This Cheat Sheet contains a summary of many of Leo’s important features. Important: The easiest way to find documentation is to search LeoDocs.leo.
When focus is in the outline pane:
Right-arrow (expand-and-go-right)
Left-arrow (contract-or-go-left)
Up-arrow (goto-prev-visible)
Down-arrow (goto-next-visible)
Regardless of focus:
Alt-Home (goto-first-visible-node)
Alt-End (goto-last-visible-node)
Alt-Right-arrow (expand-and-go-right)
Alt-Left-arrow (contract-or-go-left)
Alt-Up-arrow (goto-prev-visible)
Alt-Down-arrow (goto-next-visible)
When focus is in the outline:
Shift-Down-arrow (move-outline-down)
Shift-Left-arrow (move-outline-left)
Shift-Right-arrow (move-outline-right)
Shift-Up-arrow (move-outline-up)
Regardless of focus:
Alt-Shift-Down-arrow (move-outline-down)
Alt-Shift-Left-arrow (move-outline-left)
Alt-Shift-Right-arrow (move-outline-right)
Alt-Shift-Up-arrow (move-outline-up)
Ctrl-D (move-outline-down)
Ctrl-L (move-outline-left)
Ctrl-R (move-outline-right)
Ctrl-U (move-outline-up)
When focus is in any of Leo’s text panes (body pane, log pane, headlines):
Key
Move Cursor
Arrow keys
one character
Ctrl-LeftArrow
back one word
Ctrl-RightArrow
forward one word
Home
beginning of line
End
end of line
Ctrl-Home
beginning of the body
Ctrl-End
end of body
PageDown
down one page
PageUp
up one page
Adding the Shift key modifier to any of the keys above moves the cursor and extends the selected text.
Alt-X puts focus in the minibuffer. Ctrl-G escapes from the minibuffer.
Once there, you can use tab completion to reduce typing. For example, <Alt-X>open<tab> shows all commands that start with open.
Hit <Enter> to run a complete command.
Ctrl-P (repeat-complex-command) repeats the last command entered from the minibuffer.
Leo maintains a command history list of all minibuffer commands you have entered.
When focus is in the minibuffer, UpArrow shows the previous minibuffer command, and DnArrow show the commands before that.
The body text of an @data history-list setting node preloads commands into the command history list, ignoring lines starting with #. For example:
run-pylint
beautify-tree
cff
sort-lines
# show-data
check-clones
expand-log-pane
contract-log-pane
For much more information, see the Commands Reference.
Copy/Paste (text):
Ctrl-C (copy-text)
Ctrl-K (kill)
Ctrl-V (paste-text)
Ctrl-X (cut-text)
Ctrl-Y (yank)
Alt-Y (yank-pop)
kill-...
Files:
Ctrl-N (new)
Ctrl-O (open-outline)
Ctrl-S (save-file)
Ctrl-Q (exit-leo)
Focus:
Alt-T (focus-to-tree)
Ctrl-T (toggle-active-pane)
Ctrl-Tab (tab-cycle-next)
Help:
Alt-0 (vr-toggle)
F1 (help)
F11 (help-for-command)
F12 (help-for-python)
show-bindings
show-settings
help-for-...
Find/Replace:
Ctrl-F (search-with-present-options)
Shift-Ctrl-R (replace-string)
Ctrl-minus (replace-then-find)
F3 (find-next)
F2 (find-previous)
Minibuffer:
Alt-X (full-command)
Ctrl-G (keyboard-quit)
Tab (not a command, completes typing)
Nodes:
Ctrl-I or Insert (insert-node)
Ctrl-H (edit-headline)
<Return> (when editing a headline) (end-edit-headline)
Ctrl-Shift-C (copy-node)
Ctrl-Shift-X (cut-node)
Ctrl-Shift-V (paste-node)
Ctrl-{ (promote)
Ctrl-} (demote)
Ctrl-M (mark)
Undo:
Ctrl-Z (undo)
Ctrl-Shift-Z (redo)
The clone find commands, cfa and cff, move clones of all nodes matching the search pattern under a single organizer node, created as the last top-level node. Flattened searches put all nodes as direct children of the organizer node:
cfa clone-find-all
cff clone-find-all-flattened
The clone-marked commands move clones of all marked nodes under an organizer node. Especially useful for gathering nodes by hand:
cfam clone-find-marked
cffm clone-find-flattened-marked
Directives starting with ‘@ in the leftmost column
See the Directives reference for full details:
@ # starts doc part
@c # ends doc part
@color
@doc # starts doc part
@killcolor
@nocolor
@language python
@language c
@language rest # restructured text
@language plain # plain text: no syntax coloring.
