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Small on-board editor for PyBoard, WiPy, ESP8266, ESP32, RP2040, W60x, XBEE 3, Sipeed K210, as well as PyCom and Adafruit devices written in Python

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A small text editor written in Python running on

  • modules like the PyBoards, ESP32, ESP8266, Teensy 3.5, 3.6 and 4.x, RP2040, W60x
  • modules like WipPy, Lopy, SiPy, FiPy, GPy
  • Adafruit Circuitpython modules,
  • SiPeed MaixPy modules,
  • Linux, OS X and Android's terminal windows

It allows allows to edit files locally on the boards. The offspring was the editor widget of pfalcon at I ported it to PyBoard and the other modules and added a lot of functions:

  • Use and sys.stdout.write() for input and output of the MicroPython version.
  • Changed the read keyboard function to comply with byte-by-byte input on serial lines.
  • Added support for Tab, BackTab, Save, Del and Backspace joining lines, Find, Replace, Goto Line, Undo, Redo, Open file, Auto-Indent, Set Flags, Copy/Delete & Paste, Indent, Dedent, Block-Comment, Scrolling, line-shift
  • Handling tab (0x09) on reading & writing files,
  • Added a status line, and single line prompts for Quit, Save, Find, Replace, Goto, Open file and Flag settings.
  • Support the simultaneous editing of multiple files.
  • Basic mouse functions for scrolling up/down, setting the cursor and highlighting text.

The editor assumes a VT100 terminal. It works in Insert mode. The following list shows most of the commands.:

Key(s) Function
Up Down Left Right Cursor movement by one line or char
Ctrl-Left Move the cursor left to the start of the (next) word
Ctrl-Right Move the cursor right behind the end of the (next) word
Shift-Up -Down -Left -Right Highlight the text or extend the highlighted area
Ctrl-Shift-Left -Right Highlight the next or previous word or extend the highlighted area
Ctrl-Up Ctr-Down Scroll the windows down/up
Alt-Up Alt-Down Move the current line or highlighted area up/down by one line
Alt-Left Alt-Right Move the character under the cursor left/right
PgUp & PgDd Page up/down
Home Toggle the position between the start-of-code and the start of line
End Toggle the position between the end-of-the-code and end-of-line
Enter Enter a line break at the cursor position. Auto-indent is supported
Backspace Delete char left to the cursor (The key must be set to ASCII-Del). If text are highlighted, delete the highlighted area
Del Delete the char under the cursor. At the end of the line join the next line. If autoindent is enabled, delete also the leading spaces of the joined line. If text are highlighted, delete the highlighted area. In line edit mode, Del as first keystroke will clear the entry.
Ctrl-Del Delete the word under the cursor or space up to the next non-space
Shift-Del Delete the actual line
Ctrl-O Open a new file. If the file name is left empty, an empty buffer is opened
Ctrl-W Switch to the next file buffer
Ctrl-Q Close a file buffer or end line-edit
Ctrl-S Save to file with the option to change the file name. If a new name is given and that file already exists, ask for confirmation.
Ctrl-F Find
Ctrl-N Repeat the last find
Ctrl-H or Ctrl-R Find and Replace
Ctrl-G Go to a line
Ctrl-T Go to the first line
Ctrl-B Go to the last line
Ctrl-K Goto the bracket matching the one under the cursor
Ctrl-Home & Ctr-End Go to the first/last line
Ctrl-PgUp & Ctrl-PgDd Switch to the previous/next file
Alt-Ins Bookmark a location in a file
Alt-PgUp & Alt-PgDn Cycle trough bookmarked locations
Alt-Home & Alt-End Cycle trough locations with changes, based on the Undo list
Ctrl-L or Ctrl-Space Start highlighting at the current position, or clear the highlight. The highlight can then be extended by moving the cursor
Ctrl-X Cut the highlighted text
Ctrl-C or Ctrl-D Copy the highlighted text
Ctrl-V Insert the copied/cut text.
Ctrl-Z Undo the last change(s)
Ctrl-Y Redo the last undo(s), repeating what had been undone by undo
Ctrl-P Comment/Uncomment a line or highlighted area
Ctrl-A Change settings for tab size, search case sensitivity, auto-indent, comment string and writing tabs (opt)
Ctrl-E Redraw the screen. On the Micro devices it shows the amount of free memory
Mouse support
Mouse scroll wheel Move the cursor up and down, scrolling the content as needed.
Mouse left click Within the text: Double click starts highlighting at the current position, or clears the highlight. The click speed does not matter. If the cursor is on a word, the whole word will be highlighted. If not, just the character under the cursor. The highlight can then be extended by moving the cursor clicking at different positions.
Mouse right click Opens the "find" dialogue in a text file and the "open file" dialogue in a directory listing.
Mouse left click In line edit mode: Clicking on a word copies it to the edit line. Clicking a second time at the same place acts as enter.

