main.go

package main

import (
	"bufio"
	"golang.org/x/sys/unix"
	"os"
	"time"
)

// Erow stands for “editor row”,
//and stores a line of text as a pointer to character data and a length
type Erow struct {
	size       int
	bytes      []byte
	highlights []byte
}

type EditorConfig struct {
	cx            int
	cy            int
	rowOff        int
	colOff        int
	screenRows    int
	screenCols    int
	numRows       int
	row           []Erow
	dirty         int
	fileName      string
	statusMsg     string
	statusMsgTime time.Time
	origTermios   unix.Termios
}

var (
	E EditorConfig
)

func init() {
	w, err := unix.IoctlGetWinsize(int(os.Stdin.Fd()), unix.TIOCGWINSZ)
	if err != nil {
		panic(err)
	}

	// set cursor initial positions to 0
	E.cx = 0
	E.cy = 0
	E.rowOff = 0
	E.colOff = 0
	E.numRows = 0
	E.dirty = 0
	E.row = nil
	E.fileName = ""
	E.statusMsg = ""
	E.statusMsgTime = time.Time{}

	E.screenCols = int(w.Col)
	E.screenRows = int(w.Row) - 1
}

func main() {
	reader := bufio.NewReader(os.Stdin)

	defer clearEntireScreen()
	defer getCursorToBegin()
	defer disableRawMode()

	enableRawMode()

	if len(os.Args) > 1 {
		fileName := os.Args[1]
		E.fileName = fileName
		editorOpen(fileName)
	}

	editorSetStatusMessage("HELP: Ctrl-S = save | Ctrl-Q = quit | Ctrl-F = find")

	for {
		editorRefreshScreen()
		c := editorReadKey(reader)
		editorProcessKeypress(c)
	}
}

func ctrlKey(c byte) int {
	// The CTRL_KEY macro bitwise-ANDs a character with the value 00011111, in binary.
	ctrlKey := (c) & 0x1f
	return int(ctrlKey)
}