diff options
author | Steven Knight <knight@baldmt.com> | 2007-08-17 03:17:04 (GMT) |
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committer | Steven Knight <knight@baldmt.com> | 2007-08-17 03:17:04 (GMT) |
commit | 8cb34cccc26935bce5d07ed3f51cc29fbbd1ab03 (patch) | |
tree | 7bc281e44fe45cae35656e0e457fef8f308fbb7b /doc/user/nodes.xml | |
parent | 5b4b4c6e5384712ab1835bdcf8beea09611b6e62 (diff) | |
download | SCons-8cb34cccc26935bce5d07ed3f51cc29fbbd1ab03.zip SCons-8cb34cccc26935bce5d07ed3f51cc29fbbd1ab03.tar.gz SCons-8cb34cccc26935bce5d07ed3f51cc29fbbd1ab03.tar.bz2 |
Merged revisions 2136-2200,2202-2290,2292-2301 via svnmerge from
http://scons.tigris.org/svn/scons/branches/core
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r2145 | stevenknight | 2007-07-17 09:15:12 -0500 (Tue, 17 Jul 2007) | 3 lines
Don't put null strings (from variable expansion) in a path list.
(They get turned into the current directory on later expansion.)
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r2146 | stevenknight | 2007-07-17 10:47:39 -0500 (Tue, 17 Jul 2007) | 3 lines
Add support for optional arguments on command-line long options
by specifying nargs='?'.
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r2149 | stevenknight | 2007-07-17 15:22:24 -0500 (Tue, 17 Jul 2007) | 2 lines
Remove left-over Optik mentions.
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r2150 | stevenknight | 2007-07-17 15:39:34 -0500 (Tue, 17 Jul 2007) | 4 lines
Add a $SWIGPATH variable for finding SWIG dependencies, with
$SWIGINC{PREFIX,SUFFIX} for adding them to the command line.
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r2154 | stevenknight | 2007-07-18 20:05:31 -0500 (Wed, 18 Jul 2007) | 2 lines
Fix variable misspellings in the doc added for $SWIGOUTPUT.
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r2155 | stevenknight | 2007-07-18 20:07:28 -0500 (Wed, 18 Jul 2007) | 2 lines
Add the Python eggs info file to the RPM packaging build.
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r2156 | stevenknight | 2007-07-18 20:15:08 -0500 (Wed, 18 Jul 2007) | 2 lines
Convert documentation from DocBook SGML to XML.
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r2158 | stevenknight | 2007-07-19 17:16:19 -0500 (Thu, 19 Jul 2007) | 3 lines
Conditionally add the .egg-info the RPM file list only if the distutils
in the version of Python that rpmbuild will execute knows about them.
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r2161 | stevenknight | 2007-07-19 19:12:29 -0500 (Thu, 19 Jul 2007) | 5 lines
Capture a test case (contributed by Tilo Prutz) where instantiation of
a private class causes javac to generate an additional anonymous inner
class file. (No solution yet, but there's no sense throwing away the
preparatory work.)
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r2162 | stevenknight | 2007-07-20 11:29:56 -0500 (Fri, 20 Jul 2007) | 3 lines
Support passing a list of .java files as source to the Java() builder.
(Leanid Nazdrynau)
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r2163 | garyo | 2007-07-20 12:00:35 -0500 (Fri, 20 Jul 2007) | 1 line
Fixed cut-n-paste error in Touch factory method doc in users guide.
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r2167 | stevenknight | 2007-07-21 22:59:40 -0500 (Sat, 21 Jul 2007) | 2 lines
Don't execute the SWIGOUTDIR test if swig isn't installed.
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r2168 | stevenknight | 2007-07-21 23:14:17 -0500 (Sat, 21 Jul 2007) | 2 lines
Fix the test's ability to run under a path name containing spaces.
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r2171 | stevenknight | 2007-07-24 15:54:41 -0500 (Tue, 24 Jul 2007) | 2 lines
Handle white space in key file names in the packaging build.
