Added docparse

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)
+
+
+
+
+
+    
+