Binding#eval

binding.eval(string [, filename [,lineno]]) → obj

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 */);
}

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.

Example

def get_binding(param)
  binding
end
b = get_binding("hello")
b.eval("param")   #=> "hello"

Ruby version changes

3.0
- Binding#eval when called with one argument will use “(eval)” for __FILE__ and 1 for __LINE__ in the evaluated code. [Bug #4352] [Bug #17419]

See also #irb #local_variable_defined? also in 4.1 · 4.0 · 3.4 · 3.2 · 3.1 · 3.0

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