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r2172 | stevenknight | 2007-07-24 21:41:15 -0500 (Tue, 24 Jul 2007) | 2 lines
More efficient copying of construction environments.
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r2173 | stevenknight | 2007-07-25 10:56:02 -0500 (Wed, 25 Jul 2007) | 2 lines
Update the SCons build for Subversion and general clean-up.
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r2174 | stevenknight | 2007-07-25 11:35:16 -0500 (Wed, 25 Jul 2007) | 3 lines
Suppress the [brackets] around a node in the --tree=prune output if
the node is a source.
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r2175 | stevenknight | 2007-07-25 12:52:18 -0500 (Wed, 25 Jul 2007) | 3 lines
Commonize the skip_test() method and make its behavior configurable
via a TESTCOMMON_PASS_SKIPS environment variable.
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r2178 | stevenknight | 2007-07-25 21:43:47 -0500 (Wed, 25 Jul 2007) | 3 lines
Add $JAVACLASSPATH and $JAVASOURCEPATH construction variables. (Leanid
Nazdrynau)
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r2182 | stevenknight | 2007-07-30 12:10:20 -0500 (Mon, 30 Jul 2007) | 3 lines
Refactor Builder suffix-adjusting into its own method, so we can
(potentially) re-use it for Builders with attached source Builders.
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r2183 | stevenknight | 2007-07-30 14:51:53 -0500 (Mon, 30 Jul 2007) | 2 lines
More efficient source-builder suffix matching.
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r2184 | stevenknight | 2007-07-30 16:01:42 -0500 (Mon, 30 Jul 2007) | 4 lines
Encapsulate initialization of the default FS object by an accessor
function in SCons.Node.FS. (This also gets rid of an unnecessary
reference to SCons.Node.FS.default_fs in the LaTeX scanner.)
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r2193 | stevenknight | 2007-07-30 18:24:07 -0500 (Mon, 30 Jul 2007) | 3 lines
Fix interpretation of source arguments that have no suffix when the
called Builder has both a src_suffix and a src_builder.
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r2194 | stevenknight | 2007-07-31 10:25:31 -0500 (Tue, 31 Jul 2007) | 2 lines
Increase the number of tries for random output from three to ten.
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r2195 | stevenknight | 2007-07-31 10:52:28 -0500 (Tue, 31 Jul 2007) | 3 lines
Skip the test gracefully if the zipfile module can't read the file it
just wrote (which is the case for Python 2.1 on 64-bit systems).
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r2196 | stevenknight | 2007-07-31 13:06:21 -0500 (Tue, 31 Jul 2007) | 2 lines
Move the "import zipfile" so it doesn't fail on Python <= 2.0.
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r2197 | stevenknight | 2007-07-31 14:51:50 -0500 (Tue, 31 Jul 2007) | 3 lines
Commonize initialization of the various Java builders so they can be
hooked up into a multi-stage Builder chain. (Leanid Nazdrynau)
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r2198 | stevenknight | 2007-07-31 16:15:18 -0500 (Tue, 31 Jul 2007) | 3 lines
Fix use of ${TARGET.dir} and ${SOURCE.dir} expansions in $FORTRANMODDIR
$JARCHDIR, $JARFLAGS, $LEXFLAGS, $SWIGFLAGS, $SWIGOUTDIR and $YACCFLAGS.
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r2199 | stevenknight | 2007-07-31 16:25:48 -0500 (Tue, 31 Jul 2007) | 2 lines
Remove left-over Trace() call.
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r2202 | stevenknight | 2007-08-01 12:31:48 -0500 (Wed, 01 Aug 2007) | 3 lines
Bail out via test.skip_test() if wix ("candle") isn't found.
Put the main body of code flush left instead of under an if: block.
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r2203 | stevenknight | 2007-08-01 15:35:55 -0500 (Wed, 01 Aug 2007) | 5 lines
Fix Tool.packaging.rpm.package() so it doesn't always overwrite
$RPMFLAGS with -ta.
