finished scheme Part II

scheme/scheme.py

@@ -72,7 +72,12 @@ def eval_all(expressions, env):
     2
     """
     # BEGIN PROBLEM 7
-    return scheme_eval(expressions.first, env) # replace this with lines of your own code
+    if expressions is nil:
+        return None
+    ret = scheme_eval(expressions.first, env)
+    if expressions.rest is not nil:
+        ret = eval_all(expressions.rest, env)
+    return ret
     # END PROBLEM 7
 
 ################
@@ -127,6 +132,14 @@ def make_child_frame(self, formals, vals):
             raise SchemeError('Incorrect number of arguments to function call')
         # BEGIN PROBLEM 10
         "*** YOUR CODE HERE ***"
+        new_frame = Frame(self)
+        cur_formal = formals
+        cur_val = vals
+        while cur_formal is not nil:
+            new_frame.bindings[cur_formal.first] = cur_val.first
+            cur_formal = cur_formal.rest
+            cur_val = cur_val.rest
+        return new_frame
         # END PROBLEM 10
 
 ##############
@@ -191,11 +204,12 @@ def __init__(self, formals, body, env):
         self.body = body
         self.env = env
 
-    def make_call_frame(self, args, env):
+    def make_call_frame(self, args, env): 
         """Make a frame that binds my formal parameters to ARGS, a Scheme list
         of values, for a lexically-scoped call evaluated in environment ENV."""
         # BEGIN PROBLEM 11
         "*** YOUR CODE HERE ***"
+        return self.env.make_child_frame(self.formals, args)
         # END PROBLEM 11
 
     def __str__(self):
@@ -263,6 +277,10 @@ def do_define_form(expressions, env):
     elif isinstance(target, Pair) and scheme_symbolp(target.first):
         # BEGIN PROBLEM 9
         "*** YOUR CODE HERE ***"
+        proc_name = target.first
+        func = do_lambda_form(Pair(target.rest, expressions.rest), env)
+        env.bindings[proc_name] = func
+        return proc_name
         # END PROBLEM 9
     else:
         bad_target = target.first if isinstance(target, Pair) else target
@@ -278,6 +296,7 @@ def do_quote_form(expressions, env):
     validate_form(expressions, 1, 1)
     # BEGIN PROBLEM 6
     "*** YOUR CODE HERE ***"
+    return expressions.first
     # END PROBLEM 6
 
 def do_begin_form(expressions, env):
@@ -304,6 +323,7 @@ def do_lambda_form(expressions, env):
     validate_formals(formals)
     # BEGIN PROBLEM 8
     "*** YOUR CODE HERE ***"
+    return LambdaProcedure(expressions.first, expressions.rest, env)
     # END PROBLEM 8
 
 def do_if_form(expressions, env):
@@ -336,6 +356,15 @@ def do_and_form(expressions, env):
     """
     # BEGIN PROBLEM 12
     "*** YOUR CODE HERE ***"
+    if expressions is nil:
+        return True
+    val = scheme_eval(expressions.first, env)
+    if is_true_primitive(val):
+        if expressions.rest is nil:
+            return val
+        return do_and_form(expressions.rest, env)
+    else:
+        return False
     # END PROBLEM 12
 
 def do_or_form(expressions, env):
@@ -353,6 +382,13 @@ def do_or_form(expressions, env):
     """
     # BEGIN PROBLEM 12
     "*** YOUR CODE HERE ***"
+    if expressions is nil:
+        return False
+    val = scheme_eval(expressions.first, env)
+    if is_false_primitive(val):
+        return do_or_form(expressions.rest, env)
+    else:
+        return val
     # END PROBLEM 12
 
 def do_cond_form(expressions, env):
@@ -373,6 +409,10 @@ def do_cond_form(expressions, env):
         if is_true_primitive(test):
             # BEGIN PROBLEM 13
             "*** YOUR CODE HERE ***"
+            if clause.rest is nil:
+                return test
+            else:
+                return eval_all(clause.rest, env)
             # END PROBLEM 13
         expressions = expressions.rest
 
