Allowed programmatic access to parser

Author: tcstewar

pytry/cmdline.py

@@ -1,68 +1,37 @@
 import argparse
 import sys
 
-import pytry
+from . import parser
+from . import trial
 
 
 def run():
-    parser = argparse.ArgumentParser(
+    parser1 = argparse.ArgumentParser(
         description='pytry: Run Trials with parameters')
-    parser.add_argument('filename', metavar='FILE', type=str, nargs=1,
-                        help='.py file containing Trial object')
+    parser1.add_argument('filename', metavar='FILE', type=str, nargs=1,
+                         help='.py file containing Trial object')
 
     if len(sys.argv) < 2:
-        parser.parse_args()   # this will fail with an error message
+        parser1.parse_args()   # this will fail with an error message
     filename = sys.argv[1]
 
     with open(filename) as f:
         code = f.read()
-    objs = dict(__file__ = filename)
+    objs = dict(__file__=filename)
     compiled = compile(code, filename, 'exec')
     exec(compiled, objs)
 
     trials = []
     for x in objs.values():
         if isinstance(x, type):
-            if issubclass(x, pytry.Trial):
+            if issubclass(x, trial.Trial):
                 trials.append(x)
 
     if len(trials) == 0:
         print('Error: no pytry.Trial class found in %s' % filename)
     elif len(trials) > 1:
         print('Error: more than one pytry.Trial class found')
     else:
-        trial = trials[0]()
-        run_trial(trial, parser)
-
-
-def str2bool(text):
-    return text.lower() in ("yes", "true", "t", "1")
-
-
-def run_trial(trial, parser):
-    keys = list(trial.param_defaults.keys())
-
-    for k in sorted(keys, key=lambda x: (x in trial.system_params, x)):
-        v = trial.param_defaults[k]
-        desc = '%s (default=%r)' % (trial.param_descriptions[k], v)
-
-        if v is False:
-            parser.add_argument('--%s' % k, default=v,
-                                action='store_true',
-                                help=desc)
-        elif v is True:
-            parser.add_argument('--%s' % k, default=v,
-                                metavar='<X>',
-                                type=str2bool,
-                                action='store',
-                                help=desc)
-        else:
-            parser.add_argument('--%s' % k, type=type(v), default=v,
-                                metavar='<X>', action='store',
-                                help=desc)
-
-    args = parser.parse_args()
-    params = vars(args)
-    del params['filename']
-
-    trial.run(**params)
+        t = trials[0]()
+        args = parser.parse_args(t, args=None, allow_filename=True)
+        t.run(**args)

pytry/parser.py

@@ -0,0 +1,46 @@
+import argparse
+
+
+def str2bool(text):
+    if text.lower() in ("yes", "true", "t", "1"):
+        return True
+    elif text.lower() in ("no", "false", "f", "0"):
+        return False
+    else:
+        raise ValueError("invalid boolean value: '%s'" % text)
+
+
+def parse_args(trial, args, allow_filename=False):
+    parser = argparse.ArgumentParser(
+        description='pytry: Run Trials with parameters')
+
+    if allow_filename:
+        parser.add_argument('filename', metavar='FILE', type=str, nargs=1,
+                            help='.py file containing Trial object')
+
+    keys = list(trial.param_defaults.keys())
+
+    for k in sorted(keys, key=lambda x: (x in trial.system_params, x)):
+        v = trial.param_defaults[k]
+        desc = '%s (default=%r)' % (trial.param_descriptions[k], v)
+
+        if v is False:
+            parser.add_argument('--%s' % k, default=v,
+                                action='store_true',
+                                help=desc)
+        elif v is True:
+            parser.add_argument('--%s' % k, default=v,
+                                metavar='<X>',
+                                type=str2bool,
+                                action='store',
+                                help=desc)
+        else:
+            parser.add_argument('--%s' % k, type=type(v), default=v,
+                                metavar='<X>', action='store',
+                                help=desc)
+
+    args = parser.parse_args(args)
+    params = vars(args)
+    if allow_filename:
+        del params['filename']
+    return params

pytry/tests/test_parser.py

@@ -0,0 +1,48 @@
+import pytest
+
+import pytry
+
+class DummyTrial(pytry.Trial):
+    def params(self):
+        self.param('a', a=0)
+        self.param('b', b=0.0)
+        self.param('c', c='')
+        self.param('d', d=True)
+        self.param('e', e=False)
+    def evaluate(self, p):
+        return {}
+
+def test_parse_valid():
+    t = DummyTrial()
+
+    p = t.parse_args('--a 1 --b 0.5 --c hi --d False --e'.split())
+    assert p['a'] == 1
+    assert p['b'] == 0.5
+    assert p['c'] == 'hi'
+    assert p['d'] == False
+    assert p['e'] == True
+
+    p = t.parse_args([])
+    assert p['a'] == 0
+    assert p['b'] == 0.0
+    assert p['c'] == ''
+    assert p['d'] == True
+    assert p['e'] == False
+
+def test_parse_unknown_param():
+    t = DummyTrial()
+
+    with pytest.raises(SystemExit):
+        t.parse_args('--x 1')
+
+def test_parse_invalid_value():
+    t = DummyTrial()
+
+    with pytest.raises(SystemExit):
+        t.parse_args('--a hi'.split())
+    with pytest.raises(SystemExit):
+        t.parse_args('--a 1.5'.split())
+    with pytest.raises(SystemExit):
+        t.parse_args('--b hi'.split())
+    with pytest.raises(SystemExit):
+        t.parse_args('--d 1.2'.split())

pytry/trial.py

@@ -4,6 +4,7 @@
 import uuid
 
 from . import write
+from . import parser
 
 
 class Params(object):
@@ -22,7 +23,8 @@ def __init__(self):
     def _create_base_params(self):
         self.param('data directory', data_dir='data', system=True)
         self.param('filename for data', data_filename=None, system=True)
-        self.param('data file format [txt,npz]', data_format='txt', system=True)
+        self.param('data file format [txt,npz]',
+                   data_format='txt', system=True)
         self.param('print progress information', verbose=True, system=True)
         self.param('random number seed', seed=1)
 
@@ -108,6 +110,9 @@ def do_evaluate(self, p):
     def execute_trial(self, p):
         return self.do_evaluate(p)
 
+    def parse_args(self, args=None):
+        return parser.parse_args(self, args)
+
     def params(self):
         raise NotImplementedError