Instead of Ctrl-letter (e.g. Ctrl-Q), Alt-letter (e.g. Alt-Q) or ESC-letter (e.g. ESC followed by Q) can be used, avoiding conflicts with key binding of some terminal emulators.

The editor is contained in the files and Start pye from the REPL prompt e.g. with

from pye import pye
res = pye(object_1, object_2, ..[, tabsize=n][, undo=n])

You may also use the combined version resp. pye.mpy:

from pye import pye
res = pye(object_1, object_2, ..[, tabsize=n][, undo=n])

If object_n is a string, it's considered as the name of a file to be edited or a directory to be opened. If it’s a file, the content will be loaded, and the name of the file will be returned when pye is closed. If the file does not exist, an error is displayed, but the edit window is given that name. If it’s a directory, the list of file names will be loaded to the edit window. If object_n is a list of other items, they will be converted to strings and edited, and the edited list will be returned as strings. If no object is named, pye() will show the list of files in the current directory, creating a list of strings, unless you save to a file. In that case, the file name will be returned. It is always the last buffer closed, which determines the return value of pye().

Optional named parameters:

tabsize=n     Tab step (integer). The default is 4
undo=n        Size of the undo stack (integer). The minimal size is 4.

The Linux/Darwin version can be called from the command line with:

python3 [filename(s)]

or using the combined executable version pye:

pye [filename(s)]

Obviously, you may use micropython too.

More details can be found in the doc file. On reading files, tab characters are expanded to spaces with a tab size of 8, and trailing white space on a line will be discarded. Optionally, tabs can be written when saving the file, replacing spaces with tabs when possible. However, the original state of tabs will NOT be restored when the file is written. The screen size is determined, when the editor is started, when the Redraw-key (Ctrl-E) is hit or on any file window change (Ctrl-W).

The editor works also well in a Linux or MAC terminal environment (and also in some terminal apps of Android - tested with Termux) with both python3 and micropython. For that purpose, a small main() section is embedded in, which when called with CPython also accepts data from a pipe or redirection.


Base files

  • Core file with comments, intended to be the same for all platforms
  • Front-end for Linux CPython and Linux MicroPython
  • Front-end for Micropython and Circuitpython modules with I/O through sys.stdout and sys.stdin.
  • A front-end for Teensy 3.5 and 3.6 .
  • an experimental front end for the cmd window of Windows 10. It requires enabling the VT100 support, as detailed e.g. here:
  • Core file for XBEE 3 devices.
  • Pyboard Editor.pdf: A short documentation
  • sample Shell script which creates the different derived files out of and the front-end files, using cat and sed.
  • This one

Derived files

  •, pye.mpy: Condensed source files of + for all MicroPython boards. In order to use it on an board with small memory like the esp8266, you have to put into the directory esp8266/modules, esp32/modules or stm32/modules ( or esp32/frozen ( and rebuild micropython. A cross-compiled version may executed from the file system.
  •, pye_x3.mpy: Condensed file for XBEE 3 devices. The .mpy file can be imported from the file system, but it should be better bundled into flash with uos.bundle().
  • pye: Executable single file for Linux
  • pye_win: Executable single file for Windows 10

Further front-ends

  • Front-end provided by user @kmatch98 for Circuitpython using a LCD as output device and UART as input device. The port requires further python scripts.
  • Readme for the pye_lcd version, provided by @kmatch98.
  • Sample front-end using a tft with a SSD1963 controller as output device. The port requires the SSD1963 drivers:


Branch Features
master Actual main line with slowly changing features.
pye2 Similar to the master branch, but the column does not change during vertical moves (stale).
pye_min Feature-reduced version, which is somewhat smaller (stale).

