class BBS::Field

A one-line input field at the cursor, for a modern terminal and a Commodore 64 alike: it starts from a text that can be edited rather than typed again, the cursor keys move in it, typing inserts at the cursor and DEL (backspace) deletes before it. A text longer than the field scrolls sideways. The text and the cursor live in a BBS::TextBuffer, so the editing keys do what they do in a BBS::Editor.

The field takes width columns from where the cursor is; on a C64 keep it out of the last column. It moves the cursor with a BBS::Cursor, only sideways.

Keys:

cursor left, right: move
HOME, END: the start and the end of the text
DEL, backspace: deletes the character before the cursor
Delete: deletes the character under the cursor
RETURN: ends the input
RUN/STOP, ←, Esc: cancels it

session.write ' title> '
title = BBS::Field.new(session, text: post.title, width: 31, max: 80).run

Constants

CANCEL_KEYS: The keys that cancel the input.
LINE_END: A line end in a prompt: CRLF, CR or LF.

Public Class Methods

ask (session, prompt, text: '', max: nil, mask: nil, cols: session.term_cols)

Source

# File lib/bbs/field.rb, line 42
def self.ask(session, prompt, text: '', max: nil, mask: nil, cols: session.term_cols)
  session.write(prompt)
  last  = prompt.to_s.split(LINE_END, -1).last.to_s
  width = cols - 1 - FrameBuffer.visible_width(last)
  new(session, text: text, width: width, max: max, mask: mask).run
end

Writes prompt and runs a field after it as wide as the rest of the screen: cols less the last line of prompt and the last column. Returns what run returns: the text, or nil when cancelled.

text: the text to start from
max: the most characters the text may hold, or nil
mask: shown in place of every character, or nil
cols: the screen width; default the session’s

name = BBS::Field.ask(session, " name> ", max: 20)

new (session, width:, text: '', max: nil, mask: nil)

Source

# File lib/bbs/field.rb, line 56
def initialize(session, width:, text: '', max: nil, mask: nil)
  @session = session
  @screen  = Cursor.new(session)
  @buffer  = TextBuffer.new(text, max: max, single_line: true)
  @width   = [width, 2].max
  @mask    = mask
  @scroll  = 0
end

Creates a field for session.

text: the text to start from, the cursor at its end
width: the columns the field takes, at least 2
max: the most characters the text may hold; nil means TextBuffer::MAX_LENGTH
mask: shown in place of every character (for a password, e.g. '*'), or nil to show the text

Public Instance Methods

run ()

Source

# File lib/bbs/field.rb, line 70
def run
  paint
  loop do
    key = @screen.key
    return finish(@buffer.text) if key == :enter
    return finish(nil) if CANCEL_KEYS.include?(key)

    apply(key)
    paint
  end
end

Runs the field until RETURN or a cancel key, then writes a line end, so the cursor is at the start of the next line.

Returns the text on RETURN and nil when cancelled. Raises IOError when the caller hangs up.