Initial commit: Klammertext source distribution

Curated source subset assembled by klammertext-dev's doc/make_dist.sh: the Klammermachine (mac), the Standard Klammer Set (sks), the commands (com), editor plugins and install guides (doc), a test subset (tst), and lib/bin placeholders. Builds with 'make -C com'.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mac/error.h

@@ -0,0 +1,77 @@
+#pragma once
+
+#include <string>
+
+#include "locator.h"
+
+inline std::string command_name { "Command executed on the command line" };
+inline std::string command_pathname { "Pathname of command executed on the command line" };
+
+
+class Error : std::exception {
+public:
+    Error(std::string error_type, std::string description,
+          Locator locator = Locator(), bool do_justify = true)
+        : m_type(error_type)
+        , m_desc(description)
+        , m_loc(locator)
+        , m_just(do_justify)
+        {}
+
+    void print_message(const std::string& epilog="");
+
+    std::string m_type {};
+    std::string m_desc {};
+    Locator m_loc; // {};
+    bool m_just { true };
+};
+
+
+class Parsing_error : public Error {
+public:
+    explicit Parsing_error(
+        const std::string& description, const Locator& locator=Locator(), bool do_justify=true) 
+        : Error("parsing", description, locator, do_justify) {};
+};
+
+class File_error : public Error {
+public:
+    explicit File_error(
+        const std::string& description, const Locator& locator=Locator(), bool do_justify=true) 
+        : Error("file", description, locator, do_justify) {};
+};
+
+class Target_error : public Error {
+public:
+    explicit Target_error(
+        const std::string& description, const Locator& locator=Locator(), bool do_justify=true) 
+        : Error("target", description, locator, do_justify) {};
+};
+
+class Definition_error : public Error {
+public:
+    explicit Definition_error(
+        const std::string& description, const Locator& locator=Locator(), bool do_justify=true) 
+        : Error("definition", description, locator, do_justify) {};
+};
+
+class Argument_error : public Error {
+public:
+    explicit Argument_error(
+        const std::string& description, const Locator& locator=Locator(), bool do_justify=true) 
+        : Error("argument", description, locator, do_justify) {};
+};
+
+class Environment_error : public Error {
+public:
+    explicit Environment_error(
+        const std::string& description, const Locator& locator=Locator(), bool do_justify=true) 
+        : Error("environment", description, locator, do_justify) {};
+};
+
+class Internal_error : public Error {
+public:
+    explicit Internal_error(
+        const std::string& description, const Locator& locator=Locator(), bool do_justify=true) 
+        : Error("internal", description, locator, do_justify) {};
+};