View source for Terminal control/Restricted width positional input/No wrapping

{{draft task}}

Create a routine to obtain data entry using a specific place on the terminal screen. Data entry fields should be restricted to a specific length, and it should not be possible for the cursor to move beyond the input length.

The routine should accept parameters for row number, column number and input length, and should obtain a string
value entered by the user.

For the purpose of this task, obtain input from the user, showing data entry at row 3, column 5, with input width restricted to a maximum of 8 characters.

Note: In this task input wrapping is not allowed. (See [[Terminal control/Restricted width positional input/With wrapping]]) for input wrapping variant.

For a similar task using a graphical user interface, see [[Graphical User Interface/Restricted width positional input/No wrapping]].

[[Category:Terminal control]]

=={{header|Common Lisp}}==
==={{header|ncurses}}===
To interface ncurses from Lisp, the ''[https://www.cliki.net/croatoan croatoan]'' library is used.
<syntaxhighlight lang="lisp">;; Load the library from the quicklisp repository
(ql:quickload "croatoan")
(in-package :croatoan)

(defun field-input-no-wrapping (row column input-length)
  (with-screen (scr :input-echoing nil :cursor-visible t :enable-colors t :enable-function-keys t :input-blocking t)
    (let ((field (make-instance 'field :position (list row column) :width input-length :window scr)))
      (setf (style field)
            (list :background (list :simple-char #\.)))
      (bind field #\newline 'accept)
      (edit field)
      (clear scr)
      (refresh scr)
      ;; return the value of the field as a string
      (value field))))

;; call the routine
(field-input-no-wrapping 2 4 8)</syntaxhighlight>


=={{header|FreeBASIC}}==
<syntaxhighlight lang="freebasic">Function getInput(fila As Integer, columna As Integer, ancho As Integer) As String
    Locate fila, columna, 0
    Dim As String KBD, cadena = ""
    Do
        Do: KBD = Inkey: Loop Until KBD <> ""
        If KBD = Chr(8) Then
            cadena = Left(cadena, Len(cadena) - 1)
            Print !"\b ";
        Else
            If Len(cadena) < ancho Then cadena &= KBD
        End If
        Locate fila, columna : Print cadena;
    Loop Until KBD = Chr(13)
    
    Return cadena
End Function 

Dim As String s = getInput(3, 5, 8)
Locate 23,1 : Print "You entered: "; s
Sleep</syntaxhighlight>

=={{header|Go}}==
{{works with|Windows 10}}
{{trans|Kotlin}}
<br>
This uses _getch() rather than _getwch() as only ASCII is supported.
<syntaxhighlight lang="go">package main

/*
#include <windows.h>
#include <conio.h>
*/
import "C"
import (
    "fmt"
    "os"
    "os/exec"
)

var conOut = C.GetStdHandle(C.STD_OUTPUT_HANDLE)

func setCursor(p C.COORD) {
    C.SetConsoleCursorPosition(conOut, p)
}

func cls() {
    cmd := exec.Command("cmd", "/c", "cls")
    cmd.Stdout = os.Stdout
    cmd.Run()
}

func getInput(row, col, width int) string {
    if row < 0 || row > 20 || col < 0 || width < 1 || width > 78 || col > (79 - width) {
        panic("Invalid parameter(s) to getInput. Terminating program")
    }
    coord := C.COORD{C.short(col), C.short(row)}
    setCursor(coord)
    var sb []byte
    full := false
    loop:
    for {
        ch := C._getch()                         // gets next character, no echo
        switch c := byte(ch); c {
        case 3, 13:
            break loop                           // break on Ctrl-C or enter key
        case 8:
            if len(sb) > 0 {                     // mimic backspace
		fmt.Print("\b \b")
                sb = sb[:len(sb) - 1]
            }
        case 0, 224:
            C._getch()                           // consume extra character
        default:
            if c >= 32 && c <= 126 && !full {
                C._putch(ch)                     // echo ascii character, ignore others
                sb = append(sb, c)
            }
        }
        full = len(sb) == width                  // can't exceed width
    }
    return string(sb)
}

func main() {
    cls() // clear the console
    s := getInput(2, 4, 8) // Windows console row/col numbering starts at 0
    coord := C.COORD{0, 22}
    setCursor(coord)
    fmt.Printf("You entered '%s'\n", s)
}</syntaxhighlight>

