# table-of-contents-eng

## Table of Contents 1

## Introduction 5

## Language Mechanics 6

### Syntax 6

> #### Variable 6
>
> > **Built-in types 6**
> >
> > **Zero value concept 6**
> >
> > **Declare and initialize 7**
> >
> > **Conversion vs casting 8**
>
> #### Struct 8
>
> > **Declare and initialize 8**
> >
> > **Name type vs anonymous type 10**
>
> #### Pointer 11
>
> > **Everything is about pass by value 11**
> >
> > **Pass by value 11**
>
> #### Escape analysis 12
>
> #### Function 15
>
> #### Constant 17
>
> > **Declare and initialize 17**
> >
> > **iota 19**

### Data Structures 20

> #### Array 20
>
> > **CPU Cache 20**
> >
> > **Translation Lookaside Buffer 21**
> >
> > **Declare and initialize 21**
> >
> > **What is the cost? 22**
> >
> > **Iterate over the array of strings 23**
> >
> > **Different type arrays 24**
> >
> > **Contiguous memory allocations 24**
>
> #### Slice 25
>
> > **Declare and initialize 25**
> >
> > **Length vs Capacity 25**
> >
> > **Reference type 26**
> >
> > **Idea of appending: making slice a dynamic data structure 27**
> >
> > **Slice of slice 30**
> >
> > **Copy a slice 31**
> >
> > **Slice and reference 32**
> >
> > **UTF-8 33**
>
> #### Map 34
>
> > **Declare and initialize 35**
> >
> > **Map literals 35**
> >
> > **Delete key 36**
> >
> > **Find key 36**
> >
> > **Map key restrictions 36**

### Decoupling 37

> #### Method 37
>
> > **Value and Pointer Receiver Call 37**
> >
> > **Value and Pointer Semantics 39**
> >
> > **Methods are just functions 43**
>
> #### Interface 46
>
> > **Valueless type 46**
> >
> > **Interface via pointer receiver 50**
> >
> > **Slice of interface 53**
>
> #### Embedding 55
>
> > **Declaring fields, NOT Embedding 55**
> >
> > **Embedding types 56**
> >
> > **Embedded type and Interface 57**
> >
> > **Outer and inner type implementing the same interface 58**
>
> #### Exporting 60
>
> > **Guideline 60**
> >
> > **Exported identifier 60**
> >
> > **Accessing a value of an unexported identifier 61**
> >
> > **Unexported fields from an exported struct 62**
> >
> > **Exported types with embedded unexported types 63**

## Software Design 65

### Composition 65

> #### Grouping types 65
>
> > **Grouping By State 65**
> >
> > **Grouping By Behavior 67**
>
> #### Decoupling 70
>
> > **Struct Composition 70**
> >
> > **Decoupling With Interface 74**
> >
> > **Interface Composition 79**
> >
> > **Decoupling With Interface Composition 84**
>
> #### Conversion 89
>
> > **Interface Conversions 89**
> >
> > **Type assertion 91**
> >
> > **Runtime Type Assertion 92**
>
> #### Interface Pollution 94
>
> > **Remove Interface Pollution 96**
>
> #### Mocking 98
>
> > **Package To Mock 98**
> >
> > **Client 100**

### Error Handling 101

> #### Default error values 101
>
> #### Error variables 103
>
> #### Type as context 105
>
> #### Behavior as context 107
>
> #### Finding the bug 110
>
> #### Wrapping Errors 111

## Concurrency 114

### Mechanics 114

> #### Goroutine 114
>
> #### Language Mechanics 121
>
> > **Sequence 123**
> >
> > **Goroutine time slicing 124**
> >
> > **Goroutines and parallelism 126**
>
> #### Data race 128
>
> > **Race Detection 128**
> >
> > **Atomic Functions 131**
> >
> > **Mutexes 133**
> >
> > **Read/Write Mutex 135**
>
> #### Channel 139
>
> > **Language Mechanics 139**
> >
> > **Unbuffered channel: Signaling with data 141**
> >
> > **Unbuffered channel: Double signal 143**
> >
> > **Unbuffered channel: select and receive 144**
> >
> > **Unbuffered channel: select and send 145**
> >
> > **Buffered channel: Select and drop 146**
> >
> > **Unbuffered channel (Tennis match) 148**
> >
> > **Unbuffered channel (Replay race) 150**
> >
> > **Buffered channel: Fan Out 153**
> >
> > **Select 157**

### Patterns 164

> #### Context 164
>
> > **Store and retrieve values from a context 164**
> >
> > **WithCancel 166**
> >
> > **WithDeadline 168**
> >
> > **WithTimeout 169**
> >
> > **Request/Response 171**

## Testing and Profiling 173

### Testing 173

> #### Basic Unit Test 173
>
> > **Table Test 176**
> >
> > **Sub Test 177**
> >
> > **Web Server 181**
> >
> > **Mock Server 187**

### Benchmarking 191

> #### Basic Benchmark 191
>
> #### Sub Benchmark 192

### Profiling 193

> #### Stack Trace 193
>
> > **Review Stack Trace 193**
> >
> > **Packing 195**
>
> #### GODEBUG 196
>
> > **Memory Tracing 196**

## Keep in touch 199