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, 50 insertions, 0 deletions

diff --git a/docs/source/lang/cpp/float.rst b/docs/source/lang/cpp/float.rst
new file mode 100644
index 0000000..5195fac
--- /dev/null
+++ b/docs/source/lang/cpp/float.rst
@@ -0,0 +1,50 @@
+.. highlight:: cpp
+
+.. _lang-float:
+
+``float``
+=========
+
+Single-precision floating point number. Occupies 4 bytes. On Maple,
+the ``float`` type has a range of approximately -3.40282×10^38 to
+3.40282×10^38; the ``float`` type is subject to the same
+:ref:`overflow issues <lang-variables-rollover>` as any numeric data
+type.
+
+``float``\ s have only 6-7 decimal digits of precision. That means the
+total number of digits, not the number to the right of the decimal
+point.  You can get more precision by using a :ref:`double
+<lang-double>` (which has a precision of about 16 decimal digits).
+
+The following example declares a ``float`` value named ``myfloat``::
+
+        float myfloat;
+
+This example declares a ``float`` value named ``sensorCalibrate``,
+with value 1.117::
+
+        float sensorCalibrate = 1.117;
+
+The general syntax for declaring a float named ``var`` with value
+``val`` is::
+
+        float var = val;
+
+Here is a more extended example involving a :ref:`float cast
+<lang-floatcast>`::
+
+       int x;
+       int y;
+       float z;
+
+       x = 1;
+       y = x / 2;          // y now contains 0, ints can't hold fractions
+       z = float(x) / 2; // z now contains .5
+
+See Also
+--------
+
+-  :ref:`double <lang-double>`
+-  :ref:`Variables <lang-variables>`
+
+.. include:: /arduino-cc-attribution.txt