Set --buildroot in RPM packaging tests so they don't overwrite
each other when run simultaneously.
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r2204 | stevenknight | 2007-08-01 15:37:36 -0500 (Wed, 01 Aug 2007) | 2 lines
Fix a nested scope issue with the internal build_sources() function.
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r2205 | stevenknight | 2007-08-01 15:46:08 -0500 (Wed, 01 Aug 2007) | 5 lines
Normalize (X out) the CreationDate field inside embedded, compressed
PostScript streams within the generated PDF files. Also normalize
preceding Length field, since compression length is affected by different
patterns of input, including the variable CreationDate value.
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r2211 | stevenknight | 2007-08-02 08:52:06 -0500 (Thu, 02 Aug 2007) | 2 lines
Add the new modules from branches/packaging to the SCons packaging build.
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r2212 | stevenknight | 2007-08-02 19:59:01 -0500 (Thu, 02 Aug 2007) | 2 lines
Fix the JAVACLASSPATH test when javah isn't on the default $PATH.
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r2214 | stevenknight | 2007-08-03 15:05:21 -0500 (Fri, 03 Aug 2007) | 4 lines
Hook up the Java builders into a multi-step chain underneath a Java()
pseudo-builder (wrapper) that examines its arguments and calls the
appropriate underlying file-or-dir builder.
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r2215 | stevenknight | 2007-08-03 15:49:58 -0500 (Fri, 03 Aug 2007) | 2 lines
Fix for old Python versions: use apply() instead of *args, **kw.
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r2216 | stevenknight | 2007-08-03 16:49:31 -0500 (Fri, 03 Aug 2007) | 2 lines
Hook up the SWIG builder as a source builder for .java files.
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r2217 | stevenknight | 2007-08-03 17:28:19 -0500 (Fri, 03 Aug 2007) | 2 lines
Don't use .endswith(), which didn't appear until later Python versions.
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r2218 | stevenknight | 2007-08-03 17:29:38 -0500 (Fri, 03 Aug 2007) | 2 lines
Replace tabs with spaces.
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r2219 | stevenknight | 2007-08-04 08:06:23 -0500 (Sat, 04 Aug 2007) | 3 lines
Initialize a loop-invariant lambda for matching .java suffixes outside
the loop.
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r2220 | stevenknight | 2007-08-07 15:06:13 -0500 (Tue, 07 Aug 2007) | 2 lines
Refactor parallel class-generation loops into one.
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r2221 | stevenknight | 2007-08-07 16:04:06 -0500 (Tue, 07 Aug 2007) | 5 lines
Have the Java multi-step builder test actually check for generated files,
and fix the generation of .java and .class file names, and interaction
with the SWIG builder, so that the files are generated in the correct
place.
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r2222 | stevenknight | 2007-08-07 16:45:05 -0500 (Tue, 07 Aug 2007) | 3 lines
Fix dependencies on SWIG-generated .java files so they don't have to
be built in multiple passes.
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r2226 | stevenknight | 2007-08-07 18:00:22 -0500 (Tue, 07 Aug 2007) | 2 lines
Fix SWIG when used with BuildDir().
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r2227 | stevenknight | 2007-08-07 22:15:55 -0500 (Tue, 07 Aug 2007) | 5 lines
User's guide updates:
- Make the multiple files example match its text.
- Expand a truncated sentence about being able to use Python function actions
in the Command() Builder.
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r2228 | stevenknight | 2007-08-07 23:25:18 -0500 (Tue, 07 Aug 2007) | 3 lines
Don't generate an error if a #include file matches a same-named
directory in $CPPPATH (or $FORTRANPATH, etc.).
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r2229 | stevenknight | 2007-08-07 23:40:00 -0500 (Tue, 07 Aug 2007) | 2 lines
Fix a code example. (Gary Oberbrunner)
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r2230 | stevenknight | 2007-08-08 00:05:43 -0500 (Wed, 08 Aug 2007) | 3 lines
Capture a test case to make sure AddPostAction() doesn't interfere
with normal linking. (Matt Doar, Gary Oberbrunner)
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r2233 | stevenknight | 2007-08-08 14:15:44 -0500 (Wed, 08 Aug 2007) | 2 lines
Fix documentation typo in a construction variable cross-reference.
