"Leo is an interactive editor for organizing text fragments hierarchically and sequentially into one or more files and hierarchical folders, without arbitrary limits on the number and size of text fragments and the depth of the hierarchy.
Tangle is a tool for combining hierarchically and sequentially organized text fragments into text files, hierarchically grouped into folders, with hierarchical or sequential organization of text within the files, and without arbitrary limits on the size and number of files and the depth of the hierarchy of folders and text nesting within the files."
Steve Allen
"Leo is EXACTLY the kind of outliner I was looking for--fantastic job!"
"I am a huge fan of Leo. I think it's quite possibly the most revolutionary programming tool I have ever used and it (along with the Python language) has utterly changed my view of programming (indeed of writing) forever."
"Just a quick note to thank you for your work on Leo. It is a really nice piece of work!
It makes "literate programming" much easier. [I've been playing around from time to time, but it was tedious, so I continued with my usual way of working.]
Again, this is a great tool!"
Serge Brisson
"I want first to thank you for Leo. This is a very useful and interesting tool."
Korakot Chaovavanich
"Thank you very much for leo. I think my way of working with data will change forever.
I have just tried leo for 2-3 days, yet I am certain this will be a revolution. The revolution is as important as the change from sequential linear organization of a book into a web-like hyperlinked pages.
The main concept that impress me is that the source listing isn't the main focus any more. You focus on the 'non-linear', hierarchical, collapsible outline of the source code."
Josef Dalcolmo
Thanks for the great work--I love Leo!!!
Zak Greant, Creative Director, Nucleus Information Service Inc.:
"I have been playing around with Leo and am really very impressed! It should either replace or greatly augment the development tools that I use."
I've tried Literate Programming tools off and on for more than 10 years, mainly because the promise was so great. I've abandoned them every time because working with the various CWEB-like tools was so awkward.
Leo changes all that. The most important benefits promised by Literate Programming are realized by using Leo, without the awkwardness of the other tools.
"I wanted to thank you for the effort you've put into Leo. It looks fantastic. I've always though that Literate Programming was a good idea, but the tools were completely un-workable."
Austin King
"I was turned on too a very cool tool written in Python. Leo is a marriage of outlining and literate programming. Pure genius. The main reason I am impressed with this tool is that it doesn't affect your choice of tools. You can use whatever IDE for whatever language and switch back and forth between leo and it."
Nicola Larosa
"And yes, I've been using Leo a few hours every day for more than a week, now. :^) Actually, it's become my main development platform, and I do this for a living."
Cloning is pure genius! I'm studying for the Chartered Financial Analyst exams, and I use Leo to take notes on the voluminous course material. Along the way, I'm developing little utility functions in the array programming language J (http://www.jsoftware.com) for working the examples and the exercises in the textbooks. J is vanishingly terse, so the literate programming facilities in Leo aid comprehension of code immensely. Even more useful than the traditional lit prog for my purpose, though, is Leo's cloning facility, which allows me to create several views on the CFA course material. My main view follows the prescribed study guide. Another view is organized like the textbooks. Yet another gives me a glossary of terms. And when I'm done, I'll have some nice libraries of J functions that I can re-use later in other projects. Also, a little exporting from Leo and post-processing with noweave should give me some printable docs.
Thanks for hunting down these bugs, and thanks for producing such a cool tool. Wanting to customize and script Leo has me itching to dust the Python books off this weekend.
"I just discovered Leo today. I am one of the many droves of people that came stampeding by due to you being Slashdotted. I will say that I am extremely impressed at how stable and useful Leo appears to be. As soon as I ran though the slide presentations of how Leo works, it struck me that I have always been looking for this in an editor.
I am very impressed that you developed this app single handedly. It looks like a very impressive piece of work."
"Hey, Edward, please bear with us. I know you're overwhelmed, but you've come up with perhaps the most powerful new concept in code manipulation since VI and Emacs.
I'm blown away with how Leo can slice'n'dice C and Python files into their component parts.
Leo absolutely ROCKS! :) It's exactly the tool I've been wanting for years but have never got around to writing.
One thing I really like is the ability to create functions in any order I please, and not think about what files to put them into till later. This ability alone has freed up a lot of my thought processes with coding.
For me, Leo is proving a god-send, and speeding up the learning time considerably. In its ability to create multiple 'views' of code files, it's easy to make PalmOS programs very understandable and easy to work with."
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"For me, I'm so grateful I saw the Leo write-up on Slashdot, otherwise I would probably never have come into contact with it.
