module BBS::Text

Text a caller typed or a remote service sent, made safe to keep and to show: valid UTF-8, no control characters, no bidirectional overrides.

BBS::Text.clean("Ada\e[2J\u202Etxt.exe")   # => "Ada[2Jtxt.exe"
BBS::Text.line("Ada\n  Lovelace\t")        # => "Ada Lovelace"
BBS::Text.printable?('é')                   # => true

Constants

BIDI_CONTROLS: The bidirectional embedding, override and isolate characters, which can make a line read differently from what it holds.
CONTROLS: The C0 controls except tab and LF, DEL, the C1 controls and the BIDI_CONTROLS.
LINE_END: A line end: CR LF, LF or CR.
PRINTABLE_CHAR: One printable character: no control, no bidirectional control.
WHITESPACE: A run of whitespace.

Public Instance Methods

clean (text, keep_newlines: true)

Source

# File lib/bbs/text.rb, line 30
def clean(text, keep_newlines: true)
  text = utf8(text)
  text = text.gsub(LINE_END, ' ') unless keep_newlines
  text.gsub(CONTROLS, '')
end

Returns text (anything with to_s) as a new valid UTF-8 String with invalid bytes, C0 controls (but tab and LF), DEL, C1 controls and bidirectional controls removed. With keep_newlines: false each line end becomes a space, so the words of two lines stay apart.

line (text)

Source

# File lib/bbs/text.rb, line 38
def line(text) = clean(text, keep_newlines: false).gsub(WHITESPACE, ' ').strip

Returns text as one clean line: clean, every run of whitespace (line ends and tabs included) one space, and no space at either end.

printable? (char)

Source

# File lib/bbs/text.rb, line 42
def printable?(char) = char.is_a?(String) && char.match?(PRINTABLE_CHAR)

Returns whether char is one printable character (a String of length one that PRINTABLE_CHAR matches).

utf8 (text)

Source

# File lib/bbs/text.rb, line 45
def utf8(text) = text.to_s.dup.force_encoding(Encoding::UTF_8).scrub('')

Returns text as a new UTF-8 String with invalid bytes removed.