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r2234 | stevenknight | 2007-08-08 17:03:25 -0500 (Wed, 08 Aug 2007) | 2 lines
Changes to SCons packaging to support checkpoint releases.
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r2235 | stevenknight | 2007-08-09 10:10:01 -0500 (Thu, 09 Aug 2007) | 2 lines
Sidestep false negatives on heavily loaded systems.
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r2236 | garyo | 2007-08-09 11:16:26 -0500 (Thu, 09 Aug 2007) | 1 line
Allow unpackaged files (e.g. *.pyo) to exist in the build dir without being packaged in the RPM. Without this, on some systems the rpmbuild may error out.
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r2237 | stevenknight | 2007-08-09 11:27:56 -0500 (Thu, 09 Aug 2007) | 5 lines
Fix test/SWIG/build-dir.py so it works on old Python versions without
distutils.sysconfig.
Instead of just cutting-and-pasting initialization code from other
SWIG tests, centralize it in some new TestSCons methods.
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r2238 | garyo | 2007-08-09 11:30:58 -0500 (Thu, 09 Aug 2007) | 1 line
Use docbook 4.3 instead of 4.4 for the XML doctype since some older(?) jade parsers can't handle new 4-byte Unicode chars in the 4.4 version of isogrk4.ent.
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r2240 | stevenknight | 2007-08-09 16:35:06 -0500 (Thu, 09 Aug 2007) | 2 lines
User's Guide updates (post packaging changes).
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r2243 | stevenknight | 2007-08-10 10:31:51 -0500 (Fri, 10 Aug 2007) | 3 lines
Fix the User's Guide build to use openjade, and to accomodate a change
in the name of the main generated file (book1.html => index.html).
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r2245 | stevenknight | 2007-08-10 11:09:16 -0500 (Fri, 10 Aug 2007) | 2 lines
Update the {CHANGES,RELEASE}.txt datestamp lines.
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r2253 | stevenknight | 2007-08-10 16:21:54 -0500 (Fri, 10 Aug 2007) | 2 lines
Fix the wix Tool module's ability to handle null entries in $PATH.
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r2261 | stevenknight | 2007-08-11 23:08:12 -0500 (Sat, 11 Aug 2007) | 3 lines
Remove unnecessary files (.svnt/*, .{ae,cvs}ignore, www/*) from the
scons-src packages.
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r2262 | stevenknight | 2007-08-11 23:24:49 -0500 (Sat, 11 Aug 2007) | 2 lines
Add missing __revision__ lines.
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r2263 | stevenknight | 2007-08-11 23:33:42 -0500 (Sat, 11 Aug 2007) | 2 lines
Skip the test if the MANIFEST file hasn't been built.
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r2264 | stevenknight | 2007-08-11 23:36:30 -0500 (Sat, 11 Aug 2007) | 2 lines
Add recent compatibility modules to the relevant exceptions lists.
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r2265 | stevenknight | 2007-08-11 23:39:00 -0500 (Sat, 11 Aug 2007) | 3 lines
Update __VERSION__ strings in the QMTest/*.py modules, so that packaging
tests (src/test_*.py) will pass after builds of checkpoint releases.
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r2266 | stevenknight | 2007-08-12 07:36:19 -0500 (Sun, 12 Aug 2007) | 2 lines
Add a comment about why we construct the __VERSION__ string at run time.
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r2267 | stevenknight | 2007-08-12 07:42:30 -0500 (Sun, 12 Aug 2007) | 2 lines
Avoid reading the MANIFEST file twice. (Courtesy review by Greg Noel.)
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r2268 | stevenknight | 2007-08-12 08:14:53 -0500 (Sun, 12 Aug 2007) | 3 lines
Shift Install() and InstallAs() from being documented as functions
to being documented as Builders.