@lineending lineending
@nosearch # suppress searching for cff & cfa commands.
@pagewidth 100
@tabwidth -4 # use spaces
@tabwidth 8 # use tabs
@nowrap
@wrap
Leading whitespace is allowed (and significant) for:
@all
@others
For documentation see node: “About this file” in leoSettings.leo:
Command history: @history-list
Key bindings: @shortcuts
Visual settings: @data qt-gui-plugin-style-sheet
Enabling plugins: @enabled-plugins
To disable a binding for a key, bind it to do-nothing:
do-nothing = Insert
This overrides the following default binding in leoSettings.leo:
insert-node = Insert
Supported by Leo’s core:
@chapter
@rst, @rst-no-head, @rst-ignore, @rst-ignore-tree
@settings
@url
Within @settings trees:
@bool, @buttons, @color, @commands
@directory, @encoding
@enabled-plugins, @float, @font,
@history-list, @int
@menus, @menu, @menuat, @item
@openwith, @path, @shortcuts, @string
Supported by plugins:
bookmarks.py: @bookmarks, @bookmark
at_folder.py: @folder
at_produce.py: @produce
at_view.py: @clip, @strip, @view
expfolder.py: @expfolder
mod_scripting.py: @button, @command, @script
viewrendered.py: @graphics-script, @image
@html, @movie, @svg
See the docstring of these plugins for more details:
bookmarks.py Manages URL's used as bookmarks.
contextmenu.py Creates context menus for headlines.
demo.py Creates demos and slides.
mod_scripting.py Supports @button and @command nodes.
quicksearch.py Adds Nav tab for searching.
todo.py To-do lists and simple project management.
viewrendered.py Creates a rendering pane.
Automatically loaded by Leo's help commands.
Supports @graphics-script, @image, @html,
@movie and @svg nodes.
viewrendered3.py An enhanced version of viewrendered3.py.
vim.py & xemacs.py Interface with vim and xemacs.
@<file> nodes create external files:
@asis <filename> write only, no sentinels, exact line endings
@auto <filename> recommended
@clean <filename> recommended
@edit <filename> @edit node contains entire file
@file <filename> recommended
@nosent <filename> write only, no sentinels
This table summarizes the differences between @<file> nodes:
Sections & File data in
@<file> kind Sentinels? @others? .leo file? Notes
------------ ---------- ----------- ------------ -----
@asis no no yes
@auto no yes no 1, 2
@auto-xx no yes no 1, 2
@clean no yes yes
@edit no no no
@file yes yes no
@nosent no yes yes
@auto nodes read files using language-specific importers. By default, the file’s extension determines the importer:
Extensions Importer
---------- --------
.c, .cc, .c++, .cpp,.cxx C
.cs', .c#' C Sharp
.el Elisp
.h, .h++ C
.html, .htm HTML
.ini Config file
.ipynb Jupyter notebook
.java Java
.js JavaScript
.md Markdown
.org Org Mode
.otl Vim outline
.pas Pascal
.php PHP
.py, .pyi, .pyw Python
.rest, .rst reStructuredText
.ts TypeScript
.xml XML
You can also specify importers explicitly as follows:
@auto-xxx Importer
--------- --------
@auto-ctext ctext
@auto-markdown markdown
@auto-md markdown
@auto-org org-mode
@auto-org-mode org-mode
@auto-otl vimoutline
@auto-vim-outline vimoutline
@auto-rst reStructuredText
Important: The importers/exporters for markdown, org-mode, reStructuredText and vimoutline files automatically generate section headings corresponding to Leo’s outline level. Body text of the top-level @auto node is ignored.
See the Directives reference for full details.
Section names have the form:
<< any text, except double closing angle brackets >>
Section-definition nodes have headlines starting with a section name.
Leo performs expansions for all @<file> nodes except @asis.
Expansion of @all:
Leo replaces @all by the unexpanded body text of all nodes.
Expansion of section names and @others:
Leo replaces section names in body text by the expanded text of the corresponding section definition node.
Leo replaces @others with the expanded text of all nodes that aren’t section-definition nodes.
This section lists the ivars (instance variables), properties, functions and methods most commonly used in Leo scripts.