Version History

1.0 Initial release with all the basic functions

1.1 Same function set, but simplified keyboard mapping.

  • Removed the duplicated definitions for cursor motion keys.
  • Allowed both \r and \n for ENTER, and both \x08 and \x7f for BACKSPACE, which avoid some hassle with terminal settings.
  • Removed auto-indent from the minimal version.

1.2 Mouse support added, as well as some other minor changes.

  • Simple Mouse support for scrolling and placing the cursor
  • Flags setting for search case, auto-indent on/off and status line on/off
  • GOTO line sets cursor to the middle row
  • The function pye(..) returns a value now

1.3 UNDO added. Added a multilevel UNDO (Ctrl-Z) for most functions that

change the content. Other changes:

  • Backspace at the first non-blank character mimics BackTab, if Auto-indent is enabled
  • Added a REDRAW (Ctrl-E) function, which checks for the changed screen size after the window size has been changed.
  • Added a line number column on the left side of the screen (can be turned off).
  • Improved the scrolling speed, such that it lags less.
  • Some code simplification and straightening, such that functions group better and are easier to understand.

1.4 GET file added. Adding a function GET (Ctrl-O), which inserts the content of a file before the current line. Other changes:

  • Both HOME and END stop at start of text is passing by on their way to their destination.
  • Flag allowing to replace spaces by Tab when writing the file, complementary to what is done while reading. Tabsize is 8. A tab is inserted whenever possible, even if it replaces a single space character.
  • Fixed a mild amnesia in UNDO

1.5 WiPy Port and body shaping:

  • Support for WiPy added. WiPy runs only the minimal version.
  • Aligned function set of the minimal version, in order to comply with WiPy. Dropped Mouse support, GET file, Line number column, and write tabs; but included Tab, Backtab, the buffer functions Yank, Dup & ZAP and scrolling optimization.
  • LEFT and RIGHT move to the adjacent line if needed
  • When used with Linux and CPython, a terminal window resize cause redrawing the screen content. The REDRAW key (Ctrl-E) stays functional and is required for all other use cases, when the window size is changed.
  • HOME toggles again between start-of-line and start-of-text. END moves always to end-of-line
  • Dropped context sensitive behavior of Tab, Backtab, Backspace and Delete. Too confusing.
  • Dropped the line number column, and made the status line permanent in all modes.
  • Rearranged the code such that any platform related sections are grouped together.

1.6 WiPy fixes and further trimming:

  • Making rarely used small functions inline again, which saves some space. Important for WiPy.
  • Catch Ctrl-C on WiPy. Not really nice yet, since the next input byte is lost.
  • Tab Size can be set with the Ctrl-A command (if available).
  • Simplified Linux main(). No calling options any more.
  • Always ask when leaving w/o saving after the content was changed.

1.7 WiPy fixes and other minor changes

  • Fixed a memory leak in REDRAW, removed every instance of "del name"
  • Changed REDRAW to tell the amount of free memory
  • changed wr() for WiPy
  • Simplified the internal interface to init_tty()
  • Changed the handling of reading an empty file
  • Non-supported functions in the minimal version like REPLACE trigger a "Sorry" message
  • Try to recover from MemoryError by clearing the line-buffer and UNDO

1.7a Size reduction for WiPy & Tabbify for PyBoard

  • Reduced KEYMAP in the WiPy version by omitting entries, where the function code is identical to the key value (e.g. \x08 -> 8). Not fool proof, but it helps reducing the size.
  • Adding a "Tabbify" behavior for the full version. Tab/Backtab with the cursor at col 1 indents/unindents the line and moves the cursor one line down.

