLEM 3
 
 def scheme_apply(procedure, args, env):
@@ -44,11 +46,21 @@ def scheme_apply(procedure, args, env):
        assert False, "Not a Frame: {}".format(env)
     if isinstance(procedure, BuiltinProcedure):
         # BEGIN PROBLEM 2
-        "*** YOUR CODE HERE ***"
+        py_args = []
+        while args is not nil:
+            # A sidenote by the author:
+            # here we should view the args as a list of self-evaluating values.
+            # because in Q3 we are asked to use The map method of Pair returns a new Scheme list
+            # constructed by applying a one-argument function to every item in a Scheme list.
+            # or we could get an error: "xxx is not callable: xxx"
+            py_args.append(args.first)
+            args = args.rest
+        if procedure.need_env:
+            py_args.append(env)
         # END PROBLEM 2
         try:
             # BEGIN PROBLEM 2
-            "*** YOUR CODE HERE ***"
+            return procedure.py_func(*py_args)
             # END PROBLEM 2
         except TypeError as err:
             raise SchemeError('incorrect number of arguments: {0}'.format(procedure))
@@ -79,7 +91,13 @@ def eval_all(expressions, env):
     2
     """
     # BEGIN PROBLEM 6
-    return scheme_eval(expressions.first, env) # replace this with lines of your own code
+    last_expression = expressions
+    if last_expression is nil:
+        return
+    while last_expression.rest is not nil:
+        scheme_eval(last_expression.first, env)
+        last_expression = last_expression.rest
+    return scheme_eval(last_expression.first, env)
     # END PROBLEM 6
 
 

projects/scheme/scheme_forms.py

@@ -36,7 +36,14 @@ def do_define_form(expressions, env):
         # assigning a name to a value e.g. (define x (+ 1 2))
         validate_form(expressions, 2, 2) # Checks that expressions is a list of length exactly 2
         # BEGIN PROBLEM 4
-        "*** YOUR CODE HERE ***"
+        symbol = signature
+        value = scheme_eval(expressions.rest.first, env)
+        # sidenote: the signature has the form of Pair(A, Pair(B, nil)), 
+        # where: A is the symbol being bound, B is an expression whose value should be evaluated and bound to A
+        # what we should evaluate is B, not Pair(B, nil)
+        # ...this is a little strange...
+        env.define(symbol, value)
+        return symbol
         # END PROBLEM 4
     elif isinstance(signature, Pair) and scheme_symbolp(signature.first):
         # defining a named procedure e.g. (define (f x y) (+ x y))
@@ -56,7 +63,8 @@ def do_quote_form(expressions, env):
     """
     validate_form(expressions, 1, 1)
     # BEGIN PROBLEM 5
-    "*** YOUR CODE HERE ***"
+    # same as problem 4, the structure: Pair(A, nil), where: A is the quoted expression
+    return expressions.first
     # END PROBLEM 5
 
 def do_begin_form(expressions, env):
@@ -82,7 +90,8 @@ def do_lambda_form(expressions, env):
     formals = expressions.first
     validate_formals(formals)
     # BEGIN PROBLEM 7
-    "*** YOUR CODE HERE ***"
+    body = expressions.rest
+    return LambdaProcedure(formals, body, env)
     # END PROBLEM 7
 
 def do_if_form(expressions, env):

projects/scheme/tests/01.py

@@ -9,24 +9,17 @@
           >>> global_frame = create_global_frame()
           >>> global_frame.define("x", 3)
           >>> global_frame.parent is None
-          b1796eff8a8e977439f97b5c6881a282
-          # locked
+          True
           >>> global_frame.lookup("x")
-          3c7e8a3a2176a696c3a66418f78dff6b
-          # locked
+          3
           >>> global_frame.define("x", 2)
           >>> global_frame.lookup("x")
-          2b7cdec3904f986982cbd24a0bc12887
-          # locked
+          2
           >>> global_frame.lookup("foo")
-          ec908af60f03727428c7ee3f22ec3cd8
-          # locked
-          # choice: None
-          # choice: SchemeError
-          # choice: 3
+          SchemeError
           """,
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False
         },
         {
@@ -35,18 +28,15 @@
           >>> first_frame.define("x", 3)
           >>> second_frame = Frame(first_frame)
           >>> second_frame.parent == first_frame
-          b1796eff8a8e977439f97b5c6881a282
-          # locked
+          True
           >>> second_frame.define("y", False)
           >>> second_frame.lookup("x")
-          3c7e8a3a2176a696c3a66418f78dff6b
-          # locked
+          3
           >>> second_frame.lookup("y")
-          96ae38315990d5fb27de4225d8b470ba
-          # locked
+          False
           """,
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False
         },
         {

