main.go

// Demonstrates lexical basics: package, imports, declarations, iota, zero values.
package main

import (
	"fmt"
	"strings"
)

const (
	appName    = "lexical-demo"
	appVersion = "1.0.0"
)

type Weekday int

const (
	Sunday Weekday = iota
	Monday
	Tuesday
	Wednesday
	Thursday
	Friday
	Saturday
)

func (w Weekday) String() string {
	return [...]string{"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"}[w]
}

func main() {
	var x int
	var y = 3.14
	z := "go"
	a, b := 1, true

	fmt.Println("zero int:", x)
	fmt.Println("inferred float:", y)
	fmt.Println("short decl:", z, a, b)

	fmt.Printf("%s v%s on %s\n", appName, appVersion, strings.ToUpper("ready"))

	for d := Sunday; d <= Saturday; d++ {
		fmt.Printf("%d=%s ", d, d)
	}
	fmt.Println()

	var (
		s []int
		m map[string]int
		p *int
	)
	fmt.Println("nil slice len:", len(s))
	fmt.Println("nil map ok read:", m["missing"])
	fmt.Println("nil ptr:", p)

	s = append(s, 10, 20, 30)
	fmt.Println("after append:", s)
}