1.7b Further size reduction for WiPy

  • Moved setting of the change flag into the function add_undo()
  • Removed skipping to the adjacent line with Right/Left in the WiPy Version
  • Temporary avoidance of the memory leak when a file is not found

1.7c Re-establish try-except for file-not-found error

  • Removed the temporary fix for memory corruption by exception for file-not-found error
  • Changed string formatting to Python3 style

1.8 Clean Copy & Paste, Indent, Un-Indent

  • Added a Highlight Line key for Line Delete, Line Copy, Indent and Un-Indent
  • Fixed a glitch, that allowed to paste text longer then the available space on the status line. No harm was done, just the screen content scrolled up. After leaving the line edit mode, a redraw fixed that.
  • Changed Line Delete, Line Copy and Buffer Insert into a cleaner Copy & Paste mode
  • Added a cleaner Indent and Un-Indent method; for WiPy too
  • Removed the attempt to recover from out-of-memory situations: did not work.
  • Still runs on WiPy, but really at it's limit

1.9 Refinement of Highlight and Undo

  • Highlight setting affects Save and Replace now. With Save, only the highlighted range is written, with replace, search & replace is done in the highlighted area only.
  • The Undo history is kept after Save. So you can go back to a state before saving
  • Removed UART mode on WiPy. Not stable yet. UART mode can be achieved by redirecting REPL.
  • A variant of, called, keeps the cursor column even if the cursor is moved beyond the text in a line, instead of moving to the end of text if a line is shorter than the actual cursor column. Another variant, pye3, tries to go back to the cursor column which once was set by a horizontal move. That's more how gedit works. Not sure which I like better.

1.10 Further refinement of Highlight

  • When the highlight is set, the whole area affected is now highlighted instead of just the line with the highlight.
  • Paste, Delete and Backspace now also take notice of the line Highlight. You can Highlight a line range and delete it (or cut it). Implicit deleting highlighted lines when pressing the Enter or character key was considered but rejected (easy - just 3 lines of code).
  • Except for Delete, Backspace, Cut and Paste, Highlight has to be toggled off when not needed any more.
  • Right click (Button 2) or Ctrl-Click on the mouse sets/unsets the Highlight, left Click extends it, when set.

1.11 Minor fixes

  • Change the way a highlighted area is highlighted from reverse to a different background colour. That works well for black chars on yellow background (code 43). For white chars on black background, the setting for background colour in the function hilite() has to be changed, e.g. to blue (code 44).
  • Save to a temporary file first, and rename it to the target name when successfully written.
  • Lazy screen update: defer screen update, until all chars from the keyboard are processed. Not provided for WiPY, even if needed there most. WiPy has no way to tell if more chars are waiting in the input or at least a read with timeout.

1.12 Bracket Match and Minor changes

  • Ctrl-K causes the cursor set to the matching bracket, if any. Pretty raw, not elegant. Brackets in comments and strings are counting as well.
  • On Copy the highlight will be cleared, since it is assumed that the just copied lines will not be overwritten.
  • High level try/except catching internal errors (mostly coding errors)
  • Separate cpp options for including scroll optimization, replace or bracket match into the minimal version. Changes in script to generate the minimal wipye version too.
  • Some editorial changes and fixing of typos.

1.12b Fixing an inconsistency in the Save command

  • Fixing an inconsistency in the Save command, which caused the change flag being reset when writing just a block
  • Squeezing a few lines out of the source code

1.12c Speed up pasting again

  • Speed up pasting again. Slowing down pasting was caused by an in-function import statement in V1.11.
  • Squeezing another few lines out of the source code by combining two functions, which were anyhow called one after the other, resulting in an enormous long function handling the keyboard input.

