macro: trivial preprocessor for includes

CMakeLists.txt

@@ -425,7 +425,7 @@ target_link_libraries(cruft-util dl)
 
 
 ###############################################################################
-foreach (tool json-clean json-schema json-validate scratch)
+foreach (tool json-clean json-schema json-validate macro scratch)
     add_executable (util_${tool} tools/${tool}.cpp)
     set_target_properties (util_${tool} PROPERTIES OUTPUT_NAME ${tool})
     target_link_libraries (util_${tool} cruft-util)

tools/macro.cpp

@@ -0,0 +1,77 @@
+#include "io.hpp"
+#include "iterator.hpp"
+#include "string.hpp"
+#include "view.hpp"
+
+#include <iostream>
+#include <cstdlib>
+#include <fstream>
+
+
+enum {
+    ARG_SELF,
+    ARG_SRC,
+    ARG_DST,
+
+    MIN_ARGS = ARG_SRC+1,
+};
+
+
+///////////////////////////////////////////////////////////////////////////////
+void process (std::ostream &dst, const std::experimental::filesystem::path&);
+
+
+///////////////////////////////////////////////////////////////////////////////
+struct include {
+    template <typename IteratorA, typename IteratorB>
+    void
+    operator() (std::ostream &dst, util::view<IteratorA,IteratorB> data)
+    {
+        if (data.size () < 3)
+            throw std::invalid_argument ("invalid argument for include");
+
+        if (data[0] != '"' || data[data.size()-1] != '"')
+            throw std::invalid_argument ("invalid path specification");
+
+        process (dst, {data.begin () + 1, data.end () - 1});
+    }
+};
+
+
+///////////////////////////////////////////////////////////////////////////////
+void
+process (std::ostream &dst, const std::experimental::filesystem::path &src)
+{
+    auto data = util::slurp<char> (src);
+    include handler;
+
+    for (const auto &l: util::tokeniser (data.data (), '\n')) {
+        if (l.empty () || l[0] != '#') {
+            dst << l << '\n';
+            continue;
+        }
+
+        auto space = std::find (l.begin (), l.end (), ' ');
+        handler (dst, util::view{space+1,l.end()});
+    }
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+int
+main (const int argc, const char **argv)
+{
+    if (argc < 2) {
+        std::cerr << argv[ARG_SELF] << " <src> [dst]\n";
+        return EXIT_FAILURE;
+    }
+
+    std::experimental::filesystem::path src = argv[ARG_SRC];
+
+    if (argc == 3) {
+        std::ofstream dst (argv[ARG_DST]);
+        process (dst, src);
+    } else {
+        process (std::cout, src);
+    };
+};