consumer.yaml config file; yaml loader in HARK.parser; smoke test

HARK/parser.py

@@ -1,5 +1,16 @@
+from HARK.distribution import Bernoulli, Lognormal, MeanOneLogNormal
 from sympy.utilities.lambdify import lambdify
 from sympy.parsing.sympy_parser import parse_expr
+import yaml
+
+
+class ControlToken:
+    """
+    Represents a parsed Control variable.
+    """
+
+    def __init__(self, args):
+        pass
 
 
 class Expression:
@@ -17,10 +28,40 @@ def func(self):
         return lambdify(list(self.expr.free_symbols), self.expr, "numpy")
 
 
+def tuple_constructor_from_class(cls):
+    def constructor(loader, node):
+        value = loader.construct_mapping(node)
+        return (cls, value)
+
+    return constructor
+
+
 def math_text_to_lambda(text):
     """
     Returns a function represented by the given mathematical text.
     """
     expr = parse_expr(text)
     func = lambdify(list(expr.free_symbols), expr, "numpy")
     return func
+
+
+def harklang_loader():
+    """Add constructors to PyYAML loader."""
+    loader = yaml.SafeLoader
+    yaml.SafeLoader.add_constructor(
+        "!Bernoulli", tuple_constructor_from_class(Bernoulli)
+    )
+    yaml.SafeLoader.add_constructor(
+        "!MeanOneLogNormal", tuple_constructor_from_class(MeanOneLogNormal)
+    )
+    yaml.SafeLoader.add_constructor(
+        "!Lognormal", tuple_constructor_from_class(Lognormal)
+    )
+    yaml.SafeLoader.add_constructor(
+        "!Control", tuple_constructor_from_class(ControlToken)
+    )
+
+    return loader
+
+
+########################################################################

HARK/tests/test_parser.py

@@ -0,0 +1,51 @@
+import os
+import unittest
+
+
+import HARK.parser as parser
+import yaml
+
+
+class test_consumption_parsing(unittest.TestCase):
+    def setUp(self):
+        this_file_path = os.path.dirname(__file__)
+        consumer_yaml_path = os.path.join(this_file_path, "../models/consumer.yaml")
+
+        self.consumer_yaml_file = open(consumer_yaml_path, "r")
+
+    def test_parse(self):
+        self.consumer_yaml_file
+
+        config = yaml.load(self.consumer_yaml_file, Loader=parser.harklang_loader())
+        pass
+
+        """
+        try:
+            config = yaml.load(open('perfect_foresight_full_experimental.yaml', 'r'), Loader= get_loader())
+
+            # data is copied
+            assert config['model']['blocks']['consumption'] == config['model']['strategies'][1]['block']
+            # data is maintained once in memory and referenced in both places
+            assert config['model']['blocks']['consumption'] is config['model']['strategies'][1]['block']
+
+            # object created by parser
+            c1 = config['model']['blocks']['consumption']['dynamics']['c']
+            c2 = config['model']['strategies'][1]['block']['dynamics']['c']
+
+            # objects are equal
+            assert c1 == c2
+            # objects are identical in memory; the reference is shared.
+                assert c1 is c2
+
+            a_str = config['model']['blocks']['consumption']['dynamics']['a']
+            a_expr = parse_expr(a_str)
+            a_func = lambdify(list(a_expr.free_symbols), a_expr, "numpy")
+
+            m = np.random.random(100)
+            c = np.random.random(100)
+
+            #import pdb; pdb.set_trace()
+
+        except yaml.YAMLError as exc:
+            print("Error in configuration file:", exc)
+        """

requirements/base.txt

@@ -5,6 +5,7 @@ networkx>=3
 numba<0.60.0
 numpy>=1.23
 pandas>=1.5
+pyyaml>=6.0
 quantecon
 scipy>=1.10
 seaborn>=0.12