@@ -397,6 +437,16 @@ def make_let_frame(bindings, env):
     names, values = nil, nil
     # BEGIN PROBLEM 14
     "*** YOUR CODE HERE ***"
+    cur = bindings
+    while cur is not nil:
+        b = cur.first
+        validate_form(b, 2, 2)
+        name = b.first
+        arg = scheme_eval(b.rest.first, env)
+        names = Pair(name, names)
+        values = Pair(arg, values)
+        cur = cur.rest
+    validate_formals(names)
     # END PROBLEM 14
     return env.make_child_frame(names, values)
 

scheme/scheme_reader.py

@@ -142,6 +142,7 @@ def scheme_read(src):
     elif val == "'":
         # BEGIN PROBLEM 6
         "*** YOUR CODE HERE ***"
+        return Pair('quote', Pair(scheme_read(src), nil))
         # END PROBLEM 6
     elif val not in DELIMITERS:
         return val

scheme/tests/06.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,
           'question': 'What is the structure of the expressions argument to do_quote_form?'
         }
       ],
@@ -37,18 +37,15 @@
         {
           '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
         }
       ],
       'scored': True,
@@ -64,27 +61,18 @@
         {
           'code': r"""
           scm> ''hello
-          f675ad62f5f67e5229145843fd6bbcaa
-          # locked
-          # choice: (quote hello)
-          # choice: hello
-          # choice: (hello)
-          # choice: (quote (quote (hello)))
+          (quote hello)
           scm> (quote (1 2))
-          484e4b42665b2864d685ef07fe666107
-          # locked
+          (1 2)
           scm> (car '(1 2 3))
-          eb892a26497f936d1f6cae54aacc5f51
-          # locked
+          1
           scm> (cdr '(1 2))
-          750540b47bda75ff036b4a9aa741b087
-          # locked
+          (2)
           scm> (eval (cons 'car '('(4 2))))
-          46beb7deeeb5e9af1c8d785b12558317
-          # locked
+          4
           """,
           'hidden': False,
-          'locked': True
+          'locked': False
         }
       ],
       'scored': True,
@@ -97,22 +85,12 @@
         {
           'code': r"""
           >>> read_line(" 'x ")
-          d88f877a51ba10d1c3a834a690bb43e0
-          # locked
-          # choice: Pair('x', nil)
-          # choice: 'x'
-          # choice: Pair('quote', 'x')
-          # choice: Pair('quote', Pair('x', nil))
+          Pair('quote', Pair('x', nil))
           >>> read_line(" '(a b) ")
-          e16dd0e729d41b52ddd5d4d38cbfc7e6
-          # locked
-          # choice: Pair('a', Pair('b', nil))
-          # choice: Pair('quote', Pair(Pair('a', Pair('b', nil)), nil))
-          # choice: Pair('quote', Pair('a', 'b'))
-          # choice: Pair('quote', Pair('a', Pair('b', nil)))
+          Pair('quote', Pair(Pair('a', Pair('b', nil)), nil))
           """,
           'hidden': False,
-          'locked': True
+          'locked': False
         },
         {
           'code': r"""

