Document operations on locations.

doc/teapot.lyx

@@ -4859,6 +4859,9 @@ Operators
 Unlike other spread sheets, the operators in teapot check the type of the
  values they are applied to, which means the try to add a string to a floating
  point number will result in an type error.
+ Operators on locations in the spreadsheet, which are just triples of integers,
+ generally operate following typical rules for vectors, with particular
+ notes below.
  The following operators are available, listed in ascending precendence:
  
 \end_layout
@@ -4895,7 +4898,19 @@ y
 \emph default
  are empty, they are considered to be 0 if the other is an integer number,
  0.0 if it is a floating point number and the empty string if it is a string.
- 
+ On locations, 
+\emph on
+x<y
+\emph default
+ if every component of 
+\emph on
+x
+\emph default
+ is less than or equal to the corresponding component of
+\emph on
+y
+\emph default
+ and at least one is strictly less.
 \end_layout
 
 \begin_layout Description
@@ -4920,6 +4935,7 @@ x
 y
 \emph default
 .
+ For locations, this must hold for every component.
 \end_layout
 
 \begin_layout Description
@@ -4944,6 +4960,7 @@ x
 y
 \emph default
 .
+ For locations, this must hold for every component.
 \end_layout
 
 \begin_layout Description
@@ -4968,6 +4985,8 @@ x
 y
 \emph default
 .
+ As with <, for locations, every component must be greater than or equal,
+ and at least one must be strictly greater.
 \end_layout
 
 \begin_layout Description
@@ -5017,7 +5036,7 @@ y
 \emph default
 .
  Almost equal means, the numbers are at most neighbours.
- 
+ It is an error to use this with any type but float.
 \end_layout
 
 \begin_layout Description
@@ -5142,7 +5161,8 @@ and
 *
 \family default
  for that.
- 
+ You can multiply a location by an integer, or take the dot product of the
+ coordinates of two locations (although the use case for that is unclear).
 \end_layout
 
 \begin_layout Description
@@ -5167,6 +5187,7 @@ x
 y
 \emph default
  are numbers.
+ You can divide a location by an integer.
 \end_layout
 
 \begin_layout Description
@@ -5191,6 +5212,8 @@ x
 y
 \emph default
  are numbers.
+ You can mod a location by an integer, or operate on two locations, in which
+ case the mod operation applies componentwise.
 \end_layout
 
 \begin_layout Description
@@ -5232,7 +5255,7 @@ x
 \emph on
 x
 \emph default
- is a number.
+ is a number or location.
  If 
 \emph on
 x