Fixed parsing error with sigma baryons

doc/source/changelog.rst

@@ -5,6 +5,13 @@ MontePy Changelog
 0.5 releases
 ============
 
+#Next Version#
+--------------
+
+**Bug Fixes**
+
+* Fixed parsing bug with sigma baryon particles (e.g., ``+/-``) (:issue:`671`).
+
 0.5.4
 --------------
 

montepy/input_parser/parser_base.py

@@ -381,6 +381,7 @@ def file_name(self, p):
         "FILE_PATH",
         "NUMBER",
         "PARTICLE",
+        "PARTICLE_SPECIAL",
         "INTERPOLATE",
         "JUMP",
         "KEYWORD",

montepy/input_parser/syntax_node.py

@@ -1483,7 +1483,7 @@ def _reverse_engineer_format(self):
                 if match.group(0).isupper():
                     upper_match += 1
                 total_match += 1
-        if upper_match / total_match >= 0.5:
+        if total_match and upper_match / total_match >= 0.5:
             self._formatter["upper"] = True
 
     @property

montepy/input_parser/tokens.py

@@ -220,6 +220,13 @@ def _parse_shortcut(self, t):
                 t.type = token_type
                 return t
 
+    @_(r"([|+\-!<>/%^_~@\*\?\#]|\#\d*)+")
+    def PARTICLE_SPECIAL(self, t):
+        """
+        Particle designators that are special characters.
+        """
+        return t
+
     INTERPOLATE = r"\d*I"
     """
     An interpolate shortcut.
@@ -511,13 +518,6 @@ class DataLexer(ParticleLexer):
     A keyword flag at the beginning of a input that modifies it's behavior.
     """
 
-    @_(r"([|+\-!<>/%^_~@\*\?\#]|\#\d*)+")
-    def PARTICLE_SPECIAL(self, t):
-        """
-        Particle designators that are special characters.
-        """
-        return t
-
     @_(r"[+\-]?[0-9]*\.?[0-9]*E?[+\-]?[0-9]*[ijrml]+[a-z\./]*", r"[a-z]+[a-z\./]*")
     def TEXT(self, t):
         t = super().TEXT(t)
@@ -609,6 +609,8 @@ class SurfaceLexer(MCNP_Lexer):
     All allowed surface types.
     """
 
+    PARTICLE_SPECIAL = None
+
     @_(r"[+\-]?[0-9]*\.?[0-9]*E?[+\-]?[0-9]*[ijrml]+[a-z\./]*", r"[a-z]+[a-z\./]*")
     def TEXT(self, t):
         t = super().TEXT(t)

tests/inputs/test_complement_edge.imcnp

@@ -9,9 +9,11 @@ C Bounding water outer capsule
 61482 0
       ( 6 #61440 ) : (#61461 ( 7: -8))
      U=6000 IMP:N=1
+      imp:+,-= 0
 61441 814 0.087
       (-61867 61870 -61759):(-61868 61869 -61759): (-61870 61868 -61759 61758)
       IMP:N=0
+      imp:+ = 1
 
 1 SO 5.0
 2 PZ 0.0
@@ -34,4 +36,4 @@ m814    26000.55c 5.657-2
         24000.50c 1.581-2
         25055.51c 1.760-3
 sdef cel=2 pos=0 0 0 rad=d3 ext=d3 axs=0 0 1
-
+mode n + -