From 224b77d4f786ea09bb2632476a89f0976baafd64 Mon Sep 17 00:00:00 2001
From: Maria Matejka <mq@ucw.cz>
Date: Thu, 20 Dec 2018 14:34:35 +0100
Subject: [PATCH] Filter refactoring: Converted condition to three-args
 instruction

---
 filter/config.Y | 12 +++++-------
 filter/f-inst.c | 14 ++++++--------
 filter/filter.c |  2 +-
 3 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/filter/config.Y b/filter/config.Y
index 200c1f416..05c6f8993 100644
--- a/filter/config.Y
+++ b/filter/config.Y
@@ -559,7 +559,7 @@ filter:
 
 where_filter:
    WHERE term {
-     /* Construct 'IF term THEN ACCEPT; REJECT;' */
+     /* Construct 'IF term THEN { ACCEPT; } ELSE { REJECT; }' */
      struct filter *f = cfg_alloc(sizeof(struct filter));
      struct f_inst *i, *acc, *rej;
      acc = f_new_inst(FI_PRINT_AND_DIE);	/* ACCEPT */
@@ -571,7 +571,7 @@ where_filter:
      i = f_new_inst(FI_CONDITION);			/* IF */
      i->a1.p = $2;
      i->a2.p = acc;
-     i->next = rej;
+     i->a3.p = rej;
      f->name = NULL;
      f->root = i;
      $$ = f;
@@ -1005,12 +1005,10 @@ cmd:
      $$->a2.p = $4;
    }
  | IF term THEN block ELSE block {
-     struct f_inst *i = f_new_inst(FI_CONDITION);
-     i->a1.p = $2;
-     i->a2.p = $4;
      $$ = f_new_inst(FI_CONDITION);
-     $$->a1.p = i;
-     $$->a2.p = $6;
+     $$->a1.p = $2;
+     $$->a2.p = $4;
+     $$->a3.p = $6;
    }
  | SYM '=' term ';' {
      DBG( "Ook, we'll set value\n" );
diff --git a/filter/f-inst.c b/filter/f-inst.c
index cee5b8e76..fc960198b 100644
--- a/filter/f-inst.c
+++ b/filter/f-inst.c
@@ -259,14 +259,12 @@
     ARG_ANY(1);
     val_format(v1, &fs->buf);
     break;
-  case FI_CONDITION:	/* ? has really strange error value, so we can implement if ... else nicely :-) */
-    ARG(1, T_BOOL);
-    if (v1.val.i) {
-      ARG_ANY(2);
-      res.val.i = 0;
-    } else
-      res.val.i = 1;
-    res.type = T_BOOL;
+  case FI_CONDITION:
+    ARG_T(1, 0, T_BOOL);
+    if (res.val.i)
+      ARG_ANY_T(2,0);
+    else
+      ARG_ANY_T(3,0);
     break;
   case FI_NOP:
     debug( "No operation\n" );
diff --git a/filter/filter.c b/filter/filter.c
index a1bb74157..3b3102574 100644
--- a/filter/filter.c
+++ b/filter/filter.c
@@ -793,7 +793,7 @@ i_same(struct f_inst *f1, struct f_inst *f2)
       return 0;
     break;
   case FI_PRINT: case FI_LENGTH: ONEARG; break;
-  case FI_CONDITION: TWOARGS; break;
+  case FI_CONDITION: THREEARGS; break;
   case FI_NOP: case FI_EMPTY: break;
   case FI_PRINT_AND_DIE: ONEARG; A2_SAME; break;
   case FI_PREF_GET:
-- 
2.39.2