Generate code for flag types and context accessors

runtests

@@ -20,6 +20,7 @@ def main(sysargs=sys.argv[:]):
         'test': _test,
         'gfmxr': _gfmxr,
         'toc': _toc,
+        'gen': _gen,
     }
 
     parser = argparse.ArgumentParser()
@@ -34,7 +35,7 @@ def main(sysargs=sys.argv[:]):
 
 def _test():
     if check_output('go version'.split()).split()[2] < 'go1.2':
-        _run('go test -v .'.split())
+        _run('go test -v .')
         return
 
     coverprofiles = []
@@ -51,7 +52,7 @@ def _test():
         ])
 
     combined_name = _combine_coverprofiles(coverprofiles)
-    _run('go tool cover -func={}'.format(combined_name).split())
+    _run('go tool cover -func={}'.format(combined_name))
     os.remove(combined_name)
 
 
@@ -60,15 +61,22 @@ def _gfmxr():
 
 
 def _vet():
-    _run('go vet ./...'.split())
+    _run('go vet ./...')
 
 
 def _toc():
-    _run(['node_modules/.bin/markdown-toc', '-i', 'README.md'])
-    _run(['git', 'diff', '--quiet'])
+    _run('node_modules/.bin/markdown-toc -i README.md')
+    _run('git diff --quiet')
+
+
+def _gen():
+    _run('go generate .')
+    _run('git diff --quiet')
 
 
 def _run(command):
+    if hasattr(command, 'split'):
+        command = command.split()
     print('runtests: {}'.format(' '.join(command)), file=sys.stderr)
     check_call(command)