diff --git a/example/schcls/schcls.py b/example/schcls/schcls.py
new file mode 100644
index 0000000..b763057
--- /dev/null
+++ b/example/schcls/schcls.py
@@ -0,0 +1,179 @@
+# schcls.py
+#
+# Proof of concept--not complete
+
+from sly.docparse import DocParseMeta
+from sly import Lexer, Parser
+
+class SchLexer(Lexer):
+    tokens   = { NUMBER, NAME, DEFINE, SET }
+    ignore   = ' \t'
+    literals = ['=','+','-','*','/','(',')','.']
+
+    NAME     = '[a-zA-Z_!][a-zA-Z0-9_!]*'
+    NAME['define'] = DEFINE
+    NAME['set!'] = SET
+
+    @_(r'\d+')
+    def NUMBER(self, t):
+        t.value = int(t.value)
+        return t
+
+    @_(r'\n+')
+    def newline(self, t):
+        self.lineno = t.lineno + t.value.count('\n')
+
+    def error(self, t):
+        print(f"{self.cls_module}.{self.cls_name}:{self.lineno}: * Illegal character", repr(self.text[self.index]))
+        self.index += 1
+
+class SchParser(Parser):
+    tokens = SchLexer.tokens
+    precedence = ( 
+        ('left', '+','-'),
+        ('left', '*','/')
+        )
+    def __init__(self):
+        self.env = { }
+
+    @_('declarations',
+       '')
+    def program(self, p):
+        return self.env
+
+    @_('declarations declaration')
+    def declarations(self, p):
+        pass
+
+    @_('declaration')
+    def declarations(self, p):
+        pass
+
+    @_("'(' DEFINE NAME expression ')'")
+    def declaration(self, p):
+        self.env[p.NAME] = p.expression
+
+    @_("'(' DEFINE '(' NAME arglist ')' exprlist ')'")
+    def declaration(self, p):
+        args = ','.join(p.arglist)
+        self.env[p.NAME] = eval(f"lambda {args}: ({','.join(p.exprlist)},)[-1]")
+
+    @_("'(' SET NAME '.' NAME expression ')'")
+    def expression(self, p):
+        return f'setattr({p.NAME0}, {p.NAME1!r}, {p.expression})'
+
+    @_("")
+    def arglist(self, p):
+        return []
+
+    @_("arglist_nonempty")
+    def arglist(self, p):
+        return p.arglist_nonempty
+
+    @_("arglist_nonempty NAME")
+    def arglist_nonempty(self, p):
+        p.arglist_nonempty.append(p.NAME)
+        return p.arglist_nonempty
+
+    @_("NAME")
+    def arglist_nonempty(self, p):
+        return [ p.NAME ]
+
+    @_("NUMBER")
+    def expression(self, p):
+        return str(p.NUMBER)
+
+    @_("name")
+    def expression(self, p):
+        return p.name
+
+    @_("'(' operator exprlist ')'")
+    def expression(self, p):
+        return '(' + p.operator.join(p.exprlist) + ')'
+    
+    @_("'+'", "'-'", "'*'", "'/'")
+    def operator(self, p):
+        return p[0]
+
+    @_("'(' name exprlist ')'")
+    def expression(self, p):
+        return p.name + '(' + ','.join(p.exprlist) + ')'
+
+    @_("'(' name ')'")
+    def expression(self, p):
+        return p.name + '()'
+
+    @_('exprlist expression')
+    def exprlist(self, p):
+        p.exprlist.append(p.expression)
+        return p.exprlist
+
+    @_('expression')
+    def exprlist(self, p):
+        return [ p.expression ]
+
+    @_("NAME '.' NAME")
+    def name(self, p):
+        return f'{p.NAME0}.{p.NAME1}'
+
+    @_("NAME")
+    def name(self, p):
+        return p.NAME
+
+    def error(self, p):
+        print(f'{self.cls_module}.{self.cls_name}:{getattr(p,"lineno","")}: '
+              f'Syntax error at {getattr(p,"value","EOC")}')
+
+class SchMeta(DocParseMeta):
+    lexer = SchLexer
+    parser = SchParser
+
+class Sch(metaclass=SchMeta):
+    pass
+
+class Rat(Sch):
+    '''
+    (define (__init__ self numer denom)
+        (set! self.numer numer)
+        (set! self.denom denom)
+    )
+    (define (__add__ self other)
+        (Rat (+ (* self.numer other.denom)
+                (* self.denom other.numer))
+             (* self.denom other.denom)
+        )
+    )
