Add C & CPPX examples. Add load() builtin tests

4 files changed, 99 insertions, 2 deletions

diff --git a/examples/c/Max_array.c b/examples/c/Max_array.c
new file mode 100644
index 000000000..bc2ef8799
--- /dev/null
+++ b/examples/c/Max_array.c
@@ -0,0 +1,5 @@
+void maxArray(double* x, double* y) {
+    for (int i = 0; i < 65536; i++) {
+        if (y[i] > x[i]) x[i] = y[i];
+    }
+}
diff --git a/examples/c/Sum_over_array.c b/examples/c/Sum_over_array.c
new file mode 100644
index 000000000..601ef1600
--- /dev/null
+++ b/examples/c/Sum_over_array.c
@@ -0,0 +1,7 @@
+int testFunction(int* input, int length) {
+  int sum = 0;
+  for (int i = 0; i < length; ++i) {
+    sum += input[i];
+  }
+  return sum;
+}
diff --git a/examples/cppx/Interface.cpp b/examples/cppx/Interface.cpp
new file mode 100644
index 000000000..1af545545
--- /dev/null
+++ b/examples/cppx/Interface.cpp
@@ -0,0 +1,61 @@
+
+//====================================================================
+// Library code: implementing the metaclass (once)
+
+$class interface {
+    constexpr {
+        compiler.require($interface.variables().empty(),
+                         "interfaces may not contain data");
+        for... (auto f : $interface.functions()) {
+            compiler.require(!f.is_copy() && !f.is_move(),
+                "interfaces may not copy or move; consider a"
+                " virtual clone() instead");
+            if (!f.has_access()) f.make_public();
+            compiler.require(f.is_public(),
+                "interface functions must be public");
+            f.make_pure_virtual();
+        }
+    }
+    virtual ~interface() noexcept { }
+};
+
+
+//====================================================================
+// User code: using the metaclass to write a type (many times)
+
+interface Shape {
+    int area() const;
+    void scale_by(double factor);
+};
+
+    // try putting any of these lines into Shape to see "interface" rules
+    // enforced => using the metaclass name to declare intent makes
+    // this code more robust to such changes under maintenance
+    //
+    // int i;               // error: interfaces may not contain data
+    // private: void g();   // error: interface functions must be public
+    // Shape(const Shape&); // error: interfaces may not copy or move;
+    //                      //        consider a virtual clone() instead
+
+// Godbolt.org note: Click the "triangle ! icon" to see the output
+constexpr {
+    compiler.debug($Shape);
+}
+
+
+//====================================================================
+// And then continue to use it as "just a class" as always... this is
+// normal code just as if we'd written Shape not using a metaclass
+
+class Circle : public Shape {
+public:
+    int area() const override { return 1; }
+    void scale_by(double factor) override { }
+};
+
+#include <memory>
+
+int main() {
+    std::unique_ptr<Shape> shape = std::make_unique<Circle>();
+    shape->area();
+}
diff --git a/test/builtin-tests.js b/test/builtin-tests.js
index 98f11d2f9..4201abf8b 100644
--- a/test/builtin-tests.js
+++ b/test/builtin-tests.js
@@ -24,7 +24,8 @@
 
 const should = require('chai').should(),
     builtin = require('../lib/sources/builtin'),
-    languages = require('../lib/languages').list;
+    languages = require('../lib/languages').list,
+    _ = require('underscore-node');
 
 describe('Builtin sources', () => {
     it('Does not include default code', () => {
@@ -37,7 +38,30 @@ describe('Builtin sources', () => {
     it('Has a valid language listed', () => {
         builtin.list((_, list) => {
             list.forEach(example => {
-                should.not.equal(languages[example.lang], undefined);
+                should.not.equal(languages[example.lang], undefined, `Builtin ${example.name} has unrecognised language ${example.lang}`);
+            });
+        });
+    });
+    it('Has at least one example for each language', () => {
+        builtin.list((placeholder, list) => {
+            _.each(languages, lang => {
+                should.not.equal(_.find(list, elem => elem.lang === lang.id), undefined, `Language ${lang.name} does not have any builtins`);
+            });
+        });
+    });
+    it('Reports a string error if no example found', () => {
+        builtin.load('BADLANG', 'BADFILE', (error, result) => {
+            should.equal(result, undefined, 'A result should not be returned for bad requests');
+            error.should.be.a("string");
+        });
+    });
+    it('Reports something for every defined example', () => {
+        builtin.list((placeholder, examples) => {
+            examples.forEach(example => {
+                builtin.load(example.lang, example.file, (error, result) => {
+                    should.not.exist(error, `Can't read ${example.name} for ${example.lang} in ${example.file}`);
+                    result.file.should.be.a('string');
+                });
             });
         });
     });