During talks or screencasts I don't want to be typing code, it is too error prone and too likely to mess up my speaking flow. Purdy is both a set of programs and a library to display colourized code in a series of animations.
The purdy command takes one of a Python program, a Python REPL console file or a Bash console file. Source code is presented to the screen as if typing. For console files, the typing pauses at a prompt, waiting for interaction. Prompts are:
-
>>>or...for Python REPL -
$for Bash console
If the program is paused at a prompt, pressing the right arrow will continue. Typing animation can be skipped over by pressing the letter "s" instead. Animation can be undone by pressing the left arrow. More info on keys can be found in the help dialog, viewed by pressing "?".
Example Usage:
The result looks like this:
Once the code has been displayed, further key presses are ignored. At any time you can press "q" to quit.
The following programs come with the purdy library:
-
purdy-- Animated display that looks like a program is being typed to the screen. -
pat-- "purdy cat", prints ANSI colourized source. -
prat-- "purdy RTF cat", prints colourized source in RTF document format. Particularly useful for copying to a clipboard and pasting full colourized source into a document. On OS X prat <filename> | pbcopy will put the output directly to the clipboard. -
subpurdy-- Full set of commands to control Purdy. Sub-commands dictate behaviour. Does a variety of code presentation. Includes ANSI, RTF, HTML output as well as the typewriter animations.
More information can be found in the Command Line Program Documentation.
The following keys help you to control the TUI purdy programs:
-
?-- Help screen -
<RIGHT>-- next animation step -
<LEFT>-- previous animation step -
s-- go to the next step, skipping any animation
For custom made code using the purdy library, the following controls will also work:
-
S-- go to the next section, skipping any animation. -
<TAB>-- focus next window area in a multi Screen display -
<SHIFT><TAB>-- focus previous window area in a multi Screen display
Additionally the s, S, and <LEFT> commands all support skipping multiple steps by specifying a number first. For example the sequence 12s would skip past the next 12 steps.
The purdy script is fairly simple. You can create more complex animations by writing programs using the purdy library. Custom programs can have split screens, highlighting lines, slide transitions and more. More information can be found in the Library Documentation.
Purdy has been tested with Python 3.7 through 3.11. Terminal control is done with the Urwid library. Parsing and tokenization is done through Pygments. Both libraries are execellent and I'm grateful they're publically available.
