What does "lexical" mean in the statement "C# implements lexical closure"?

Question

I'm reading about C# and closure, various articles, Jon Skeet's awesome "C# in Depth" and I see statements like "C# and ruby implement lexical closure".

Why do the authors include the word "lexical"? Why not just say they "implement closure"?

What would it mean if it just implemented "closure", and not "lexical closure (if that's even possible)?

Salzman

type "lexical closure" into a search engine: en.wikipedia.org/wiki/Closure_(computer_science) – Ultranationalism

Watch this video explain how to compiler implements clousures and what is a clousure – Woodworker

@MitchWheat I read that wiki article...it uses the word lexical a lot, but doesn't really tell me what it means...kinda like defining a word with itself. – Salzman

@Woodworker Thanks...I know what closures are, and how c# implements them, but I am confused by the word "lexical"... – Salzman

Close voter, please explain. – Salzman

en.wikipedia.org/wiki/… – Duff

IMHO, this is one of the worst nomenclatures I've ever seen in the real of software development. Lexical in every dictionary means "of words, related to words". So, what it can mean in a compound word like "lexical scope"? Even static scoping is not a good term. Based on what I've understood, I would prefer something like "contextual scope". – Antipasto

@SaeedNeamati I agree. It seems overly complicated and misleading to me. – Salzman

Answer 1

Lexical closure is just a more specific name for closure.

As you know, a closure allows a function to use variables from the scope where it was created, even if is executed from a different scope. Such a scope is also called a lexical environment, and that's where the term lexical comes from here.

Pyxis

Ok...I guess I will dig more into the word lexical in regards to CS and lexical environments. – Salzman