=={{header|Julia}}==
Requires an ANSI compatible terminal and a system C library implementing _getch() for unbuffered keyboard input. Note the code below is identical to the code in [[Terminal_control/Restricted_width_positional_input/No_wrapping]] but with no width argument in the input call.
<syntaxhighlight lang="julia">getch() = UInt8(ccall(:_getch, Cint, ()))
cls() = print("\33[2J")
reposition(row, col) = print("\u001b[$row;$(col)H")
clearfromcursor() = print("\u001b[K")

function input_y_x_upto(row, col, cmax, width=cmax)
    buf = ""
    while (buflen = length(buf)) < cmax && !((c = getch()) in [0xff, 0x0d, 0x0a])
        reposition(row, col)
        clearfromcursor()
        if c == '\b' && buflen > 0
            buf = buf[1:end-1]
        else
            buf = buf * Char(c)
        end
        print(buf[(buflen > width ? buflen - width + 1 : 1):end])
    end
    return buf
end

cls()
reposition(3, 5)
s = input_y_x_upto(3, 5, 8)
println("\n\n\nResult:  You entered <<$s>>")
</syntaxhighlight>

=={{header|Kotlin}}==
{{works with|Windows 10}}
This assumes an 80 x 25 Windows console and uses the Win32 function _getwch() to get character input without (immediately) echoing it to the console. Only ASCII characters in the range 32 to 126 are then printed if the maximum width would not be exceeded. 

Apart from these, only the backspace key (8), return key (13) and Ctrl-C (3) are handled, all other keys being ignored. Some keys (such as the function and arrow keys) return a two character sequence starting with either 0 or 224 and so, after the first character is trapped, the second character needs to be removed from the buffer.

It would also be possible to allow for printable Unicode characters (>= 160) to be entered by adding an extra clause to the 'when' statement. However, for this to work properly, you will need to be using a suitable code page (65001, say) and a suitable font (Lucida Console, say).
<syntaxhighlight lang="scala">// Kotlin Native v0.5

import kotlinx.cinterop.*
import platform.windows.*
import platform.posix.*

val ascii = 32..126
val conOut = GetStdHandle(STD_OUTPUT_HANDLE)!!

fun setCursor(p: COORD) = SetConsoleCursorPosition(conOut, p.readValue())

fun getInput(row: Short, col: Short, width: Int): String {
    require(row in 0..20 && col in 0..(79 - width) && width in 1..78) { "Invalid parameter(s)" }
    memScoped {
        val coord = alloc<COORD>().apply { X = col; Y = row }
        setCursor(coord)
    }
    val sb = StringBuilder(width)
    var full = false
    loop@ while (true) {
        val ch = _getwch()                                                   // gets next character, no echo
        when (ch.toInt()) {
                3, 13 -> break@loop                                          // break on Ctrl-C or enter key
                    8 -> if (sb.length > 0) { print("\b \b"); sb.length-- }  // mimic backspace
               0, 224 -> _getwch()                                           // consume extra character
             in ascii -> if (!full) { _putwch(ch); sb.append(ch.toChar()) }  // echo ascii character
                 else -> {}                                                  // igore other characters
        }
        full = sb.length == width                                            // can't exceed width
    }
    return sb.toString()
}

fun main(args: Array<String>) {
    system("cls")  // clear the console
    val s = getInput(2, 4, 8)  // Windows console row/col numbering starts at 0
    memScoped {
        val coord = alloc<COORD>().apply { X = 0 ; Y = 22 }
        setCursor(coord)
    }
    println("You entered '$s'")
}</syntaxhighlight>

=={{header|Nim}}==
{{trans|Julia}}
As in the Julia version we translated, the code is identical to the code in [[Terminal_control/Restricted_width_positional_input/No_wrapping]] but with no width argument in the input call. See this version for some general comments about the code.

