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My *fake* ocd kicked in
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Nami-Doc 2014-09-05 15:05:13 +02:00
parent dc2487aced
commit 0846eaa0e7
1 changed files with 23 additions and 23 deletions
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@ -12,7 +12,7 @@ contributors:
- ["Alexej Friesen", "https://github.com/heyalexej"] - ["Alexej Friesen", "https://github.com/heyalexej"]
--- ---
Go was created out of the need to get work done. It's not the latest trend Go was created out of the need to get work done. It's not the latest trend
in computer science, but it is the newest fastest way to solve real-world in computer science, but it is the newest fastest way to solve real-world
problems. problems.
@ -26,7 +26,7 @@ Go comes with a great standard library and an enthusiastic community.
```go ```go
// Single line comment // Single line comment
/* Multi- /* Multi-
line comment */ line comment */
// A package clause starts every source file. // A package clause starts every source file.
// Main is a special name declaring an executable rather than a library. // Main is a special name declaring an executable rather than a library.
@ -41,8 +41,8 @@ import (
"strconv" // String conversions. "strconv" // String conversions.
) )
// A function definition. Main is special. It is the entry point for the // A function definition. Main is special. It is the entry point for the
// executable program. Love it or hate it, Go uses brace brackets. // executable program. Love it or hate it, Go uses brace brackets.
func main() { func main() {
// Println outputs a line to stdout. // Println outputs a line to stdout.
// Qualify it with the package name, fmt. // Qualify it with the package name, fmt.
@ -77,7 +77,7 @@ func learnTypes() {
s2 := `A "raw" string literal s2 := `A "raw" string literal
can include line breaks.` // Same string type. can include line breaks.` // Same string type.
// Non-ASCII literal. Go source is UTF-8. // Non-ASCII literal. Go source is UTF-8.
g := 'Σ' // rune type, an alias for int32, holds a unicode code point. g := 'Σ' // rune type, an alias for int32, holds a unicode code point.
f := 3.14195 // float64, an IEEE-754 64-bit floating point number. f := 3.14195 // float64, an IEEE-754 64-bit floating point number.
@ -94,9 +94,9 @@ can include line breaks.` // Same string type.
var a4 [4]int // An array of 4 ints, initialized to all 0. var a4 [4]int // An array of 4 ints, initialized to all 0.
a3 := [...]int{3, 1, 5} // An array of 3 ints, initialized as shown. a3 := [...]int{3, 1, 5} // An array of 3 ints, initialized as shown.
// Slices have dynamic size. Arrays and slices each have advantages // Slices have dynamic size. Arrays and slices each have advantages
// but use cases for slices are much more common. // but use cases for slices are much more common.
s3 := []int{4, 5, 9} // Compare to a3. No ellipsis here. s3 := []int{4, 5, 9} // Compare to a3. No ellipsis here.
s4 := make([]int, 4) // Allocates slice of 4 ints, initialized to all 0. s4 := make([]int, 4) // Allocates slice of 4 ints, initialized to all 0.
var d2 [][]float64 // Declaration only, nothing allocated here. var d2 [][]float64 // Declaration only, nothing allocated here.
bs := []byte("a slice") // Type conversion syntax. bs := []byte("a slice") // Type conversion syntax.
@ -116,7 +116,7 @@ can include line breaks.` // Same string type.
fmt.Println(s) // Updated slice is now [1 2 3 4 5 6 7 8 9] fmt.Println(s) // Updated slice is now [1 2 3 4 5 6 7 8 9]
p, q := learnMemory() // Declares p, q to be type pointer to int. p, q := learnMemory() // Declares p, q to be type pointer to int.
fmt.Println(*p, *q) // * follows a pointer. This prints two ints. fmt.Println(*p, *q) // * follows a pointer. This prints two ints.
// Maps are a dynamically growable associative array type, like the // Maps are a dynamically growable associative array type, like the
// hash or dictionary types of some other languages. // hash or dictionary types of some other languages.
@ -142,7 +142,7 @@ func learnNamedReturns(x, y int) (z int) {
return // z is implicit here, because we named it earlier. return // z is implicit here, because we named it earlier.
} }
// Go is fully garbage collected. It has pointers but no pointer arithmetic. // Go is fully garbage collected. It has pointers but no pointer arithmetic.
// You can make a mistake with a nil pointer, but not by incrementing a pointer. // You can make a mistake with a nil pointer, but not by incrementing a pointer.
func learnMemory() (p, q *int) { func learnMemory() (p, q *int) {
// Named return values p and q have type pointer to int. // Named return values p and q have type pointer to int.
@ -220,7 +220,7 @@ func learnFlowControl() {
func(a, b int) int { func(a, b int) int {
return (a + b) * 2 return (a + b) * 2
}(10, 2)) // Called with args 10 and 2 }(10, 2)) // Called with args 10 and 2
// => Add + double two numbers: 24 // => Add + double two numbers: 24
// When you need it, you'll love it. // When you need it, you'll love it.
goto love goto love
@ -267,7 +267,7 @@ type pair struct {
x, y int x, y int
} }
// Define a method on type pair. Pair now implements Stringer. // Define a method on type pair. Pair now implements Stringer.
func (p pair) String() string { // p is called the "receiver" func (p pair) String() string { // p is called the "receiver"
// Sprintf is another public function in package fmt. // Sprintf is another public function in package fmt.
// Dot syntax references fields of p. // Dot syntax references fields of p.
