Sunday, April 19, 2015 Draw flowcharts online, in ASCII

By Vasudev Ram

Saw this today: is a site that allows you to draw flowcharts online, on their site, using the metaphor of a drag-and-drop paint program like MS Paint, but the flowcharts are drawn entirely using ASCII characters.

I tried it out a bit. Innovative.

One point is that to save the flowchart, it requires access to your Google Drive account.

The image at the top of this page, is of a flowchart that I created with I did not use the Save feature, but instead took a screenshot and saved it as a PNG file (using MS Paint, ha ha). The flowchart shows a diagram that illustrates the concept of a UNIX command pipeline, where the standard output of a preceding program becomes the standard input of a succeeding one (in the pipeline). (How's that for using web-based and Windows software to illustrate something about UNIX? :)

For another example of the innovative use of ASCII characters, check out this post I wrote somewhat recently, about the Python library called PrettyTable, which lets you generate visually appealing tables of data, bordered and boxed by ASCII characters:

PrettyTable to PDF is pretty easy with xtopdf

Also, since we're talking about standard input and output and UNIX pipelines, these two posts may be of interest:

1) [xtopdf] PDFWriter can create PDF from standard input

(The post at the above link also has an example of eating your own dog food.)

2) Print selected text pages to PDF with Python, selpg and xtopdf on Linux

Generalizing from a fragment of code in post 1) above, I'll also note that making a Python program usable as a component of a UNIX pipeline, can, in some cases, be as simple as having something like this in your code:
import sys
# ...
    for lin in sys.stdin:
        lin = process(lin)
which could be shortened to:
for lin in sys.stdin:
Due to this (being able to easily make a Python program into a component of a UNIX pipeline), you can do things like this (and more):

$ foo | bar | baz

where foo may be a built-in UNIX command (a filter) or a shell script, bar may be (for example) a Perl program that leverages some powerful Perl features, and baz may be a Python program that leverages some powerful Python features, thereby leveraging the UNIX philosophy concept of writing small programs, each of which do one thing well, or in this case, leveraging the features of different languages (each of which may do some things better than others), to write individual components in those respective languages. The possibilities are limitless ...

- Enjoy.

- Vasudev Ram - Online Python and Linux training;
freelance Python programming

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Vasudev Ram said...

Just realized that I used the words "leverages" and "leveraging" twice each in a single paragraph in the above post. Oh well ...

Shalin Siriwaradhana said...

Another online flowchart solution software would be creately. It is online and supports all platforms. And cloud based collaboration is also supported with real-time collaboration enabled.