From 8ec8f29055a8e2da158db1ec25c2b74e5e0018c4 Mon Sep 17 00:00:00 2001
From: rhaas <rhaas@17b73243-c579-4c4c-a9d2-2d5706c11dac>
Date: Thu, 19 Apr 2012 00:15:34 +0000
Subject: expand expression language, add error checking, and more
 documentation

git-svn-id: http://svn.cactuscode.org/flesh/trunk@4804 17b73243-c579-4c4c-a9d2-2d5706c11dac
---
 doc/UsersGuide/Notes.tex | 49 ++++++++++++++++++++++++++++++------------------
 1 file changed, 31 insertions(+), 18 deletions(-)

(limited to 'doc/UsersGuide')

diff --git a/doc/UsersGuide/Notes.tex b/doc/UsersGuide/Notes.tex
index ff0a6f42..d0d897bf 100644
--- a/doc/UsersGuide/Notes.tex
+++ b/doc/UsersGuide/Notes.tex
@@ -1318,48 +1318,61 @@ expressions in place of explicit values. The usual arithmetic operations
 as well as C-like transcendental functions and relational operations are
 supported. Integer division is handled as in C, and any non-null value is
 interpreted as logical true, which the relational operators return as unity.
+The return value of any function whose arguments are integers will be
+truncated towards zero.
+The remainder operator \verb|%| is internally mapped to the \verb|fmod|
+function for both integer and real valued arguments so inherits its
+semantics.
+The exponentiation operator \verb|**| as well as the unary operators
+associate to the left which differs from the common convention in
+mathematics. When in doubt use explicit parenthesis to force a desired
+order of evaluation.
 Table~\ref{tab:expression_functions} lists the supported functions.
 Expressions can refer to already set parameters by using the fully qualified
 name \texttt{thorn::parameter} as described below.
 \begin{table}
     \begin{tabular}{|ll@{\hspace{.5cm}}|ll|}
         \hline
-        \multicolumn{2}{|c|}{Relational operators} & \multicolumn{2}{c|}{Mathematical functions} \\
+        \multicolumn{2}{|c|}{Logical operators}        & \verb|+| & no-op\\ 
         \hline
-        \verb|=| & tests for equality		 & \verb|!| & logical not\\
+        \verb|&&| & logical and		               & \verb|!| & logical not\\
         \hline
-        \verb|<| & tests for less than		 & \verb|acos| & inverse cosine\\
+        \verb%||% & logical or		               & \multicolumn{2}{c|}{Mathematical functions}\\
         \hline
-        \verb|>| & tests for greater than	 & \verb|asin| & inverse sine\\
+        \multicolumn{2}{|c|}{Relational operators}     & \verb|acos| & inverse cosine\\
         \hline
-        \verb|<=| & tests for less or equal	 & \verb|atan| & inverse tangent \\
+        \verb|==| & tests for equality		       & \verb|asin| & inverse sine\\
         \hline
-        \verb|>=| & tests for greater or equal	 & \verb|ceil| & round up to nearest integer \\
+        \verb|!=| & tests for inequality	       & \verb|atan| & inverse tangent \\
         \hline
-        \verb|&&| & logical and		         & \verb|cos| & cosine \\
+        \verb|<| & tests for less than		       & \verb|ceil| & round up to nearest integer \\
         \hline
-        \verb%||% & logical or		         & \verb|cosh| & hyperbolic cosine \\
+        \verb|>| & tests for greater than	       & \verb|cos| & cosine \\
         \hline
-        \multicolumn{2}{|c|}{Unary operators}	 & \verb|exp| & exponentiation $e^x$\\
+        \verb|<=| & tests for less or equal	       & \verb|cosh| & hyperbolic cosine \\
         \hline
-        \verb|-| & negate sign		         & \verb|fabs| & absolute value $|x|$\\
+        \verb|>=| & tests for greater or equal	       & \verb|exp| & exponentiation $e^x$\\
         \hline
-        \verb|+| & no-op                         & \verb|floor| & round down to nearest integer \\
+        \multicolumn{2}{|c|}{Binary operators}	       & \verb|fabs| & absolute value $|x|$\\
         \hline
-        \multicolumn{2}{|c|}{Binary operators}	 & \verb|log| & natural logarithm \\
+        \verb|+| & addition		               & \verb|floor| & round down to nearest integer \\
         \hline
-        \verb|+| & addition		         & \verb|log10| & base-10 logarithm \\
+        \verb|-| & subtraction		               & \verb|log| & natural logarithm \\
         \hline
-        \verb|-| & subtraction		         & \verb|sin| & sine \\
+        \verb|/| & C-like division		       & \verb|log10| & base-10 logarithm \\
         \hline
-        \verb|/| & C-like division		 & \verb|sinh| & hyperbolic sine \\
+        \verb|%| & remainder of division	       & \verb|sin| & sine \\
         \hline
-        \verb|*| & multiplication		 & \verb|sqrt| & square root \\
+        \verb|*| & multiplication		       & \verb|sinh| & hyperbolic sine \\
         \hline
-        \verb|^| & exponentiation $x^y$		 & \verb|tan| & tangent \\
+        \verb|**| & exponentiation $x^y$	       & \verb|sqrt| & square root \\
         \hline
-                 &                               & \verb|tanh| & hyperbolic tangent \\
+        \multicolumn{2}{|c|}{Unary operators}	       & \verb|tan| & tangent \\
         \hline
+        \verb|-| & negate sign		               & \verb|tanh| & hyperbolic tangent \\
+        \hline
+                                                     & & \verb|trunc| & integer part of $x$\\
+	\hline
     \end{tabular}
     \caption{Supported functions inside of expressions, in increasing order of
     precedence.}
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