1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
<!--
Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 The SCons Foundation
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-->
<para>
The &AddMethod; function is used to add a method
to an environment. It's typically used to add a "pseudo-builder,"
a function that looks like a &Builder; but
wraps up calls to multiple other &Builder;s
or otherwise processes its arguments
before calling one or more &Builder;s.
In the following example,
we want to install the program into the standard
<filename>/usr/bin</filename> directory hierarchy,
but also copy it into a local <filename>install/bin</filename>
directory from which a package might be built:
</para>
<programlisting>
def install_in_bin_dirs(env, source):
"""Install source in both bin dirs"""
i1 = env.Install("$BIN", source)
i2 = env.Install("$LOCALBIN", source)
return [i1[0], i2[0]] # Return a list, like a normal builder
env = Environment(BIN='/usr/bin', LOCALBIN='#install/bin')
env.AddMethod(install_in_bin_dirs, "InstallInBinDirs")
env.InstallInBinDirs(Program('hello.c')) # installs hello in both bin dirs
</programlisting>
<para>
This produces the following:
</para>
<screen>
% <userinput>scons -Q /</userinput>
cc -o hello.o -c hello.c
cc -o hello hello.o
Install file: "hello" as "/usr/bin/hello"
Install file: "hello" as "install/bin/hello"
</screen>
<para>
As mentioned, a psuedo-builder also provides more flexibility
in parsing arguments than you can get with a &Builder;.
The next example shows a pseudo-builder with a
named argument that modifies the filename, and a separate argument
for the resource file (rather than having the builder figure it out
by file extension). This example also demonstrates using the global
&AddMethod; function to add a method to the global Environment class,
so it will be used in all subsequently created environments.
</para>
<programlisting>
def BuildTestProg(env, testfile, resourcefile, testdir="tests"):
"""Build the test program;
prepends "test_" to src and target,
and puts target into testdir."""
srcfile = "test_%s.c" % testfile
target = "%s/test_%s" % (testdir, testfile)
if env['PLATFORM'] == 'win32':
resfile = env.RES(resourcefile)
p = env.Program(target, [srcfile, resfile])
else:
p = env.Program(target, srcfile)
return p
AddMethod(Environment, BuildTestProg)
env = Environment()
env.BuildTestProg('stuff', resourcefile='res.rc')
</programlisting>
<para>
This produces the following on Linux:
</para>
<screen>
% <userinput>scons -Q</userinput>
cc -o test_stuff.o -c test_stuff.c
cc -o tests/test_stuff test_stuff.o
</screen>
<para>
And the following on Windows:
</para>
<screen>
C:\><userinput>scons -Q</userinput>
scons: warning: No installed VCs
File "<stdin>", line 67, in __call__
scons: warning: No version of Visual Studio compiler found - C/C++ compilers most likely not set correctly
File "<stdin>", line 67, in __call__
scons: warning: No installed VCs
File "<stdin>", line 67, in __call__
scons: warning: No version of Visual Studio compiler found - C/C++ compilers most likely not set correctly
File "<stdin>", line 67, in __call__
rc /fores.res res.rc
cl /Fotest_stuff.obj /c test_stuff.c /nologo
link /nologo /OUT:tests\test_stuff.exe test_stuff.obj res.res
</screen>
<para>
Using &AddMethod; is better than just adding an instance method
to a &consenv; because it gets called as a proper method,
and because &AddMethod; provides for copying the method
to any clones of the &consenv; instance.
</para>
|
