# Pickaxe: "Top-Level Execution Environment"

**URL:** <https://www.ruby-forum.com/t/pickaxe-top-level-execution-environment/120451>\
**Category:** Ruby\
**Created:** [November 17, 2007, 1:19am UTC](https://www.ruby-forum.com/t/pickaxe-top-level-execution-environment/120451 "2007-11-17T01:19:51Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![S-gw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ed655f/32.png) [@S-gw](https://www.ruby-forum.com/u/S-gw)\
**Post date:** [November 17, 2007, 1:19am UTC](https://www.ruby-forum.com/t/pickaxe-top-level-execution-environment/120451/1 "2007-11-17T01:19:51Z")

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I have a bone to pick with the generally-wonderful Pickaxe regarding  
“Top-Level Execution Environment”, which states:

At the top-level, we’re executing in the context of some predefined  
object [of class Object]. When we define methods, we’re actually  
creating (private) instance methods for class Object.

The second sentence is true and helpful. But the first sentence is only  
sort of true, and only because of some unexplained magic. Here’s what I  
mean.

I’m not aware that “in the context of some … object” has an  
established meaning other than what “instance\_eval” does; and  
“instance\_eval” does not provide a context for constant definitions.  
Also, “instance\_eval” interprets "def"s in the context of the  
singleton-class of the object (I think), which is inconsistent with the  
second (correct) sentence.

The second sentence remedies both of these deficiencies. But the  
consistency of the two sentences requires some magic: Most code of  
interest is evaluated in the context of “class Object … end”, AND self  
is not Object.

Mightn’t it be better to have self == Object at the top-level? Then no  
magic would be required.

PS: My interest in eliminating the magic is that I built up some very  
bad intuition from seeing methods invoked in their definition context.  
It would have helped a lot if I had initially seen:

```
def foo ; "foo" ; end # a method of all objects
foo # same as self.foo; and self (ie, Object) is an object

```

This is tricky. But because it is not magical, it teaches something  
useful.

---

<div class="post-metadata">

**Author:** ![S-gw](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ed655f/32.png) [@S-gw](https://www.ruby-forum.com/u/S-gw)\
**Post date:** [November 17, 2007, 2:26am UTC](https://www.ruby-forum.com/t/pickaxe-top-level-execution-environment/120451/2 "2007-11-17T02:26:07Z")

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On Nov 16, 7:19 pm, Greg W. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> is not Object.
> 
> Mightn’t it be better to have self == Object at the top-level? Then no  
> magic would be required.

A fair suggestion, but I bet three was a reason. Personally think they  
should be separate things altogether. You can always add to Object,  
but this “magic” prevents us from creating top-level methods without  
infecting all other objects. I 'd rather see an implied:

module Main  
extend self

```
...code...

```

end

T.