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r2269 | garyo | 2007-08-13 08:49:52 -0500 (Mon, 13 Aug 2007) | 1 line
Tests: Skip some more Java tests if javac is not installed on the test machine so they don't get marked as failing.
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r2270 | garyo | 2007-08-13 11:09:39 -0500 (Mon, 13 Aug 2007) | 1 line
Fixed typo in test (shows up on non-Linux platforms).
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r2271 | garyo | 2007-08-13 14:09:05 -0500 (Mon, 13 Aug 2007) | 4 lines
Test portability fixes for Darwin/OSX and IRIX.
This does not make all the tests pass on those OSes,
but it takes care of some of the more obvious errors that
I have time for right now. More to come.
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r2272 | stevenknight | 2007-08-13 15:33:29 -0500 (Mon, 13 Aug 2007) | 2 lines
Tab => space fix.
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r2273 | stevenknight | 2007-08-13 15:33:52 -0500 (Mon, 13 Aug 2007) | 2 lines
Test for swig, too, which is used to build from the .i file.
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r2277 | garyo | 2007-08-14 10:40:00 -0500 (Tue, 14 Aug 2007) | 8 lines
Test portability on IRIX: test/Actions/pre-post creates target file
before building target, then IRIX CC does not chmod +x afterwards.
I think this change is safe on all OSes.
test/AS/ml.py: I think this is only supposed to be run on win32
(not skipped only on win32); the sense of the skip test was backwards.
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r2278 | stevenknight | 2007-08-14 11:04:40 -0500 (Tue, 14 Aug 2007) | 2 lines
Add -tt when running tests, to catch inconsistent tab usage.
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r2279 | stevenknight | 2007-08-14 14:00:43 -0500 (Tue, 14 Aug 2007) | 2 lines
Minor refactor of logic in File.retrieve_from_cache().
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r2280 | stevenknight | 2007-08-15 01:11:40 -0500 (Wed, 15 Aug 2007) | 2 lines
Refactor CacheDir support into its own module.
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r2281 | stevenknight | 2007-08-15 07:24:51 -0500 (Wed, 15 Aug 2007) | 2 lines
Move the cachepath() method from FS.File to the CacheDir class.
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r2282 | stevenknight | 2007-08-15 08:31:34 -0500 (Wed, 15 Aug 2007) | 2 lines
Python 1.5.2 fix in the new Null class.
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r2283 | stevenknight | 2007-08-15 10:45:53 -0500 (Wed, 15 Aug 2007) | 5 lines
Refactor CacheDir unit tests to:
- restore functionality that was dropped in the transition;
- commonize creation of test Nodes and other (mock) objects
- separate CacheDir tests from tests of CacheDir through Node.FS.File.
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r2284 | stevenknight | 2007-08-15 11:46:38 -0500 (Wed, 15 Aug 2007) | 3 lines
Replace the Executor.Null.NullEnvironment object with a real Null object,
so it will absorb the CacheDir method calls as well.
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r2285 | stevenknight | 2007-08-15 11:52:57 -0500 (Wed, 15 Aug 2007) | 5 lines
Add a get_CacheDir() method to a construction environment, which will
be used to fetch per-environment CacheDir specifications. (Right now
all calls to it still just return the one attached to underlying default
FS object.)
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r2286 | stevenknight | 2007-08-15 15:15:46 -0500 (Wed, 15 Aug 2007) | 2 lines
Support per-construction-environment configuration of CacheDir().
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r2287 | stevenknight | 2007-08-15 15:33:04 -0500 (Wed, 15 Aug 2007) | 2 lines
Move the tests of CacheDir()-related command-line options into test/CacheDir.
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r2293 | stevenknight | 2007-08-16 11:14:49 -0500 (Thu, 16 Aug 2007) | 3 lines
Add the Package() builder description to the documentation build,
fixing the XML so that it will build.
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r2294 | stevenknight | 2007-08-16 12:51:19 -0500 (Thu, 16 Aug 2007) | 3 lines
Reorganize packaging documentation: alphabetize the variable definitions
(and function names), document Tag() as a function, not a builder.
