[Boost-build] Patch for generate.jam to generate to be wrapped by other rules

From: Jonathan Biggar (jon_at_[hidden])
Date: 2008-07-18 12:44:35

The generate main target currently only works if you pass it a 
<generating-rule> using the '@' construction.  If you don't, it silently 
just doesn't do anything.

Here's a patch that cleans this up so that it properly gives an error if 
it can't run the <generating-rule>, and also just tries to call the rule 
via indirect.call if no '@' prefix is found, which allows people to 
write wrapper rules that use generate.

-- 
Jon Biggar
Floorboard Software
jon_at_[hidden]
jon_at_[hidden]

==== //depot/orb_main/corba/tools/build/v2/tools/generate.jam#1 (text) - //depot/orb_main/corba/tools/build/v2/tools/generate.jam#3 (text) ==== content
@@ -44,24 +44,35 @@
         local result ;
         local gr = [ $(property-set).get <generating-rule> ] ;
 
-        # FIXME: this is copy-paste from virtual-target.jam. Must
-        # have n utilty rule to call a rule like this.
-        local rule-name = [ MATCH ^@(.*) : $(gr) ] ;
-        if $(rule-name)
+        if ($gr)
         {
-            if $(tag[2])
+            # FIXME: this is copy-paste from virtual-target.jam. Must
+            # have n utilty rule to call a rule like this.
+            local rule-name = [ MATCH ^@(.*) : $(gr) ] ;
+            if $(rule-name)
+            {
+                if $(gr[2])
+                {
+                    errors.error "<generating-rule>@rulename is present but is not the only <generating-rule> feature" ;
+                }
+
+                result = [ indirect.call $(rule-name) $(self.project) $(name)
+                    : $(property-set) : $(sources) ] ;
+            }
+            else
             {
-                errors.error "<tag>@rulename is present but is not the only <tag> feature" ;
+                result = [ indirect.call $(gr) $(self.project) $(name) : $(property-set) : $sources) ] ;
             }
 
-            result = [ indirect.call $(rule-name) $(self.project) $(name)
-                : $(property-set) : $(sources) ] ;
-
             if ! $(result)
             {
                 ECHO "warning: Unable to construct" [ full-name ] ;
             }
         }
+        else
+        {
+            errors.error "no <generating-rule> specified" ;
+        }
 
         local ur ;
         local targets ;