lsst.daf.base  17.0.1-1-gaef33af+2
yaml.py
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1 # This file is part of daf_base
2 #
3 # Developed for the LSST Data Management System.
4 # This product includes software developed by the LSST Project
5 # (http://www.lsst.org/).
6 # See the COPYRIGHT file at the top-level directory of this distribution
7 # for details of code ownership.
8 #
9 # This program is free software: you can redistribute it and/or modify
10 # it under the terms of the GNU General Public License as published by
11 # the Free Software Foundation, either version 3 of the License, or
12 # (at your option) any later version.
13 #
14 # This program is distributed in the hope that it will be useful,
15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 # GNU General Public License for more details.
18 #
19 # You should have received a copy of the GNU General Public License
20 # along with this program. If not, see <http://www.gnu.org/licenses/>.
21 
22 """This module defines YAML I/O for key lsst.daf.base classes."""
23 
24 # If yaml package is not installed there is no reason to fail everywhere
25 try:
26  import yaml
27 except ImportError:
28  yaml = None
29 
30 from .dateTime import DateTime
31 from .propertyContainer import PropertyList, getPropertyListState, setPropertyListState, \
32  getPropertySetState, setPropertySetState, PropertySet
33 
34 # For YAML >= 5.1 need a different Loader for the constructor
35 loaderList = []
36 if yaml:
37  loaderList = [yaml.Loader, yaml.CLoader]
38  try:
39  loaderList.append(yaml.FullLoader)
40  except AttributeError:
41  pass
42  try:
43  loaderList.append(yaml.UnsafeLoader)
44  except AttributeError:
45  pass
46 
47 
48 # YAML representers for key lsst.daf.base classes
49 
50 
51 def dt_representer(dumper, data):
52  """Represent an lsst.daf.base.DateTime (as ISO8601-formatted string in TAI)
53  """
54  return dumper.represent_scalar('lsst.daf.base.DateTime',
55  data.toString(DateTime.TAI))
56 
57 
58 if yaml:
59  yaml.add_representer(DateTime, dt_representer)
60 
61 
62 def pl_representer(dumper, data):
63  """Represent an lsst.daf.base.PropertyList as an ordered sequence of
64  name/type/value/comment lists)"""
65  # Turn the tuples into lists for cleaner representation in yaml
66  result = getPropertyListState(data, asLists=True)
67  return dumper.represent_sequence('lsst.daf.base.PropertyList', result,
68  flow_style=None)
69 
70 
71 if yaml:
72  yaml.add_representer(PropertyList, pl_representer)
73 
74 
75 def ps_representer(dumper, data):
76  """Represent an lsst.daf.base.PropertySet as a mapping from names to
77  type/value pairs."""
78  # Turn the tuples into lists for cleaner representation in yaml
79  result = getPropertySetState(data, asLists=True)
80  return dumper.represent_sequence('lsst.daf.base.PropertySet', result,
81  flow_style=None)
82 
83 
84 if yaml:
85  yaml.add_representer(PropertySet, ps_representer)
86 
87 
88 
89 # YAML constructors for key lsst.daf.base classes
90 
91 
92 def dt_constructor(loader, node):
93  """Construct an lsst.daf.base.DateTime from an ISO8601-formatted string in
94  TAI"""
95  dt = loader.construct_scalar(node)
96  return DateTime(str(dt), DateTime.TAI)
97 
98 
99 def pl_constructor(loader, node):
100  """Construct an lsst.daf.base.PropertyList from a YAML pickle-like structure."""
101  pl = PropertyList()
102  yield pl
103  state = loader.construct_sequence(node, deep=True)
104  setPropertyListState(pl, state)
105 
106 
107 def ps_constructor(loader, node):
108  """Construct an lsst.daf.base.PropertyList from a YAML pickle-like structure."""
109  ps = PropertySet()
110  yield ps
111  state = loader.construct_sequence(node, deep=True)
112  setPropertySetState(ps, state)
113 
114 
115 if yaml:
116  for loader in loaderList:
117  yaml.add_constructor('lsst.daf.base.PropertyList', pl_constructor, Loader=loader)
118  yaml.add_constructor('lsst.daf.base.PropertySet', ps_constructor, Loader=loader)
119  yaml.add_constructor('lsst.daf.base.DateTime', dt_constructor, Loader=loader)
def pl_representer(dumper, data)
Definition: yaml.py:62
def dt_representer(dumper, data)
Definition: yaml.py:51
def ps_representer(dumper, data)
Definition: yaml.py:75
Class for storing generic metadata.
Definition: PropertySet.h:68