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r2296 | stevenknight | 2007-08-16 12:55:01 -0500 (Thu, 16 Aug 2007) | 2 lines
Add a build command.
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r2300 | stevenknight | 2007-08-16 16:49:13 -0500 (Thu, 16 Aug 2007) | 2 lines
First cut at documenting packaging variables.
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r2301 | stevenknight | 2007-08-16 16:51:21 -0500 (Thu, 16 Aug 2007) | 3 lines
Construct the .src.rpm and .arch.rpm file names independnetly, not
by trying to massage one into the other.
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Diffstat (limited to 'doc/user/nodes.xml')
-rw-r--r-- | doc/user/nodes.xml | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/doc/user/nodes.xml b/doc/user/nodes.xml new file mode 100644 index 0000000..4ada5b7 --- /dev/null +++ b/doc/user/nodes.xml @@ -0,0 +1,373 @@ +<!-- + + __COPYRIGHT__ + + 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> + + Internally, &SCons; represents all of the files + and directories it knows about as &Nodes;. + These internal objects + (not object <emphasis>files</emphasis>) + can be used in a variety of ways + to make your &SConscript; + files portable and easy to read. + + </para> + + <section> + <title>Builder Methods Return Lists of Target Nodes</title> + + <para> + + All builder methods return a list of + &Node; objects that identify the + target file or files that will be built. + These returned &Nodes; can be passed + as source files to other builder methods, + + </para> + + <para> + + For example, suppose that we want to build + the two object files that make up a program with different options. + This would mean calling the &b-link-Object; + builder once for each object file, + specifying the desired options: + + </para> + + <programlisting> + Object('hello.c', CCFLAGS='-DHELLO') + Object('goodbye.c', CCFLAGS='-DGOODBYE') + </programlisting> + + <para> + + One way to combine these object files + into the resulting program + would be to call the &b-link-Program; + builder with the names of the object files + listed as sources: + + </para> + + <programlisting> + Object('hello.c', CCFLAGS='-DHELLO') + Object('goodbye.c', CCFLAGS='-DGOODBYE') + Program(['hello.o', 'goodbye.o']) + </programlisting> + + <para> + + The problem with listing the names as strings + is that our &SConstruct; file is no longer portable + across operating systems. + It won't, for example, work on Windows + because the object files there would be + named &hello_obj; and &goodbye_obj;, + not &hello_o; and &goodbye_o;. + + </para> + + <para> + + A better solution is to assign the lists of targets + returned by the calls to the &b-Object; builder to variables, + which we can then concatenate in our + call to the &b-Program; builder: + + </para> + + <programlisting> + hello_list = Object('hello.c', CCFLAGS='-DHELLO') + goodbye_list = Object('goodbye.c', CCFLAGS='-DGOODBYE') + Program(hello_list + goodbye_list) + </programlisting> + + <para> + + This makes our &SConstruct; file portable again, + the build output on Linux looking like: + + </para> + + <screen> + % <userinput>scons -Q</userinput> + cc -o goodbye.o -c -DGOODBYE goodbye.c + cc -o hello.o -c -DHELLO hello.c + cc -o hello hello.o goodbye.o + </screen> + + <para> + + And on Windows: + + </para> + + <screen> + C:\><userinput>scons -Q</userinput> + cl -DGOODBYE /c goodbye.c /Fogoodbye.obj + cl -DHELLO /c hello.c /Fohello.obj + link /nologo /OUT:hello.exe hello.obj goodbye.obj + </screen> + + <para> + + We'll see examples of using the list of nodes + returned by builder methods throughout + the rest of this guide. + + </para> + + </section> + + <section> + <title>Explicitly Creating File and Directory Nodes</title> + + <para> + + It's worth mentioning here that + &SCons; maintains a clear distinction + between Nodes that represent files + and Nodes that represent directories. + &SCons; supports &File; and &Dir; + functions that, repectively, + return a file or directory Node: + + </para> + + <programlisting> + hello_c = File('hello.c') + Program(hello_c) + + classes = Dir('classes') + Java(classes, 'src') + </programlisting> + + <para> + + Normally, you don't need to call + &File; or &Dir; directly, + because calling a builder method automatically + treats strings as the names of files or directories, + and translates them into + the Node objects for you. + The &File; and &Dir; functions can come in handy + in situations where you need to explicitly + instruct &SCons; about the type of Node being + passed to a builder or other function, + or unambiguously refer to a specific + file in a directory tree. + <!