ltlfilt, autfilt: add support for --nth

* bin/autfilt.cc, bin/ltlfilt.cc: Implement it.
* NEWS: Mention it.
* tests/core/genaut.test, tests/core/genltl.test: Add test cases.

NEWS

@@ -14,13 +14,17 @@ New in spot 2.8.6.dev (not yet released)
     spot-accepted-word: "!a; cycle{a}"
     spot-rejected-word: "!a; !a; cycle{a}"
 
-  - When running translators ltlcross will now display {names} when
-    supplied.
-
   - autfilt learned the --partial-degeneralize option, to remove
     conjunctions of Inf, or disjunction of Fin that appears in
     arbitrary conditions.
 
+  - ltlfilt and autfilt learned a --nth=RANGE (a.k.a. -N) option to
+    select a range of their input formulas or automata (assuming a
+    1-based numbering).
+
+  - When running translators ltlcross will now display {names} when
+    supplied.
+
   - ltlcross is now using the generic emptiness check procedure
     introduced in Spot 2.7, as opposed to removing Fin acceptance
     before using a classical emptiness check.

bin/autfilt.cc

@@ -267,6 +267,9 @@ static const argp_option options[] =
       "keep automata that accept WORD", 0 },
     { "reject-word", OPT_REJECT_WORD, "WORD", 0,
       "keep automata that reject WORD", 0 },
+    { "nth", 'N', "RANGE", 0,
+      "assuming input automata are numbered from 1, keep only those in RANGE",
+      0 },
     /**************************************************/
     RANGE_DOC_FULL,
     WORD_DOC,
@@ -612,6 +615,7 @@ static bool opt_terminal_sccs_set = false;
 static range opt_nondet_states = { 0, std::numeric_limits<int>::max() };
 static bool opt_nondet_states_set = false;
 static int opt_max_count = -1;
+static range opt_nth = { 0, std::numeric_limits<int>::max() };
 static bool opt_destut = false;
 static char opt_instut = 0;
 static bool opt_is_empty = false;
@@ -709,6 +713,9 @@ parse_opt(int key, char* arg, struct argp_state*)
     case 'n':
       opt_max_count = to_pos_int(arg, "-n/--max-count");
       break;
+    case 'N':
+      opt_nth = parse_range(arg, 0, std::numeric_limits<int>::max());
+      break;
     case 'u':
       opt->uniq =
         std::unique_ptr<unique_aut_t>(new std::set<std::vector<tr_t>>());
@@ -1310,6 +1317,9 @@ namespace
     int
     process_automaton(const spot::const_parsed_aut_ptr& haut) override
     {
+      static unsigned order = 0;
+      ++order;
+
       spot::process_timer timer;
       timer.start();
 
@@ -1350,6 +1360,7 @@ namespace
 
       bool matched = true;
 
+      matched &= opt_nth.contains(order);
       matched &= opt_states.contains(aut->num_states());
       matched &= opt_edges.contains(aut->num_edges());
       matched &= opt_accsets.contains(aut->acc().num_sets());

bin/ltlfilt.cc

@@ -1,5 +1,5 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2012-2019 Laboratoire de Recherche et Développement
+// Copyright (C) 2012-2020 Laboratoire de Recherche et Développement
 // de l'Epita (LRDE).
 //
 // This file is part of Spot, a model checking library.
@@ -223,6 +223,9 @@ static const argp_option options[] =
     { "stutter-invariant", 0, nullptr, OPTION_ALIAS, nullptr, 0 },
     { "ap", OPT_AP_N, "RANGE", 0,
       "match formulas with a number of atomic propositions in RANGE", 0 },
+    { "nth", 'N', "RANGE", 0,
+      "assuming input formulas are numbered from 1, keep only those in RANGE",
+      0 },
     { "invert-match", 'v', nullptr, 0, "select non-matching formulas", 0},
     { "unique", 'u', nullptr, 0,
       "drop formulas that have already been output (not affected by -v)", 0 },
@@ -309,6 +312,7 @@ static spot::relabeling_style style = spot::Abc;
 static bool remove_x = false;
 static bool stutter_insensitive = false;
 static range ap_n = { -1, -1 };
+static range opt_nth = { 0, std::numeric_limits<int>::max() };
 static int opt_max_count = -1;
 static long int match_count = 0;
 static const char* from_ltlf = nullptr;
@@ -356,6 +360,9 @@ parse_opt(int key, char* arg, struct argp_state*)
     case 'n':
       opt_max_count = to_pos_int(arg, "-n/--max-count");
       break;
+    case 'N':
+      opt_nth = parse_range(arg, 0, std::numeric_limits<int>::max());
+      break;
     case 'q':
       output_format = quiet_output;
       break;
@@ -605,6 +612,8 @@ namespace
     process_formula(spot::formula f,
                     const char* filename = nullptr, int linenum = 0) override
     {
+      static unsigned order = 0;
+      ++order;
       spot::process_timer timer;
       timer.start();
 
@@ -618,7 +627,7 @@ namespace
       if (negate)
         f = spot::formula::Not(f);
 
-      bool matched = true;
+      bool matched = opt_nth.contains(order);
 
       if (from_ltlf)
         {

tests/core/genaut.test

@@ -1,6 +1,6 @@
 #!/bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2017, 2018, 2019 Laboratoire de Recherche et Développement
+# Copyright (C) 2017, 2018, 2019, 2020 Laboratoire de Recherche et Développement
 # de l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
@@ -60,3 +60,12 @@ genaut --l-nba='1..3?' 2>err && exit 1
 grep 'invalid range.*trailing garbage' err
 genaut --l-nba='1..' 2>err && exit 1
 grep 'invalid range.*missing end' err
+
+
+# Tests for autfilt -N/--nth
+genaut --ks-nca=1..5 | autfilt -N 2..4 > range1.hoa
+genaut --ks-nca=2..4 > range2.hoa
+diff range1.hoa range2.hoa
+genaut --ks-nca=1..5 | autfilt -v --nth 3..5 > range1.hoa
+genaut --ks-nca=1..2 > range2.hoa
+diff range1.hoa range2.hoa

tests/core/genltl.test

@@ -1,6 +1,6 @@
 #!/bin/sh
 # -*- coding: utf-8 -*-
-# Copyright (C) 2016-2019 Laboratoire de Recherche et Développement
+# Copyright (C) 2016-2020 Laboratoire de Recherche et Développement
 # de l'Epita (LRDE).
 #
 # This file is part of Spot, a model checking library.
@@ -259,3 +259,11 @@ test "`cat err`" = "genltl: no pattern sb-patterns=0, supported range is 1..27"
 genltl --sejk-patterns=0 2> err && exit 1
 test $? = 2
 test "`cat err`" = "genltl: no pattern sejk-patterns=0, supported range is 1..3"
+
+# Tests for ltlfilt -N/--nth
+genltl --sb-patterns=1..20 | ltlfilt -N 5..10 > range1.ltl
+genltl --sb-patterns=5..10 > range2.ltl
+diff range1.ltl range2.ltl
+genltl --sb-patterns=1..20 | ltlfilt -v --nth 10..20 > range1.ltl
+genltl --sb-patterns=1..9 > range2.ltl
+diff range1.ltl range2.ltl