IOUtils: document alias option to variables in file readersvn

git-svn-id: http://svn.cactuscode.org/arrangements/CactusBase/IOUtil/trunk@308 b32723a9-ab3a-4a60-88e2-2e5d99d7c17a

1 files changed, 7 insertions, 0 deletions

diff --git a/doc/documentation.tex b/doc/documentation.tex
index 6bf20d0..882851e 100644
--- a/doc/documentation.tex
+++ b/doc/documentation.tex
@@ -551,6 +551,13 @@ read from file(s) as initial data:
     string with the key {\tt cctk\_iteration} and an associated integer scalar
     value to the variable name denoting the iteration number to choose, like in
     {\tt IO::filereader\_ID\_vars = "wavetoy::phi\{ cctk\_iteration = 10 \}"}.
+    The file reader supports a further option {\tt alias} and an associated
+    string scalar value which can be used to set the dataset in the initial
+    data files that will be read into this variable. For example {\tt
+    IO::filereader\_ID\_vars = "wavetoy::phi\{ alias='wavetoy::psi' \}"} will
+    read the data of variable {\tt wavetoy::psi} from file into 
+    {\tt wavetoy::phi}. This option requires that explicit variable names are
+    used, group names are not supported for the {\tt alias} option.
 \end{itemize}
 
 Thorn {\bf IOUtil} also provides a filereader API which can be called