From 9722f57891b99694a60d2fcb376375606741445e Mon Sep 17 00:00:00 2001
From: Thomas Letan <lthms@soap.coffee>
Date: Sun, 20 Dec 2020 12:47:37 +0100
Subject: Provide some insight on how literate programming projects are built

---
 site/cleopatra.org                      |  8 +++-
 site/cleopatra/literate-programming.org | 67 +++++++++++++++++++++++----------
 2 files changed, 54 insertions(+), 21 deletions(-)

(limited to 'site')

diff --git a/site/cleopatra.org b/site/cleopatra.org
index 313007f..77e8ff1 100644
--- a/site/cleopatra.org
+++ b/site/cleopatra.org
@@ -40,7 +40,13 @@ written as literate programs.
 
 - [[file:cleopatra/coq.org][Authoring Contents As Coq Documents ~(TODO)~]] ::
 
-- [[./cleopatra/literate-programming.org][Authoring Literate Programs ~(TODO)~]] ::
+- [[./cleopatra/literate-programming.org][Authoring Literate Programs]] ::
+  Literate programming is an interesting exercice, and it is
+  particularly well-suited for blog posts, since at the very least it
+  provides the tool to enforce the code presented to readers is
+  correct. We use Emacs and ~org-mode~ to tangle the literate
+  programming projects present in the ~posts/~ directory of this
+  website.
 
 - [[./cleopatra/org.org][Authoring Contents As Org Documents ~(TODO)~]] ::
 
diff --git a/site/cleopatra/literate-programming.org b/site/cleopatra/literate-programming.org
index 3b56924..be25097 100644
--- a/site/cleopatra/literate-programming.org
+++ b/site/cleopatra/literate-programming.org
@@ -2,12 +2,56 @@
 <h1>Literate Programming Projects</h1>
 #+END_EXPORT
 
+Literate programming is an interesting exercice. It forces programmers
+to think about how to present their code for other people to
+understand it. It poses several significant challenges, in particular
+in terms of code refactoring. If a given piece of code is too much
+entangled with proses explaining it, rewriting it becomes cumbersome.
+
+That being said, literate programming is particularly well-suited for
+blog posts, since at the very least it provides the tool to enforce
+the code presented to readers is correct.
+
+We use Emacs and ~org-mode~ to tangle the literate programming
+projects present in the ~posts/~ directory of this website. This is
+done with the following emacs lisp script.
+
+#+BEGIN_SRC emacs-lisp :tangle export-lp.el
+(cleopatra:configure) ; opinionated configuration provided by cleopatra
+
+(org-babel-do-load-languages
+ 'org-babel-load-languages
+ '((shell . t))) ; allow the execution of shell block code
+
+ ;; scan the posts/ directory and tangled it into lp/
+(setq org-publish-project-alist
+      '(("lp"
+         :base-directory "site/posts"
+         :publishing-directory "lp"
+         :recursive t
+         :publishing-function cleopatra:tangle-publish)))
+
+(org-publish-all)
+#+END_SRC
+
+Tangling literate programming is done in the =prebuild= phase of
+*~cleopatra~*.
+
 #+BEGIN_SRC makefile :tangle literate-programming.mk
 literate-programming-prebuild :
 	@cleopatra echo "Tangling" "literate programming project"
 	@cleopatra exec -- cleopatra-run-elisp export-lp.el \
 	    >> build.log 2>&1
 
+ARTIFACTS += lp/ site/posts/deps.svg
+#+END_SRC
+
+In the =build= phase, we actually try to compile the tangled projects.
+As of now, there is only one literate program: [[../posts/CoqffiEcho.org][the Echo server
+implemented in Coq]] which demonstrates how ~coqffi~ can be used to
+implement realistic software projects.
+
+#+BEGIN_SRC makefile :tangle literate-programming.mk
 COQFFI_ARCHIVE := site/files/coqffi-tutorial.tar.gz
 
 coqffi-tutorial-build : literate-programming-prebuild
@@ -15,28 +59,11 @@ coqffi-tutorial-build : literate-programming-prebuild
 	@cd lp/coqffi-tutorial; dune build --display quiet
 	@cleopatra echo "Archiving" "coqffi tutorial"
 	@rm -f ${COQFFI_ARCHIVE}
-	@tar --exclude="_build" -C lp/ -czvf ${COQFFI_ARCHIVE} coqffi-tutorial >> build.log
+	@tar --exclude="_build" -C lp/ -czvf ${COQFFI_ARCHIVE} coqffi-tutorial \
+	      2>&1 >> build.log
 
 site/posts/CoqffiEcho.html : coqffi-tutorial-build
 literate-programming-build : coqffi-tutorial-build
 
-ARTIFACTS += lp/ ${COQFFI_ARCHIVE} site/posts/deps.svg
-
-#+END_SRC
-
-#+BEGIN_SRC emacs-lisp :tangle export-lp.el
-(cleopatra:configure)
-
-(org-babel-do-load-languages
- 'org-babel-load-languages
- '((shell . t)))
-
-(setq org-publish-project-alist
-      '(("lp"
-         :base-directory "site/posts"
-         :publishing-directory "lp"
-         :recursive t
-         :publishing-function cleopatra:tangle-publish)))
-
-(org-publish-all)
+ARTIFACTS += ${COQFFI_ARCHIVE}
 #+END_SRC
-- 
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