1.12d Split undo of Indent/Un-Indent

  • Split undo for Indent and Un-Indent
  • Fixed a minor inconvenience when going left at the line start (squeezed too much in v1.12b)
  • Move a few lines around, such that keys which are more likely used with fast repeats are checked for earlier.
  • Some editorial changes

2.0 Edit multiple files

  • Support for editing multiple files at once and copy/paste between them
  • Ctrl-W steps through the list of files/buffers
  • Ctrl-O opens a new file/buffer.

2.1 Some shrinking for WiPy

  • Make Indent/Un-Indent optional in the WiPy version, to allow all variants to get compiled w/o running out of memory. The final code saving is just a few hundred bytes, so it's still not clear to me why these few extra lines don’t fit.
  • Fixing a glitch which added an extra line when undoing the delete of all lines
  • Some shifting around of code lines
  • Making the MOUSE support an extra option
  • Removed the extra indent after ':' as the last char on the line. More confusing than helpful.
  • Update of the doc file

2.2 Further cleaning and some slight improvements

  • Moved error catching one level up to the function pye(), catching load-file errors too.
  • If open file names a directory, the list of files is loaded to the edit buffer.
  • Ctrl-V in line edit mode inserts the first line of the paste buffer
  • The WiPy version does not support undo for Indent/Un-indent, even if Indent is enabled. It is too memory consuming at runtime. It's questionable whether this is needed at all.
  • And of course: update of the doc file

2.3 Minor fixes & changes

  • Catched file not found errors when starting pye, introduced in version 2.2
  • Added a flag to pye2 such that it supports both vertical cursor movement types
  • use uos.stat with micropython, since os.stat is not supported on linux-micropython
  • When opening a directory, replace the name '.' by the result of os.getcwd(), avoiding error 22 on PyBoard and WiPy

2.4 Fix for the regular expression search variant

  • Fix a glitch, that the regular expression variant of search and replace did not find patterns anchored at the end, single line starts or single line endings. That fix required changes not only to the find function, such that all variants of pye are affected.
  • Consider '.' and '..' in file open as directory names, avoiding stat() on these.

2.5 Fix a small bug of edit_line()'s paste command

  • Fixed a glitch, that allowed to paste text longer then the available space on the status line. No harm was done, just the screen content scrolled up. After leaving the line edit mode, a redraw fixed that.

2.6 Adapted to change lib names in micropython

  • For micropython replaced _io with uio
  • Preliminary esp8266 version.

2.7 Change file save method and settings dialogue

  • Further adaptation to esp8266, which is now identical to the WiPy version
  • Changed file save method, such that it works now across devices
  • Made settings dialogue visible in basic mode, allowing to change both the autoindent flag and the search case flag
  • Create the ESP8266 version with all features but mouse support.

2.8 Support of UTF-8 characters on keyboard input

  • This in implemented for all versions. However WiPy does not support it in the lower levels of sys.stdin.

2.9 Support for teensy 3.5 and 3.6

  • The only change was to add the teensy names to the platform detection
  • Implement full function set for line-edit by default

2.10 Support for esp32; simplified mouse handling

  • The only change was adding the esp32 name to the platform detection
  • Do not use global symbols for mouse parameters

2.11 Small changes to the esp8266 version

  • Faster paste from the keyboard
  • Enabled Mouse support as default

2.12 Use the kbd_intr() method to disable Keyboard Interrupts on Ctrl-C.

This method is supported by (almost) all ports and maybe sometime also supported by the ports. The method of trying to catch KeyboardInterrupt is still present.

2.13 Reduce the number of derived variants and make the full version the default one. Update the documentation.

2.14 Remove the PyBoard support using an UART as keyboard/display interface. Use kbd_intr() too on Pyboard.

2.15 Make a combined MicroPython version, which runs on all boards except Teensy 3.5 / 3.6. For teensy, a short wrapper is included.

2.16 Optimize search with Regular expressions

2.17 Remove all option variants from the source files, and make a pure micropython boards version with reduced function set. The only options remaining are Linux/CPython vs. MicroPython

2.18 On deleting the end of a line, remove space characters from the joined line, if autoindent is active. This behavior mirrors autoindent.