@ -275,13 +275,13 @@ func (p pair) String() string { // p is called the "receiver"
} }
func learnInterfaces() { func learnInterfaces() {
// Brace syntax is a "struct literal." It evaluates to an initialized // Brace syntax is a "struct literal". It evaluates to an initialized
// struct. The := syntax declares and initializes p to this struct. // struct. The := syntax declares and initializes p to this struct.
p := pair{3, 4} p := pair{3, 4}
fmt.Println(p.String()) // Call String method of p, of type pair. fmt.Println(p.String()) // Call String method of p, of type pair.
var i Stringer // Declare i of interface type Stringer. var i Stringer // Declare i of interface type Stringer.
i = p // Valid because pair implements Stringer i = p // Valid because pair implements Stringer
// Call String method of i, of type Stringer. Output same as above. // Call String method of i, of type Stringer. Output same as above.
fmt.Println(i.String()) fmt.Println(i.String())
// Functions in the fmt package call the String method to ask an object // Functions in the fmt package call the String method to ask an object
@ -319,7 +319,7 @@ func learnErrorHandling() {
// prints 'strconv.ParseInt: parsing "non-int": invalid syntax' // prints 'strconv.ParseInt: parsing "non-int": invalid syntax'
fmt.Println(err) fmt.Println(err)
} }
// We'll revisit interfaces a little later. Meanwhile, // We'll revisit interfaces a little later. Meanwhile,
learnConcurrency() learnConcurrency()
} }
@ -330,12 +330,12 @@ func inc(i int, c chan int) {
// We'll use inc to increment some numbers concurrently. // We'll use inc to increment some numbers concurrently.
func learnConcurrency() { func learnConcurrency() {
// Same make function used earlier to make a slice. Make allocates and // Same make function used earlier to make a slice. Make allocates and
// initializes slices, maps, and channels. // initializes slices, maps, and channels.
c := make(chan int) c := make(chan int)
// Start three concurrent goroutines. Numbers will be incremented // Start three concurrent goroutines. Numbers will be incremented
// concurrently, perhaps in parallel if the machine is capable and // concurrently, perhaps in parallel if the machine is capable and
// properly configured. All three send to the same channel. // properly configured. All three send to the same channel.
go inc(0, c) // go is a statement that starts a new goroutine. go inc(0, c) // go is a statement that starts a new goroutine.
go inc(10, c) go inc(10, c)
go inc(-805, c) go inc(-805, c)
@ -348,7 +348,7 @@ func learnConcurrency() {
go func() { c <- 84 }() // Start a new goroutine just to send a value. go func() { c <- 84 }() // Start a new goroutine just to send a value.
go func() { cs <- "wordy" }() // Again, for cs this time. go func() { cs <- "wordy" }() // Again, for cs this time.
// Select has syntax like a switch statement but each case involves // Select has syntax like a switch statement but each case involves
// a channel operation. It selects a case at random out of the cases // a channel operation. It selects a case at random out of the cases
// that are ready to communicate. // that are ready to communicate.
select { select {
case i := <-c: // The value received can be assigned to a variable, case i := <-c: // The value received can be assigned to a variable,
@ -358,7 +358,7 @@ func learnConcurrency() {
case <-ccs: // Empty channel, not ready for communication. case <-ccs: // Empty channel, not ready for communication.
fmt.Println("didn't happen.") fmt.Println("didn't happen.")
} }
// At this point a value was taken from either c or cs. One of the two // At this point a value was taken from either c or cs. One of the two
// goroutines started above has completed, the other will remain blocked. // goroutines started above has completed, the other will remain blocked.
learnWebProgramming() // Go does it. You want to do it too. learnWebProgramming() // Go does it. You want to do it too.
@ -397,15 +397,15 @@ func requestServer() {
The root of all things Go is the [official Go web site](http://golang.org/). The root of all things Go is the [official Go web site](http://golang.org/).
There you can follow the tutorial, play interactively, and read lots. There you can follow the tutorial, play interactively, and read lots.
The language definition itself is highly recommended. It's easy to read The language definition itself is highly recommended. It's easy to read
and amazingly short (as language definitions go these days.) and amazingly short (as language definitions go these days.)
You can play around with the code on [Go playground](https://play.golang.org/p/tnWMjr16Mm). Try to change it and run it from your browser! Note that you can use [https://play.golang.org](https://play.golang.org) as a [REPL](https://en.wikipedia.org/wiki/Read-eval-print_loop) to test things and code in your browser, without even installing Go. You can play around with the code on [Go playground](https://play.golang.org/p/tnWMjr16Mm). Try to change it and run it from your browser! Note that you can use [https://play.golang.org](https://play.golang.org) as a [REPL](https://en.wikipedia.org/wiki/Read-eval-print_loop) to test things and code in your browser, without even installing Go.
On the reading list for students of Go is the [source code to the standard On the reading list for students of Go is the [source code to the standard
library](http://golang.org/src/pkg/). Comprehensively documented, it library](http://golang.org/src/pkg/). Comprehensively documented, it
demonstrates the best of readable and understandable Go, Go style, and Go demonstrates the best of readable and understandable Go, Go style, and Go
idioms. Or you can click on a function name in [the idioms. Or you can click on a function name in [the
documentation](http://golang.org/pkg/) and the source code comes up! documentation](http://golang.org/pkg/) and the source code comes up!
Another great resource to learn Go is [Go by example](https://gobyexample.com/). Another great resource to learn Go is [Go by example](https://gobyexample.com/).