Parsing lists or vectors with parentheses or brackets in units expressions fixed

Author: dprada

pyunitwizard/parse.py

@@ -5,6 +5,28 @@
 import ast
 from typing import Optional
 
+def _find_closing_bracket_position(string):
+    stack = 0
+    for i, char in enumerate(string):
+        if char == '[':
+            stack += 1
+        elif char == ']':
+            stack -= 1
+            if stack == 0:
+                return i
+    raise ValueError  # If there is no closing bracket
+
+def _find_closing_parenthesis_position(string):
+    stack = 0
+    for i, char in enumerate(string):
+        if char == '(':
+            stack += 1
+        elif char == ')':
+            stack -= 1
+            if stack == 0:
+                return i
+    raise ValueError  # If there is no closing parenthesis
+
 def _parse_with_pint(string: str):
     """ Parses a string and returns a pint quantity.
 
@@ -19,13 +41,22 @@ def _parse_with_pint(string: str):
             A pint quantity.
     """
     # Check if it's a non scalar quantity
-    if string.startswith('[') or string.startswith('('):
+    if string.startswith('['):
 
-        end_list = max(string.rfind(')')+1, string.rfind(']')+1)
-        value_string = string[:end_list]
-        unit_string = string[end_list:]
+        end_list = _find_closing_bracket_position(string)
+        value_string = string[:(end_list+1)]
+        unit_string = string[(end_list+1):]
 
         return ast.literal_eval(value_string)*dict_translate_quantity['string']['pint'](unit_string)
+
+    elif string.startswith('('):
+
+        end_list = _find_closing_parenthesis_position(string)
+        value_string = string[:(end_list+1)]
+        unit_string = string[(end_list+1):]
+
+        return ast.literal_eval(value_string)*dict_translate_quantity['string']['pint'](unit_string)
+
     else:
        return dict_translate_quantity['string']['pint'](string)
 

tests/test_parse.py

@@ -22,9 +22,9 @@ def test_parse_with_pint_array():
     assert np.allclose(quantity.magnitude, np.array([3, 2, 1]))
     assert str(quantity.units) == "meter"
 
-    quantity = _parse_with_pint("[[2, 5, 7], [7, 8, 9]] joules")
+    quantity = _parse_with_pint("[[2, 5, 7], [7, 8, 9]] kilojoules/(mol*nanometer)")
     assert np.allclose(quantity.magnitude, np.array([[2, 5, 7], [7, 8, 9]]))
-    assert str(quantity.units) == "joule"
+    assert str(quantity.units) == "kilojoule / mole / nanometer"
 
 def test_parse_to_pint():