Use syntax highlighting in doc/api-r.rst

doc/api-r.rst

@@ -4,30 +4,36 @@ R (``rixmp`` package)
 *********************
 
 An R interface to the `ixmp` is provided by the ``rixmp`` package.
-``rixmp`` uses the `reticulate <https://rstudio.github.io/reticulate/>`_ R-to-Python adapter to provide access to all features of the :mod:`ixmp` *Python* package::
+``rixmp`` uses the `reticulate <https://rstudio.github.io/reticulate/>`_ R-to-Python adapter to provide access to all features of the :mod:`ixmp` *Python* package
 
-    # Load the rixmp package
-    library(rixmp)
-    ixmp <- import('ixmp')
+.. code-block:: R
 
-    # An 'ixmp' object is added to the global namespace.
-    # It can be used in the same way as the Python ixmp package.
-    mp <- ixmp$Platform(dbtype = 'HSQLDB')
-    scen <- ixmp$Scenario(mp, 'model name', 'scenario name', version = 'new')
+   # Load the rixmp package
+   library(rixmp)
+   ixmp <- import('ixmp')
 
-    # etc.
+   # An 'ixmp' object is added to the global namespace.
+   # It can be used in the same way as the Python ixmp package.
+   mp <- ixmp$Platform(dbtype = 'HSQLDB')
+   scen <- ixmp$Scenario(mp, 'model name', 'scenario name', version = 'new')
+
+   # etc.
 
 One additional method, :meth:`adapt_to_ret` is provided.
-Access its documentation with::
+Access its documentation with
+
+.. code-block:: R
+
+   ?rixmp::adapt_to_ret
 
-    ?rixmp::adapt_to_ret
+This function is useful when adding :class:`data.frames` objects to a Scenario:
 
-This function is useful when adding :class:`data.frames` objects to a Scenario::
+.. code-block:: R
 
-    scen$init_set("i")
-    i.set = c("seattle", "san-diego")
-    scen$add_set("i", i.set)
-    # load dataframes
-    scen$init_par("a", c("i"))
-    a.df = data.frame(i = i.set, value = c(350, 600) , unit = 'cases')
-    scen$add_par("a", adapt_to_ret(a.df))
+   scen$init_set("i")
+   i.set = c("seattle", "san-diego")
+   scen$add_set("i", i.set)
+   # load dataframes
+   scen$init_par("a", c("i"))
+   a.df = data.frame(i = i.set, value = c(350, 600) , unit = 'cases')
+   scen$add_par("a", adapt_to_ret(a.df))