Running Qalculate in the browser

[flaviut]

Hi, I've done some work on getting Qalculate running in the browser at https://github.com/flaviut/qalculate-wasm. You can test it at https://flaviutamas.com/qalculate-wasm/

I've only had to apply one patch, at https://github.com/flaviut/qalculate-wasm/blob/master/libqalculate-popen.patch, since emscripten doesn't support popen.

I'd like to hear some thoughts, especially as far as:

• modifying libqalculate to not do any popens
• doing compiled definitions using something besides gio (since glib probably impossible to port)

Performance is actually quite good:

• 1+1 takes about 18 μs to evaluate in Chrome and 12us in Firefox
• The compressed source code is 1.22MiB gziped, which isn't wonderful, but absolutely acceptable

[hanna-kn]

Compiled definitions without GIO (or any other requirements) has now been implemented.

popen is only used when invoking Gnuplot. I assume that it won't be possible to run Gnuplot in the browser. The patch disables checking for the presence of gnuplot in path, which seems to be the correct way to handle it in the browser version. Ideally this should be done with an #ifdef statement instead of a patch.