merge libmaple docs ("leaflabs-docs") into ./docs

In the past, libample documentation was forked out of this repository
because the documentation had increased in scope. For the librambutan,
and the rambutan project in general, we will try to keep documentation
closer to the source code, so the librambutan-specific documentation
should live here. Other sections of leaflabs-docs will be culled in a
following commit.

This merge attempts to maintain history by using a subtree strategy.
Followed directions at:

    http://nuclearsquid.com/writings/subtree-merging-and-you/

Full history for files should be accessible using the "--follow" flag to
git log, eg:

    git log --follow docs/source/adc.rst

It should be possible to pull patches from leaflabs-docs with:

    git pull -s subtree leaflabs-docs master

... at least until the docs in this repository diverge significantly.

1 files changed, 30 insertions, 0 deletions

diff --git a/docs/source/lang/api/assert.rst b/docs/source/lang/api/assert.rst
new file mode 100644
index 0000000..76330b6
--- /dev/null
+++ b/docs/source/lang/api/assert.rst
@@ -0,0 +1,30 @@
+.. highlight:: cpp
+
+.. _lang-assert:
+
+``ASSERT(...)``
+===============
+
+ASSERT() can be very useful for basic program debugging. It accepts a
+boolean; for example::
+
+  ASSERT(state == WAIT);
+
+Zero is false and any other number is true.  If the boolean is true,
+the assertion passes and the program continues as usual.  If it is
+false, the assertion fails: the program is halted, debug information
+is printed to USART2, and the status LED begins to throb (it's
+noticeably different from blinking). The debug information is printed
+at 9600 baud and consists of the filename and line number where the
+ASSERT() failed.
+
+Including assertions in a program increases the program size. When
+using libmaple **from the command line only**, they can be disabled by
+making the definition ::
+
+  #define DEBUG_LEVEL DEBUG_NONE
+
+before including either wirish.h or libmaple.h. In this case, all
+assertions will pass without any lost clock cycles.  Note that this
+will **not work in the IDE**; even with this definition, assertions
+will still be enabled.