instance method

Object#inspect

() -> ::String

obj.inspect → string

static VALUE
rb_obj_inspect(VALUE obj)
{
    VALUE ivars = rb_check_funcall(obj, id_instance_variables_to_inspect, 0, 0);
    st_index_t n = 0;
    if (UNDEF_P(ivars) || NIL_P(ivars)) {
        n = rb_ivar_count(obj);
        ivars = Qnil;
    }
    else if (RB_TYPE_P(ivars, T_ARRAY)) {
        n = RARRAY_LEN(ivars);
    }
    else {
        rb_raise(
            rb_eTypeError,
            "Expected #instance_variables_to_inspect to return an Array or nil, but it returned %"PRIsVALUE,
            rb_obj_class(ivars)
        );
    }

    if (n > 0) {
        VALUE c = rb_class_name(CLASS_OF(obj));
        VALUE args[2] = {
            rb_sprintf("-<%"PRIsVALUE":%p", c, (void*)obj),
            ivars
        };
        return rb_exec_recursive(inspect_obj, obj, (VALUE)args);
    }
    else {
        return rb_any_to_s(obj);
    }
}

Returns a string containing a human-readable representation of obj. The default inspect shows the object’s class name, an encoding of its memory address, and a list of the instance variables and their values (by calling inspect on each of them). User defined classes should override this method to provide a better representation of obj. When overriding this method, it should return a string whose encoding is compatible with the default external encoding.

Example

[ 1, 2, 3..4, 'five' ].inspect   #=> "[1, 2, 3..4, \"five\"]"
Time.new.inspect                 #=> "2008-03-08 19:43:39 +0900"

class Foo
end
Foo.new.inspect                  #=> "#<Foo:0x0300c868>"

class Bar
  def initialize
    @bar = 1
  end
end
Bar.new.inspect                  #=> "#<Bar:0x0300c868 @bar=1>"

If obj responds to instance_variables_to_inspect, then only the instance variables listed in the returned array will be included in the inspect string.

Example

class DatabaseConfig
  def initialize(host, user, password)
    @host = host
    @user = user
    @password = password
  end

private
  def instance_variables_to_inspect = [:@host, :@user]
end

conf = DatabaseConfig.new("localhost", "root", "hunter2")
conf.inspect #=> #<DatabaseConfig:0x0000000104def350 @host="localhost", @user="root">

See also #hash #instance_of? #freeze #instance_variable_defined? also in 4.1 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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