actual recursive unification for transforms

Still stops at the first solution but that's not too bad.

.gitignore

@@ -0,0 +1 @@
+test/

Makefile

@@ -0,0 +1,14 @@
+#! /usr/bin/env make -f
+
+py = g35pe2_ml_patch.py
+src = $(filter-out $(wildcard test/*-E2.g1a),$(wildcard test/*.g1a))
+out = $(src:.g1a=-E2.g1a)
+
+test: $(out)
+
+test/%-E2.g1a: test/%.g1a $(py)
+	@echo -e "\n\e[33;1mPatching $<...\x1b[0m"
+	@ python $(py) $< $@
+
+# Always redo all the tests
+.PHONY: test

g35pe2_ml_patch.py

@@ -104,29 +104,39 @@ class Transform:
         self.insn = [(make_pattern(p), make_pattern(repl))
                      for p, repl in patterns]
 
+def match_transform_recursive(insn, vars, offsets, data, start, end):
+    if not insn:
+        return (vars, offsets)
+
+    p, repl = insn[0]
+    n = len(p.nibbles) // 2
+    insn = insn[1:]
+
+    # Try all matching offsets
+    for offset in range(start, end, 2):
+        d = data[offset:offset+n]
+        v = match_pattern(p, d, vars)
+        if v != False:
+            o = offsets + [offset]
+            v2, o2 = match_transform_recursive(insn, v, o, data, start, end)
+            if v2 != False:
+                # TODO: Yield here to explore all options
+                return (v2, o2)
+
+    return (False, [])
+
+
 def match_transform(tr, base_vars, data, start, end):
     """Matches all instructions from <tr> in <data> between <start> and <end>,
        returning either (False, []) or a pair (<vars>, [<offset>...])
-       indicating where instructions matched and with what variables."""
+       indicating where instructions matched and with what variables. Only the
+       first solution found to the unification problem is returned."""
 
     start, end = align(start, end, 2)
     vars = base_vars.copy()
     offsets = []
 
-    for p, repl in tr.insn:
-        n = len(p.nibbles) // 2
-
-        for offset in range(start, end, 2):
-            d = data[offset:offset+n]
-            v = match_pattern(p, d, vars)
-            if v != False:
-                offsets.append(offset)
-                vars = v
-                break
-        else:
-            return (False, [])
-
-    return (vars, offsets)
+    return match_transform_recursive(tr.insn, vars, offsets, data, start, end)
 
 def apply_transform(tr, vars, offsets, data):
     """Apply replacements from <tr> on <data> in-place, using the <offsets> and