4987 - support `browse_trace` tool in SubX

I've extracted it into a separate binary, independent of my Mu prototype.

I also cleaned up my tracing layer to be a little nicer. Major improvements:

- Realized that incremental tracing really ought to be the default.
  And to minimize printing traces to screen.

- Finally figured out how to combine layers and call stack frames in a
  single dimension of depth. The answer: optimize for the experience of
  `browse_trace`. Instructions occupy a range of depths based on their call
  stack frame, and minor details of an instruction lie one level deeper
  in each case.

Other than that, I spent some time adjusting levels everywhere to make
`browse_trace` useful.

1 files changed, 2 insertions, 2 deletions

diff --git a/045closure_name.cc b/045closure_name.cc
index 6b2defd3..b4a8ea24 100644
--- a/045closure_name.cc
+++ b/045closure_name.cc
@@ -42,7 +42,7 @@ Transform.push_back(collect_surrounding_spaces);  // idempotent
 
 :(code)
 void collect_surrounding_spaces(const recipe_ordinal r) {
-  trace(9991, "transform") << "--- collect surrounding spaces for recipe " << get(Recipe, r).name << end();
+  trace(101, "transform") << "--- collect surrounding spaces for recipe " << get(Recipe, r).name << end();
   for (int i = 0;  i < SIZE(get(Recipe, r).steps);  ++i) {
     const instruction& inst = get(Recipe, r).steps.at(i);
     if (inst.is_label) continue;
@@ -69,7 +69,7 @@ void collect_surrounding_spaces(const recipe_ordinal r) {
         raise << "recipe '" << get(Recipe, r).name << "' can have only one 'surrounding' recipe but has '" << get(Recipe, get(Surrounding_space, r)).name << "' and '" << surrounding_recipe_name << "'\n" << end();
         continue;
       }
-      trace(9993, "name") << "lexically surrounding space for recipe " << get(Recipe, r).name << " comes from " << surrounding_recipe_name << end();
+      trace(103, "name") << "lexically surrounding space for recipe " << get(Recipe, r).name << " comes from " << surrounding_recipe_name << end();
       if (!contains_key(Recipe_ordinal, surrounding_recipe_name)) {
         raise << "can't find recipe providing surrounding space for '" << get(Recipe, r).name << "'; looking for '" << surrounding_recipe_name << "'\n" << end();
         continue;