Very important: use Alt-1 (toggle-autocompleter) and Alt-2 (toggle-calltips) to recreate these lists as you type.
execute-script predefines:
c: The commander of the present outline.
g: The leo.core.leoGlobals module.
p: The presently selected position, c.p.
Ivars:
g.app A LeoApp instance.
g.app.gui A LeoGui instance.
g.app.pluginsController A LeoPluginsController instance.
g.app.* Leo's global variables.
Ivars:
c.config c's configuration object
c.frame c's outer frame, a leoFrame instance.
c.undoer c's undo handler.
c.user_dict A temporary dict for use of scripts and plugins.
SubCommanders:
# In leo/core...
c.atFileCommands
c.chapterController
c.fileCommands
c.findCommands
c.importCommands
c.keyHandler = c.k
c.persistenceController
c.printingController
c.rstCommands
c.shadowController
c.tangleCommands
c.testManager
c.vimCommands
# In leo/commands...
c.abbrevCommands
c.controlCommands
c.convertCommands
c.debugCommands
c.editCommands
c.editFileCommands
c.gotoCommands
c.helpCommands
c.keyHandlerCommands
c.killBufferCommands
c.rectangleCommands
c.spellCommands
Generators (New in Leo 5.5: All generators yield distinct positions):
c.all_positions()
c.all_unique_positions()
Most useful methods:
c.isChanged()
c.deletePositionsInList(aList, callback=None)
# safely deletes all the positions in aList.
c.positionExists(p)
c.redraw(p=None) # Redraw the screen. Select p if given.
c.save() # Save the present outline.
c.selectPosition()
Using Command names
When learning Leo’s codebase, it may be easier to refer to a command by its ‘command name’. You can therefore use c.doCommandByName(‘command-name’) instead of calling the proper method on the commander. This will return the same value as that method.
Leo Script Return Values
Commands created with @command and @button nodes can return values as well. Since top-level return statements aren’t allowed in scripts executed with exec, you can define a global variable named result, and Leo will return its value:
global result
result = 42
Official ivars of any leoFrame f:
f.c is the frame’s commander.
f.body is a leoBody instance.
f.body.bodyCtl is a leoQTextEditWidget instance.
f.body.bodyCtrl.widget is a LeoQTextBrowser(QTextBrowser) instance.
f.log is a leoLog instance.
f.tree is a leoQtTree instance.
f.tree.treeWidget is a LeoQTreeWidget (a QTreeWidget) instance.
Use autocompletion to explore these objects!
If you want to make a command undoable, you must create “before” and “after” snapshots of the parts of the outline that may change. Here are some examples. Leo’s source code contains many other examples.
To undo a single change to body text:
command = 'my-command-name'
b = c.undoer.beforeChangeNodeContents(p, oldYScroll=ypos)
# Change p's body text.
c.undoer.afterChangeNodeContents(p,
command=command, bunch=b, dirtyVnodeList=[])
If your command changes multiple nodes, the pattern is:
u, undoType = c.undoer, 'command-name'
u.beforeChangeGroup(c.p, undoType)
dirtyVnodeList = []
changed = False
# For each change, do something like the following:
for p in to_be_changed_nodes:
# Change p.
dirtyVnodeList.append(p.v)
u.afterChangeNodeContents(p, undoType, bunch)
changed = True
if changed:
u.afterChangeGroup(c.p, undoType,
reportFlag=False,
dirtyVnodeList=dirtyVnodeList)
Ivars:
v.b: v's body text.
v.gnx v's gnx.
v.h: v's headline text.
v.u: v.unknownAttributes, a persistent Python dictionary.
v.u (uA’s or unknownAttributes or userAttributes) allow plugins or scripts to associate persistent data with vnodes. For details see the section about userAttributes in the Customizing Leo chapter.
Important: Generally speaking, vnode properties are fast, while the corresponding position properties are much slower. Nevertheless, scripts should usually use position properties rather than vnode properties because the position properties handle recoloring and other details. Scripts should use vnode properties only when making batch changes to vnodes.
Properties
p.b: same as p.v.b. *Warning*: p.b = s is expensive.
p.h: same as p.v.h. *Warning*: p.h = s is expensive.
p.u: same as p.v.u.
