1483 - *really* check color screens in scenarios

Required fixing two levels of bugs:

a) The hack in tangle to drop initial comments a '%' directive..

b) ..was masking a bug where run_mu_scenario wasn't robust to initial
comments.

Mildly concerned that neither of the sub-issues have their own tests,
but I'm just removing hacks, and writing tests for that throwaway
function like run_mu_scenario seems pointless. Instead I've solved the
problem by disallowing comments before '%' directives.

I've also taken this opportunity to at least try to document the
'scenarios' and '%' directives at the first layer where they appear.

1 files changed, 2 insertions, 1 deletions

diff --git a/050scenario.cc b/050scenario.cc
index c4acc688..06c14c8e 100644
--- a/050scenario.cc
+++ b/050scenario.cc
@@ -494,8 +494,9 @@ recipe main [
 void run_mu_scenario(const string& form) {
   istringstream in(form);
   in >> std::noskipws;
+  skip_whitespace_and_comments(in);
   string _scenario = next_word(in);
-//?   cout << _scenario << '\n'; //? 1
+//?   cout << _scenario << '\n'; //? 2
   assert(_scenario == "scenario");
   scenario s = parse_scenario(in);
   run_mu_scenario(s);