projects/scheme/tests/02.py

@@ -10,23 +10,21 @@
           >>> twos = Pair(2, Pair(2, nil))
           >>> plus = BuiltinProcedure(scheme_add) # + procedure
           >>> scheme_apply(plus, twos, env) # Type SchemeError if you think this errors
-          46beb7deeeb5e9af1c8d785b12558317
-          # locked
+          4
           """,
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False
         },
         {
           'code': r"""
           >>> env = create_global_frame()
           >>> plus = BuiltinProcedure(scheme_add) # + procedure
           >>> scheme_apply(plus, nil, env) # Remember what (+) evaluates to in scheme
-          a384c59daad07475a000a57b0b47b74f
-          # locked
+          0
           """,
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False
         },
         {
@@ -35,11 +33,10 @@
           >>> twos = Pair(2, Pair(2, nil))
           >>> oddp = BuiltinProcedure(scheme_oddp) # odd? procedure
           >>> scheme_apply(oddp, twos, env) # Type SchemeError if you think this errors
-          ec908af60f03727428c7ee3f22ec3cd8
-          # locked
+          SchemeError
           """,
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False
         },
         {

projects/scheme/tests/03.py

@@ -8,22 +8,18 @@
           'code': r"""
           >>> expr = read_line('(+ 2 2)')
           >>> scheme_eval(expr, create_global_frame()) # Type SchemeError if you think this errors
-          46beb7deeeb5e9af1c8d785b12558317
-          # locked
+          4
           >>> scheme_eval(Pair('+', Pair(2, Pair(2, nil))), create_global_frame()) # Type SchemeError if you think this errors
-          46beb7deeeb5e9af1c8d785b12558317
-          # locked
+          4
           >>> expr = read_line('(+ (+ 2 2) (+ 1 3) (* 1 4))')
           >>> scheme_eval(expr, create_global_frame()) # Type SchemeError if you think this errors
-          4c5d1a42692bacbca88ab48bbcf75c52
-          # locked
+          12
           >>> expr = read_line('(yolo)')
           >>> scheme_eval(expr, create_global_frame()) # Type SchemeError if you think this errors
-          ec908af60f03727428c7ee3f22ec3cd8
-          # locked
+          SchemeError
           """,
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False
         }
       ],
@@ -40,14 +36,12 @@
         {
           'code': r"""
           scm> (* (+ 3 2) (+ 1 7)) ; Type SchemeError if you think this errors
-          a692eb3d6b9f6889d113635424465221
-          # locked
+          40
           scm> (1 2) ; Type SchemeError if you think this errors
-          ec908af60f03727428c7ee3f22ec3cd8
-          # locked
+          SchemeError
           """,
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False
         },
         {

projects/scheme/tests/04.py

@@ -5,7 +5,7 @@
     {
       'cases': [
         {
-          'answer': 'e92e90f58a272e7a74651635251ade14',
+          'answer': 'Pair(A, Pair(B, nil)), where: A is the symbol being bound, B is an expression whose value should be evaluated and bound to A',
           'choices': [
             r"""
             Pair(A, Pair(B, nil)), where:
@@ -34,20 +34,20 @@
             """
           ],
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False,
           'question': 'What is the structure of the expressions argument to do_define_form?'
         },
         {
-          'answer': '0ed53dce7bacc4766422abc478c5c895',
+          'answer': 'define',
           'choices': [
             'make_child_frame',
             'define',
             'lookup',
             'bindings'
           ],
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False,
           'question': r"""
           What method of a Frame instance will bind
@@ -63,20 +63,16 @@
         {
           'code': r"""
           scm> (define size 2)
-          cc3c061fb8167d02a4ddda1f1c19966e
-          # locked
+          size
           scm> size
-          2b7cdec3904f986982cbd24a0bc12887
-          # locked
+          2
           scm> (define x (+ 7 3))
-          38ba916dc1f41eb239567ee41a251ecd
-          # locked
+          x
           scm> x
-          4bc2fb48972a5d1ec1201b01e766a044
-          # locked
+          10
           """,
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False
         },
         {

projects/scheme/tests/05.py

@@ -5,7 +5,7 @@
     {
       'cases': [
         {
-          'answer': 'fd4dd892ccea3adcf9446dc4a9738d47',
+          'answer': 'Pair(A, nil), where: A is the quoted expression',
           'choices': [
             r"""
             Pair('quote', Pair(A, nil)), where:
@@ -25,7 +25,7 @@
             """
           ],
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False,
           'question': 'What is the structure of the expressions argument to do_quote_form?'
         }
@@ -38,18 +38,15 @@
         {
           'code': r"""
           >>> do_quote_form(Pair(3, nil), global_frame)
-          3c7e8a3a2176a696c3a66418f78dff6b
-          # locked
+          3
           >>> do_quote_form(Pair('hi', nil), global_frame)
-          95448591e64e04a7a7885d5fb9b45583
-          # locked
+          'hi'
           >>> expr = Pair(Pair('+', Pair('x', Pair(2, nil))), nil)
           >>> do_quote_form(expr, global_frame) # Make sure to use Pair notation
-          2301ee746b57783004f00f39498fdaed
-          # locked
+          Pair('+', Pair('x', Pair(2, nil)))
           """,
           'hidden': False,
-          'locked': True,
+          'locked': False,
           'multiline': False
         }
       ],