Generators (New in Leo 5.5: All generators yield distinct positions)
p.children()
p.parents()
p.self_and_parents()
p.self_and_siblings()
p.following_siblings()
p.subtree()
p.self_and_subtree()
Getters These return new positions
p.back()
p.children()
p.copy()
p.firstChild()
p.hasBack()
p.hasChildren()
p.hasNext()
p.hasParent()
p.hasThreadBack()
p.hasThreadNext()
p.isAncestorOf(p2)
p.isAnyAtFileNode()
p.isAt...Node()
p.isCloned()
p.isDirty()
p.isExpanded()
p.isMarked()
p.isRoot()
p.isVisible()
p.lastChild()
p.level()
p.next()
p.nodeAfterTree()
p.nthChild()
p.numberOfChildren()
p.parent()
p.parents()
p.threadBack()
p.threadNext()
p.visBack()
p.visNext()
Setters
p.setDirty() *Warning*: p.setDirty() is expensive.
p.setMarked()
Operations on nodes
p.clone()
p.contract()
p.doDelete(new_position)
p.expand()
p.insertAfter()
p.insertAsNthChild(n)
p.insertBefore()
p.moveAfter(p2)
p.moveToFirstChildOf(parent,n)
p.moveToLastChildOf(parent,n)
p.moveToNthChildOf(parent,n)
p.moveToRoot(oldRoot=None)
# oldRoot **must** be the old root position if it exists.
Moving positions
The following move positions themselves: they change the node to which a position refers. They do not change outline structure in any way! Use these when generators are not flexible enough:
p.moveToBack()
p.moveToFirstChild()
p.moveToLastChild()
p.moveToLastNode()
p.moveToNext()
p.moveToNodeAfterTree(p2)
p.moveToNthChild(n)
p.moveToParent()
p.moveToThreadBack()
p.moveToThreadNext()
p.moveToVisBack(c)
p.moveToVisNext(c)
For full details, see @file leoGlobals.py in LeoPyRef.leo.
g vars
g.app
g.app.gui
g.app.windowlist
g.unitTesting
g.user_dict # a temporary dict for use of scripts and plugins.
g decorator
@g.command(command-name)
g functions (the most interesting: there are many more in leoGlobals.py)
g.angleBrackets()
g.app.commanders()
g.app.gui.guiName()
g.es(*args,**keys)
g.es_print(*args,**keys)
g.es_exception()
g.getScript(c,p,
useSelectedText=True,
forcePythonSentinels=True,
useSentinels=True)
g.openWithFileName(fileName,old_c=None,gui=None)
g.os_path_... # Wrappers for os.path methods.
g.pdb(message='')
g.toEncodedString(s,encoding='utf-8',reportErrors=False)
g.toUnicode(s, encoding='utf-8',reportErrors=False)
g.trace(*args,**keys)
g.warning(*args,**keys)
The Position methods p.b, p.h, and p.setDirty() are slow.
The VNode methods p.v.b, p.v.b, and p.v.setDirty() are fast.
However, it’s usually better to use the Position methods, despite their cost, because Position methods update Leo’s outline completely.
Use the VNode methods only for repetitive commands, like cff, replace-all and recursive import.
@g.command('i1')
def i1_command(event):
c = event.get('c')
if not c: return
def callback(args, c, event):
g.trace(args)
c.bodyWantsFocus()
c.interactive(callback, event, prompts=['Prompt: '])
@g.command('i2')
def i2_command(event):
c = event.get('c')
if not c: return
def callback(args, c, event):
g.trace(args)
c.bodyWantsFocus()
c.interactive(callback, event,
prompts=['Find: ', ' Replace: '])
@g.command('i3')
def i3_command(event):
c = event.get('c')
if not c: return
def callback(args, c, event):
g.trace(args)
c.bodyWantsFocus()
c.interactive(callback, event,
prompts=['One: ', ' Two: ', ' Three: '])
LeoPyRef.leo contains all of Leo’s core source code.
Leo’s code uses the following conventions throughout:
c: a commander.
ch: a character.
d: a dialog or a dict.
f: an open file.
fn: a file name.
g: the leoGlobals module.
i, j, k: indices into a string.
p: a Position.
s: a string.
t: a text widget.
u: an undoer.
w: a gui widget.
v: a Vnode
z: a local temp.
