Bugs or suggestions? Visit the issue tracker and file an issue. We welcome your bug reports and feature suggestions!
Would you like to contribute? That’s awesome! Pull Requests are always welcome!
Blessed is a fork of blessings. Apologies for the fork, I just couldn’t get the Keyboard, and later Location or Measuring code accepted upstream after two major initiatives, the effort was better spent in a fork, where the code is accepted.
Furthermore, a project in the node.js language of the same name, blessed, is not related, or a fork of each other in any way.
Install and run tox:
pip install --upgrade tox tox
Py.test is used as the test runner, and with the tox target supporting positional arguments, you may for example use looponfailing with python 3.7, stopping at the first failing test case, and looping (retrying) after a filesystem save is detected:
tox -epy37 -- -fx
The test runner (
tox) ensures all code and documentation complies with standard python style
guides, pep8 and pep257, as well as various static analysis tools.
When you contribute a new feature, make sure it is covered by tests.
Likewise, some bug fixes should include a test demonstrating the bug.
As a developer’s API, blessed is often bundled with frameworks and toolsets that dive deeper into
Terminal I/O programming than
Terminal offers. Here are some recommended readings to
help you along:
The termios(3) of your preferred posix-like operating system.
The TTY demystified by Linus Åkesson.
A Brief Introduction to Termios by Nelson Elhage.
Richard Steven’s Advance Unix Programming (“AUP”) provides two very good chapters, “Terminal I/O” and “Pseudo Terminals”.
GNU’s The Termcap Manual by Richard M. Stallman.
Chapter 11 of the IEEE Open Group Base Specifications Issue 7, “General Terminal Interface”
The GNU C Library documentation, section Low-Level Terminal Interface
The source code of many popular terminal emulators. If there is ever any question of “the meaning of a terminal capability”, or whether or not your preferred terminal emulator actually handles them, read the source! Many modern terminal emulators are now based on libvte.
The source code of the tty(4), pty(7), and the given “console driver” for any posix-like operating system. If you search thoroughly enough, you will eventually discover a terminal sequence decoder, usually a
caseswitch that translates
\x1b[0minto a “reset color” action towards the video driver. Though
tty.clinked here is probably not the most interesting, it can get you started:
Thomas E. Dickey has been maintaining xterm, as well as a primary maintainer of many related packages such as ncurses for quite a long while. His consistent, well-documented, long-term dedication to xterm, curses, and the many related projects is world-renown.
termcap & terminfo (O’Reilly Nutshell) by Linda Mui, Tim O’Reilly, and John Strang.
Note that System-V systems, also known as Unix98 (SunOS, HP-UX, AIX and others) use a Streams interface. On these systems, the ioctl(2) interface provides the
POPparameters to communicate with a Streams device driver, which differs significantly from Linux and BSD.
Many of these systems provide compatible interfaces for Linux, but they may not always be as complete as the counterpart they emulate, most especially in regards to managing pseudo-terminals.
The misnomer of ANSI¶
When people say ‘ANSI’, they are discussing:
- Standard ECMA-48: Control Functions for Coded Character Sets
- ANSI X3.64 from 1981, when the American National Standards Institute adopted the ECMA-48 as standard, which was later withdrawn in 1997 (so in this sense it is not an ANSI standard).
- The ANSI.SYS driver provided in MS-DOS and clones. The popularity of the IBM Personal Computer and MS-DOS of the era, and its ability to display colored text further populated the idea that such text “is ANSI”.
- The various code pages used in MS-DOS Personal Computers, providing “block art” characters in the 8th bit (int 127-255), paired with ECMA-48 sequences supported by the MS-DOS ANSI.SYS driver to create artwork, known as ANSI art.
- The ANSI terminal database entry and its many descendants in the terminfo database. This is mostly due to terminals compatible with SCO UNIX, which was the successor of Microsoft’s Xenix, which brought some semblance of the Microsoft DOS ANSI.SYS driver capabilities.
- Select Graphics Rendition (SGR) on vt100 clones, which include many of the common sequences in ECMA-48.
- Any sequence started by the Control-Sequence-Inducer is often mistakenly termed as an “ANSI
Escape Sequence” though not appearing in ECMA-48 or interpreted by the ANSI.SYS driver. The
adjoining phrase “Escape Sequence” is so termed because it follows the ASCII character for the
escape key (ESC,