-- + (For an example of when you might + need to use &File; or &Dir; to + prevent ambiguous interpretation of a string + naming a file or directory, see + <xref linkend="chap-hierarchy">.) + --> + + </para> + + <para> + + There are also times when you may need to + refer to an entry in a file system + without knowing in advance + whether it's a file or a directory. + For those situations, + &SCons; also supports an &Entry; function, + which returns a Node + that can represent either a file or a directory. + + </para> + + <programlisting> + xyzzy = Entry('xyzzy') + </programlisting> + + <para> + + The returned <literal>xyzzy</literal> Node + will be turned into a file or directory Node + the first time it is used by a builder method + or other function that + requires one vs. the other. + + </para> + + </section> + + <section> + <title>Printing &Node; File Names</title> + + <para> + + One of the most common things you can do + with a Node is use it to print the + file name that the node represents. + For example, the following &SConstruct; file: + + </para> + + <programlisting> + hello_c = File('hello.c') + Program(hello_c) + + classes = Dir('classes') + Java(classes, 'src') + + object_list = Object('hello.c') + program_list = Program(object_list) + print "The object file is:", object_list[0] + print "The program file is:", program_list[0] + </programlisting> + + <para> + + Would print the following file names on a POSIX system: + + </para> + + <screen> + % <userinput>scons -Q</userinput> + The object file is: hello.o + The program file is: hello + cc -o hello.o -c hello.c + cc -o hello hello.o + </screen> + + <para> + + And the following file names on a Windows system: + + </para> + + <screen> + C:\><userinput>scons -Q</userinput> + The object file is: hello.obj + The program file is: hello.exe + cl /nologo /c hello.c /Fohello.obj + link /nologo /OUT:hello.exe hello.obj + </screen> + + </section> + + <section> + <title>Using a &Node;'s File Name as a String</title> + + <para> + + Printing a &Node;'s name + as described in the previous section + works because the string representation of a &Node; + is the name of the file. + If you want to do something other than + print the name of the file, + you can fetch it by using the builtin Python + &str; function. + For example, if you want to use the Python + <function>os.path.exists</function> + to figure out whether a file + exists while the &SConstruct; file + is being read and executed, + you can fetch the string as follows: + + </para> + + <programlisting> + import os.path + program_list = Program('hello.c') + program_name = str(program_list[0]) + if not os.path.exists(program_name): + print program_name, "does not exist!" + </programlisting> + + <para> + + Which executes as follows on a POSIX system: + + </para> + + <screen> + % <userinput>scons -Q</userinput> + hello does not exist! + cc -o hello.o -c hello.c + cc -o hello hello.o + </screen> + + </section> + + <!-- + + <section> + <title>Fetching the Contents of a &Node;</title> + + <para> + + XXX Describe using read() and readlines() + when we add that as a public interface. + + </para> + + <scons_example name="read"> + <file name="SConstruct" printme="1"> + hello_c = File('hello.c') + contents = hello_c.read() + print "contents are:" + print contents + </file> + <file name="hello.c"> + int main() { printf("Hello, world!\n"); } + </file> + </scons_example> + + <para> + + Which executes as follows on a POSIX system: + + </para> + + <scons_output example="read" os="posix"> + <scons_output_command>scons -Q</scons_output_command> + </scons_output> + + </section> + + --> + + <!-- + + <section> + <title>Python Value &Node;</title> + + <para> + + XXX Value() + + </para> + + </section> + + --> |