From f567e99f3372d86d4feac2626e34ac8e8cbdb1b0 Mon Sep 17 00:00:00 2001
From: Maria Matejka <mq@ucw.cz>
Date: Mon, 19 Jun 2023 17:24:30 +0200
Subject: [PATCH] Filter: Print instructions take only one value
 (simplification)

---
 filter/config.Y | 33 +++++++--------------------------
 filter/f-inst.c |  9 ++++-----
 filter/f-inst.h |  1 +
 filter/f-util.c | 25 +++++++++++++++++++++++++
 4 files changed, 37 insertions(+), 31 deletions(-)

diff --git a/filter/config.Y b/filter/config.Y
index 0014b4bd..9dd59471 100644
--- a/filter/config.Y
+++ b/filter/config.Y
@@ -373,7 +373,7 @@ CF_KEYWORDS(FUNCTION, PRINT, PRINTN, UNSET, RETURN,
 %nonassoc ELSE
 
 %type <xp> cmds_int cmd_prep
-%type <x> term cmd cmd_var cmds cmds_scoped constant constructor print_list var var_init var_list function_call symbol_value bgp_path_expr bgp_path bgp_path_tail term_dot_method method_name_cont
+%type <x> term cmd cmd_var cmds cmds_scoped constant constructor var var_init var_list function_call symbol_value bgp_path_expr bgp_path bgp_path_tail term_dot_method method_name_cont
 %type <fda> dynamic_attr
 %type <fsa> static_attr
 %type <f> filter where_filter
@@ -955,16 +955,6 @@ break_command:
  | ERROR { $$ = F_ERROR; }
  ;
 
-print_list: /* EMPTY */ { $$ = NULL; }
- | term { $$ = $1; }
- | term ',' print_list {
-     ASSERT($1);
-     ASSERT($1->next == NULL);
-     $1->next = $3;
-     $$ = $1;
-   }
- ;
-
 var_init:
    /* empty */ { $$ = f_const_empty(this_var_type); }
  | '=' term { $$ = $2; }
@@ -1041,23 +1031,14 @@ cmd:
  | UNSET '(' dynamic_attr ')' ';' {
      $$ = f_new_inst(FI_EA_UNSET, $3);
    }
- | break_command print_list ';' {
-    struct f_inst *breaker = f_new_inst(FI_DIE, $1);
-    if ($2) {
-      struct f_inst *printer = f_new_inst(FI_PRINT, $2);
-      struct f_inst *flusher = f_new_inst(FI_FLUSH);
-      printer->next = flusher;
-      flusher->next = breaker;
-      $$ = printer;
-    } else
-      $$ = breaker;
+ | break_command var_list ';' {
+    $$ = f_print($2, !!$2, $1);
    }
- | PRINT print_list ';' {
-    $$ = f_new_inst(FI_PRINT, $2);
-    $$->next = f_new_inst(FI_FLUSH);
+ | PRINT var_list ';' {
+    $$ = f_print($2, 1, F_NOP);
    }
- | PRINTN print_list ';' {
-    $$ = f_new_inst(FI_PRINT, $2);
+ | PRINTN var_list ';' {
+    $$ = f_print($2, 0, F_NOP);
    }
  | function_call ';' { $$ = f_new_inst(FI_DROP_RESULT, $1); }
  | CASE term '{' switch_body '}' {
diff --git a/filter/f-inst.c b/filter/f-inst.c
index e7e19cca..9d71b93a 100644
--- a/filter/f-inst.c
+++ b/filter/f-inst.c
@@ -613,13 +613,12 @@
       LINE(3,0);
   }
 
-  INST(FI_PRINT, 0, 0) {
+  INST(FI_PRINT, 1, 0) {
     NEVER_CONSTANT;
-    VARARG;
+    ARG_ANY(1);
 
-    if (whati->varcount && !(fs->flags & FF_SILENT))
-      for (uint i=0; i<whati->varcount; i++)
-	val_format(&(vv(i)), &fs->buf);
+    if (!(fs->flags & FF_SILENT))
+      val_format(&v1, &fs->buf);
   }
 
   INST(FI_FLUSH, 0, 0) {
diff --git a/filter/f-inst.h b/filter/f-inst.h
index faee95b0..a7eecafb 100644
--- a/filter/f-inst.h
+++ b/filter/f-inst.h
@@ -96,6 +96,7 @@ void f_add_lines(const struct f_line_item *what, struct filter_iterator *fit);
 
 struct filter *f_new_where(struct f_inst *);
 struct f_inst *f_for_cycle(struct symbol *var, struct f_inst *term, struct f_inst *block);
+struct f_inst *f_print(struct f_inst *vars, int flush, enum filter_return fret);
 
 static inline struct f_dynamic_attr f_new_dynamic_attr(u8 type, enum f_type f_type, uint code) /* Type as core knows it, type as filters know it, and code of dynamic attribute */
 { return (struct f_dynamic_attr) { .type = type, .f_type = f_type, .ea_code = code }; }   /* f_type currently unused; will be handy for static type checking */
diff --git a/filter/f-util.c b/filter/f-util.c
index ab5b9094..98b7d1a8 100644
--- a/filter/f-util.c
+++ b/filter/f-util.c
@@ -75,6 +75,31 @@ f_for_cycle(struct symbol *var, struct f_inst *term, struct f_inst *block)
   return ms->method->new_inst(term, loop_start);
 }
 
+struct f_inst *
+f_print(struct f_inst *vars, int flush, enum filter_return fret)
+{
+#define AX(...)  do { struct f_inst *_tmp = f_new_inst(__VA_ARGS__); _tmp->next = output; output = _tmp; } while (0)
+  struct f_inst *output = NULL;
+  if (fret != F_NOP)
+    AX(FI_DIE, fret);
+
+  if (flush)
+    AX(FI_FLUSH);
+
+  while (vars)
+  {
+    struct f_inst *tmp = vars;
+    vars = vars->next;
+    tmp->next = NULL;
+
+    AX(FI_PRINT, tmp);
+  }
+
+  return output;
+#undef AX
+}
+
+
 #define CA_KEY(n)	n->name, n->fda.type
 #define CA_NEXT(n)	n->next
 #define CA_EQ(na,ta,nb,tb)	(!strcmp(na,nb) && (ta == tb))