In more limited contexts, the following conventions apply:
si: a g.ShortcutInfo object.
ks: a g.KeyStroke object
stroke: a KeyStroke object.
btw: leoFrame.BaseTextWrapper
stw: leoFrame.StringTextWrapper
bqtw: qt_text.BaseQTextWrapper
lqtb: qt_text.LeoQTextBrowser
qhlw: qt_text.QHeadlineWrapper
qmbw: qt_text.QMinibufferWrapper
qlew: qt_text.QLineEditWrapper
qsciw: qt_text.QScintiallaWrapper
qtew: qt_text.QTextEditWrapper
Names defined in Leo’s core are unlikely to change, especially names used outside their defining module. This includes virtually everything in leoGlobals.py, and many names in leoCommands.py and other files.
The following ‘official’ ivars (instance vars) will always exist:
c.frame The frame containing the log,body,tree, etc.
c.frame.body The body pane.
c.frame.body.widget The gui widget for the body pane.
c.frame.body.wrapper The high level interface for the body widget.
c.frame.iconBar The icon bar.
c.frame.log The log pane.
c.frame.log.widget The gui widget for the log pane.
c.frame.log.wrapper The high-level interface for the log pane.
c.frame.tree The tree pane.
The following were official ivars that no longer exist:
c.frame.body.bodyCtrl Use c.frame.body.wrapper instead.
c.frame.log.logCtrl Use c.frame.log.wrapper instead.
A widget is an actual Qt widget. Leo’s core seldom accesses widgets directly. Instead, a wrapper class defines a standard api that hides the details of the underlying gui text widgets.
Leo’s core uses the wrapper api almost exclusively. That is, Leo’s core code treats wrappers as if they were only text widgets there are!
A back door exists for special cases. All wrapper classes define an official widget ivar, so core or plugin code can gain access to the real Qt widget using wrapper.widget. Searching for wrapper.widget will find all gui-dependent snippets of code in Leo’s core.
usage: launchLeo.py [options] file1, file2, ...
options:
-h, --help show this help message and exit
-b, --black-sentinels write black-compatible sentinel comments
--diff use Leo as an external git diff
--fail-fast stop unit tests after the first failure
--fullscreen start fullscreen
--gui=GUI specify gui: browser,console,curses,qt,text,null
--listen-to-log start log_listener.py on startup
--maximized start maximized
--minimized start minimized
--no-plugins disable all plugins
--no-splash disable the splash screen
--quit quit immediately after loading
--save-session always save session data when Leo closes
--script=PATH execute a script and then exit
--script-window execute script using default gui
--select=ID headline or gnx of node to select
--silent disable all log messages
--theme=NAME use the named theme file
--trace=LIST add one or more strings to g.app.debug
A comma-separated list. Valid values are:
abbrev, beauty, cache, coloring, drawing, events, focus, git, gnx,
importers, keys, layouts, plugins, save, select, sections,
shutdown, size, speed, startup, themes, undo, verbose, zoom.
--trace-binding=KEY trace commands bound to a key
--trace-setting=NAME trace where named setting is set
--window-size=SIZE initial window size: (height x width)
--window-spot=SPOT initial window position: (top x left)
-v, --version print version number and exit
Leo’s Code Academy posts discuss how to do useful things in Leo. The following are distilled from online discussions about Leo’s scripting.
uA’s (user Attributes) associate arbitrary data with any vnode. uA’s are dictionaries of dictionaries–an outer dictionary and zero or more inner dictionaries. The outer dictionary associates plugin names (or Leo’s core) with inner dictionaries. The inner dictionaries carry the actual data.
The v.u or p.v properties get and set uA’s. You can think of p.u as a synonym for p.v.unknownAttributes on both sides of an assignment. For example:
plugin_name = 'test_plugin'
d = p.u.get(plugin_name,{})
d ['n'] = 8
p.u [plugin_name] = d
p.u is the outer dictionary. p.u.get.(plugin_name, {}) is the inner dictionary. The last line is all that is needed to update the outer dictionary!
It is easy to search for particular uA’s. The following script prints all the keys in the outer-level uA dictionaries:
for p in c.all_unique_positions():
if p.u:
print(p.h, sorted(p.u.keys()))
This is a typical usage of Leo’s generators. Generators visit each position (or node) quickly. Even if you aren’t going to program much, you should be aware of how easy it is to get and set the data in each node. In fact, now would be a great time to read Leo’s Scripting Tutorial again :-) This will allow you to “dream bigger” with Leo.
The following script creates a list of all positions having an icon, that is, an outer uA dict with a ‘icon’ key:
aList = [p.copy() for p in c.all_unique_positions() if 'icon' in p.u]
print('\n'.join([p.h for p in aList]))
Important: If you don’t understand these lines, please study Python’s list comprehensions. They are incredibly useful. ‘n’.join(aList) is a great idiom to know. str.join is one of python’s most useful string methods. It converts between lists and strings.
