Produce the whole file

Author: vkucera

Common/Constants/include/CommonConstants/make_pdg_header.py

@@ -18,6 +18,7 @@
 """
 
 import os
+import sys
 from ctypes import c_bool
 from enum import Enum
 
@@ -161,7 +162,7 @@ def mass(code):
 
 def declare_mass(pdg, val_type="double") -> str:
     """Returns a C++ declaration of a particle mass constant."""
-    return f"constexpr {val_type} Mass{pdg.name[1:]} = {mass(pdg.value)};\n"
+    return f"constexpr {val_type} Mass{pdg.name[1:]} = {mass(pdg.value)};"
 
 
 def main():
@@ -170,46 +171,88 @@ def main():
     name_script = os.path.basename(__file__)
 
     # Comment at the beginning of the output
-    str_block_begin = "// BEGINNING OF THE GENERATED BLOCK."
+    block_begin = "// BEGINNING OF THE GENERATED BLOCK."
     # Preamble with instructions
-    str_block_preamble = (
+    block_preamble = (
         "// DO NOT EDIT THIS BLOCK DIRECTLY!"
         f"\n// It has been generated by the {name_script} script."
-        "\n// For modifications, edit the script and generate this block again.\n"
+        "\n// For modifications, edit the script and generate this block again."
     )
     # Comment at the end of the output
-    str_block_end = "// END OF THE GENERATED BLOCK"
+    block_end = "// END OF THE GENERATED BLOCK"
     # Start of enum declarations of additional particles
-    str_enum_head = (
+    enum_o2_head = (
         "/// \\brief Declarations of named PDG codes of particles missing in ROOT PDG_t"
         "\n/// \\note Follow kCamelCase naming convention"
         "\n/// \\link https://root.cern/doc/master/TPDGCode_8h.html"
         "\nenum Pdg {"
     )
     # End of enum declarations of additional particles
-    str_enum_foot = "};\n"
+    enum_o2_foot = "};"
     # Documentation string for mass declarations of additional particles
-    str_mass_o2_head = "/// \\brief Declarations of masses for additional particles"
+    mass_o2_head = "/// \\brief Declarations of masses for additional particles"
     # Documentation string for mass declarations of PDG_t particles
-    str_mass_root_head = "/// \\brief Declarations of masses for particles in ROOT PDG_t"
+    mass_root_head = "/// \\brief Declarations of masses for particles in ROOT PDG_t"
+
+    # Get header content before and after the generated block.
+    path_header = "PhysicsConstants.h"
+    try:
+        with open(path_header, encoding="utf-8") as file:
+            content_old = file.readlines()
+    except OSError:
+        print(f'Failed to open file "{path_header}".')
+        sys.exit(1)
+    lines_header_before: list[str] = []
+    lines_header_after: list[str] = []
+    got_block_begin = False
+    got_block_end = False
+    for line in content_old:
+        line = line.strip()
+        if line == block_begin:
+            got_block_begin = True
+        if not got_block_begin:
+            lines_header_before.append(line)
+        if got_block_end:
+            lines_header_after.append(line)
+        if line == block_end:
+            got_block_end = True
+    if not got_block_begin:
+        raise ValueError("Did not find the beginning of the block.")
+    if not got_block_end:
+        raise ValueError("Did not find the end of the block.")
 
     # Additional particles
-    str_enum = str_enum_head
-    str_mass_o2 = str_mass_o2_head
-    for c in Pdg:
-        str_enum += f"  {c.name} = {c.value},\n"
-        str_mass_o2 += declare_mass(c)
-    str_enum = str_enum[:-2] + "\n"  # Remove the last comma.
-    str_enum += str_enum_foot
+    lines_enum_o2: list[str] = [enum_o2_head]
+    lines_mass_o2: list[str] = [mass_o2_head]
+    for pdg_o2 in Pdg:
+        lines_enum_o2.append(f"  {pdg_o2.name} = {pdg_o2.value},")
+        lines_mass_o2.append(declare_mass(pdg_o2))
+    lines_enum_o2[-1] = lines_enum_o2[-1][:-1]  # Remove the last comma.
+    lines_enum_o2.append(enum_o2_foot)
 
     # PDG_t particles
-    str_mass_root = str_mass_root_head
-    for d in PdgROOT:
-        str_mass_root += declare_mass(d)
+    lines_mass_root: list[str] = [mass_root_head]
+    for pdg_root in PdgROOT:
+        lines_mass_root.append(declare_mass(pdg_root))
 
     # Header body
-    str_header = "\n".join((str_block_begin, str_block_preamble, str_enum, str_mass_o2, str_mass_root, str_block_end))
-    print(str_header)
+    content_new = "\n".join(
+        (
+            *lines_header_before,
+            block_begin,
+            block_preamble,
+            "",
+            *lines_enum_o2,
+            "",
+            *lines_mass_o2,
+            "",
+            *lines_mass_root,
+            "",
+            block_end,
+            *lines_header_after,
+        )
+    )
+    print(content_new)
 
 
 if __name__ == "__main__":