From 6a0e08db272f09091ffdfc3f8766c91979138750 Mon Sep 17 00:00:00 2001
From: Henri Menke <henrimenke@gmail.com>
Date: Wed, 17 Jun 2020 20:32:22 +1200
Subject: [PATCH] Add options to Lua examples #640 #839

---
 .../lua/pgf/gd/force/ControlElectric.lua      | 28 ++++++++++++-------
 .../pgf/lua/pgf/manual/DocumentParser.lua     | 25 +++++++++++++----
 2 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/tex/generic/pgf/graphdrawing/lua/pgf/gd/force/ControlElectric.lua b/tex/generic/pgf/graphdrawing/lua/pgf/gd/force/ControlElectric.lua
index 47e3cee45..c9f129c28 100644
--- a/tex/generic/pgf/graphdrawing/lua/pgf/gd/force/ControlElectric.lua
+++ b/tex/generic/pgf/graphdrawing/lua/pgf/gd/force/ControlElectric.lua
@@ -39,16 +39,24 @@ declare {
     Two typical effects of increasing the |electric charge| are distortion
     of symmetries and an upscaling of the drawings.
   "]],
-  examples = {[["
-    \tikz \graph [spring electrical layout, horizontal=0 to 1]
-      { 0 [electric charge=1] -- subgraph C_n [n=10] };
-  "]],[["
-    \tikz \graph [spring electrical layout, horizontal=0 to 1]
-      { 0 [electric charge=5] -- subgraph C_n [n=10] };
-  "]],[["
-    \tikz \graph [spring electrical layout, horizontal=0 to 1]
-      { [clique] 1 [electric charge=5], 2, 3, 4 };
-  "]]
+  examples = {
+    {
+      options = [["preamble={\usetikzlibrary{graphs,graphdrawing} \usegdlibrary{force}}"]],
+      code = [["
+        \tikz \graph [spring electrical layout, horizontal=0 to 1]
+          { 0 [electric charge=1] -- subgraph C_n [n=10] };
+      "]]
+    },{
+      code = [["
+        \tikz \graph [spring electrical layout, horizontal=0 to 1]
+          { 0 [electric charge=5] -- subgraph C_n [n=10] };
+      "]]
+    },{
+      code = [["
+        \tikz \graph [spring electrical layout, horizontal=0 to 1]
+          { [clique] 1 [electric charge=5], 2, 3, 4 };
+      "]]
+    }
   }
 }
 
diff --git a/tex/generic/pgf/lua/pgf/manual/DocumentParser.lua b/tex/generic/pgf/lua/pgf/manual/DocumentParser.lua
index d2f678082..bd2a7026a 100644
--- a/tex/generic/pgf/lua/pgf/manual/DocumentParser.lua
+++ b/tex/generic/pgf/lua/pgf/manual/DocumentParser.lua
@@ -159,7 +159,17 @@ local function process_examples(t)
 
   local n = {}
   for i=1,#t do
-    n[i] = process_string(strip_quotes(t[i]))
+    local code, options
+    if type(t[i]) == "table" then
+      code = assert(t[i].code)
+      options = t[i].options
+    else
+      code = t[i]
+    end
+    n[i] = {
+      options = process_string(strip_quotes(options)),
+      code = process_string(strip_quotes(code))
+    }
   end
   return n
 end
@@ -391,8 +401,9 @@ DocumentParser.addRenderer (
       print_on_output(output,
                       "\\par\\smallskip\\emph{Example" .. (((#e>1) and "s") or "") .. "}\\par")
       for _,example in ipairs(e) do
-        print_on_output(output, "\\begin{codeexample}[]")
-        print_lines_on_output(output, example)
+        local opts = table.concat(example.options or {}, "")
+        print_on_output(output, "\\begin{codeexample}[" .. opts .. "]")
+        print_lines_on_output(output, example.code)
         print_on_output(output, "\\end{codeexample}")
       end
     end
@@ -417,8 +428,12 @@ DocumentParser.addRenderer (
 
 
 function print_lines_on_output(output, lines)
-  for _,l in ipairs(lines or {}) do
-    output[#output+1] = l
+  for n,l in ipairs(lines or {}) do
+    if (n == 1 or n == #lines) and l == "" then
+       -- skip leading and trailing blank lines
+    else
+      output[#output+1] = l
+    end
   end
 end