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examples: add a simple text editor example to term.ui (#6808)

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Larpon 2020-11-13 15:27:12 +01:00 committed by GitHub
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examples/term.ui/text_editor.v 100644
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// Copyright (c) 2020 Lars Pontoppidan. All rights reserved.
// Use of this source code is governed by the MIT license distributed with this software.
// Don't use this editor for any serious work.
// A lot of funtionality is missing compared to your favourite editor :)
import strings
import os
import term
import term.ui
type InputType = byte | rune | string
fn (ipt InputType) len() int {
match ipt {
byte, rune {
return 1
}
string {
return it.len
}
}
}
fn (ipt InputType) str() string {
match ipt {
byte, rune {
return ipt.str()
}
string {
return ipt.str()
}
}
}
enum Movement {
up
down
left
right
home
end
}
struct View {
pub:
raw string
cursor Cursor
}
struct App {
mut:
ti &ui.Context = 0
ed &Buffer = 0
file string
status string
t int
}
fn (mut a App) set_status(msg string, duration_ms int) {
a.status = msg
a.t = duration_ms
}
fn (mut a App) save() {
if a.file.len > 0 {
b := a.ed
os.write_file(a.file, b.raw())
a.set_status('saved', 2000)
} else {
a.set_status('No file loaded', 4000)
}
}
fn (mut a App) footer() {
w, h := term.get_terminal_size()
term.set_cursor_position({
x: 0
y: h - 1
})
mut b := a.ed
flat := b.flat()
snip := if flat.len > 19 { flat[..20] } else { flat }
mut finfo := ''
if a.file.len > 0 {
finfo = ' (' + os.file_name(a.file) + ')'
}
mut status := a.status
if a.t <= 0 {
status = ''
}
line := '─'.repeat(w) + '\n'
footer := line + '$finfo Line ${b.cursor.pos.y + 1}/$b.lines.len, Column ${b.cursor.pos.x +
1}/$b.cur_line().len index: $b.cursor_index() (ESC = quit, Ctrl+s = save) Raw: "$snip" $status'
print(footer)
flush()
a.t -= 33
if a.t < 0 {
a.t = 0
}
}
struct Buffer {
line_break string = '\n'
tab_width int = 4
pub mut:
lines []string
cursor Cursor
}
fn (b Buffer) flat() string {
return b.raw().replace(b.line_break, r'\n').replace('\t', r'\t')
}
fn (b Buffer) raw() string {
return b.lines.join(b.line_break)
}
fn (b Buffer) view() View {
l := b.cur_line()
mut x := 0
for i := 0; i < b.cursor.pos.x && i < l.len; i++ {
if l[i] == `\t` {
x += b.tab_width
continue
}
x++
}
p := CursorPosition{
y: b.cursor.pos.y
x: x
}
return View{
raw: b.raw().replace('\t', strings.repeat(` `, b.tab_width))
cursor: Cursor{
pos: p
}
}
}
fn (b Buffer) cur_line() string {
_, y := b.cursor.xy()
if b.lines.len == 0 {
return ''
}
return b.lines[y]
}
fn (b Buffer) cursor_index() int {
mut i := 0
for y, line in b.lines {
if b.cursor.pos.y == y {
i += b.cursor.pos.x
break
}
i += line.len + 1
}
return i
}
fn (mut b Buffer) put(ipt InputType) {
s := ipt.str()
has_line_ending := s.contains(b.line_break)
x, y := b.cursor.xy()
if b.lines.len == 0 {
b.lines.prepend('')
}
line := b.lines[y]
l := line[..x]
r := line[x..]
if has_line_ending {
mut lines := s.split(b.line_break)
lines[0] = l + lines[0]
lines[lines.len - 1] += r
b.lines.delete(y)
b.lines.insert(y, lines)
last := lines[lines.len - 1]
b.cursor.set(last.len, y + lines.len - 1)
if s == b.line_break {
b.cursor.set(0, b.cursor.pos.y)
}
} else {
b.lines[y] = l + s + r
b.cursor.set(x + s.len, y)
}
$if debug {
flat := s.replace(b.line_break, r'\n')
eprintln(@MOD + '.' + @STRUCT + '::' + @FN + ' "$flat"')
}
}
fn (mut b Buffer) del(amount int) string {
if amount == 0 {
return ''
}
x, y := b.cursor.xy()
if amount < 0 { // don't delete left if we're at 0,0
if x == 0 && y == 0 {
return ''
}
} else {
if x >= b.cur_line().len && y >= b.lines.len - 1 {
return ''
}
}
mut removed := ''
if amount < 0 { // backspace (backward)
i := b.cursor_index()
removed = b.raw()[i + amount..i]
mut left := amount * -1
for li := y; li >= 0 && left > 0; li-- {
ln := b.lines[li]
if left > ln.len {
b.lines.delete(li)
if ln.len == 0 { // line break delimiter
left--
if y == 0 {
return ''
}
line_above := b.lines[li - 1]
b.cursor.pos.x = line_above.len
} else {
left -= ln.len
}
b.cursor.pos.y--
} else {
if x == 0 {
if y == 0 {
return ''
}
line_above := b.lines[li - 1]
if ln.len == 0 { // at line break
b.lines.delete(li)
b.cursor.pos.y--
b.cursor.pos.x = line_above.len
} else {
b.lines[li - 1] = line_above + ln
b.lines.delete(li)
b.cursor.pos.y--
b.cursor.pos.x = line_above.len
}
} else if x == 1 {
b.lines[li] = b.lines[li][left..]
