embed.pl was relying on embed.fnc starting with a pre-processor directive.

Fix this subtle bug, and add comments.

diff --git a/regen/embed.pl b/regen/embed.pl
index 71422bb..5be3744 100755 (executable)
--- a/regen/embed.pl
+++ b/regen/embed.pl
@@ -106,9 +106,31 @@ my (@core, @ext, @api);
 {
     # Cluster entries in embed.fnc that have the same #ifdef guards.
     # Also, split out at the top level the three classes of functions.
+    # Output structure is actually the same as input structure - an
+    # (ordered) list of array references, where the elements in the reference
+    # determine what it is - a reference to a 1-element array is a
+    # pre-processor directive, a reference to 2+ element array is a function.
+
+    # Records the current pre-processor state:
     my @state;
+    # Nested structure to group functions by the pre-processor conditions that
+    # control when they are compiled:
     my %groups;
-    my $current;
+
+    sub current_group {
+       my $group = \%groups;
+       # Nested #if blocks are effectively &&ed together
+       # For embed.fnc, ordering within the && isn't relevant, so we can
+       # sort them to try to group more functions together.
+       foreach (sort @state) {
+           $group->{$_} ||= {};
+           $group = $group->{$_};
+       }
+       return $group->{''} ||= [];
+    }
+
+    my $current = current_group();
+
     foreach (@embed) {
        if (@$_ > 1) {
            push @$current, $_;
@@ -129,17 +151,7 @@ my (@core, @ext, @api);
        } else {
            die "Unhandled pre-processor directive '$_->[0]' in embed.fnc";
        }
-       $current = \%groups;
-       # Nested #if blocks are effectively &&ed together
-       # For embed.fnc, ordering withing the && isn't relevant, so we can
-       # sort them to try to group more functions together.
-       my @sorted = sort @state;
-       while (my $directive = shift @sorted) {
-           $current->{$directive} ||= {};
-           $current = $current->{$directive};
-       }
-       $current->{''} ||= [];
-       $current = $current->{''};
+       $current = current_group();
     }
 
     sub add_level {