+    (define (__sub__ self other)
+        (Rat (- (* self.numer other.denom)
+                (* self.denom other.numer))
+             (* self.denom other.denom)
+        )
+    )
+    (define (__mul__ self other) 
+        (Rat (* self.numer other.numer)
+             (* self.denom other.denom)
+        )
+    )
+    (define (__truediv__ self other) 
+        (Rat (* self.numer other.denom)
+             (* self.denom other.numer)
+        )
+    )
+    '''
+    def __repr__(self):
+        return f'Rat({self.numer}, {self.denom})'
+
+if __name__ == '__main__':
+    a = Rat(2, 3)
+    b = Rat(1, 4)
+    print(a + b)
+    print(a - b)
+    print(a * b)
+    print(a / b)
+
+
+
+
+
+    
+    
diff --git a/sly/ast.py b/sly/ast.py
new file mode 100644
index 0000000..7b79ac5
--- /dev/null
+++ b/sly/ast.py
@@ -0,0 +1,25 @@
+# sly/ast.py
+import sys
+
+class AST(object):
+    
+    @classmethod
+    def __init_subclass__(cls, **kwargs):
+        mod = sys.modules[cls.__module__]
+        if not hasattr(cls, '__annotations__'):
+            return
+
+        hints = list(cls.__annotations__.items())
+
+        def __init__(self, *args, **kwargs):
+            if len(hints) != len(args):
+                raise TypeError(f'Expected {len(hints)} arguments')
+            for arg, (name, val) in zip(args, hints):
+                if isinstance(val, str):
+                    val = getattr(mod, val)
+                if not isinstance(arg, val):
+                    raise TypeError(f'{name} argument must be {val}')
+                setattr(self, name, arg)
+
+        cls.__init__ = __init__
+
diff --git a/sly/docparse.py b/sly/docparse.py
new file mode 100644
index 0000000..d5a83ce
--- /dev/null
+++ b/sly/docparse.py
@@ -0,0 +1,60 @@
+# docparse.py
+#
+# Support doc-string parsing classes
+
+__all__ = [ 'DocParseMeta' ]
+
+class DocParseMeta(type):
+    '''
+    Metaclass that processes the class docstring through a parser and
+    incorporates the result into the resulting class definition. This
+    allows Python classes to be defined with alternative syntax. 
+    To use this class, you first need to define a lexer and parser:
+
+        from sly import Lexer, Parser
+        class MyLexer(Lexer):
+           ...
+
+        class MyParser(Parser):
+           ...
+
+    You then need to define a metaclass that inherits from DocParseMeta.
+    This class must specify the associated lexer and parser classes.
+    For example:
+
+        class MyDocParseMeta(DocParseMeta):
+            lexer = MyLexer
+            parser = MyParser
+
+    This metaclass is then used as a base for processing user-defined
+    classes:
+
+        class Base(metaclass=MyDocParseMeta):
+            pass
+
+        class Spam(Base):
+            """
+            doc string is parsed
+            ...
+            """
+
+    It is expected that the MyParser() class would return a dictionary. 
+    This dictionary is used to create the final class Spam in this example.
+    '''
+
+    @staticmethod
+    def __new__(meta, clsname, bases, clsdict):
+        if '__doc__' in clsdict:
+            lexer = meta.lexer()
+            parser = meta.parser()
+            lexer.cls_name = parser.cls_name = clsname
+            lexer.cls_qualname = parser.cls_qualname = clsdict['__qualname__']
+            lexer.cls_module = parser.cls_module = clsdict['__module__']
+            parsedict = parser.parse(lexer.tokenize(clsdict['__doc__']))
+            assert isinstance(parsedict, dict), 'Parser must return a dictionary'
+            clsdict.update(parsedict)
+        return super().__new__(meta, clsname, bases, clsdict)
+
+    @classmethod
+    def __init_subclass__(cls):
+        assert hasattr(cls, 'parser') and hasattr(cls, 'lexer')