This script inserts three icons in the current outline node. Running the script again will insert three more:
table = (
'edittrash.png',
'connect_no.png',
'error.png',
)
for icon in table:
fn = g.os_path_finalize_join(g.app.loadDir,
'..', 'Icons', 'Tango', '16x16', 'status', icon)
if g.os_path_exists(fn):
c.editCommands.insertIconFromFile(path=fn)
This deletes all icons of the node at position p:
c.editCommands.deleteNodeIcons(p=p)
Using Leo’s latest sources from GitHub is highly recommended. Once git is installed, the following gets the latest Leo sources:
git clone https://github.com/leo-editor/leo-editor.git
Thereafter, you can update Leo’s sources with:
git pull
Git is great in tracking history and reverting unwanted changes. And it has many other benefits.
Using git is very similar to using bzr or hg or any other SCCS. To change Leo, you add files, you commit files, and you push files. That’s about it.
c.cloneFindByPredicate is a powerful new addition to Leo. Here is its docstring:
Traverse the tree given using the generator, cloning all positions for
which predicate(p) is True. Undoably move all clones to a new node, created
as the last top-level node. Returns the newly-created node. Arguments:
generator, The generator used to traverse the tree.
predicate, A function of one argument p returning true if
p should be included.
failMsg=None, Message given if nothing found. Default is no message.
flatten=False, True: Move all node to be parents of the root node.
iconPath=None, Full path to icon to attach to all matches.
redraw=True, True: redraw the screen.
undo_type=None, The undo/redo name shown in the Edit:Undo menu.
The default is 'clone-find-predicate'
For example, clone-find-all-marked command is essentially:
@cmd('clone-find-all-marked')
def cloneFindMarked(self, flatten):
def isMarked(p):
return p.isMarked()
self.cloneFindByPredicate(
generator = self.all_unique_positions,
predicate = isMarked,
failMsg = 'nothing found',
flatten = flatten,
undoType = 'clone-find-marked',
)
The predicate could filter on an attribute or combination of attributes. For example, the predicate could return p has attributes A and B but not attribute C. This instantly gives Leo full database query capabilities. If we then hoist the resulting node we see all and only those nodes satisfying the query.
These following position methods make it easy to skip @ignore trees or @<file> trees containing @all:
p.is_at_all() True if p is an @<file> node containing an @all directive.
p.in_at_all() True if p is in an @<file> tree whose root contains @all.
p.is_at_ignore() True if p is an @ignore node
p.in_at_ignore_tree() True if p is in an @ignore tree.
For example, here is how to gather only those marked nodes that lie outside any @ignore tree:
def isMarked(p):
return p.isMarked() and not p.in_at_ignore_tree()
c.cloneFindByPredicate(
generator = self.all_unique_positions,
predicate = isMarked,
flatten = flatten,
undoType = 'gather-marked',
)
Leo University is a project devoted to help people become Leo developers.
Here is the main page. It contains links to individual lessons. https://github.com/leo-editor/leo-editor/issues/816
Leo uses a model/view/controller architecture.
Controller: The Commands class and its helpers in leoCommands.py and leoEditCommands.py.
Model: The VNode and Position classes in leoNodes.py.
View: The gui-independent base classes are in the node “Gui Base Classes”. The Qt-Specific subclasses are in the node “Qt gui”.
Important: The general organization of these classes have changed hardly at all in Leo’s 20+ year history. The reason is that what each class does is fairly obvious. How the gets the job done may have changed drastically, but that’s an internal implementation detail of the class itself. This is the crucial design principle that allows Leo’s code to remain stable. Classes do not know or meddle in the internal details of other classes. As a result, nobody, including EKR, needs to remember internal details.
Leo syntax colors clickable links in the body pane. For example:
Leo’s home page: https://leo-editor.github.io/leo-editor/
The status area shows the UNL (Universal Node Locator) for each node.
Control-clicking a UNL will take you to its target node, even if the target is in another Leo file! gnx-based UNLs won’t break even if you move or rename the target node.
Try these examples!
The “Key bindings” node in this file: unl:gnx://CheatSheet.leo#ekr.20131019184243.16685
The “6.7.5 release notes” node in LeoDocs.leo. unl:gnx://LeoDocs.leo#ekr.20230703101804.1
