From fccebd4724cf2265a9d63b6d5f96e3985cb40431 Mon Sep 17 00:00:00 2001
From: mhx <github@mhxnet.de>
Date: Mon, 25 Oct 2021 14:46:00 +0200
Subject: [PATCH] Fix constexpr accepts() implementation to be C++11 compliant
 (#452)

In C++11, `constexpr` functions must not contain compound statements.
This change makes the implementation of `message_packet::accepts` use
a single conjunction instead of a `switch` statement.

See https://gcc.godbolt.org/z/zKbsx3nY5.

Co-authored-by: John Wellbelove <jwellbelove@users.noreply.github.com>
---
 .../etl/generators/message_packet_generator.h | 24 +++++++++----------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/etl/generators/message_packet_generator.h b/include/etl/generators/message_packet_generator.h
index d29f5ef0..f4239fc1 100644
--- a/include/etl/generators/message_packet_generator.h
+++ b/include/etl/generators/message_packet_generator.h
@@ -367,16 +367,16 @@ namespace etl
 
   /*[[[cog
     import cog
-    def joined_elements(prefix, suffix, elem_fmt, joiner, elem_range, indent = None, chunk_size = 4):
-        if indent is None:
-            indent = ''
-        lines = [joiner.join([elem_fmt % i for i in r]) for r in [
-            elem_range[i:i + chunk_size] for i in range(0, len(elem_range), chunk_size)
-        ]]
-        for ix, line in enumerate(lines):
-            line = (prefix if ix == 0 else indent) + line
-            line += suffix if ix == len(lines) - 1 else joiner.rstrip()
-            cog.outl(line)
+    def accepts_return(num_id):
+        cog.out("    return")
+        for i in range(1, num_id + 1):
+            cog.out(" T%d::ID == id" % i)
+            if i < num_id:
+                cog.out(" ||")
+                if i % 4 == 0:
+                    cog.outl("")
+                    cog.out("          ")
+        cog.outl(";")
     ################################################
     # The first definition for all of the messages.
     ################################################
@@ -494,7 +494,7 @@ namespace etl
     cog.outl("  //**********************************************")
     cog.outl("  static ETL_CONSTEXPR bool accepts(etl::message_id_t id)")
     cog.outl("  {")
-    joined_elements('    return ', ';', 'T%d::ID == id', ' || ', range(1, int(Handlers) + 1), ' '*11)
+    accepts_return(int(Handlers))
     cog.outl("  }")
     cog.outl("")
     cog.outl("  //**********************************************")
@@ -721,7 +721,7 @@ namespace etl
         cog.outl("  //**********************************************")
         cog.outl("  static ETL_CONSTEXPR bool accepts(etl::message_id_t id)")
         cog.outl("  {")
-        joined_elements('    return ', ';', 'T%d::ID == id', ' || ', range(1, n + 1), ' '*11)
+        accepts_return(n)
         cog.outl("  }")
         cog.outl("")
         cog.outl("  //**********************************************")