Kyle Simpson
Scope and Closures
Scope and Closures
by Kyle Simpson
Copyright © 2014 Getify Solutions, Inc. All rights reserved.
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March 2014: First Edition
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2014-03-06: First release
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ISBN: 978-1-449-33558-8
[LSI]
Table of Contents
Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
1.
What Is Scope?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Compiler Theory 1
Understanding Scope 3
Nested Scope 8
Errors 10
Review 11
2.
Lexical Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Lex-time 13
Cheating Lexical 16
Review 21
3.
Function Versus Block Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Scope From Functions 23
Hiding in Plain Scope 24
Functions as Scopes 28
Blocks as Scopes 33
Review 39
4.
Hoisting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Chicken or the Egg? 41
The Compiler Strikes Again 42
Functions First 44
iii
