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)

sks/kutil/klammer_base.cpp

@@ -5,7 +5,7 @@
 #include "klammer_base.h"
 #include "show.h"
 
-std::string Klammer_base::get(std::string name)
+std::string Klammer_base::get(const std::string& name)
 {
     //std::cout << "GET " << name << "\n";
     std::string result = m_machine.m_state.value(name);
@@ -49,7 +49,7 @@ std::string Klammer_base::result()
         throw Target_error("Unknown target: " + target);
 }
 
-void Klammer_base::show(std::string klammer_name)
+void Klammer_base::show(const std::string& klammer_name)
 {
     std::cout << "Arguments of klammer \"" << klammer_name << "\"\n"
               << m_machine.m_state.describe() << "\n";

sks/kutil/klammer_base.h

@@ -18,14 +18,14 @@ public:
         {};
     virtual ~Klammer_base() {};
 
-    std::string get(std::string);
+    std::string get(const std::string& name);
     std::string get(const char* name);
     virtual std::string html();
     virtual std::string tex();
     virtual std::string txt();
 
     std::string result();
-    void show(std::string klammer_name);
+    void show(const std::string& klammer_name);
 
     Machine m_machine;
 };

sks/kutil/kutil.cpp

@@ -10,7 +10,7 @@
 
 #include <filesystem>
 
-std::string read_file(std::string filename)
+std::string read_file(const std::string& filename)
 {
   std::ifstream stream {};
   std::ostringstream buffer {};
@@ -36,7 +36,7 @@ std::string klammertext_dir()
   return kdir;
 }
 
-bool in_subset(std::string base, std::vector<std::string> subset)
+bool in_subset(const std::string& base, const std::vector<std::string>& subset)
 {
     return subset.empty() ||
         (std::find(subset.begin(), subset.end(), base) != subset.end());
@@ -44,7 +44,7 @@ bool in_subset(std::string base, std::vector<std::string> subset)
 
     
 
-std::vector<std::string> sks_files_of_type(std::string extension, std::vector<std::string> subset)
+std::vector<std::string> sks_files_of_type(const std::string& extension, const std::vector<std::string>& subset)
 {
     bool dbg = false;
     std::string kdir = klammertext_dir();
@@ -85,7 +85,7 @@ std::vector<std::string> sks_files_of_type(std::string extension, std::vector<st
     return result;
 }
 
-std::string find_kt_file(std::string filename)
+std::string find_kt_file(const std::string& filename)
 {
     std::string result {};
     std::vector<std::string> prefix {"", "kt/"};
@@ -117,7 +117,7 @@ std::string find_kt_file(std::string filename)
 }
 
 
-std::string caption_marker(std::string name, std::string caption, std::string delimiter)
+std::string caption_marker(const std::string& name, const std::string& caption, const std::string& delimiter)
 {
     std::string result {caption};
     if (caption.size() > 0) {
@@ -128,7 +128,7 @@ std::string caption_marker(std::string name, std::string caption, std::string de
 }
 
 /*
-std::string process(Machine& M, std::string target, fs::path source_filename,
+std::string process(Machine& M, const std::string& target, const fs::path& source_filename,
                     bool post_process, bool unescape_chars)
 {
     // Text text(source_filename, false, false);
@@ -144,7 +144,7 @@ std::string process(Machine& M, std::string target, fs::path source_filename,
     return processed;
 }
 
-std::string process(Machine& M, std::string target, std::string source_text,
+std::string process(Machine& M, const std::string& target, const std::string& source_text,
                     bool post_process, bool unescape_chars)
 {
     Text text(source_text, false, false);
@@ -157,8 +157,8 @@ std::string process(Machine& M, std::string target, std::string source_text,
     return processed;
 }
 
-std::string process(Machine& M, std::string target,
-                    std::string source_text, fs::path source_filename,
+std::string process(Machine& M, const std::string& target,
+                    const std::string& source_text, const fs::path& source_filename,
                     bool post_process, bool unescape_chars)
 {
     Text text({source_text}, {source_filename}, false, false);

sks/kutil/kutil.h

@@ -12,24 +12,24 @@ std::vector<std::string> sks_basenames { // removed "book"
 
 const std::string caption_delimiter = "__CAPTION__";
 
-std::string read_file(std::string filename);
+std::string read_file(const std::string& filename);
 
 std::string klammertext_dir();
 
-std::vector<std::string> old_sks_files_of_type(std::string extension);
-std::vector<std::string> sks_files_of_type(std::string extension, std::vector<std::string> subset={});
+std::vector<std::string> old_sks_files_of_type(const std::string& extension);
+std::vector<std::string> sks_files_of_type(const std::string& extension, const std::vector<std::string>& subset={});
 
-std::string caption_marker(std::string name, std::string caption, std::string delimiter=" – ");
+std::string caption_marker(const std::string& name, const std::string& caption, const std::string& delimiter=" – ");
 
-std::string find_kt_file(std::string filename);
+std::string find_kt_file(const std::string& filename);
 
-std::string process(Machine& M, std::string target, std::string source_text,
+std::string process(Machine& M, const std::string& target, const std::string& source_text,
                     bool post_process=false, bool unescape_chars=false);
 
-std::string process(Machine& M, std::string target, fs::path source_filename,
+std::string process(Machine& M, const std::string& target, const fs::path& source_filename,
                     bool post_process=false, bool unescape_chars=false);
 
-std::string process(Machine& M, std::string target,
-                    std::string source_text, fs::path source_filename,
+std::string process(Machine& M, const std::string& target,
+                    const std::string& source_text, const fs::path& source_filename,
                     bool post_process, bool unescape_chars);