Klammerset: the @@@klammerset construct, its search path, and const correctness

The @@@klammerset system command formally declares a klammerset — a
named, logically related group of klammer definitions — with an
operative, idempotent declaration (:requires and :files load in order
at the declaration point, relative to the declaring file). A bare
symbol given to ktext -k, kdesc --input, or :requires resolves to
x/x.k on the search path: the document's directory, then
KLAMMERTEXT_KLAMMERSETS, then KLAMMERTEXT_HOME; kdesc --klammerset
lists the available sets. sks/sks.k is the first declared klammerset,
so `-k sks` loads the SKS by name. The engine's lookup classes were
renamed *_set → *_registry to keep the two concepts apart, and the
whole C++ tree now follows standard const-correctness conventions.
tst/ gains klammerset_test.sh (18 cases).

(from dev 64b1abf23e56)

com/kdesc.cpp

@@ -5,7 +5,8 @@
 #include "font_store.h"
 #include "ktype.h"
 #include "log.h"
-#include "argtype_set.h"
+#include "argtype_registry.h"
+#include "klammerset_registry.h"
 #include "character.h"
 #include "show.h"
 #include "util.h"
@@ -32,6 +33,37 @@ static void font_usage()
         "and then in the default font set.\n";
 }
 
+static void klammerset_usage()
+{
+    std::cout <<
+        "Klammerset commands:\n"
+        "  --klammerset                  List the klammersets on the search path\n"
+        "  --klammerset list             The same\n"
+        "  --klammerset help             This description\n"
+        "\n"
+        "A klammerset symbol x names the declaration file x/x.k, searched for in:\n"
+        "the current directory (for ktext, the input document's directory), the\n"
+        "KLAMMERTEXT_KLAMMERSETS directories (colon-separated; default\n"
+        "$HOME/.klammertext/klammersets), and $KLAMMERTEXT_HOME.  The first hit\n"
+        "wins, so a document-local klammerset shadows an installed one, which\n"
+        "shadows a distributed one.\n";
+}
+
+static void klammerset_command(const strings_t& words)
+{
+    std::string verb = words.empty() ? "list" : words[0];
+    if (verb == "list") {
+        std::cout << boldblack << "Klammersets\n" << black
+                  << describe_klammerset_search(fs::current_path().string());
+    } else if (verb == "help") {
+        klammerset_usage();
+    } else {
+        std::cout << "Unrecognized klammerset command: --klammerset "
+                  << join(words, " ") << "\n\n";
+        klammerset_usage();
+    }
+}
+
 static void font_command(const strings_t& words)
 {
     std::string verb = words.empty() ? "list" : words[0];
@@ -70,13 +102,14 @@ int main(int argc, char* argv[])
         args.flag("targets", "Show targets defined by the input file");
         args.flag("klammers", "Show klammers defined by the input file");
         args.var("font", "List installed fonts.  Enter \"--font help\" for font maintenance commands.");
+        args.var("klammerset", "List the klammersets on the search path.  Enter \"--klammerset help\" for details.");
         args.opt("v",  "'verbosity'", "n", "0", "'verbosity'");
 
         if (show_usage(argc, argv)) {
             args.usage(file_basename(argv[0]));
             exit(1);
         }
-        auto p = [&](std::string name) { return args.get(name) == "true"; };
+        auto p = [&](const std::string& name) { return args.get(name) == "true"; };
 
         args.parse(argc, argv);
         verbose_level = stoi(args.get("v"));
@@ -90,7 +123,7 @@ int main(int argc, char* argv[])
         }
 
         if (p("a")) {
-            Argtype_set argtypes;
+            Argtype_registry argtypes;
             std::cout << boldblack << "\nStandard klammer argument types\n" << black;
             std::cout << argtypes.describe() << "\n";
         }
@@ -116,6 +149,19 @@ int main(int argc, char* argv[])
             return 0;
         }
 
+        // The --klammerset subcommands operate on the search path
+        // (filesystem enumeration) and load no klammer set.
+        if (args.given("klammerset")) {
+            strings_t words {};
+            for (const std::string& w : args.as_vector("klammerset")) {
+                if (!w.empty()) {
+                    words.push_back(w);
+                }
+            }
+            klammerset_command(words);
+            return 0;
+        }
+
         Machine M;
 
         strings_t input_filenames = resolve_filename_list(args.get("input"));
@@ -124,6 +170,13 @@ int main(int argc, char* argv[])
             M.read(fs::path(M.m_state.value("KLAMMERTEXT_HOME") + "/sks/sks.k"));
         } else {
             for (auto fname : input_filenames) {
+                if (is_klammerset_symbol(fname)) {
+                    // A bare symbol resolves on the klammerset search
+                    // path; kdesc has no input document, so the local
+                    // stage is the cwd.
+                    fname = resolve_klammerset_symbol(
+                        fname, fs::current_path().string(), Locator()).string();
+                }
                 std::cout << "Read " << fname << "\n";
                 M.read(fs::path(absolute_pathname(fname)));
             }

com/kdiag.cpp

@@ -45,7 +45,7 @@ int main(int argc, char* argv[])
             args.usage(file_basename(argv[0]));
             exit(1);
         }
-        auto p = [&](std::string name) { return args.get(name) == "true"; };
+        auto p = [&](const std::string& name) { return args.get(name) == "true"; };
 
         args.parse(argc, argv);
         verbose_level = args.as_int("v");

com/ktext.cpp

@@ -7,7 +7,8 @@
 #include "util.h"
 #include "machine.h"
 #include "show.h"
-#include "target_set.h"
+#include "target_registry.h"
+#include "klammerset_registry.h"
                 
 int main(int argc, char* argv[])
 {
@@ -17,10 +18,10 @@ int main(int argc, char* argv[])
         args.req("filenames", "Input files in Klammertext format. ", "'list'");
         args.opt("s", "Text processed before input files.", "input-string", "", "'text'");
         args.opt("t","Output target; default is general (unspecified)", "target",
-                 Target_set::general_name, "'word'");
+                 Target_registry::general_name, "'word'");
         args.opt("o", "Output basename; meaning and default defined by target.", "basename",
                  "", "'word'");
-        args.opt("k", "File containing the klammerset definition; default is the Standard Klammer Set. With a value of \"none\", no klammerset is loaded.",
+        args.opt("k", "Klammerset symbol (resolved on the klammerset search path) or the pathname of a klammerset definition file; default is the Standard Klammer Set. With a value of \"none\", no klammerset is loaded.",
                  "pathname", "", "'word'");
         args.flag("d", "Display the output to the screen, rather than writing files.");
         args.flag("m", "Show the Klammermachine state at the beginning of processing.");
@@ -83,6 +84,12 @@ int main(int argc, char* argv[])
         if (klammerset_filename != "none") {
             if (klammerset_filename.empty()) {
                 klammerset_filename = M.m_state.value("KLAMMERTEXT_HOME") + "/sks/sks.k";
+            } else if (is_klammerset_symbol(klammerset_filename)) {
+                // A bare symbol resolves on the klammerset search path;
+                // the local stage is the input document's directory (the
+                // cwd when the input is a string).
+                klammerset_filename = resolve_klammerset_symbol(
+                    klammerset_filename, M.m_state.value("K_input_dir"), Locator()).string();
             }
             K::log(1, "Reading klammerset filename: "  + klammerset_filename);
             M.read(fs::path(klammerset_filename));