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readline: reworked dispatch architecture for easier features add

This commit is contained in:
Henrixounez 2019-08-31 19:09:02 +02:00 committed by Alexander Medvednikov
parent e1dd8716fb
commit 95b107cbc6

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@ -8,6 +8,8 @@
module readline module readline
import term
#include <termios.h> #include <termios.h>
struct termios { struct termios {
@ -20,9 +22,31 @@ mut:
} }
struct Readline { struct Readline {
pub mut: mut:
is_raw bool is_raw bool
orig_termios termios orig_termios termios
current string // Line being edited
cursor int // Cursor position
overwrite bool
}
// Defines actions to execute
enum Action {
eof
nothing
insert_character
commit_line
delete_left
delete_right
move_cursor_left
move_cursor_right
move_cursor_begining
move_cursor_end
move_cursor_word_left
move_cursor_word_right
history_previous
history_next
overwrite
} }
// Toggle raw mode of the terminal by changing its attributes // Toggle raw mode of the terminal by changing its attributes
@ -62,44 +86,114 @@ pub fn (r Readline) disable_raw_mode() {
} }
// Read single char // Read single char
// TODO: Maybe handle UNICODE
fn (r Readline) read_char() byte { fn (r Readline) read_char() byte {
return C.getchar() return C.getchar()
} }
// Delete character in the string and in the terminal // Main function of the readline module
fn (r Readline) delete_character(s string, cursor int) string { // Will loop and ingest characters until EOF or Enter
print('\b \b') // Returns the completed line
return s.left(cursor - 1) + s.right(cursor) pub fn (r mut Readline) read_line() string {
} r.current = ''
r.cursor = 0
pub fn (r Readline) read_line() string {
mut s := ''
mut cursor := 0
for { for {
c := r.read_char() c := r.read_char()
// Check if ending string a := r.analyse(c)
if c == `\0` || c == 0x3 || c == 0x4 || c == 255 { if r.execute(a, c) {
break break
} }
// Check if backspace
if c == `\b` || c == 127 {
if cursor > 0 {
s = r.delete_character(s, cursor)
cursor--
} }
} else { return r.current
// Add new character according to cursor position }
s = s.left(cursor) + c.str() + s.right(cursor)
cursor++ fn (r Readline) analyse(c byte) Action {
} switch c {
// Check if enter case `\0`: return Action.eof
if c == `\n` || c == `\r` { case 0x3 : return Action.eof // End of Text
println('') case 0x4 : return Action.eof // End of Transmission
break case 255 : return Action.eof
} else { case `\n`: return Action.commit_line
print(c.str()) case `\r`: return Action.commit_line
} case `\b`: return Action.delete_left // Backspace
} case 127 : return Action.delete_left // DEL
return s case 27 : return r.analyse_control() // ESC
case 1 : return Action.move_cursor_begining // ^A
case 5 : return Action.move_cursor_end // ^E
default : return Action.insert_character
}
}
fn (r Readline) analyse_control() Action {
c := r.read_char()
switch c {
case `[`:
sequence := r.read_char()
println('seq: $sequence')
switch sequence {
case `C`: return Action.move_cursor_right
case `D`: return Action.move_cursor_left
case `E`: return Action.history_next
case `F`: return Action.history_previous
// TODO : CTRL+Left and CTRL+Right
}
}
return Action.nothing
}
fn (r mut Readline) execute(a Action, c byte) bool {
switch a {
case Action.eof: return true
case Action.insert_character: r.insert_character(c)
case Action.commit_line: return r.commit_line()
case Action.delete_left: r.delete_character()
}
return false
}
// Will redraw the line
// TODO: Refreshing on wrapped line
fn (r Readline) refresh_line() {
term.cursor_back(r.cursor)
term.erase_toend()
print(r.current)
term.cursor_back(r.current.len - r.cursor)
}
fn (r mut Readline) insert_character(c byte) {
// Small ASCII, to expand
if c >= 127 {
return
}
// TODO: Add character if overwrite at end
if !r.overwrite {
r.current = r.current.left(r.cursor) + c.str() + r.current.right(r.cursor)
} else {
// Overwriting
}
r.cursor++
// Simply print new character if at end of line
// Otherwise refresh the line if cursor != r.current.len
if r.cursor == r.current.len {
print(c.str())
} else {
//
}
}
// Removes the character behind cursor.
fn (r mut Readline) delete_character() {
if r.cursor <= 0 {
return
}
r.current = r.current.left(r.cursor - 1) + r.current.right(r.cursor)
r.refresh_line()
r.cursor--
}
// Add a line break then stops the main loop
fn (r mut Readline) commit_line() bool {
r.insert_character(`\n`)
return true
} }