* Class Parameters: important change of behavior for more safety to avoid

potential confusion.

* Detail of the important changes:

  1) by default now the function's local variables are not included in the
     lookup chain. Use _localvars_ flag if you insist on doing that; but
     be aware of the caveat (see Parameters' documentation).

  2) the default _kwparam_ and _userparam_ names are now passed on to the
     child Parameters object instead of the override values given through
     the _create_ function argument.
     Rationale: To begin with, the default names defined during the creation
     of the parent Parameters object should be used by *all* the relevant
     functions.
     Overrides should be regarded as exceptional rather than common cases.

  3) Value overrides (_kwparam_, _userparam_, etc.) in _create_ must now
     be specified in keyword=value manner rather than as positional argument.
     Rationale: Those overrides must be made conspicuous.
     The keyword=value approach also makes the code more resilient to minor
     API changes.
     All unnamed parameters are supposed to be low-priority defaults.

params/params_flat_test.py

@@ -1,8 +1,14 @@
-# $Id: params_flat_test.py,v 1.1 2010-09-30 16:16:38 wirawan Exp $
+# $Id: params_flat_test.py,v 1.2 2011-09-09 18:58:48 wirawan Exp $
 # 20100930
 
 from wpylib.params import flat as params
 
+global_defaults = params(
+  nbasis= 275,
+  npart= 29,
+  deltau= 0.01,
+)
+
 def test1():
   defaults = {
     'nbasis': 320,
@@ -10,7 +16,9 @@ def test1():
     'deltau': 0.025,
   }
   p = params(defaults, nbasis=332)
+  nbasis = 327
 
+  print "test1()"
   print "self-defined values = ", p
   print "nbasis = ", p.nbasis
   print "npart = ", p.npart
@@ -19,6 +27,37 @@ def test1():
   print "new deltau = ", p.deltau
 
 
+def test2(**_opts_):
+  p = global_defaults._create_(_localvars_=1)
+  nbasis = 327
+
+  print "test2()"
+  print "self-defined values = ", p
+  print "nbasis = ", p.nbasis  # gives 275 -- although _localvars_ already requested.
+  print "npart = ", p.npart
+  print "deltau = ", p.deltau
+  p.deltau = 0.01
+  print "new deltau = ", p.deltau
+
+
+def test2b(**_opts_):
+  nbasis = 327
+  p = global_defaults._create_(_localvars_=1)
+
+  nbasis = 3270
+
+  print "test2()"
+  print "self-defined values = ", p
+  print "nbasis = ", p.nbasis   # gives 327. Changes to local vars won't alter anything.
+  print "npart = ", p.npart
+  print "deltau = ", p.deltau
+  p.deltau = 0.01
+  print "new deltau = ", p.deltau
+
+
+
+
 if __name__ == "__main__":
   test1()
-
+  test2()
+  test2b()