--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/chapters/25.markdown Fri Oct 14 00:34:25 2011 -0400
@@ -0,0 +1,101 @@
+Numbers
+=======
+
+Now it's time to start taking a closer look at the different types of variables
+you can use. First we'll go over Vim's numeric types.
+
+Vimscript has two types of numeric variables: Numbers and Floats. A Number is
+a 32 bit signed integer. A Float is, obviously, a floating point number.
+
+Number Formats
+--------------
+
+You can specify Numbers in a few different ways. Run the following command.
+
+ :echom 100
+
+No surprises here -- Vim displays "100". Now run this command:
+
+ :echom 0xff
+
+This time Vim displays "255". You can specify numbers in hex notation by
+prefixing them with `0x` or `0X`. Now run this command:
+
+ :echom 010
+
+You can also use octal by starting a number with a `0`. Be careful with this,
+because it's easy to make mistakes. Try the following commands:
+
+ :echom 017
+ :echom 019
+
+Vim will print "15" for the first command, because "18" in octal is equal to
+"18" in decimal. For the second command Vim treats it as a decimal number, even
+though it starts with a `0`, because it's not a valid octal number.
+
+Because Vim silently does the wrong thing in this case, I'd recommend avoiding
+the use of octal numbers when possible.
+
+Float Formats
+-------------
+
+Floats can also be specified in multiple ways. Run the following command:
+
+ :echo 100.1
+
+Notice that we're using `echo` here and not `echom` like we usually to. We'll
+talk why in a moment.
+
+Vim displays "100.1" as expected. You can also use exponential notation. Run
+this command:
+
+ :echo 5.45e+3
+
+Vim displays "5450.0". A negative exponent can also be used. Run this command:
+
+ :echo 15.45e-2
+
+Vim displays "0.1545". The `+` or `-` before the power of ten is optional, if
+it's omitted the it's assumed to be positive. Run the following command:
+
+ :echo 15.3e9
+
+Vim will display "1.53e10", which is equivalent. The decimal point and number
+after it are *not* optional. Run the following command and see that it crashes:
+
+ :echo 5e10
+
+Coercion
+--------
+
+When you combine a Number and a Float through arithmetic, comparison, or any
+other operation Vim will cast the Number to a Float, resulting in a Float. Run
+the following command:
+
+ :echo 2 * 2.0
+
+Vim displays "2.0".
+
+Division
+--------
+
+When dividing two Numbers, the remainder is dropped. Run the following command:
+
+ :echo 3 / 2
+
+Vim displays "1". If you want Vim to perform float point division one of the
+numbers needs to be a Float, which will cause the other one to be coerced to
+a Float as well. Run this command:
+
+ :echo 3 / 2.0
+
+Vim displays "1.5". The "3" is coerced to a Float, and then normal floating
+point division is performed.
+
+Exercises
+---------
+
+Read `:help Float`. When might floating point number not work in Vimscript?
+
+Read `:help floating-point-precision`. What might this mean if you're writing
+a Vim plugin that deals with floating point numbers?
--- a/outline.org Thu Oct 13 23:54:12 2011 -0400
+++ b/outline.org Fri Oct 14 00:34:25 2011 -0400
@@ -24,8 +24,10 @@
** DONE comparisons
** DONE functions
** DONE function arguments
+** DONE numbers
** TODO strings
** TODO string functions
+** TODO regexes
** TODO normal!
** TODO execute
** TODO execute normal!