[bckygldstn]

This line style API was included MATLAB[0] (and perhaps designed elsewhere earlier) in the Olden Days where terseness was both more necessary (due to space and performance constraints) and more accepted. MATLAB development started in the 60s, though this DSL was likely added in the 80s.

Later, Python's matplotlib library started life as an emulator for MATLAB graphics in Python so naturally included the same plotting DSL.

Only later still did matplotlib morph into the defacto general Python plotting library. And then because plotting is so complex and matplotlib exposes so much control, most subsequent plotting libraries were based on matplotlib, opting to add value via high-level abstractions and better defaults, often exposing the underlying matplotlib objects to allow for fine-tweaking. And so the linestyle API leaks into those libraries too.

All of that to say, this DSL was likely invented by a scientist in a lab in 1981 and has survived through inertia and "jumping hosts" a couple times, rather than careful design.

I think the DSL is bad. And the matplotlib developers may agree, because while you can pass a combo like "ro--", you can also pass these parameters separately and more descriptively like

   color='#f00', linestyle='dashed', marker=matplotlib.markers.CARETDOWNBASE

[0] https://www.mathworks.com/help/matlab/creating_plots/specify...

[trollerator23]

Indeed this comes from MATLAB which is god-awful, and I say this as an enthusiast hardcore MATLAB user.