Merge pull request #94 from lsst/tickets/DM-14503

DM-14503: Implement YAML I/O for PropertySet/List.

python/lsst/daf/persistence/baseYaml.py

@@ -0,0 +1,97 @@
+# This file is part of daf_persistence
+#
+# Developed for the LSST Data Management System.
+# This product includes software developed by the LSST Project
+# (http://www.lsst.org/).
+# See the COPYRIGHT file at the top-level directory of this distribution
+# for details of code ownership.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+"""This module defines YAML I/O for key lsst.daf.base classes."""
+
+import yaml
+
+import lsst.daf.base
+
+
+# YAML representers for key lsst.daf.base classes
+
+
+def dt_representer(dumper, data):
+    """Represent an lsst.daf.base.DateTime (as ISO8601-formatted string in TAI)
+    """
+    return dumper.represent_scalar(u'lsst.daf.base.DateTime',
+                                   data.toString(lsst.daf.base.DateTime.TAI))
+
+
+yaml.add_representer(lsst.daf.base.DateTime, dt_representer)
+
+
+def pl_representer(dumper, data):
+    """Represent an lsst.daf.base.PropertyList as an ordered sequence of
+    name/type/value/comment tuples)"""
+    result = lsst.daf.base.getstate(data)
+    return dumper.represent_sequence(u'lsst.daf.base.PropertyList', result,
+                                     flow_style=None)
+
+
+yaml.add_representer(lsst.daf.base.PropertyList, pl_representer)
+
+
+def ps_representer(dumper, data):
+    """Represent an lsst.daf.base.PropertySet as a mapping from names to
+    type/value pairs."""
+    result = lsst.daf.base.getstate(data)
+    return dumper.represent_sequence(u'lsst.daf.base.PropertySet', result,
+                                     flow_style=None)
+
+
+yaml.add_representer(lsst.daf.base.PropertySet, ps_representer)
+
+###############################################################################
+
+# YAML constructors for key lsst.daf.base classes
+
+
+def dt_constructor(loader, node):
+    """Construct an lsst.daf.base.DateTime from an ISO8601-formatted string in
+    TAI"""
+    dt = loader.construct_scalar(node)
+    return lsst.daf.base.DateTime(str(dt), lsst.daf.base.DateTime.TAI)
+
+
+yaml.add_constructor(u'lsst.daf.base.DateTime', dt_constructor)
+
+
+def pl_constructor(loader, node):
+    """Construct an lsst.daf.base.PropertyList from a pickle-state."""
+    pl = lsst.daf.base.PropertyList()
+    yield pl
+    state = loader.construct_sequence(node, deep=True)
+    lsst.daf.base.setstate(pl, state)
+
+
+yaml.add_constructor(u'lsst.daf.base.PropertyList', pl_constructor)
+
+
+def ps_constructor(loader, node):
+    """Construct an lsst.daf.base.PropertyList from a pickle-state."""
+    ps = lsst.daf.base.PropertySet()
+    yield ps
+    state = loader.construct_sequence(node, deep=True)
+    lsst.daf.base.setstate(ps, state)
+
+
+yaml.add_constructor(u'lsst.daf.base.PropertySet', ps_constructor)