Exception: NameError

Inherits:
StandardError show all
Defined in:
error.c,
error.c

Overview

Raised when a given name is invalid or undefined.

puts foo

raises the exception:

NameError: undefined local variable or method `foo' for main:Object

Since constant names must start with a capital:

Integer.const_set :answer, 42

raises the exception:

NameError: wrong constant name answer

Direct Known Subclasses

NoMethodError

Defined Under Namespace

Classes: message

Instance Method Summary collapse

Methods inherited from Exception

#==, #backtrace, #backtrace_locations, #cause, #exception, exception, #full_message, #inspect, #message, #set_backtrace, #to_s, to_tty?

Constructor Details

#new(msg = nil, name = nil, receiver: nil) ⇒ Object

Construct a new NameError exception. If given the name parameter may subsequently be examined using the NameError#name method. receiver parameter allows to pass object in context of which the error happened. Example:

[1, 2, 3].method(:rject) # NameError with name "rject" and receiver: Array
[1, 2, 3].singleton_method(:rject) # NameError with name "rject" and receiver: [1, 2, 3]

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# File 'error.c', line 1702

static VALUE
name_err_initialize(int argc, VALUE *argv, VALUE self)
{
    ID keywords[1];
    VALUE values[numberof(keywords)], name, options;

    argc = rb_scan_args(argc, argv, "*:", NULL, &options);
    keywords[0] = id_receiver;
    rb_get_kwargs(options, keywords, 0, numberof(values), values);
    name = (argc > 1) ? argv[--argc] : Qnil;
    rb_call_super(argc, argv);
    name_err_init_attr(self, values[0], name);
    return self;
}

Instance Method Details

#local_variablesArray

Return a list of the local variable names defined where this NameError exception was raised.

Internal use only.

Returns:


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# File 'error.c', line 1756

static VALUE
name_err_local_variables(VALUE self)
{
    VALUE vars = rb_attr_get(self, id_local_variables);

    if (NIL_P(vars)) {
	VALUE iseqw = rb_attr_get(self, id_iseq);
	if (!NIL_P(iseqw)) vars = rb_iseqw_local_variables(iseqw);
	if (NIL_P(vars)) vars = rb_ary_new();
	rb_ivar_set(self, id_local_variables, vars);
    }
    return vars;
}

#nameString?

Return the name associated with this NameError exception.

Returns:


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# File 'error.c', line 1740

static VALUE
name_err_name(VALUE self)
{
    return rb_attr_get(self, id_name);
}

#receiverObject

Return the receiver associated with this NameError exception.

Returns:


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# File 'error.c', line 2000

static VALUE
name_err_receiver(VALUE self)
{
    VALUE *ptr, recv, mesg;

    recv = rb_ivar_lookup(self, id_recv, Qundef);
    if (recv != Qundef) return recv;

    mesg = rb_attr_get(self, id_mesg);
    if (!rb_typeddata_is_kind_of(mesg, &name_err_mesg_data_type)) {
	rb_raise(rb_eArgError, "no receiver is available");
    }
    ptr = DATA_PTR(mesg);
    return ptr[NAME_ERR_MESG__RECV];
}