Changes between Version 4 and Version 5 of DependencyAnalysis

Timestamp:

08/13/07 09:24:35 (6 years ago)

Author:

pgavin@…

Comment:

--

DependencyAnalysis

@@ -51 +51 @@
 }}}
 
-So, please, if you have any other ideas, please put them here.  I want to get gtk2hs working with cabal, and this is a necessary step in that process.  I'd write some actual code, but I want to know what others are thinking and doing, so I don't duplicate work :)
-
-Pete
-
 == Interleaving dep chasing and building ==
 
@@ -65 +61 @@
 
 So the question is, what is a good interface between the dependency chaser and a make layer.
+
+----
+
+I agree that having the dependency generation and make layers separate would be a good thing, but I don't know if that's 100% feasible.  Consider that the only time we will have a complete dependency graph is when the build is nearly done.  So, I don't really think we should try to build the graph at all (at least, in the direct sense).
+
+Here's the pseudocode for the algorithm I have in my head:
+
+{{{
+
+for every target file T:
+  
+  find the rule chain R that will build the file. (there should only be one)
+  
+  starting from the final entry in the rule chain (e.g. the .chs.pp->.chs rule) and working backwards:
+    
+    call the current source file A, and the target file B. (e.g. A=.chs.pp, B=.chs)
+    if B is older than A:
+        for each file D that is needed to build B from A:
+            if D is already on the stack, bail out
+            otherwise, recurse on D
+        compile B
+
+}}}
+
+Of course, other things are needed, but I think this is a good starting point.