Meson has a common pattern of using 'if len(foo) == 0:' or
'if len(foo) != 0:', however, this is a common anti-pattern in python.
Instead tests for emptiness/non-emptiness should be done with a simple
'if foo:' or 'if not foo:'
Consider the following:
>>> import timeit
>>> timeit.timeit('if len([]) == 0: pass')
0.10730923599840025
>>> timeit.timeit('if not []: pass')
0.030033907998586074
>>> timeit.timeit('if len(['a', 'b', 'c', 'd']) == 0: pass')
0.1154778649979562
>>> timeit.timeit("if not ['a', 'b', 'c', 'd']: pass")
0.08259823200205574
>>> timeit.timeit('if len("") == 0: pass')
0.089759664999292
>>> timeit.timeit('if not "": pass')
0.02340641999762738
>>> timeit.timeit('if len("foo") == 0: pass')
0.08848102600313723
>>> timeit.timeit('if not "foo": pass')
0.04032287199879647
And for the one additional case of 'if len(foo.strip()) == 0', which can
be replaced with 'if not foo.isspace()'
>>> timeit.timeit('if len(" ".strip()) == 0: pass')
0.15294511600222904
>>> timeit.timeit('if " ".isspace(): pass')
0.09413968399894657
>>> timeit.timeit('if len(" abc".strip()) == 0: pass')
0.2023209120015963
>>> timeit.timeit('if " abc".isspace(): pass')
0.09571301700270851
In other words, it's always a win to not use len(), when you don't
actually want to check the length.
When cross compiling and looking for moc/uic/rcc you really want the
host binary.
Still fall back to QT_INSTALL_BINS as it appears that's the only
variable available with qt4.
zipapp only has a single entry point, so only the `meson` command will
work. `mesontest`, `mesonconf`, `mesonintrospect` won't, which is
terrible, really.
Ideally we should have a single entry point for all these instead, but
until that happens, we should not recommend zipapps.
It's much faster to do 'if a in dict' instead of 'if a in dict.keys()',
since the latter constructs an iterator and walks that iterator and then
tests equality at each step, and the former does a single hash lookup.
The intel fortran compiler "ifort" was not listed in the list of
default fortran compilers. This caused it to not be found unless
explicitly set via the FC.
This uses the ABC's in collections to implement an OrderedSet class.
Internally an OrderedDict is still wrapped so that the ordering is
maintained, this adds the full interface and behavior of an Set, but
with ordering by first insertion.
This allows us to more easily have the documentation in sync with
the source code as people will have to document new features etc
right at the time where they implement it.
Using Meson from outside a git repo results in an error when trying to
resolve submodule subprojects. Running git from inside subproject root
should be enough to fix it.
Partially fixes#1679
Signed-off-by: Ernestas Kulik <ernestas.kulik@gmail.com>
After an initial checkout, submodules aren’t initialized and thus trying
to update them fails.
Partially fixes#1679
Signed-off-by: Ernestas Kulik <ernestas.kulik@gmail.com>
Peter Hutterer
Patrick Griffis
Jussi Pakkanen
Dylan Baker
Gabríel Arthúr Pétursson
John Gallagher
Corey Ashford
Ernestas Kulik
Elliott Sales de Andrade
Jon Turney
Paolo Borelli
Wade Berrier
Thibault Saunier
Nirbheek Chauhan
Mathieu Duponchelle
Guillaume Poirier-Morency
Igor Gnatenko
Thomas Hindoe Paaboel Andersen
Thibault Saunier