scheme/tests/07.py

@@ -7,34 +7,24 @@
         {
           'code': r"""
           >>> eval_all(Pair(2, nil), env)
-          2b7cdec3904f986982cbd24a0bc12887
-          # locked
-          # choice: 2
-          # choice: SchemeError
+          2
           >>> eval_all(Pair(4, Pair(5, nil)), env)
-          b33c0f7206201b4aaeae595493888600
-          # locked
-          # choice: 4
-          # choice: 5
-          # choice: (4 5)
-          # choice: SchemeError
+          5
           >>> eval_all(nil, env) # return None (meaning undefined)
           """,
           'hidden': False,
-          'locked': True
+          'locked': False
         },
         {
           'code': r"""
           >>> lst = Pair(1, Pair(2, Pair(3, nil)))
           >>> eval_all(lst, env)
-          3c7e8a3a2176a696c3a66418f78dff6b
-          # locked
+          3
           >>> lst     # The list should not be mutated!
-          4ced98984f008e5161274d6481e4b568
-          # locked
+          Pair(1, Pair(2, Pair(3, nil)))
           """,
           'hidden': False,
-          'locked': True
+          'locked': False
         }
       ],
       'scored': True,
@@ -50,39 +40,28 @@
         {
           'code': r"""
           scm> (begin (+ 2 3) (+ 5 6))
-          20169e9f217f8370ba4f37a3cf0cc2b3
-          # locked
+          11
           scm> (begin (define x 3) x)
-          3c7e8a3a2176a696c3a66418f78dff6b
-          # locked
+          3
           """,
           'hidden': False,
-          'locked': True
+          'locked': False
         },
         {
           'code': r"""
           scm> (begin 30 '(+ 2 2))
-          85d97cf58c044cc51a6a7d4315b4ad71
-          # locked
-          # choice: (+ 2 2)
-          # choice: '(+ 2 2)
-          # choice: 4
-          # choice: 30
+          (+ 2 2)
           scm> (define x 0)
-          38ba916dc1f41eb239567ee41a251ecd
-          # locked
+          x
           scm> (begin (define x (+ x 1)) 42 (define y (+ x 1)))
-          1a9a3321b8b99a0f9291d89be986e74c
-          # locked
+          y
           scm> x
-          eb892a26497f936d1f6cae54aacc5f51
-          # locked
+          1
           scm> y
-          2b7cdec3904f986982cbd24a0bc12887
-          # locked
+          2
           """,
           'hidden': False,
-          'locked': True
+          'locked': False
         },
         {
           'code': r"""

scheme/tests/08.py

@@ -7,14 +7,12 @@
         {
           'code': r"""
           scm> (lambda (x y) (+ x y))
-          1456de84c3edf333b6f7aee0c0624b20
-          # locked
+          (lambda (x y) (+ x y))
           scm> (lambda (x)) ; type SchemeError if you think this causes an error
-          ec908af60f03727428c7ee3f22ec3cd8
-          # locked
+          SchemeError
           """,
           'hidden': False,
-          'locked': True
+          'locked': False
         },
         {
           'code': r"""
@@ -46,14 +44,12 @@
           >>> lambda_line = read_line("(lambda (a b c) (+ a (* b c)))")
           >>> lambda_proc = do_lambda_form(lambda_line.rest, env)
           >>> lambda_proc.formals
-          d106bb7be6b014a9d16d74410be4a8a5
-          # locked
+          Pair('a', Pair('b', Pair('c', nil)))
           >>> lambda_proc.body # Remember that the body is a *list* of expressions!
-          3fec54ce56372bf73c4e4854aa74fc10
-          # locked
+          Pair(Pair('+', Pair('a', Pair(Pair('*', Pair('b', Pair('c', nil))), nil))), nil)
           """,
           'hidden': False,
-          'locked': True
+          'locked': False
         },
         {
           'code': r"""

scheme/tests/09.py

@@ -7,18 +7,12 @@
         {
           'code': r"""
           scm> (define (f x y) (+ x y))
-          715124391110b4a3beec8c9ba1ec3097
-          # locked
+          f
           scm> f
-          1456de84c3edf333b6f7aee0c0624b20
-          # locked
-          # choice: (lambda (x y) (+ x y))
-          # choice: (lambda (f x y) (+ x y))
-          # choice: (f (x y) (+ x y))
-          # choice: (define f (lambda (x y) (+ x y)))
+          (lambda (x y) (+ x y))
           """,
           'hidden': False,
-          'locked': True
+          'locked': False
         },
         {
           'code': r"""