<syntaxhighlight lang="nim">import strformat, terminal

proc eraseLineEnd() = stdout.write("\e[K")

proc inputXYUpto(row, col, cmax: int; width = cmax): string =
  while result.len < cmax and not ((let c = getch(); c) in ['\xff', '\f', '\r']):
    setCursorPos(row, col)
    eraseLineEnd()
    if c in ['\b', '\x7f'] and result.len > 0:
      result.setLen(result.len - 1)
    else:
      result.add c
    stdout.write result[(if result.len > width: result.len - width else: 0)..result.high]

eraseScreen()
setCursorPos(3, 5)
let s = inputXYUpto(3, 5, 8)
echo &"\n\n\nResult:  You entered <<{s}>>"</syntaxhighlight>

=={{header|Perl}}==
Works on ArchLinux in an xterm.
<syntaxhighlight lang="perl">#!/usr/bin/perl

use strict; # https://rosettacode.org/wiki/Terminal_control/Restricted_width_positional_input/No_wrapping
use warnings;
use List::Util qw( min max );
$| = 1;

sub label { printf "\e[%d;%dH%s", @_; }

sub getinput
  {
  my ($row, $column, $length, $prompt) = @_;
  defined $prompt and length $prompt < $column - 1 and
    label( $row, $column - length $prompt, $prompt);
  my $at = "\e[%d;%dH%-$length.${length}s\e[%d;%dH";
  my $input = '';
  my $pos = 0;
  use Term::ReadKey;
  eval
    {
    ReadMode 'cbreak';
    local $_;
    my $more = 1;
    while( $more )
      {
      printf $at, $row, $column, $input, $row, $column + $pos;
      0 < sysread *STDIN, $_, 1024 or last;
      print "\e[10;1H\e[J"; use Data::Dump 'dd'; dd	$_;
      for( /\e[O\[][0-9;]*[A-~]|./gs )
        {
        /^[\n\r\e]\z/ ? do { $more = 0 } :
        /^[ -~]\z/ ? do {
          substr $input, $pos++, 0, $_; $input &= "\xff" x $length;
          $pos = min $pos, $length } :
        $_ eq "\b" ? do { $pos = max $pos - 1, 0; substr $input, $pos, 1, '' } :
        $_ eq "\e[D" ? do { $pos = max 0, $pos - 1 } :
        $_ eq "\e[C" ? do { $pos = min length $input, $pos + 1 } :
        $_ eq "\e[H" ? do { $pos = 0 } :
        $_ eq "\e[F" ? do { $pos = length $input } :
        $_ eq "\e[3~" ? do { length $input and substr $input, $pos, 1, ''; } :
        0;
        }
      }
    };
  ReadMode 'restore';
  return $input;
  }

print "\e[H\e[J";
#label(2, 5, "Enter input below");
my $text = getinput( 3, 25, 8, "test string: " );
print "\n\nyour input <$text>\n";</syntaxhighlight>

=={{header|Phix}}==
<!--<syntaxhighlight lang="phix">(notonline)-->
 <span style="color: #008080;">without</span> <span style="color: #008080;">js</span> <span style="color: #000080;font-style:italic;">-- (position, wait_key, backspace)</span>
 <span style="color: #008080;">function</span> <span style="color: #000000;">getInput</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">row</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">col</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">width</span><span style="color: #0000FF;">)</span>
     <span style="color: #7060A8;">position</span><span style="color: #0000FF;">(</span><span style="color: #000000;">row</span><span style="color: #0000FF;">,</span><span style="color: #000000;">col</span><span style="color: #0000FF;">)</span>
     <span style="color: #004080;">string</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">""</span>
     <span style="color: #008080;">while</span> <span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
         <span style="color: #004080;">integer</span> <span style="color: #000000;">ch</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">wait_key</span><span style="color: #0000FF;">()</span>
         <span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">=</span><span style="color: #008000;">'\r'</span> <span style="color: #008080;">then</span> <span style="color: #008080;">exit</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #008080;">if</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">=</span><span style="color: #008000;">'\b'</span> <span style="color: #008080;">then</span>
             <span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">)></span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
                 <span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"\b \b"</span><span style="color: #0000FF;">)</span>
                 <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">1</span><span style="color: #0000FF;">..$-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span>
             <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #008080;">elsif</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;">>=</span><span style="color: #008000;">' '</span> <span style="color: #008080;">and</span> <span style="color: #000000;">ch</span><span style="color: #0000FF;"><=</span><span style="color: #008000;">'~'</span> <span style="color: #008080;">then</span>
             <span style="color: #008080;">if</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">)<=</span><span style="color: #000000;">width</span> <span style="color: #008080;">then</span>
                 <span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">ch</span><span style="color: #0000FF;">)</span>
                 <span style="color: #000000;">s</span> <span style="color: #0000FF;">&=</span> <span style="color: #000000;">ch</span>
             <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
         <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
     <span style="color: #008080;">end</span> <span style="color: #008080;">while</span>
     <span style="color: #008080;">return</span> <span style="color: #000000;">s</span>
 <span style="color: #008080;">end</span> <span style="color: #008080;">function</span> 
  
