Golang program for implementation of Random Maze Generator

package main
 
import (
    "bytes"
    "fmt"
    "math/rand"
    "time"		
)   
 
type Maze struct { 
    c,h,v  []byte
    cell,hor,ver [][]byte    
}
 
func DrawMaze(rows, cols int) *Maze {
    c := make([]byte, rows*cols)
    h := bytes.Repeat([]byte{'-'}, rows*cols)
    v := bytes.Repeat([]byte{'|'}, rows*cols)
    cell := make([][]byte, rows)
    hor := make([][]byte, rows)
    ver := make([][]byte, rows)
    for i := range hor {
        cell[i] = c[i*cols : (i+1)*cols]
        hor[i] = h[i*cols : (i+1)*cols]
        ver[i] = v[i*cols : (i+1)*cols]
    }
    return &Maze{c, h, v, cell, hor, ver}
}
 
func (m *Maze) String() string {
    hWall := []byte("+---")
    hOpen := []byte("+   ")
    vWall := []byte("|   ")
    vOpen := []byte("    ")
    rightCorner := []byte("+\n") 
    rightWall := []byte("|\n")
    var b []byte
    // for all rows 
    for r, hw := range m.hor {
        // draw h walls
        for _, h := range hw { 
            if h == '-' || r == 0 {
                b = append(b, hWall...)
            } else {
                b = append(b, hOpen...)
            }
        }
        b = append(b, rightCorner...)
        // draw v walls
        for c, vw := range m.ver[r] {
            if vw == '|' || c == 0 {
                b = append(b, vWall...)
            } else {
                b = append(b, vOpen...)
            }
            // draw cell contents
            if m.cell[r][c] != 0 {
                b[len(b)-2] = m.cell[r][c]
            }
        }
        b = append(b, rightWall...)
    }
    // draw bottom edge of maze
    for _ = range m.hor[0] {
        b = append(b, hWall...)
    }
    b = append(b, rightCorner...)
    return string(b)
}
 
func (m *Maze) generator() {
	// Allocate the maze with recursive method
    m.recursion(rand.Intn(len(m.cell)), rand.Intn(len(m.cell[0])))
}
 
const (
    up = iota
    down
    right
    left
)
 
func (m *Maze) recursion(row, col int) {	
	rand.Seed(time.Now().UnixNano())
    m.cell[row][col] = ' '
    for _, wall := range rand.Perm(4) {
        switch wall {
		 //　Whether cells up is out or not
        case up:
            if row > 0 && m.cell[row-1][col] == 0 {
                m.hor[row][col] = 0
                m.recursion(row-1, col)
            }
		// Whether cells down is out or not
		case down:
            if row < len(m.cell)-1 && m.cell[row+1][col] == 0 {
                m.hor[row+1][col] = 0
                m.recursion(row+1, col)
            }
		// Whether cells left is out or not
        case left:
            if col > 0 && m.cell[row][col-1] == 0 {
                m.ver[row][col] = 0
                m.recursion(row, col-1)
            }
		// Whether cells to the right is out or not		
        case right:
            if col < len(m.cell[0])-1 && m.cell[row][col+1] == 0 {
                m.ver[row][col+1] = 0
                m.recursion(row, col+1)
            }
        }
    }
}
 
func main() {   
    d := DrawMaze(5,7)
    d.generator()
    fmt.Print(d)
}