Add README for examples

examples/cxx_demo/README.md

@@ -2,7 +2,7 @@
 
 This example tries to replicate [the CXX demo](https://github.com/dtolnay/cxx/tree/master/demo) using Zngur. It tries to keep it as close
 as possible to the original CXX example, so it doesn't use Zngur features that may make the code easier, more readable, and more
-performant. To see an example that uses all Zngur features in C++ to Rust codes, go to s2 example.
+performant. To see an example that uses all Zngur features in C++ to Rust codes, go to the osmium example.
 
 To run this example:
 

examples/memory_management/README.md

@@ -0,0 +1,10 @@
+# Example: Memory management
+
+Explains the corner cases of memory management by code. The output is available at `out.txt`.
+
+To run this example:
+
+```
+make
+./a.out
+```

examples/osmium/README.md

@@ -0,0 +1,10 @@
+# Example: Osmium
+
+This example contains a Rusty wrapper around osmium, a C++ library for working with the open street map. It also contains
+a simple usage of that library inside the Rust code.
+
+To run this example:
+
+```
+cargo run
+```

examples/osmium/impl.cpp

@@ -12,11 +12,19 @@
 
 using namespace rust::crate;
 using namespace std;
+template <typename T, typename E>
+using Result = rust::std::result::Result<T, E>;
 
-Reader rust::exported_functions::new_blob_store_client(Flags f) {
-  Reader o(rust::ZngurCppOpaqueOwnedObject::build<osmium::io::Reader>(
-      "map.osm", static_cast<osmium::osm_entity_bits::type>(f.bits())));
-  return o;
+Result<Reader, rust::std::string::String>
+rust::exported_functions::new_reader(Flags f) {
+  try {
+    Reader o(rust::ZngurCppOpaqueOwnedObject::build<osmium::io::Reader>(
+        "map.osm", static_cast<osmium::osm_entity_bits::type>(f.bits())));
+    return Result<Reader, rust::std::string::String>::Ok(move(o));
+  } catch (const exception &ex) {
+    return Result<Reader, rust::std::string::String>::Err(
+        rust::Str::from_char_star(ex.what()).to_string());
+  }
 }
 
 class RustHandler : public osmium::handler::Handler {
@@ -28,8 +36,8 @@ class RustHandler : public osmium::handler::Handler {
   RustHandler(BendHandler &&inner) : inner(std::move(inner)) {}
 };
 
-rust::Tuple<> rust::exported_functions::apply(rust::Ref<Reader> reader,
-                                              BendHandler handler) {
+rust::Tuple<> rust::Impl<Reader>::apply(rust::Ref<Reader> reader,
+                                        BendHandler handler) {
   using IndexType =
       osmium::index::map::SparseMemArray<osmium::unsigned_object_id_type,
                                          osmium::Location>;

examples/osmium/main.zng

@@ -18,6 +18,7 @@ type str {
 
     fn as_ptr(&self) -> *const u8;
     fn len(&self) -> usize;
+    fn to_string(&self) -> ::std::string::String;
 }
 
 type ::std::option::Option<&str> {
@@ -42,6 +43,13 @@ type crate::Reader {
     #cpp_value "0" "::osmium::io::Reader";
 }
 
+type ::std::result::Result<crate::Reader, ::std::string::String> {
+    #layout(size = 24, align = 8);
+
+    constructor Ok(crate::Reader);
+    constructor Err(::std::string::String);
+}
+
 type crate::Way {
     #cpp_ref "::osmium::Way";
 }
@@ -71,8 +79,11 @@ type crate::Flags {
 }
 
 extern "C++" {
-    fn new_blob_store_client(crate::Flags) -> crate::Reader;
-    fn apply(&crate::Reader, crate::BendHandler);
+    fn new_reader(crate::Flags) -> ::std::result::Result<crate::Reader, ::std::string::String>;
+
+    impl crate::Reader {
+        fn apply(&self, crate::BendHandler);
+    }
 
     impl crate::Way {
         fn nodes(&self) -> &crate::WayNodeList;

examples/osmium/src/main.rs

@@ -80,6 +80,6 @@ impl Handler for BendHandler {
 
 fn main() {
     let f = Flags::way | Flags::node;
-    let reader = generated::new_blob_store_client(f);
-    generated::apply(&reader, BendHandler { count: 0 });
+    let reader = generated::new_reader(f).unwrap();
+    reader.apply(BendHandler { count: 0 });
 }

examples/rayon/README.md

@@ -1,6 +1,6 @@
 # Example: Rayon
 
-Calculates the number of prime numbers in `1..10000000` with multiple cores using [rayon](https://github.com/rayon-rs/rayon).
+Calculates the sum and the number of prime numbers in `1..10000000` with multiple cores using [rayon](https://github.com/rayon-rs/rayon).
 
 To run this example:
 

examples/simple/README.md

@@ -0,0 +1,10 @@
+# Example: Simple
+
+A simple example, used as a demo in the main README file.
+
+To run this example:
+
+```
+make
+./a.out
+```

examples/tutorial/README.md

@@ -0,0 +1,10 @@
+# Example: Tutorial
+
+Full code of the [Tutorial](https://hkalbasi.github.io/zngur/tutorial.html) in the Zngur book.
+
+To run this example:
+
+```
+make
+./a.out
+```