variants for the waf-project build tool

waf_variants.py

#!/usr/bin/env python
# encoding: utf-8
# Roland Puntaier, 2017

"""If there is a *variants* variable in the main wscript

- x_variant commandline arguments are created
  for x in {configure, build, clean, install, uninstall}
- an x command line argument is expanded to all x_variant's 
- the associated x function context contains :py:const:`variant`

Variant strings can use the `/` path separator to produce an according output tree.

####################### begin example wscript ##################################

                        from itertools import product as prod
                        from string import Template
                        import time
                        import os
                        import waf_variants

                        variants = ['/'.join(v) for v in prod('Tim Jan'.split(),'X Y'.split())]

                        def touch(x,txt=''):
                                with open(x,'w') as f:
                                        f.write(txt)

                        def filltime(tsk):
                                ifn = tsk.inputs[0].abspath()
                                ofn = tsk.outputs[0].abspath()
                                with open(ifn,'r') as f:
                                        s = f.read()
                                with open(ofn,'w') as f:
                                        f.write(time.strftime(Template(s).substitute(tsk.env),time.localtime()))

                        asrc = 'tst.txt.tm'
                        atgt = os.path.splitext(asrc)[0]
                        def init(ini):
                                touch(asrc,'$name, it is %$timeformat.')#Template,then strftime

                        def configure(cfg):
                                v = cfg.variant
                                cfg.env.name,cfg.env.timeformat = v.split('/')
                                if 'Tim' in v:
                                        cfg.env.name = 'Timi'

                        def build(bld):
                                v=bld.variant
                                bld(rule=lambda t:filltime(t),source=asrc,target=atgt)

                        def clean(cln):
                                pass

####################### end example wscript ##################################

waf configure
waf build
waf build_Y
waf build_Jan/Y
waf clean_X
waf clean_Tim
waf clean_Tim/X
...

"""

from waflib.Build import BuildContext, CleanContext, InstallContext, UninstallContext
from waflib.Configure import ConfigurationContext
from waflib import Context
from waflib import Options

class VariantContext(Context.Context):
	"wscript global variants implicitly expanded to configure_x, build_x,..."
	cmd = 'init'
	fun = 'init'
	def execute(self):
		try:
			Context.Context.execute(self)
			vs = list(Context.g_module.variants)
			cls = [cl for cl in Context.classes if issubclass(cl,BuildContext)]
			for y in [ConfigurationContext]+cls:
				c = y.__name__.replace('Context','').replace('ation','e').lower()
				cvs = []
				for v in vs:
					cv = self.add_variant(y,c,v)
					cvs.append(cv)
				cmds = []
				for k in Options.commands:
					if k.startswith(c):
						kk = k[len(c):].strip('_')
						cmds.extend([acv for acv in cvs if kk in acv])
					else:
						cmds.append(k)
				Options.commands[:] = cmds
		except AttributeError:
			pass
	def add_variant(self,y,c,v):
		cv = c + '_' + v
		class _variant_context(y):
			cmd = cv
			fun = c
			variant = v
			def __init__(s, **kw):
				y.__init__(s, **kw)
				if c[-1]=='e':#configure
					s.setenv(v)
		return cv

waf build_X will build Tim/X and Jan/X in the example