Add propane and initial scene grammar

.gitignore

@@ -1,5 +1,6 @@
 /fart
 *.bmp
 *.png
+/.propane*
 /.rscons*
 /build/

Rsconscript

@@ -6,7 +6,16 @@ fart_env = env "fart" do |env|
   env["DFLAGS"] += %w[-Werror -O2]
   env["D_IMPORT_PATH"] += %w[src]
 
-  env["sources"] = glob("src/**/*.d")
+  env.Command("^/src/sceneparser.d", "src/sceneparser.propane",
+              "CMD" => %w[./propane ${_SOURCES} ${_TARGET}],
+              "CMD_DESC" => "Generating scene parser")
+  env.add_build_hook do |builder|
+    if builder.sources.first =~ /sceneparser\.d/
+      builder.vars["DFLAGS"] -= %w[-Werror]
+    end
+  end
+
+  env["sources"] = glob("src/**/*.d") + ["^/src/sceneparser.d"]
   env.Program("fart", "${sources}")
 end
 

src/sceneparser.propane

@@ -0,0 +1,22 @@
+<<
+import std.conv;
+>>
+
+token background;
+token comma /,/;
+token number /\d+(\.\d+)?/;
+token lt /</;
+token gt />/;
+token semicolon /;/;
+
+Start -> Statements;
+
+Statements -> ;
+
+Statements -> Statement Statements;
+
+Statement -> BackgroundStatement;
+
+BackgroundStatement -> background Vec3 semicolon;
+
+Vec3 -> lt number comma number comma number gt;