[12] allow template operations

VERSION

@@ -1 +1 @@
-1.18.2-develop11
+1.18.2-develop12

modules/meta.py

@@ -474,8 +474,16 @@ class DataFile:
                                 return og_txt
                             elif str(og_txt) == f"<<{var}>>":
                                 return actual_value
-                            elif f"<<{var}>>" in str(og_txt):
+                            elif f"<<{var}" in str(og_txt):
-                                return str(og_txt).replace(f"<<{var}>>", str(actual_value))
+                                final = str(og_txt).replace(f"<<{var}>>", str(actual_value)) if f"<<{var}>>" in str(og_txt) else str(og_txt)
+                                if f"<<{var}" in final:
+                                    match = re.search(f"<<({var}([+-])(\d+))>>", final)
+                                    if match:
+                                        try:
+                                            final = final.replace(f"<<{match.group(1)}>>", str(int(actual_value) + (int(match.group(3)) * (-1 if match.group(2) == "-" else 1))))
+                                        except ValueError:
+                                            raise Failed(f"Template Error: {actual_value} must be a number to use {match.group(1)}")
+                                return final
                             else:
                                 return og_txt
                         if _debug: