From daa57a1f471d868c335a9063fe35af4e89ccebee Mon Sep 17 00:00:00 2001
From: Loic Nageleisen <loic.nageleisen@gmail.com>
Date: Fri, 24 Jan 2014 23:11:18 +0100
Subject: [PATCH] basic ast

---
 repl.py            |  6 ++++--
 wasp/ast.py        | 52 ++++++++++++++++++++++++++++++++++++++++++++++
 wasp/parser/box.py | 25 ++++++++++++++++++++++
 3 files changed, 81 insertions(+), 2 deletions(-)
 create mode 100644 wasp/ast.py

diff --git a/repl.py b/repl.py
index 0dd107f..c47fa4e 100644
--- a/repl.py
+++ b/repl.py
@@ -2,7 +2,9 @@ import wasp.parser as parser
 
 line = raw_input(">> ")
 while line != "":
-    tree = parser.parse(line)
-    print "^^", tree
+    ptree = parser.parse(line)
+    print " ^ %s" % ptree
+    ast = ptree.ast()
+    print " ‡ %r" % ast
     #tree.eval()
     line = raw_input(">> ")
diff --git a/wasp/ast.py b/wasp/ast.py
new file mode 100644
index 0000000..d234eb8
--- /dev/null
+++ b/wasp/ast.py
@@ -0,0 +1,52 @@
+class Node(object):
+    pass
+
+
+class List(Node):
+    def __init__(self, car, cdr=None):
+        self.car = car
+        self.cdr = cdr
+
+    def eval(self):
+        pass
+
+    def __repr__(self):
+        return "<List %r %r>" % (self.car, self.cdr)
+
+
+class Atom(Node):
+    pass
+
+
+class Operator(Node):
+    pass
+
+
+class Number(Atom):
+    def __init__(self, value):
+        self.value = value
+
+    def eval(self):
+        return self.value
+
+    def __repr__(self):
+        return "<Number %s>" % self.value
+
+
+class Symbol(Atom):
+    pass
+
+
+class Quote(Node):
+    def __init__(self, sexpr):
+        self.sexpr = sexpr
+
+    def eval(self):
+        return self.sexpr.eval()
+
+    def __repr__(self):
+        return "<Quote %r>" % self.sexpr
+
+
+class Lambda(Node):
+    pass
diff --git a/wasp/parser/box.py b/wasp/parser/box.py
index 0cc5ee7..30ea671 100644
--- a/wasp/parser/box.py
+++ b/wasp/parser/box.py
@@ -1,4 +1,5 @@
 from rply.token import BaseBox
+from wasp import ast
 
 
 class Quote(BaseBox):
@@ -11,6 +12,9 @@ class Quote(BaseBox):
     def __str__(self):
         return "'%s" % self.sexpr
 
+    def ast(self):
+        return ast.Quote(self.sexpr.ast())
+
 
 class Pair(BaseBox):
     def __init__(self, x, y=None):
@@ -24,6 +28,24 @@ class Pair(BaseBox):
             y = self.y
         return "(%s . %s)" % (self.x, y)
 
+    def r_cdr(self, cdr):
+        if self.y is None:
+            return (self.x.ast(), )
+        else:
+            return cdr + (self.x.ast(), ) + self.y.r_cdr(cdr)
+
+    def ast(self):
+        car = self.x.ast()
+
+        if self.y is None:
+            cdr = None
+        elif type(self.y) is Pair:
+            cdr = list(self.y.r_cdr(()))
+        else:
+            cdr = self.y.ast()
+
+        return ast.List(car, cdr)
+
 
 class Atom(BaseBox):
     def __init__(self, atom):
@@ -34,3 +56,6 @@ class Atom(BaseBox):
 
     def __str__(self):
         return "%s" % (self.atom)
+
+    def ast(self):
+        return ast.Number(int(self.atom))