Add custom code for CV_E* constants to convert-constants

Currently, the cluster verify errors are defined as follows:

CV_ECLUSTER_FOO = (TCLUSTER, "ECLUSTER_FOO", "description")

This means there's no standalone name for the string "ECLUSTER_FOO",
which makes it hard to derive automatically a type for this union in
Haskell.

There are three possible fixes:

- manually separate the CV_ECLUSTER_FOO_STR = "ECLUSTER_FOO" in
  constants.py
- manually extract the strings in Haskell code
- change convert-constants to automatically export virtual constants
  for those

After discussion on IRC, I've taken the latter approach; even though a
bit hack-ish, it avoids manual work and potential errors.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

diff --git a/autotools/convert-constants b/autotools/convert-constants
index 1d18540..e61a723 100755 (executable)
--- a/autotools/convert-constants
+++ b/autotools/convert-constants
@@ -231,6 +231,13 @@ def ConvertVariable(prefix, name, value, all_items):
                                      value[k], all_items))
   elif isinstance(value, tuple):
     tvs = [HaskellTypeVal(elem) for elem in value]
+    # Custom rule for special cluster verify error tuples
+    if name.startswith("CV_E") and len(value) == 3 and tvs[1][0] is not None:
+      cv_ename = hs_name + "Code"
+      lines.append("-- | Special cluster verify code %s" % name)
+      lines.append("%s :: %s" % (cv_ename, tvs[1][0]))
+      lines.append("%s = %s" % (cv_ename, tvs[1][1]))
+      lines.append("")
     if compat.all(e is not None for e in tvs):
       ttypes = ", ".join(e[0] for e in tvs)
       tvals = FormatListElems(all_items, pfx_name, value, [e[1] for e in tvs])