added some docs + tests and refactored some code. Also removed Delaye…

…d class.

decorators.py

@@ -0,0 +1,111 @@
+from functools import wraps
+
+
+#
+# Decorators
+#
+
+def onetime(varname: str):
+    """
+    Prevents basic Python types from being changed after setting.
+    Numpy arrays also need the read-only flag set on them.
+    For use with Python setters, must be decorated before (closer to the function) @setter is
+    called.
+
+    Parameters
+    ----------
+    varname
+        Name of the variable being tested. It does not need to be defined at interpretation
+        time.
+
+    Returns
+    -------
+
+    """
+
+    def decorator(func):
+        @wraps(func)
+        def wrapper(self, *args, **kwargs):
+            if getattr(self, varname, None) is not None:
+                print("Trying to set a one-time attribute {varname}. Ignored")
+                return
+            func(self, *args, **kwargs)
+
+        return wrapper
+
+    return decorator
+
+
+def cache(varname: str):
+    """
+    Returns a variable if it is already defined. Otherwise, it calls the code in the property.
+    Must be decorated before (closer to the function) @property.
+
+    Parameters
+    ----------
+    varname
+        Name of variable to cache. It does not need to be defined at interpretation.
+
+    Returns
+    -------
+
+    """
+
+    def decorator(func):
+        @wraps(func)
+        def wrapper(self, *args, **kwargs):
+            val = getattr(self, varname, None)
+            if val is None:
+                val = func(self, *args, **kwargs)
+                setattr(self, varname, val)
+            return val
+
+        return wrapper
+
+    return decorator
+
+
+def delayed(func):
+    """
+    Safety check to make sure the instance has the second stage of instantiation.
+    The function decorated will return AttributeError if the function with @finalize has not
+    been called yet.
+
+    Parameters
+    ----------
+    func
+
+    Returns
+    -------
+
+    """
+
+    @wraps(func)
+    def wrapper(self, *args, **kwargs):
+        if not getattr(self, "init_finished", False):
+            print("Instance must finalize instantiation before calling compute functions.")
+            raise AttributeError
+        return func(self, *args, **kwargs)
+
+    return wrapper
+
+
+def finalize(func):
+    """
+    When the function decorated completes, the instance will be marked as fully instantiated.
+
+    Parameters
+    ----------
+    func
+
+    Returns
+    -------
+
+    """
+
+    @wraps(func)
+    def wrapper(self, *args, **kwargs):
+        func(self, *args, **kwargs)
+        self.init_finished = True
+
+    return wrapper

example_glue.py

@@ -2,76 +2,25 @@
 import grid
 import iodata
 import numpy as np
-from functools import wraps
+from abc import ABCMeta
 from meanfield import *
 
 
-#
-# Decorators
-#
-
-def onetime(varname):
-    def decorator(func):
-        @wraps(func)
-        def wrapper(self, *args, **kwargs):
-            if getattr(self, varname) is not None:
-                print("Trying to set a one-time attribute {varname}. Ignored")
-                return
-            func(self, *args, **kwargs)
-
-        return wrapper
-
-    return decorator
-
-
-def cache(varname):
-    def decorator(func):
-        @wraps(func)
-        def wrapper(self, *args, **kwargs):
-            if getattr(self, varname) is None:
-                val = func(self, *args, **kwargs)
-                setattr(self, varname, val)
-            return getattr(self, varname)
-
-        return wrapper
-
-    return decorator
-
-
-def delayed(func):
-    @wraps(func)
-    def wrapper(self, *args, **kwargs):
-        if not self.init_finished:
-            print("Instance must finalize instantiation before calling compute functions.")
-            raise AttributeError
-        return func(self, *args, **kwargs)
-
-    return wrapper
-
-
-def finalize(func):
-    @wraps(func)
-    def wrapper(self, *args, **kwargs):
-        func(self, *args, **kwargs)
-        self.init_finished = True
-
-    return wrapper
-
-
 #
 # Options classes
 #
 
-class Options:
+class Options(metaclass=ABCMeta):
+    """
+    Users instantiate child classes of this class to specify which options they want
+    for calculations.
+    """
+
     # __init__ is for options. finish_init is for inputs used in calculations.
     def finish_init(self):
         raise NotImplementedError
 
 
-class DelayedInit:
-    init_finished = False
-
-
 class Molecule(Options):
     def __init__(self, coords, atomic_numbers, pseudo_numbers=None, charge=None, multiplicity=None):
         self._coords = coords
@@ -90,6 +39,9 @@ def __init__(self, coords, atomic_numbers, pseudo_numbers=None, charge=None, mul
 
         self._multiplicity = multiplicity or default_multiplicity
 
+    def finish_init(self):
+        pass
+
     @classmethod
     def from_file(cls, filename):
         # TODO: load from file
@@ -143,7 +95,7 @@ def nelec_beta(self):
         return self.nelec[1]
 
 
-class Basis(Options, DelayedInit):
+class Basis(Options):
     def __init__(self, bset=None):
         """Specify basis set options.
         bset can be a string containing the basis set name, or a nested tuple like ((int, string),)
@@ -243,7 +195,7 @@ def make_guess(self):
         guess_core_hamiltonian(self._olp, self._one, *self._orbs)
 
 
-class Grid(Options, DelayedInit):
+class Grid(Options):
     def __init__(self, accuracy='coarse'):
         self._accuracy = accuracy
 
@@ -260,7 +212,7 @@ def grid(self):
         return self._grid
 
 
-class Orbitals(Options, DelayedInit):
+class Orbitals(Options):
     def __init__(self, spin="U"):
         self._spin = spin
 
@@ -316,7 +268,7 @@ def __init__(self, *args, **kwargs):
 # Compute classes
 #
 
-class Method:
+class Method(Options):
     def __init__(self):
         self._ham = None
         self._basis = None
@@ -349,7 +301,7 @@ def _calculate_energy(self):
         return self._ham.energy
 
 
-class HF(Options, Method, DelayedInit):
+class HF(Method):
     @finalize
     def finish_init(self, coords, basis, scf, occ_model, orb, grid):
         super().finish_init(coords, basis, scf)
@@ -379,7 +331,7 @@ def finish_init(self, coords, basis, scf, occ_model, orb, grid):
             raise NotImplementedError
 
 
-class DFT(Options, Method, DelayedInit):
+class DFT(Method):
     def __init__(self, xc=None, x=None, c=None, frac=None):
         if xc and (x or c or frac):
             print("Cannot specify xc and also x or c functionals or exchange fraction")

test/test_example_glue.py

@@ -0,0 +1,52 @@
+from numpy.testing import assert_raises
+
+from decorators import onetime, cache, delayed, finalize
+
+
+def test_onetime():
+    class A:
+        _x = 5
+
+        @property
+        def x(self):
+            return self._x
+
+        @x.setter
+        @onetime("_x")
+        def x(self, y):
+            self._x = y
+
+    a = A()
+    a.x = 10
+    assert a.x == 5
+
+
+def test_cache():
+    class A:
+        _x = 5
+
+        @property
+        @cache("_x")
+        def x(self):
+            return 10
+
+    a = A()
+    assert a.x == 5
+
+
+def test_delayed_finalize():
+    class A:
+        @finalize
+        def finish(self):
+            pass
+
+        @delayed
+        def do(self):
+            pass
+
+    a = A()
+    with assert_raises(AttributeError):
+        a.do()
+
+    a.finish()
+    a.do()