Added support for setting default platforms and implemented the VS action.

src/_premake_init.lua

@@ -173,6 +173,12 @@
 		},
 	}
 
+	api.register {
+		name = "defaultplatform",
+		scope = "project",
+		kind = "string",
+	}
+
 	api.register {
 		name = "defines",
 		scope = "config",

src/actions/vstudio/vs2005_solution.lua

@@ -172,9 +172,22 @@
 
 		-- Now I can output the sorted list of solution configuration descriptors
 
+		-- Visual Studio assumes the first configurations as the defaults.
+		if sln.defaultplatform then
+			_p(1,'GlobalSection(SolutionConfigurationPlatforms) = preSolution')
+			table.foreachi(sorted, function (cfg)
+				if cfg.platform == sln.defaultplatform then
+					_p(2,'%s = %s', descriptors[cfg], descriptors[cfg])
+				end
+			end)
+			_p(1,"EndGlobalSection")
+		end
+
 		_p(1,'GlobalSection(SolutionConfigurationPlatforms) = preSolution')
 		table.foreachi(sorted, function (cfg)
-			_p(2,'%s = %s', descriptors[cfg], descriptors[cfg])
+			if not sln.defaultplatform or cfg.platform ~= sln.defaultplatform then
+				_p(2,'%s = %s', descriptors[cfg], descriptors[cfg])
+			end
 		end)
 		_p(1,"EndGlobalSection")
 

tests/actions/vstudio/sln2005/test_platforms.lua

@@ -736,3 +736,23 @@
 	EndGlobalSection
 		]]
 	end
+
+-- Check that when a default platform is specified it is written in a separate
+-- configuration block so that Visual Studio picks it up as default.
+
+	function suite.onDefaultPlatforms()
+		platforms { "x32", "x64" }
+		defaultplatform "x64"
+		project "MyProject"
+		prepare()
+		test.capture [[
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|x64 = Debug|x64
+		Release|x64 = Release|x64
+	EndGlobalSection
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Win32 = Debug|Win32
+		Release|Win32 = Release|Win32
+	EndGlobalSection
+		]]
+	end