Golang Note One

Basics

• Every Go program is made up of packages.
• Programs start running in package main.
• factored import statement.

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import (
    "fmt"
    "math"
)

• In Go, a name is exported if it begins with a capital letter.
• Functions in Golang

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func add(x int, y int) int {
    return x + y
}

• When two or more consecutive named function parameters share a type, you can omit the type from all but the last.
• A function can return any number of results.
• Go’s return values may be named and act just like variables.
• A return statement without arguments returns the current values of the results. This is known as a “naked” return.
• Naked return statements should be used only in short function, as with the example shown here. They can harm readability in longer functions.

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func split(sum int) (x, y int) {
    x = sum * 4 / 9
    y = sum - x
    return
}

• The var statement declares a list of variables; as in function argument lists, the type is last.
• A var statement can be at package or function level.
• If an initializer is present, the type can be omitted; the variable will take the type of the initializer.
• Short variable declarations: inside a function, the := short assignment statement can be used in place of a var declaration with implicit type.
• Outside a function, every statement begins with a keyword (var, func, and so on) and so the := construct is not available.
• Variable declarations may be “factored” into blocks, as with import statements.
• Variables declared without an explicit initial value are given their zero value.
• Type conversions: The expression T(v) converts the value v to the type T.
• Type inference: When declaring a variable without specifying its type (using var without a type or the := syntax), the variable’s type is inferred from the value on the right hand side.
• Constants are declared like variables, but with the const keyword.
• Constants cannot be declared using the := syntax.
• An untyped constant takes the type needed by its context.