 <span style="color: #7060A8;">clear_screen</span><span style="color: #0000FF;">()</span> <span style="color: #000080;font-style:italic;">-- clear the console</span>
 <span style="color: #004080;">string</span> <span style="color: #000000;">s</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">getInput</span><span style="color: #0000FF;">(</span><span style="color: #000000;">3</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">5</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">8</span><span style="color: #0000FF;">)</span>
 <span style="color: #7060A8;">position</span><span style="color: #0000FF;">(</span><span style="color: #000000;">23</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span>
 <span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"You entered '%s'\n"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">s</span><span style="color: #0000FF;">})</span>
<!--</syntaxhighlight>-->

=={{header|Raku}}==
(formerly Perl 6)
{{works with|Rakudo|2018.10}}
Should work with any termios compatible terminal.

All printable character keys work, as does backspace and enter. Ctrl-c to exit. All other keys / key-combos are ignored. 

<syntaxhighlight lang="raku" line>use Term::termios;

constant $saved   = Term::termios.new(fd => 1).getattr;
constant $termios = Term::termios.new(fd => 1).getattr;
# raw mode interferes with carriage returns, so
# set flags needed to emulate it manually
$termios.unset_iflags(<BRKINT ICRNL ISTRIP IXON>);
$termios.unset_lflags(<ECHO ICANON IEXTEN ISIG>);
$termios.setattr(:DRAIN);


END {
    $saved.setattr(:NOW); # reset terminal to original settings
    print "\e[?25h \e[H\e[J"; # clear and reset screen
}

my $row     = 3;
my $column  = 5;
my $field   = '';
my $spacer  = ' ' x 8;
my $pointer = 0;

my ($rows,$cols) = qx/stty size/.words; # get screen size

my @screen = "\e[41m{' ' x $cols}\e[0m" xx $rows;

update($spacer);

loop {
    my $key = $*IN.read(4).decode;
    given $key {
        when ' '..'~' {
            if $pointer < 8 {
                $field ~= $_;
                $spacer = ' ' x 8 - $field.chars;
                $pointer +=1;
                update($field~$spacer)
            }
        }
        when "\c[127]" { # backspace
            if $pointer > 0 {
                $field.=substr(0,*-1);
                $spacer = ' ' x 8 - $field.chars;
                $pointer -= 1;
                update($field~$spacer)
            }
        }
        when "\c[13]" {
            update('        ');
            print "\e[10;6H\e[1;33;41mYou entered: $field\e[0m\e[$row;{$column}H";
            $field = '';
            $pointer = 0;
        }
        when "\c[0003]" { exit } # Ctrl-c
        default { }
    }
}

sub update ($str) {
    ($rows,$cols) = qx/stty size/.words;
    @screen = "\e[41m{' ' x $cols}\e[0m" xx $rows;
    print "\e[H\e[J{@screen.join: "\n"}\e[$row;{$column}H$str\e[$row;{$column + $pointer}H";
}</syntaxhighlight>