A funny observation with Leo is that when I 'Leo-ise' other people's code, Leo makes the code's structure so transparent that design faults become very quickly apparent - eg maintenance pain caused by lack of factorization.
Thanks again for a wonderful (I won't say 'editor' because the word doesn't do Leo justice) code structuring system."
"We who use Leo know that it is a breakthrough tool and a whole new way of writing code.
Leo is a powerful tool for organizing text into tree structures, and for just generally attacking a number of problems from a tree-based perspective.
<opinion>There has been a lot of hype about XML and all the uses to which it can be put. But, to my mind, the greatest benefit of XML is that it allows people to easily work with tree structures. All the benefits of XML really flow from that. Leo is the best application I've seen for conceiving and planning the trees that are then put into action via various XML technologies.</opinion>
Outlining Editors have existed for a while (e.g. PC-Outline, MORE) but Leo takes a major leap beyond previous tools for three reasons:
...
"The Word outlines are very useful. But Leo makes Word look like a clunky toy.
#1 Reason would probably be clone nodes. One node can point to another. Another way of putting this is that a leaf can be on more than one tree. For example, suppose you have a list of recipes. You simultaneously put a single recipe under multiple categories or even multiple hierarchies. You could put "3 bean enchilada" simultaneously under Recipes-Mexican and Food-Gas. Another example would be, if you are a biologist trying to decide under which genus to put a new species, you could put the species under two simultaneously. In effect, you can build a 3-D tree. For a further illustration see http://www.3dtree.com/ev/e/sbooks/leo/sbframetoc_ie.htm
#2 Reason would probably be that Leo outlines can be embedded in external text files. So, a Leo outline is more than an outline, it is a meta-structure that can be added to another text without changing that text, but rather providing an external roadmap to the text. Microsoft Word has a text (xml) version with a commenting convention, so Leo can even be used to add outlines into Word docs, although it isn't set up to do that now. For example, see http://www.3dtree.com/ev/e/sbooks/leo/sbframetoc_ie.htm In this case, the upper window of Leo is the metastructure, and the bottom window is the file to which the metastructure is being applied, viewed one node at a time.
I may not have made #2 very clear, but it is actually a very useful feature. It takes some getting used to before one sees all of the possibilities though. One way to think of it is that Leo allows you to throw external documents into your outline, and yet the external document remains independent and can still be edited separately.
Some other cool things about Leo which Word doesn't feature:
- Pure xml output that is easy to transform into other formats (next version of Word will have true XML format, but not as easy to work with). One consequence of this is that Leo files can be transformed pretty easily to web pages with their outlining capability intact.
- Easy to add features since is programmed in Tk and open source. Maybe your average user can't start hacking on it, but a surprising amount can be tacked on by flipping thru the Tk manual.
- Free, Open Source, multi-platform.
- Leo is scriptable with Python. It should be possible to build a Tickler into Leo using Python scripting, for example."
Marshall Parsons
"I only have one week of Leo experience but I already know it will be my default IDE/project manager. I have seen several old threads on comp.lang.python where people complain about the lack of a project manager for the free/standard Python IDE's like Idle. Leo clearly solves that problem and in a way that commercial tools can't touch."
Bruce Rafnel
"Hi, I have been interested in creation of a hierarchal text-editor for a while and I just came across Leo, which I found to be almost exactly what I had in mind, which is fantastic because I don't have to code anything!"
"I am an amateur photographer. I use plain old 35mm. film for my pictures. Over the weekend, I used Leo to organize my lists of pictures. It is quite helpful--I can have separate nodes for pictures I have enlarged, as well as pictures I have submitted to our local camera club. Thanks!"
"Just as structured programming reveals and disciplines the flow control of a program, Leo allows the designer to reveal and discipline structure at many layers simultaneously: data structures, object structure, entity-relationship structure, client-server structure, design pattern structure, temporal structure, project management structure, and any other structure relevant to the system."
"Leo reminds me a great deal of things I loved when I used Userland's Frontier (an outlining cms with a native oodb) - but Frontier wasn't hackable enough for me, and it wasn't oriented towards coding and literate programming, and you couldn't round-trip rendered pages (big Leo win). This is really a super tool - in a matter of days I've started to use it on all my projects and I still haven't figured out how I lived without it."
Brian Takita
"Leo is a very good concept and is a revolutionary step in the right direction for programming. I appreciate your work."
Kent Tenney
"Leo files are so wonderful at organizing information, it'd be powerful if we could share them on the web with minimal effort.