b.cursor.pos.x = 0
} else {
b.lines[li] = ln[..x - left] + ln[x..]
b.cursor.pos.x -= left
}
left = 0
break
}
}
} else { // delete (forward)
i := b.cursor_index() + 1
removed = b.raw()[i - amount..i]
mut left := amount
for li := y; li >= 0 && left > 0; li++ {
ln := b.lines[li]
if x == ln.len { // at line end
if y + 1 <= b.lines.len {
b.lines[li] = ln + b.lines[y + 1]
b.lines.delete(y + 1)
left--
b.del(left)
}
} else if left > ln.len {
b.lines.delete(li)
left -= ln.len
} else {
b.lines[li] = ln[..x] + ln[x + left..]
left = 0
}
}
}
$if debug {
flat := removed.replace(b.line_break, r'\n')
eprintln(@MOD + '.' + @STRUCT + '::' + @FN + ' "$flat"')
}
return removed
}
fn (mut b Buffer) free() {
$if debug {
eprintln(@MOD + '.' + @STRUCT + '::' + @FN)
}
for line in b.lines {
line.free()
}
unsafe {b.lines.free()}
}
// move_cursor will navigate the cursor within the buffer bounds
fn (mut b Buffer) move_cursor(amount int, movement Movement) {
pos := b.cursor.pos
cur_line := b.cur_line()
match movement {
.up {
if pos.y - amount >= 0 {
b.cursor.move(0, -amount)
// Check the move
line := b.cur_line()
if b.cursor.pos.x > line.len {
b.cursor.set(line.len, b.cursor.pos.y)
}
}
}
.down {
if pos.y + amount < b.lines.len {
b.cursor.move(0, amount)
// Check the move
line := b.cur_line()
if b.cursor.pos.x > line.len {
b.cursor.set(line.len, b.cursor.pos.y)
}
}
}
.left {
if pos.x - amount >= 0 {
b.cursor.move(-amount, 0)
}
}
.right {
if pos.x + amount <= cur_line.len {
b.cursor.move(amount, 0)
}
}
.home {
b.cursor.set(0, b.cursor.pos.y)
}
.end {
b.cursor.set(cur_line.len, b.cursor.pos.y)
}
}
}
// Cursor related
struct CursorPosition {
pub mut:
x int
y int
}
struct Cursor {
pub mut:
pos CursorPosition
}
fn (mut c Cursor) set(x int, y int) {
c.pos.x = x
c.pos.y = y
}
fn (mut c Cursor) move(x int, y int) {
c.pos.x += x
c.pos.y += y
}
fn (c Cursor) xy() (int, int) {
return c.pos.x, c.pos.y
}
// App callbacks
fn init(x voidptr) {
mut app := &App(x)
app.ed = &Buffer{}
if app.file.len > 0 {
if os.is_file(app.file) {
mut b := app.ed
content := os.read_file(app.file) or {
panic(err)
}
b.put(content)
}
}
}
fn frame(x voidptr) {
mut app := &App(x)
mut ed := app.ed
term.erase_clear()
term.erase_del_clear()
term.set_cursor_position({
x: 0
y: 0
})
view := ed.view()
print('$view.raw')
flush()
app.footer()
term.set_cursor_position({
x: view.cursor.pos.x + 1
y: view.cursor.pos.y + 1
})
}
fn cleanup(x voidptr) {
mut app := &App(x)
app.ed.free()
}
fn fail(error string) {
eprintln(error)
}
fn event(e &ui.Event, x voidptr) {
mut app := &App(x)
mut buffer := app.ed
if e.typ == .key_down {
match e.code {
.escape {
term.set_cursor_position({
x: 0
y: 0
})
exit(0)
}
.backspace {
buffer.del(-1)
}
.delete {
buffer.del(1)
}
.left {
buffer.move_cursor(1, .left)
}
.right {
buffer.move_cursor(1, .right)
}
.up {
buffer.move_cursor(1, .up)
}
.down {
buffer.move_cursor(1, .down)
}
.home {
buffer.move_cursor(1, .home)
}
.end {
buffer.move_cursor(1, .end)
}
48...57 { // 0 - 9
buffer.put(e.ascii)
}
97...122 { // a-zA-Z
if e.modifiers == ui.ctrl && e.code == .s {
app.save()
} else {
buffer.put(e.ascii)
}
}
else {
buffer.put(e.utf8.bytes().bytestr())
}
}
}
}
// main
mut file := ''
if os.args.len > 1 {
file = os.args[1]
}
mut app := &App{
file: file
}
app.ti = ui.init({
user_data: app
init_fn: init
frame_fn: frame
cleanup_fn: cleanup
event_fn: event
fail_fn: fail
capture_events: true
frame_rate: 30
})
app.ti.run()