vrepl: add support for Home and End keys (#16116)

vlib/builtin/utf8.c.v

@@ -57,30 +57,3 @@ pub fn string_from_wide2(_wstr &u16, len int) string {
 		return ''
 	}
 }
-
-// Reads an utf8 character from standard input
-pub fn utf8_getchar() int {
-	c := C.getchar()
-	len := utf8_len(u8(~c))
-	if c < 0 {
-		return 0
-	} else if len == 0 {
-		return c
-	} else if len == 1 {
-		return -1
-	} else {
-		mut uc := c & ((1 << (7 - len)) - 1)
-		for i := 0; i + 1 < len; i++ {
-			c2 := C.getchar()
-			if c2 != -1 && (c2 >> 6) == 2 {
-				uc <<= 6
-				uc |= (c2 & 63)
-			} else if c2 == -1 {
-				return 0
-			} else {
-				return -1
-			}
-		}
-		return uc
-	}
-}

vlib/builtin/utf8.v

@@ -124,29 +124,6 @@ pub fn (_bytes []u8) utf8_to_utf32() ?rune {
 	return res
 }
 
-// Calculate length to read from the first byte
-fn utf8_len(c u8) int {
-	mut b := 0
-	mut x := c
-	if (x & 240) != 0 {
-		// 0xF0
-		x >>= 4
-	} else {
-		b += 4
-	}
-	if (x & 12) != 0 {
-		// 0x0C
-		x >>= 2
-	} else {
-		b += 2
-	}
-	if (x & 2) == 0 {
-		// 0x02
-		b++
-	}
-	return b
-}
-
 // Calculate string length for formatting, i.e. number of "characters"
 // This is simplified implementation. if you need specification compliant width,
 // use utf8.east_asian.display_width.

vlib/readline/readline_linux.c.v

@@ -122,8 +122,8 @@ pub fn (mut r Readline) disable_raw_mode() {
 }
 
 // read_char reads a single character.
-pub fn (r Readline) read_char() int {
-	return utf8_getchar()
+pub fn (r Readline) read_char() !int {
+	return int(term.utf8_getchar() or { return err })
 }
 
 // read_line_utf8 blocks execution in a loop and awaits user input
@@ -151,7 +151,7 @@ pub fn (mut r Readline) read_line_utf8(prompt string) ?[]rune {
 	print(r.prompt)
 	for {
 		unsafe { C.fflush(C.stdout) }
-		c := r.read_char()
+		c := r.read_char() or { return err }
 		a := r.analyse(c)
 		if r.execute(a, c) {
 			break
@@ -239,15 +239,17 @@ fn (r Readline) analyse(c int) Action {
 
 // analyse_control returns an `Action` based on the type of input read by `read_char`.
 fn (r Readline) analyse_control() Action {
-	c := r.read_char()
+	c := r.read_char() or { panic('Control sequence incomplete') }
 	match u8(c) {
 		`[` {
-			sequence := r.read_char()
+			sequence := r.read_char() or { panic('Control sequence incomplete') }
 			match u8(sequence) {
 				`C` { return .move_cursor_right }
 				`D` { return .move_cursor_left }
 				`B` { return .history_next }
 				`A` { return .history_previous }
+				`H` { return .move_cursor_begining }
+				`F` { return .move_cursor_end }
 				`1` { return r.analyse_extended_control() }
 				`2`, `3` { return r.analyse_extended_control_no_eat(u8(sequence)) }
 				else {}
@@ -259,7 +261,7 @@ fn (r Readline) analyse_control() Action {
 	//TODO
 match c {
 	case `[`:
-	sequence := r.read_char()
+	sequence := r.read_char()?
 	match sequence {
 	case `C`: return .move_cursor_right
 	case `D`: return .move_cursor_left
@@ -282,11 +284,11 @@ match c {
 // analyse_extended_control returns an `Action` based on the type of input read by `read_char`.
 // analyse_extended_control specialises in cursor control.
 fn (r Readline) analyse_extended_control() Action {
-	r.read_char() // Removes ;
-	c := r.read_char()
+	r.read_char() or { panic('Control sequence incomplete') } // Removes ;
+	c := r.read_char() or { panic('Control sequence incomplete') }
 	match u8(c) {
 		`5` {
-			direction := r.read_char()
+			direction := r.read_char() or { panic('Control sequence incomplete') }
 			match u8(direction) {
 				`C` { return .move_cursor_word_right }
 				`D` { return .move_cursor_word_left }
@@ -301,7 +303,7 @@ fn (r Readline) analyse_extended_control() Action {
 // analyse_extended_control_no_eat returns an `Action` based on the type of input byte given in `c`.
 // analyse_extended_control_no_eat specialises in detection of delete and insert keys.
 fn (r Readline) analyse_extended_control_no_eat(last_c u8) Action {
-	c := r.read_char()
+	c := r.read_char() or { panic('Control sequence incomplete') }
 	match u8(c) {
 		`~` {
 			match last_c {

vlib/term/utf8.c.v

@@ -0,0 +1,6 @@
+module term
+
+[inline]
+fn getchar() int {
+	return C.getchar()
+}

vlib/term/utf8.v

@@ -0,0 +1,54 @@
+module term
+
+// utf8_getchar returns an utf8 rune from standard input
+pub fn utf8_getchar() ?rune {
+	c := getchar()
+	if c == C.EOF {
+		return none
+	}
+	len := utf8_len(u8(~c))
+	if c < 0 {
+		return 0
+	} else if len == 0 {
+		return c
+	} else if len == 1 {
+		return -1
+	} else {
+		mut uc := c & ((1 << (7 - len)) - 1)
+		for i := 0; i + 1 < len; i++ {
+			c2 := getchar()
+			if c2 != -1 && (c2 >> 6) == 2 {
+				uc <<= 6
+				uc |= (c2 & 63)
+			} else if c2 == -1 {
+				return 0
+			} else {
+				return -1
+			}
+		}
+		return uc
+	}
+}
+
+// utf8_len calculates the length of a utf8 rune to read, according to its first byte
+pub fn utf8_len(c u8) int {
+	mut b := 0
+	mut x := c
+	if (x & 240) != 0 {
+		// 0xF0
+		x >>= 4
+	} else {
+		b += 4
+	}
+	if (x & 12) != 0 {
+		// 0x0C
+		x >>= 2
+	} else {
+		b += 2
+	}
+	if (x & 2) == 0 {
+		// 0x02
+		b++
+	}
+	return b
+}