In Files

  • proc.c




Objects of class Binding encapsulate the execution context at some particular place in the code and retain this context for future use. The variables, methods, value of self, and possibly an iterator block that can be accessed in this context are all retained. Binding objects can be created using Kernel#binding, and are made available to the callback of Kernel#set_trace_func.

These binding objects can be passed as the second argument of the Kernel#eval method, establishing an environment for the evaluation.

class Demo
  def initialize(n)
    @secret = n
  def getBinding
    return binding()

k1 =
b1 = k1.getBinding
k2 =
b2 = k2.getBinding

eval("@secret", b1)   #=> 99
eval("@secret", b2)   #=> -3
eval("@secret")       #=> nil

Binding objects have no class-specific methods.

Public Instance Methods

clone() click to toggle source
               static VALUE
binding_clone(VALUE self)
    VALUE bindval = binding_dup(self);
    CLONESETUP(bindval, self);
    return bindval;
dup() click to toggle source
               static VALUE
binding_dup(VALUE self)
    VALUE bindval = binding_alloc(rb_cBinding);
    rb_binding_t *src, *dst;
    GetBindingPtr(self, src);
    GetBindingPtr(bindval, dst);
    dst->env = src->env;
    return bindval;
eval(string [, filename [,lineno]]) => obj click to toggle source

Evaluates the Ruby expression(s) in string, in the binding's context. If the optional filename and lineno parameters are present, they will be used when reporting syntax errors.

def getBinding(param)
  return binding
b = getBinding("hello")
b.eval("param")   #=> "hello"
               static VALUE
bind_eval(int argc, VALUE *argv, VALUE bindval)
    VALUE args[4];

    rb_scan_args(argc, argv, "12", &args[0], &args[2], &args[3]);
    args[1] = bindval;
    return rb_f_eval(argc+1, args, Qnil /* self will be searched in eval */);