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 end def getBinding return binding() end end k1 = Demo.new(99) b1 = k1.getBinding k2 = Demo.new(-3) b2 = k2.getBinding eval("@secret", b1) #=> 99 eval("@secret", b2) #=> -3 eval("@secret") #=> nil
Binding objects have no class-specific methods.
MISSING: documentation
/* * MISSING: documentation */ static VALUE proc_clone(self) VALUE self; { struct BLOCK *orig, *data; VALUE bind; Data_Get_Struct(self, struct BLOCK, orig); bind = Data_Make_Struct(rb_obj_class(self),struct BLOCK,blk_mark,blk_free,data); CLONESETUP(bind, self); blk_dup(data, orig); return bind; }
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 end b = getBinding("hello") b.eval("param") #=> "hello"
/* * call-seq: * binding.eval(string [, filename [,lineno]]) => obj * * Evaluates the Ruby expression(s) in <em>string</em>, in the * <em>binding</em>'s context. If the optional <em>filename</em> and * <em>lineno</em> parameters are present, they will be used when * reporting syntax errors. * * def getBinding(param) * return binding * end * b = getBinding("hello") * b.eval("param") #=> "hello" */ static VALUE bind_eval(argc, argv, bindval) 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 */); }