=={{header|REXX}}==
(This REXX program only works with: &nbsp; REXX/Personal)
<syntaxhighlight lang="rexx">/*REXX pgm reads text from the terminal screen from a certain  row,  column, and length.*/
parse arg row col len .                          /*obtain optional arguments from the CL*/
if row=='' | row==","  then row= 3               /*Not specified?  Then use the default.*/
if col=='' | col==","  then col= 5               /* "      "         "   "   "     "    */
if len=='' | len==","  then len= 8               /* "      "         "   "   "     "    */
parse upper version v .                          /*obtain the version of REXX being used*/

if v\=='REXX/PERSONAL'  then do;  say            /*Not correct version?   Tell err msg. */
                                  say '***error***:'
                                  say 'This REXX program requires Personal REXX version.'
                                  say
                                  exit 13
                             end
$= scrread(row, col, len)
say 'data read from terminal row '  row  "    col "  col  '    length '  len  "   is:"
say $
exit 0                                           /*stick a fork in it,  we're all done. */</syntaxhighlight>

=={{header|Wren}}==
Due to a bug the ''Stdin.readByte()'' method can currently process only the first byte of a multi-byte character. The others are skipped.
<syntaxhighlight lang="wren">import "io" for Stdin, Stdout

var textAtPos = Fn.new { |text, r, c|
    System.write("\e[%(r);%(c)H%(text)")
    Stdout.flush()
}

var input = Fn.new { |r, c, maxWidth|
    System.write("\e[2J")
    textAtPos.call("", r, c)
    Stdin.isRaw = true
    var w = 0
    var res = List.filled(maxWidth, "")
    while (true) {
        var byte = Stdin.readByte()
        if (byte >= 32 && byte < 127) {        // All printable ASCII characters
            var char = String.fromByte(byte)
            textAtPos.call(char, r, c+w)
            if (w < maxWidth-1) {
                res[w] = char
                w = w + 1
            } else {
                System.write("\b")
                Stdout.flush()
                res[w] = char
            }
        } else if (byte == 127 && w > 0) {     // Backspace/delete (127 used rather than 8)
            System.write("\b \b")
            Stdout.flush()
            w = w - 1
            res[w] = ""
        } else if (byte == 13 || byte == 10) { // Carriage return or line feed
            System.print()
            break
        } else if (byte == 3 || byte == 4) {   // Ctrl-C or Ctrl-D
            Fiber.abort("\nScript aborted")
        }
    }
    Stdin.isRaw = false
    return res.join().trimEnd(" ")
}

var res = input.call(3, 5, 8)
System.print(res)</syntaxhighlight>

=={{header|XPL0}}==
<syntaxhighlight lang="xpl0">proc GetData(Col, Row, Width, Str);
int  Col, Row, Width;  char Str;
int  I, C;
string 0;
[Cursor(Col, Row);
I:= 0;
loop    [C:= ChIn(1);           \Ctrl+C aborts
        if C = $0D \CR\ then
            [Str(I):= 0; \terminate\  quit];
        if C = $08 \BS\ then
            [if I > 0 then
                [I:= I-1;
                ChOut(0, C);    \echo backspace
                ChOut(0, ^ );   \erase character
                ChOut(0, C);    \echo backspace
                ];
            ];
        if I<Width & C>=$20 & C<=$7E then
            [ChOut(0, C);       \echo character
            Str(I):= C;
            I:= I+1;
            ];
        ];
];

char Str(8+1);
[ChOut(0, $0C \FF\);            \clear screen
GetData(5, 3, 8, Str);
Text(0, "
You entered: ");
Text(0, Str);
]</syntaxhighlight>

=={{header|Yabasic}}==
<syntaxhighlight lang="yabasic">// Rosetta Code problem: http://rosettacode.org/wiki/Restricted_width_positional_input/No_wrapping
// by Galileo, 04/2022

clear screen

sub getInput$(r, c, long)
    local text$, c$
    
    c = c - 1
    r = r - 1
    print at(c, r);
    do
        c$ = inkey$
        if c$ = "enter" break
        if c$ = "backspace" then
            text$ = left$(text$, len(text$) - 1)
            print "\b ";
        else
            if len(text$) < long text$ = text$ + c$
        end if
        print at(c, r) text$;
    loop
    
    return text$
end sub

text$ = getInput$(3, 5, 8)
 
print at(1, 23) "You entered: ", text$</syntaxhighlight>