Added tests for some of the code snippets in "calling C libraries". Fixed a forgotten import.

docs/examples/tutorial/clibraries/c-algorithms/src/queue.h

+/* queue.h */
+
+typedef struct _Queue Queue;
+typedef void *QueueValue;
+
+Queue *queue_new(void);
+void queue_free(Queue *queue);
+
+int queue_push_head(Queue *queue, QueueValue data);
+QueueValue queue_pop_head(Queue *queue);
+QueueValue queue_peek_head(Queue *queue);
+
+int queue_push_tail(Queue *queue, QueueValue data);
+QueueValue queue_pop_tail(Queue *queue);
+QueueValue queue_peek_tail(Queue *queue);
+
+int queue_is_empty(Queue *queue);

docs/examples/tutorial/clibraries/cqueue.pxd

+# cqueue.pxd
+
+cdef extern from "c-algorithms/src/queue.h":
+    ctypedef struct Queue:
+        pass
+    ctypedef void* QueueValue
+
+    Queue* queue_new()
+    void queue_free(Queue* queue)
+
+    int queue_push_head(Queue* queue, QueueValue data)
+    QueueValue  queue_pop_head(Queue* queue)
+    QueueValue queue_peek_head(Queue* queue)
+
+    int queue_push_tail(Queue* queue, QueueValue data)
+    QueueValue queue_pop_tail(Queue* queue)
+    QueueValue queue_peek_tail(Queue* queue)
+
+    bint queue_is_empty(Queue* queue)

docs/examples/tutorial/clibraries/queue.pyx

+# queue.pyx
+
+cimport cqueue
+
+cdef class Queue:
+    cdef cqueue.Queue* _c_queue
+
+    def __cinit__(self):
+        self._c_queue = cqueue.queue_new()

docs/examples/tutorial/clibraries/queue2.pyx

+# queue.pyx
+
+cimport cqueue
+
+cdef class Queue:
+    cdef cqueue.Queue* _c_queue
+
+    def __cinit__(self):
+        self._c_queue = cqueue.queue_new()
+        if self._c_queue is NULL:
+            raise MemoryError()

docs/examples/tutorial/clibraries/test_queue.py

+from __future__ import print_function
+
+import time
+
+import queue
+
+Q = queue.Queue()
+
+Q.append(10)
+Q.append(20)
+print(Q.peek())
+print(Q.pop())
+print(Q.pop())
+try:
+    print(Q.pop())
+except IndexError as e:
+    print("Error message:", e)  # Prints "Queue is empty"
+
+i = 10000
+
+values = range(i)
+
+start_time = time.time()
+
+Q.extend(values)
+
+end_time = time.time() - start_time
+
+print("Adding {} items took {:1.3f} msecs.".format(i, 1000 * end_time))
+
+for i in range(41):
+    Q.pop()
+
+Q.pop()
+print("The answer is:")
+print(Q.pop())

docs/src/tutorial/clibraries.rst

@@ -33,48 +33,15 @@ Defining external declarations
 You can download CAlg `here <https://github.com/fragglet/c-algorithms/archive/master.zip>`_.
 
 The C API of the queue implementation, which is defined in the header
-file ``c-algorithms/src/queue.h``, essentially looks like this::
+file ``c-algorithms/src/queue.h``, essentially looks like this:
 
-    /* file: queue.h */
-
-    typedef struct _Queue Queue;
-    typedef void *QueueValue;
-
-    Queue *queue_new(void);
-    void queue_free(Queue *queue);
-
-    int queue_push_head(Queue *queue, QueueValue data);
-    QueueValue queue_pop_head(Queue *queue);
-    QueueValue queue_peek_head(Queue *queue);
-
-    int queue_push_tail(Queue *queue, QueueValue data);
-    QueueValue queue_pop_tail(Queue *queue);
-    QueueValue queue_peek_tail(Queue *queue);
-
-    int queue_is_empty(Queue *queue);
+.. literalinclude:: ../../examples/tutorial/clibraries/c-algorithms/src/queue.h
+    :language: C
 