A Leo file is an ideal documentation tool, collecting the assorted readme.txt files, the comments from the source files...as well as the config files themselves."
"I have been using Leo for about 3 weeks and I hardly use my other programming editor anymore...I find it easy and enjoyable to use. I plan to adopt it as my presentation tool for code reviews."
"First of all, kudos to you for the excellent progress you've been making with Leo...I think you're really showing what open source can do and your current trajectory puts you on track to kick Emacs into the dustbin of computing history. So today I copied all my data (personal information manager and project management stuff) out of my old outliner (ThoughtManager, which synchs with and runs on the Palm) and put it into Leo. It took me hours to do it and then to rearrange it the way I really wanted it. But having the ability to make clones and have different ways to view my data is, as you know, fabulous. In my case, for personal information and project management things, I used the flexibility of clones to allow me to see my data in several different views: 1) by project, the logical hierarchical breakdown by topic, 2) by person, so whenever I'm talking to someone I can easily see all the pending items related to them which may be spread over multiple projects, 3) by priority, so I can see what needs to get done sooner and what can wait for later and, 4) a special case of priority called "Today" for the things I'm going to focus on in the coming hours.
Now here's why I don't miss the ability of my old outliner to synch the entire outline with the Palm. It turns out the main thing I really want in the Palm is the top category "Today" so all I have to do is have Leo flatten that one heading into a text file (and it kindly remembers the name and directory of the file I used last time) and then I'm done because I've told the Palm Hotsync manager that that file should be sent to Palm memo pad every time I synch. The Palm Hotsync manager does a nice job of sending a text file to the Palm memo pad and even breaks the file up into multiple memo records if it's too big to fit in just one. So that gives me enough to be able to browse (or full text search) the small amount of data that I really want right inside my Palm (which is also my cell phone). Quick and dirty but it works.
For times when I want my whole outline with me, Leo wins again because thanks to its cross platform nature I can take my whole outline with me on my Mac iBook, even though I usually edit it on a Windows PC (which is the only kind of machine my old outliner would run on). Quite frankly, although my old outliner was able to shoehorn the whole thing into my palm/cellphone, it was a pain to access it on the small screen and slow processor. Now when I anticipate I'll need the whole thing, for example when I'm going to a meeting, I can put it on my Mac iBook (under X and Fink for now until Python can do it native under Aqua) and have real, full access to it all.
I think now in addition to being great for programming Leo is also a great PIM. Being able to flatten a strategically chosen portion of the outline into a known file name that the Palm synch manager has been told to send to the Palm on every synch does the trick for me. I wonder if you would consider something like an @flatten directive so I can have that done automatically for me every time I save my outline? For now it's up to me to flatten the node I want manually, although once I've done that the transfer to the Palm is automatic.
You're my hero! Thank you so much."
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"Another day, another breakthrough using Leo -- now I realize Leo is the best URL bookmark manager there is. No more bookmarks menus or favorites lists inside the browser for me. With the @url directive I can just double click on the URL to open it in my browser. Leo lets me arrange the URLs in a hierarchy (or multiple hierarchies), attach notes to them, save clippings of things I read on the sites. It's sooo much better than anything the browsers have built in and it lets me easily use different browsers on different platforms and different machines (try that with the browsers' built-in bookmark managers).
When using Leo as a project manager and personal information manager as I do I can heavily annotate every task and project with helpful and relevant URLs. And since URLs can be of the file:// form, they're not just for web pages or HTML documents; I can link to any file on my disk of any type to be opened by any program.
Leo is a quantum leap for me in terms of how many projects I can manage and how much information I can find and organize and store in a useful way. I'm a data-mining army of one now and the web is my playground. Every time I find a web page that has interesting links to others, those links get stored in my Leo outline too, right where I can find them and make practical use of them. I can easily accept dozens of valuable links every day and integrate them into what I'm doing in a way that I'm confidant they won't get lost or forgotten. Before I always used to get bogged down by the difficulty of managing bookmarks inside the browser. But now I'm no longer the victim of information overload buried in the knowledge landslide of the Internet; instead I'm the professional strip miner with the world's biggest bulldozer. I eagerly plunge into mountains of data and emerge with all the valuable information nuggets neatly stored and organized. And my storehouse of knowledge is a flexible thing where I can reorganize and prioritize and massage the data to my heart's content as I learn more about it and decide to use it in different ways for different purposes. It's the difference between the pick axe and the steam shovel for me."