1 files changed, 166 insertions, 0 deletions
diff --git a/external/construct/lib/expr.py b/external/construct/lib/expr.py
new file mode 100644
index 0000000..783c947
--- /dev/null
+++ b/external/construct/lib/expr.py
@@ -0,0 +1,166 @@
+import operator
+
+if not hasattr(operator, "div"):
+    operator.div = operator.truediv
+
+
+opnames = {
+    operator.add : "+",
+    operator.sub : "-",
+    operator.mul : "*",
+    operator.div : "/",
+    operator.floordiv : "//",
+    operator.mod : "+",
+    operator.pow : "**",
+    operator.xor : "^",
+    operator.lshift : "<<",
+    operator.rshift : ">>",
+    operator.and_ : "and",
+    operator.or_ : "or",
+    operator.not_ : "not",
+    operator.neg : "-",
+    operator.pos : "+",
+    operator.contains : "in",
+    operator.gt : ">",
+    operator.ge : ">=",
+    operator.lt : "<",
+    operator.le : "<=",
+    operator.eq : "==",
+    operator.ne : "!=",
+}
+
+
+class ExprMixin(object):
+    __slots__ = ()
+    def __add__(self, other):
+        return BinExpr(operator.add, self, other)
+    def __sub__(self, other):
+        return BinExpr(operator.sub, self, other)
+    def __mul__(self, other):
+        return BinExpr(operator.mul, self, other)
+    def __floordiv__(self, other):
+        return BinExpr(operator.floordiv, self, other)
+    def __truediv__(self, other):
+        return BinExpr(operator.div, self, other)
+    __div__ = __floordiv__
+    def __mod__(self, other):
+        return BinExpr(operator.mod, self, other)
+    def __pow__(self, other):
+        return BinExpr(operator.pow, self, other)
+    def __xor__(self, other):
+        return BinExpr(operator.xor, self, other)
+    def __rshift__(self, other):
+        return BinExpr(operator.rshift, self, other)
+    def __lshift__(self, other):
+        return BinExpr(operator.rshift, self, other)
+    def __and__(self, other):
+        return BinExpr(operator.and_, self, other)
+    def __or__(self, other):
+        return BinExpr(operator.or_, self, other)
+    
+    def __radd__(self, other):
+        return BinExpr(operator.add, other, self)
+    def __rsub__(self, other):
+        return BinExpr(operator.sub, other, self)
+    def __rmul__(self, other):
+        return BinExpr(operator.mul, other, self)
+    def __rfloordiv__(self, other):
+        return BinExpr(operator.floordiv, other, self)
+    def __rtruediv__(self, other):
+        return BinExpr(operator.div, other, self)
+    __rdiv__ = __rfloordiv__
+    def __rmod__(self, other):
+        return BinExpr(operator.mod, other, self)
+    def __rpow__(self, other):
+        return BinExpr(operator.pow, other, self)
+    def __rxor__(self, other):
+        return BinExpr(operator.xor, other, self)
+    def __rrshift__(self, other):
+        return BinExpr(operator.rshift, other, self)
+    def __rlshift__(self, other):
+        return BinExpr(operator.rshift, other, self)
+    def __rand__(self, other):
+        return BinExpr(operator.and_, other, self)
+    def __ror__(self, other):
+        return BinExpr(operator.or_, other, self)
+
+    def __neg__(self):
+        return UniExpr(operator.neg, self)
+    def __pos__(self):
+        return UniExpr(operator.pos, self)
+    def __invert__(self):
+        return UniExpr(operator.not_, self)
+    __inv__ = __invert__
+    
+    def __contains__(self, other):
+        return BinExpr(operator.contains, self, other)
+    def __gt__(self, other):
+        return BinExpr(operator.gt, self, other)
+    def __ge__(self, other):
+        return BinExpr(operator.ge, self, other)
+    def __lt__(self, other):
+        return BinExpr(operator.lt, self, other)
+    def __le__(self, other):
+        return BinExpr(operator.le, self, other)
+    def __eq__(self, other):
+        return BinExpr(operator.eq, self, other)
+    def __ne__(self, other):
+        return BinExpr(operator.ne, self, other)
+
+
+class UniExpr(ExprMixin):
+    __slots__ = ["op", "operand"]
+    def __init__(self, op, operand):
+        self.op = op
+        self.operand = operand
+    def __repr__(self):
+        return "%s %r" % (opnames[self.op], self.operand)
+    def __call__(self, context):
+        operand = self.operand(context) if callable(self.operand) else self.operand
+        return self.op(operand)
+
+
+class BinExpr(ExprMixin):
+    __slots__ = ["op", "lhs", "rhs"]
+    def __init__(self, op, lhs, rhs):
+        self.op = op
+        self.lhs = lhs
+        self.rhs = rhs
+    def __repr__(self):
+        return "(%r %s %r)" % (self.lhs, opnames[self.op], self.rhs)
+    def __call__(self, context):
+        lhs = self.lhs(context) if callable(self.lhs) else self.lhs
+        rhs = self.rhs(context) if callable(self.rhs) else self.rhs
+        return self.op(lhs, rhs)
+
+
+class Path(ExprMixin):
+    __slots__ = ["__name", "__parent"]
+    def __init__(self, name, parent = None):
+        self.__name = name
+        self.__parent = parent
+    def __repr__(self):
+        if self.__parent is None:
+            return self.__name
+        return "%r.%s" % (self.__parent, self.__name)
+    def __call__(self, context):
+        if self.__parent is None:
+            return context
+        context2 = self.__parent(context)
+        return context2[self.__name]
+    def __getattr__(self, name):
+        return Path(name, self)
+
+
+# let the magic begin!
+this = Path("this")
+
+
+if __name__ == "__main__":
+    x = ~((this.foo * 2 + 3 << 2) % 11)
+    print (x)
+    print (x({"foo" : 7}))
+
+
+
+