 To get started, the first step is to redefine the C API in a ``.pxd``
-file, say, ``cqueue.pxd``::
-
-    # file: cqueue.pxd
-
-    cdef extern from "c-algorithms/src/queue.h":
-        ctypedef struct Queue:
-            pass
-        ctypedef void* QueueValue
-
-        Queue* queue_new()
-        void queue_free(Queue* queue)
-
-        int queue_push_head(Queue* queue, QueueValue data)
-        QueueValue  queue_pop_head(Queue* queue)
-        QueueValue queue_peek_head(Queue* queue)
-
-        int queue_push_tail(Queue* queue, QueueValue data)
-        QueueValue queue_pop_tail(Queue* queue)
-        QueueValue queue_peek_tail(Queue* queue)
+file, say, ``cqueue.pxd``:
 
-        bint queue_is_empty(Queue* queue)
+.. literalinclude:: ../../examples/tutorial/clibraries/cqueue.pxd
 
 Note how these declarations are almost identical to the header file
 declarations, so you can often just copy them over.  However, you do
@@ -144,16 +111,9 @@ class that should wrap the C queue.  It will live in a file called
        library, there must not be a ``.pyx`` file with the same name
        that Cython associates with it.
 
-Here is a first start for the Queue class::
+Here is a first start for the Queue class:
 
-    # file: queue.pyx
-
-    cimport cqueue
-
-    cdef class Queue:
-        cdef cqueue.Queue* _c_queue
-        def __cinit__(self):
-            self._c_queue = cqueue.queue_new()
+.. literalinclude:: ../../examples/tutorial/clibraries/queue.pyx
 
 Note that it says ``__cinit__`` rather than ``__init__``.  While
 ``__init__`` is available as well, it is not guaranteed to be run (for
@@ -190,16 +150,9 @@ that case, it will return ``NULL``, whereas it would normally return a
 pointer to the new queue.
 
 The Python way to get out of this is to raise a ``MemoryError`` [#]_.
-We can thus change the init function as follows::
-
-    cimport cqueue
+We can thus change the init function as follows:
 
-    cdef class Queue:
-        cdef cqueue.Queue* _c_queue
-        def __cinit__(self):
-            self._c_queue = cqueue.queue_new()
-            if self._c_queue is NULL:
-                raise MemoryError()
+.. literalinclude:: ../../examples/tutorial/clibraries/queue2.pyx
 
 .. [#] In the specific case of a ``MemoryError``, creating a new
    exception instance in order to raise it may actually fail because
@@ -587,44 +540,9 @@ instead that accepts an arbitrary Python iterable::
 
 
 Now we can test our Queue implementation using a python script,
-for example here :file:`test_queue.py`.::
-
-    from __future__ import print_function
-
-    import queue
-
-
-    Q = queue.Queue()
-
-    Q.append(10)
-    Q.append(20)
-    print(Q.peek())
-    print(Q.pop())
-    print(Q.pop())
-    try:
-        print(Q.pop())
-    except IndexError as e:
-        print("Error message:", e)  # Prints "Queue is empty"
-
-    i = 10000
-
-    values = range(i)
-
-    start_time = time.time()
-
-    Q.extend(values)
-
-    end_time = time.time() - start_time
-
-    print("Adding {} items took {:1.3f} msecs.".format(i, 1000 * end_time))
-
-    for i in range(41):
-        Q.pop()
-
-    Q.pop()
-    print("The answer is:")
-    print(Q.pop())
+for example here :file:`test_queue.py`:
 
+.. literalinclude:: ../../examples/tutorial/clibraries/test_queue.py
 
 As a quick test with 10000 numbers on the author's machine indicates,
 using this Queue from Cython code with C ``int`` values is about five