From c09f2e4c7bcb242ca7f320be5777e7bd641f78ec Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Wed, 30 Dec 2020 09:10:05 +0100
Subject: [PATCH] %merge: delegate the generation of calls to mergers to m4

Don't generate C code from bison, leave that to the skeletons.

* src/output.c (merger_output): Emit invocations to b4_call_merger.
* data/skeletons/glr.c, data/skeletons/glr2.cc (b4_call_merger): New.
---
 data/skeletons/glr.c   | 11 ++++++++++-
 data/skeletons/glr2.cc |  8 ++++++++
 src/output.c           |  8 ++------
 3 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/data/skeletons/glr.c b/data/skeletons/glr.c
index 78e255e1..08dd7817 100644
--- a/data/skeletons/glr.c
+++ b/data/skeletons/glr.c
@@ -1,4 +1,4 @@
-                                                                    -*- C -*-
+#                                                             -*- C -*-
 
 # GLR skeleton for Bison
 
@@ -147,6 +147,15 @@ m4_define([b4_rhs_location],
 [(b4_rhs_data([$1], [$2]).yyloc)])
 
 
+# b4_call_merger(MERGER-NUM, MERGER-NAME, SYMBOL-SUM)
+# ---------------------------------------------------
+m4_define([b4_call_merger],
+[b4_case([$1],
+         [    b4_symbol_if([$3], [has_type],
+                           [yy0->b4_symbol($3, type) = $2 (*yy0, *yy1);],
+                           [*yy0 = $2 (*yy0, *yy1);])])])
+
+
 ## -------------- ##
 ## Declarations.  ##
 ## -------------- ##
diff --git a/data/skeletons/glr2.cc b/data/skeletons/glr2.cc
index 4f476124..8210c628 100644
--- a/data/skeletons/glr2.cc
+++ b/data/skeletons/glr2.cc
@@ -122,6 +122,14 @@ m4_define([b4_rhs_location],
 [(b4_rhs_data([$1], [$2]).yyloc)])
 
 
+# b4_call_merger(MERGER-NUM, MERGER-NAME, SYMBOL-SUM)
+# ---------------------------------------------------
+m4_define([b4_call_merger],
+[b4_case([$1],
+         [    b4_symbol_if([$3], [has_type],
+                           [yy0->b4_symbol($3, type) = $2 (*yy0, *yy1);],
+                           [*yy0 = $2 (*yy0, *yy1);])])])
+
 # b4_lex
 # ------
 # Call yylex.
diff --git a/src/output.c b/src/output.c
index e58d8b75..1d63c043 100644
--- a/src/output.c
+++ b/src/output.c
@@ -554,12 +554,8 @@ merger_output (FILE *out)
   int n;
   merger_list* p;
   for (n = 1, p = merge_functions; p != NULL; n += 1, p = p->next)
-    if (p->sym && p->sym->content->type_name)
-      fprintf (out, "  case %d: yy0->%s = %s (*yy0, *yy1); break;\n",
-               n, p->sym->content->type_name, p->name);
-    else
-      fprintf (out, "  case %d: *yy0 = %s (*yy0, *yy1); break;\n",
-               n, p->name);
+    fprintf (out, "]b4_call_merger([%d], [%s], [%d])[\n",
+             n, p->name, p->sym->content->number);
   fputs ("]])\n\n", out);
 }