add specific error message for missiing graphviz dependency about slipbox

[epogrebnyak]

Aha, I am missing dot, but this is not exactly the error message:

Q:\slipbox
λ python -c"from shutil import which; print(which('dot'))"
None

[epogrebnyak]

So it appears

slipbox/slipbox/__main__.py

Lines 30 to 31 in f6b1871

	if not check_requirements(app):
	error("pandoc not found")

checks for both pandoc and dot, but the error message will be pandoc not found even if pandoc is present and dot is missing.

I can split the check into two functions and add extra error message if you'd advise me to.

My initial problem is solved by installing graphviz, and I'm looking forward to experimenting with slipbox, very excited about it.

[epogrebnyak]

Probably even a more simple fix for a PR is adding more verbose error message, eg "Either pandoc or graphviz not found, aborting..."

or

to do has_pandoc(app) and has_dot(app) in dependency.py (which I think simplifies the check a lot and allows to separate the error handling):

def has_pandoc(app):
   return which(app.config.pandoc)

def has_dot(app):
   return which(app.config.dot)

[lggruspe]

fixed in c15afe0

[epogrebnyak]

slipbox/slipbox/dependencies.py

Lines 8 to 14 in f6b1871

	def check_requirements(app: RootlessApp) -> bool:
	"""Check if all runtime requirements are satisfied."""
	requirements = [
	app.config.pandoc,
	app.config.dot,
	]
	return all(map(which, requirements))

[lggruspe]

I would go with the second option, so the error messages can be more specific.

[epogrebnyak]

Thank you for following up on this @lggruspe !