I cannot fathom how ttfp is important. It's time to first plot, not to every plot. After it's down to ~10 seconds, why on earth does anyone care?
I personally do care for my concrete usage pattern.
This is my use case: A long shell script that does a lot of things. At some point, inside a loop that runs hundreds of times, it needs to solve a couple of small linear systems and plot a simple graph. There's hundreds of png graphs, that are then combined into a video sequence. Right now, the computation is done by calling octave (inside the loop) and then gnuplot (to create the actual graph from the octave computed data points). I would like to replace each call to octave+gnuplot to a single call to julia. Yet, this would make my script run in a few hours instead of a few seconds, because for this usage pattern all plots are first plots
Before you suggest that I should rewrite the whole thing in julia, maybe you are right but
1) it would take me a few weeks that I don't have
2) that's not my point. A good tool is a tool that can be used for purposes that it was not intended to, like this. If the time to first plot in julia was a millisecond instead of 10 seconds, then julia would be a much better tool.
I do all my plotting with Gnuplot.jl, as gnuplot is fast, and I can save .gpt files which reproduce the plots for later reference and making publication-quality.
Well I love julia the language. It's the interpreter quirks that I find annoying. If julia had something lean and superfast like luajit it would be incredible!
Are there any downsides to this? You never care how long does a system update take. You always care how long do your programs run.
It really doesn't if you use a module.
It's not perfect but it's something.
That said, there is some very interesting work happening on getting around these restrictions. There was a PR from Tim Holy a while ago that could have allowed it, but there were some problems with the PR, and there were also some associated costs that were deemed too steep to pay.
That said, there's other great work on other ways around this. For instance, you can dynamically redefine structs all you want in Pluto.jl notebooks and there's no performance penalty!
This is something that kinda just fell out as a natural consequence of it's reactive design.
And not that long before that you would print the results out and manually plot them on graph paper.