Fix conversion of repeat shortcut to handle non-integers

Author: paulromano

src/openmc_mcnp_adapter/parse.py

@@ -44,9 +44,27 @@
 _SAB_RE = re.compile(r'\s*[Mm][Tt](\d+)((?:\s+\S+)+)')
 _MODE_RE = re.compile(r'\s*mode(?:\s+\S+)*')
 _COMPLEMENT_RE = re.compile(r'(#)[ ]*(\d+)')
-_REPEAT_RE = re.compile(r'(\d+)\s+(\d+)[rR]')
 _NUM_RE = re.compile(r'(\d)([+-])(\d)')
 
+_REPEAT_RE = re.compile(r"""
+    (?P<value>                  # The numeric value to be repeated
+      [+-]?                     #   Optional sign
+      (?:                       #   Mantissa
+        \d+(?:\.\d*)?           #     Digits with optional fractional part (e.g., 3 or 3. or 3.0)
+        |                       #     or
+        \.\d+                   #     Leading-dot form (e.g., .25)
+      )
+      (?:                       #   Optional exponent
+        [eEdD][+-]?\d+          #     E/D exponent with optional sign (e.g., 1e-3, 2D+3)
+        |                       #     or MCNP "bare" exponent without E/D
+        [+-]\d+                 #     appended sign+digits (e.g., 1.0-3 -> 1.0e-3)
+      )?
+    )
+    \s+                         # One or more spaces between value and count
+    (?P<count>\d+)              # The repeat count
+    [rR]                        # The 'R' or 'r' suffix
+""", re.VERBOSE)
+
 
 def float_(val):
     """Convert scientific notation literals that don't have an 'e' in them to float"""
@@ -346,11 +364,11 @@ def sanitize(section: str) -> str:
     section = re.sub('\n {5}', ' ', section)
 
     # Expand repeated numbers
-    m = _REPEAT_RE.search(section)
-    while m is not None:
-        section = _REPEAT_RE.sub(' '.join((int(m.group(2)) + 1)*[m.group(1)]),
-                                 section, 1)
-        m = _REPEAT_RE.search(section)
+    section = _REPEAT_RE.sub(
+        lambda m: ' '.join([m.group('value')] * (int(m.group('count')) + 1)),
+        section,
+    )
+
     return section
 
 

tests/test_syntax.py

@@ -0,0 +1,25 @@
+from textwrap import dedent
+
+from openmc_mcnp_adapter import mcnp_str_to_model
+
+
+def test_repeat_shortcut():
+    mcnp_str = dedent("""
+    title
+    1   0 -1
+
+    1   gq  1.0 3r 0.0 5r
+
+    m1   1001.80c  3.0
+    """)
+    model = mcnp_str_to_model(mcnp_str)
+    surf = model.geometry.get_all_surfaces()[1]
+    print(surf)
+
+    # Make sure A, B, C, and D parameters are 1.0
+    for attr in 'abcd':
+        assert getattr(surf, attr) == 1.0
+
+    # Make sure E, F, G, H, J, and K parameters are 0.0
+    for attr in 'efghj':
+        assert getattr(surf, attr) == 0.0