Added 'read_setup_file()' to read old-style Setup files. Could make life

easier for people porting Makefile.pre.in-based extensions to Distutils.
Also loosened argument-checking in Extension constructor to make life
  easier for 'read_setup_file()'.

Lib/distutils/extension.py

@@ -7,6 +7,7 @@
 
 __revision__ = "$Id$"
 
+import os, string
 from types import *
 
 
@@ -89,9 +90,8 @@ def __init__ (self, name, sources,
 
         assert type(name) is StringType, "'name' must be a string"
         assert (type(sources) is ListType and
-                len(sources) >= 1 and
                 map(type, sources) == [StringType]*len(sources)), \
-                "'sources' must be a non-empty list of strings"
+                "'sources' must be a list of strings"
 
         self.name = name
         self.sources = sources
@@ -107,3 +107,111 @@ def __init__ (self, name, sources,
         self.export_symbols = export_symbols or []
 
 # class Extension
+
+
+def read_setup_file (filename):
+    from distutils.sysconfig import \
+         parse_makefile, expand_makefile_vars, _variable_rx
+    from distutils.text_file import TextFile
+    from distutils.util import split_quoted
+
+    # First pass over the file to gather "VAR = VALUE" assignments.
+    vars = parse_makefile(filename)
+
+    # Second pass to gobble up the real content: lines of the form
+    #   <module> ... [<sourcefile> ...] [<cpparg> ...] [<library> ...]
+    file = TextFile(filename,
+                    strip_comments=1, skip_blanks=1, join_lines=1,
+                    lstrip_ws=1, rstrip_ws=1)
+    extensions = []
+
+    while 1:
+        line = file.readline()
+        if line is None:                # eof
+            break
+        if _variable_rx.match(line):    # VAR=VALUE, handled in first pass
+            continue
+
+        if line[0] == line[-1] == "*":
+            file.warn("'%s' lines not handled yet" % line)
+            continue
+
+        #print "original line: " + line
+        line = expand_makefile_vars(line, vars)
+        words = split_quoted(line)
+        #print "expanded line: " + line
+
+        # NB. this parses a slightly different syntax than the old
+        # makesetup script: here, there must be exactly one extension per
+        # line, and it must be the first word of the line.  I have no idea
+        # why the old syntax supported multiple extensions per line, as
+        # they all wind up being the same.
+
+        module = words[0]
+        ext = Extension(module, [])
+        append_next_word = None
+
+        for word in words[1:]:
+            if append_next_word is not None:
+                append_next_word.append(word)
+                append_next_word = None
+                continue
+
+            suffix = os.path.splitext(word)[1]
+            switch = word[0:2] ; value = word[2:]
+
+            if suffix in (".c", ".cc", ".cpp", ".cxx", ".c++"):
+                # hmm, should we do something about C vs. C++ sources?
+                # or leave it up to the CCompiler implementation to
+                # worry about?
+                ext.sources.append(word)
+            elif switch == "-I":
+                ext.include_dirs.append(value)
+            elif switch == "-D":
+                equals = string.find(value, "=")
+                if equals == -1:        # bare "-DFOO" -- no value
+                    ext.define_macros.append((value, None))
+                else:                   # "-DFOO=blah"
+                    ext.define_macros.append((value[0:equals],
+                                              value[equals+2:]))
+            elif switch == "-U":
+                ext.undef_macros.append(value)
+            elif switch == "-C":        # only here 'cause makesetup has it!
+                ext.extra_compile_args.append(word)
+            elif switch == "-l":
+                ext.libraries.append(value)
+            elif switch == "-L":
+                ext.library_dirs.append(value)
+            elif switch == "-R":
+                ext.runtime_library_dirs.append(value)
+            elif word == "-rpath":
+                append_next_word = ext.runtime_library_dirs
+            elif word == "-Xlinker":
+                append_next_word = ext.extra_link_args
+            elif switch == "-u":
+                ext.extra_link_args.append(word)
+                if not value:
+                    append_next_word = ext.extra_link_args
+            elif suffix in (".a", ".so", ".sl", ".o"):
+                # NB. a really faithful emulation of makesetup would
+                # append a .o file to extra_objects only if it
+                # had a slash in it; otherwise, it would s/.o/.c/
+                # and append it to sources.  Hmmmm.
+                ext.extra_objects.append(word)
+            else:
+                file.warn("unrecognized argument '%s'" % word)
+
+        extensions.append(ext)
+
+        #print "module:", module
+        #print "source files:", source_files
+        #print "cpp args:", cpp_args
+        #print "lib args:", library_args
+
+        #extensions[module] = { 'sources': source_files,
+        #                       'cpp_args': cpp_args,
+        #                       'lib_args': library_args }
+        
+    return extensions
+
+# read_setup_file ()