2.19 Add a toggle key for commenting/uncommenting a line or highlighted area. The default comment string is '#', but can be changed through the settings command.

2.20 Change the End-Key to toggle between EOL and last non-space char.

2.21 Add Ctrl-\ as alternative key to close a file

2.22 Add Ctrl-Space asl alternative to highlight line (Ctrl-L), and Block comment adds the comment string after leading spaces.

2.23 Change the End key to toggle between end-of-line and end-of-code

2.24 Changed the Paste key in line edit mode, in that it pastes the word under the cursor of the active window.

2.25 Version number is shown with redraw command, and thus at startup and window change

2.26 Better separation of port-specific and OS-specific flags

2.27 Change Home/End key behavior. Py w/o filename will open a window with the list of files in the current dir

2.28 Add word left & right with ctrl-left and ctrl-right

2.29 Add shift-up and shift-down for setting/extending the highlighted area

2.30 Add Delete Word with Ctr-Del

2.31 Re-Map Ctrl-Up and Ctrl-Down for scrolling

2.32 Comment toggle ignores empty lines

2.33 Scroll step is 1 for keyboard and 3 for mouse

2.34 Added a branch with character mode highlight/cut/paste/delete. Intended to be the new master

2.35 Change behavior of the column position during vertical moves, in that it tries to keep the position

2.36 Add the redo function, which restates changes undone by undo.

2.37 Entering text replaces an highlighted area.

2.38 Add Ctrl-Shift-Left and Ctrl-Shift-Right for move & highlight

2.39 Move a line with Alt-Up and Alt-Dn

2.40 Extend move up/down to move highlighted areas too.

2.47 Move all terminal control strings into an list.

2.48 Split into a core file and port specific front-ends. If a single file is required, just put the core and the front-end into a single file.

2.49 Change the default search item behavior of find and replace as well as open file.

2.50 Limit the span for bracket match to 50 lines and improve the speed

2.51 Re-establish automatic screen redraw on resize for Linux

2.52 Fix regression error on file creation

2.53 Fix regression error on handling directories

2.54 Fix regression error in the Linux variant

2.55 Cope with the change from renaming the sys module to usys

2.56 Fix regression error when opening multiple files

2.57 Slight speed improvement when pasting

2.58 Fix a glitch in redo after undo after pasting a full line.

2.59 Change mouse support. Clicking twice at the same position enables/disables marking.

2.60 Extend mouse support

2.61 Further straighten mouse support. Double Click is click at the cursor position, and the mark can be extended to both sides with the mouse without affecting what was already marked.

2.62 Ask for confirmation before overwriting an existing file other than the one initially opened.

2.63 Change mouse behavior again. Right click opens the "find" dialogue in a text window or "open file" dialogue in a directory listing.

2.64 Enable additional file name chars in the file save dialogue (was omitted)

2.65 Check for invalid key sequence. Show the search item in "not found" messages

2.66 Fix an display error when doing a left click beyond the end of text during line edit

2.67 Make double click in the text more consistent. Mark/Unmark always requires a double click.

2.68 Make double click timed. Time is < 2 seconds

2.69 Minor reorganisation in the function get_input. Firt version of a Window 10 front-end.

2.70 Move character under the cursor left/right with the Alt-Left/Alt-Right key.

2.72 Add delete line and force quit

2.73 Use Ctrl-PgUp and Ctr-PgDn to switch files.

2.74 Add functions to bookmark locations and go to them, using Alt-Home and Alt-PgUp / Alt-PgDn

2.75 Fix an error with character swap.

2.76 Cycle through places with changes.

2.77 Change key binding for bookmark location to Alt-Ins, using Alt-Home and Alt-End to cycle through locations with changes.


Small on-board editor for PyBoard, WiPy, ESP8266, ESP32, RP2040, W60x, XBEE 3, Sipeed K210, as well as PyCom and Adafruit devices written in Python