Allow conditional features to use regex matching.

Author: stefanseefeld

src/faber/artefacts/python.py

@@ -8,7 +8,7 @@
 
 from ..feature import set
 from ..artefacts.library import library
-from ..tools.compiler import link
+from ..tools.compiler import link, ldflags
 from ..tools.python import python
 from os.path import join, normpath
 
@@ -19,7 +19,10 @@ def __init__(self, *args, **kwds):
         library.__init__(self, *args, **kwds)
         p = python.instance(self.features)
         self.features |= set(p.include, p.linkpath, link('shared'))
+        # on windows we need to link with libpython
         self.features |= p.libs(condition=(set.cc.name=='msvc')|(set.cxx.name=='msvc'))
+        # on darwin we need to add `-undefined dynamic_lookup` to prevent undefined symbols errors
+        self.features |= ldflags('-undefined dynamic_lookup', condition=(set.target.os.matches('darwin.*')))
         self._suffix = p.ext_suffix
 
     @property

src/faber/feature/condition.py

@@ -7,6 +7,7 @@
 # (Consult LICENSE or http://www.boost.org/LICENSE_1_0.txt)
 
 import operator
+import re
 
 
 def contains(op1, op2):
@@ -15,6 +16,12 @@ def contains(op1, op2):
     return False if isinstance(op1, false) else operator.contains(op1, op2)
 
 
+def matches(op1, op2):
+    # allow op1 to be `false`, so `set.nonexistent.match('x')`
+    # becomes a valid expression
+    return False if isinstance(op1, false) else re.match(op2, str(op1))
+
+
 class expr(object):
 
     # we can't overload __not__ as that has to return a bool...
@@ -30,6 +37,7 @@ def contains(self, other): return binary(contains, self, other)
     def __bool__(self): raise ValueError('invalid expression "{}" !'.format(self))
     def __nonzero__(self): return self.__bool__()
     def __call__(self, ctx): return True
+    def matches(self, other): return binary(matches, self, other)
 
 
 class true(expr):

tests/test_feature.py

@@ -284,3 +284,14 @@ def test_delayed():
     fs.eval()
     assert fs.define == ('MACRO', 'SHARED', 'GXX', 'CXX')
     assert fs.include == ('a', 'b', '/some/path',)
+
+
+def test_condition():
+
+    tool = feature('tool', feature('name', sub=True), feature('version', sub=True))
+    target = feature('target', feature('os', sub=True), feature('arch', sub=True))
+    define = feature('define', attributes=multi)
+    fs = set(tool(name='g++', version='6.3'), target(os='gnu-linux', arch='x86_64'))
+    fs += define('LINUX', condition=set.target.os.matches('.*-linux'))
+    fs.eval()
+    assert fs.define == ('LINUX',)