Started a section on code cells

lia/nfdi-emacs-lia-workshop.lia.md

@@ -45,6 +45,10 @@ Let’s make an executive summary of org-mode:
 Org-mode is a magnificent tool when it comes to reproducible research [^1], since this combines a
 well documented way of analysing a data set.
 
+By combining org-mode with code, we can create a document which not only describes and explains
+a process or analysis in the style of literate programming, but also can be automatically run to
+generate nicely formatted files run on the most recently available data.
+
 [^1]: Stanisic, Luka, and Arnaud Legrand. 2014. “Effective Reproducible   Research with Org-Mode
 and Git.” In /Euro-Par 2014: Parallel Processing Workshops/, edited by Luís Lopes, Julius
 Žilinskas, Alexandru Costan, Roberto G. Cascella, Gabor Kecskemeti, Emmanuel Jeannot, Mario
@@ -56,8 +60,67 @@ Cannataro, et al., 475–86. Cham: Springer International Publishing.
 
 ### How to write a Code Cell
 
-- syntax
-- optional parameters
+Code blocks in org-babel always start and end the same way:
+
+```
+#+BEGIN_SRC <language>
+
+#+END_SRC
+```
+
+We can also add plenty of metadata before the block:
+
+- `#+NAME` Provides the block with a name, so that we can easily reference it from other code cells
+
+- `#+CAPTION` Provide a caption under the cell when the document is exported
+
+There are also switches we can add after the language that affect how the cell is executed or
+processed:
+
+- `:results` Controls how the results of the code execution are handled.
+
+  - `:results output` outputs the results of the cell in the document
+
+  - `:results silent`supresses all output from the cell
+
+  - `:results file` creates a file to contain the output
+
+- `:exports` Controls how the code block itself is treated in the document.
+
+  - `:exports code` includes the code block itself in the document
+
+  - `:exports results` supresses the code, but shows any results generated by the code
+
+  - `:exports both` includes both the code and the results in the document
+
+- `:eval`
+
+ - `:eval yes` The code cell will be evaluated when the document is exported
+
+ - `:eval no` The code cell will not be evaluated when the document is exported. You might use
+ this when
+
+ - `:eval no-export` The code will not be evaluated when exporting, but will execute within the
+ org-mode buffer
+
+- `:tangle yes` The code in this block will be "tangled" (extracted) into a seperate source file.
+This could be useful if you are documenting how to create a script and part of the result of the
+document is the final script itself.
+
+There are some additional switches we can add that are specific to the language used in the cell.
+For example:
+
+- In Python or R, we can use the `:session <name>` switch to ensure more than one code block share
+a session
+
+- In R, we can use `:colnames yes` or `:colnames no` to dictate whether or not column names should
+appear in the results. There is a similar switch called `:rownames`
+
+### Variables
+
+We can use `var=<value>` to set a variable that will be available in the code block. This variable
+can either be a constant or a reference to another cell's `#+NAME`, in which case the value of the
+variable will be set to whatever the result of that cell is.
 
 # Preparing Data