2711 - permit boolean<-number conversions

I might change my mind on this, but it's worth a try after watching Ella
run up against it today. I got her to build the recipe 'odd?', but then
it failed to run because she couldn't convert a numeric remainder to a
number without a conditional (which I haven't taught her yet).

For now I don't change the value in the boolean, so booleans can store
arbitrary bit patterns like in C. We just say that 0 is false and
anything else is true. I *think* that doesn't break the type system..

1 files changed, 9 insertions, 0 deletions

diff --git a/021check_instruction.cc b/021check_instruction.cc
index f65dd398..bf139ea8 100644
--- a/021check_instruction.cc
+++ b/021check_instruction.cc
@@ -88,12 +88,21 @@ recipe main [
 +mem: storing 1 in location 2
 $error: 0
 
+:(scenario write_number_to_boolean_allowed)
+recipe main [
+  1:number <- copy 34
+  2:boolean <- copy 1:number
+]
++mem: storing 34 in location 2
+$error: 0
+
 :(code)
 // types_match with some leniency
 bool types_coercible(const reagent& to, const reagent& from) {
   if (types_match(to, from)) return true;
   if (is_mu_address(from) && is_mu_number(to)) return true;
   if (is_mu_boolean(from) && is_mu_number(to)) return true;
+  if (is_mu_number(from) && is_mu_boolean(to)) return true;
   // End types_coercible Special-cases
   return false;
 }