autfilt: easier simplification defaults

This is motivated by an email from Fanda.

* src/bin/common_post.cc, src/bin/common_post.hh: Add variables to
detect when level or pref are sets.
* src/bin/autfilt.cc: Adjust default for pref/sets.
* src/tests/readsave.test: Add test cases.
* NEWS: Mention it.

NEWS

@@ -5,6 +5,14 @@ New in spot 1.99.4a (not yet released)
   * autfilt has gained a --complement option.
     It currently work only for deterministic automata.
 
+  * By default, autfilt does not simplify automata (this has not
+    changed), as if the --low --any options where used.  But now, if
+    one of --small, --deterministic, or --any is given, the
+    optimization level automatically defaults to --high (unless
+    specified otherwise).  For symmetry, if one of --low, --medium, or
+    --high is given, thn the translation intent defaults to --small
+    (unless specified otherwise).
+
   Library:
 
   * Rename dtgba_complement() as dtwa_complement(), rename the header

src/bin/autfilt.cc

@@ -210,6 +210,14 @@ static const argp_option options[] =
     { "acc-sets", OPT_ACC_SETS, "RANGE", 0,
       "keep automata whose number of acceptance sets are in RANGE", 0 },
     RANGE_DOC_FULL,
+    { nullptr, 0, nullptr, 0,
+      "If any option among --small, --deterministic, or --any is given, "
+      "then the optimization level defaults to --high unless specified "
+      "otherwise.  If any option among --low, --medium, or --high is given, "
+      "then the translation intent defaults to --small unless specified "
+      "otherwise.  If none of those options are specified, then autfilt "
+      "acts as is --any --low were given: these actually disable the "
+      "simplification routines.", 22 },
     /**************************************************/
     { nullptr, 0, nullptr, 0, "Miscellaneous options:", -1 },
     { "extra-options", 'x', "OPTS", 0,
@@ -714,6 +722,11 @@ main(int argc, char** argv)
       if (int err = argp_parse(&ap, argc, argv, ARGP_NO_HELP, nullptr, nullptr))
 	exit(err);
 
+      if (level_set && !pref_set)
+	pref = spot::postprocessor::Small;
+      if (pref_set && !level_set)
+	level = spot::postprocessor::High;
+
       if (jobs.empty())
 	jobs.emplace_back("-", true);
 

src/bin/common_post.cc

@@ -27,6 +27,9 @@ spot::postprocessor::output_pref comp = spot::postprocessor::Any;
 spot::postprocessor::output_pref sbacc = spot::postprocessor::Any;
 spot::postprocessor::optimization_level level = spot::postprocessor::High;
 
+bool level_set = false;
+bool pref_set = false;
+
 enum {
   OPT_HIGH = 1,
   OPT_LOW,
@@ -63,7 +66,7 @@ static const argp_option options_disabled[] =
     { "small", OPT_SMALL, nullptr, 0, "prefer small automata", 0 },
     { "deterministic", 'D', nullptr, 0, "prefer deterministic automata", 0 },
     { "any", 'a', nullptr, 0, "no preference, do not bother making it small "
-      "or deterministic (default)", 0 },
+      "or deterministic", 0 },
     { "complete", 'C', nullptr, 0, "output a complete automaton (combine "
       "with other intents)", 0 },
     { "state-based-acceptance", 'S', nullptr, 0,
@@ -71,7 +74,7 @@ static const argp_option options_disabled[] =
     { "sbacc", 0, nullptr, OPTION_ALIAS, nullptr, 0 },
     /**************************************************/
     { nullptr, 0, nullptr, 0, "Optimization level:", 21 },
-    { "low", OPT_LOW, nullptr, 0, "minimal optimizations (fast, default)", 0 },
+    { "low", OPT_LOW, nullptr, 0, "minimal optimizations (fast)", 0 },
     { "medium", OPT_MEDIUM, nullptr, 0, "moderate optimizations", 0 },
     { "high", OPT_HIGH, nullptr, 0,
       "all available optimizations (slow)", 0 },
@@ -86,12 +89,14 @@ parse_opt_post(int key, char*, struct argp_state*)
     {
     case 'a':
       pref = spot::postprocessor::Any;
+      pref_set = true;
       break;
     case 'C':
       comp = spot::postprocessor::Complete;
       break;
     case 'D':
       pref = spot::postprocessor::Deterministic;
+      pref_set = true;
       break;
     case 'S':
       sbacc = spot::postprocessor::SBAcc;
@@ -99,17 +104,21 @@ parse_opt_post(int key, char*, struct argp_state*)
     case OPT_HIGH:
       level = spot::postprocessor::High;
       simplification_level = 3;
+      level_set = true;
       break;
     case OPT_LOW:
       level = spot::postprocessor::Low;
       simplification_level = 1;
+      level_set = true;
       break;
     case OPT_MEDIUM:
       level = spot::postprocessor::Medium;
       simplification_level = 2;
+      level_set = true;
       break;
     case OPT_SMALL:
       pref = spot::postprocessor::Small;
+      pref_set = true;
       break;
     default:
       return ARGP_ERR_UNKNOWN;

src/bin/common_post.hh

@@ -31,3 +31,7 @@ extern spot::postprocessor::output_pref pref;
 extern spot::postprocessor::output_pref comp;
 extern spot::postprocessor::output_pref sbacc;
 extern spot::postprocessor::optimization_level level;
+// True if --low, --medium, or --high has been given
+extern bool level_set;
+// True if --any, --small, or --deterministic has been given
+extern bool pref_set;

src/tests/readsave.test

@@ -715,6 +715,8 @@ State: 2 {0 1} [0] 2
 EOF
 
 $autfilt -H --small --high input4 >output4
+$autfilt -H --small input4 >output4b
+$autfilt -H --high input4 >output4c
 cat output4
 
 cat >expect4<<EOF
@@ -737,3 +739,5 @@ State: 2 {0}
 EOF
 
 diff output4 expect4
+diff output4b expect4
+diff output4c expect4