From 710bd7fceaa8735fc3c0fb42e509dd919308cb0d Mon Sep 17 00:00:00 2001
From: Henri Menke <henri@icp.uni-stuttgart.de>
Date: Thu, 25 Apr 2019 16:43:43 +1200
Subject: [PATCH] Produce compilable examples from extract.lua #640

---
 doc/generic/pgf/extract.lua | 76 +++++++++++++++++++++++++++++--------
 1 file changed, 60 insertions(+), 16 deletions(-)

diff --git a/doc/generic/pgf/extract.lua b/doc/generic/pgf/extract.lua
index e5ab08975..8b88092ac 100644
--- a/doc/generic/pgf/extract.lua
+++ b/doc/generic/pgf/extract.lua
@@ -1,11 +1,34 @@
+-- TODO: this has to go
+local preamble = [[
+\usetikzlibrary{3d,arrows,arrows.spaced,arrows.meta,bending,babel,calc,
+  fit,patterns,plotmarks,shapes.geometric,shapes.misc,shapes.symbols,
+  shapes.arrows,shapes.callouts,shapes.multipart,shapes.gates.logic.US,
+  shapes.gates.logic.IEC,circuits.logic.US,circuits.logic.IEC,
+  circuits.logic.CDH,circuits.ee.IEC,datavisualization,
+  datavisualization.polar,datavisualization.formats.functions,er,automata,
+  backgrounds,chains,topaths,trees,petri,mindmap,matrix,calendar,folding,
+  fadings,shadings,spy,through,turtle,positioning,scopes,
+  decorations.fractals,decorations.shapes,decorations.text,
+  decorations.pathmorphing,decorations.pathreplacing,decorations.footprints,
+  decorations.markings,shadows,lindenmayersystems,intersections,
+  fixedpointarithmetic,fpu,svg.path,external,graphs,graphs.standard,quotes,
+  math,angles,views,animations,rdf,perspective}
+\usetikzlibrary{graphdrawing}
+\usegdlibrary{trees,circular,layered,examples,force,phylogenetics,routing}
+]]
+
 local lfs = require("lfs")
-local lpeg = require"lpeg"
+local lpeg = require("lpeg")
 local C, Cf, Cg, Ct, P, S, V = lpeg.C, lpeg.Cf, lpeg.Cg, lpeg.Ct, lpeg.P, lpeg.S, lpeg.V
 
 -- strip leading and trailing whitespace
 local function strip(str)
     return str:match"^%s*(.-)%s*$"
 end
+-- strip braces
+local function strip_braces(str)
+    return str:match"^{?(.-)}?$"
+end
 
 -- optional whitespace
 local ws = S" \t\n\r"^0
@@ -21,14 +44,14 @@ local function set(t,k,v)
     -- strip whitespace from keys
     k = strip(k)
     -- if the value is empty, set it to invalid character
-    v = v or invalid
+    v = v and strip_braces(v) or invalid
     return rawset(t,k,v)
 end
 
 -- Grammar to extract code examples
 local extractor = lpeg.P{"document",
     name =
-        C((1 - S"]=")^1),
+        C((1 - S",]=")^1),
 
     pair =
         Cg(V"name" * (lit"=" * V"braces")^0) * lit","^-1,
@@ -78,42 +101,63 @@ local basename = function(file)
 end
 
 -- Main loop
-sourcedir = "text-en/"
-targetdir = "/tmp/"
+if #arg ~= 2 then
+    print("Usage: " .. arg[-1] .. " " .. arg[0] .. " <source-dir> <target-dir>")
+    os.exit(1)
+end
+local pathsep = package.config:sub(1,1)
+sourcedir = arg[1] .. pathsep
+targetdir = arg[2] .. pathsep
+assert(lfs.attributes(sourcedir, "mode") == "directory", sourcedir .. " is not a directory")
+assert(lfs.attributes(targetdir, "mode") == "directory", targetdir .. " is not a directory")
 
 for file in lfs.dir(sourcedir) do
     if lfs.attributes(sourcedir .. file, "mode") == "file" then
+        print("Processing " .. file)
+
         -- Read file into memory
         local f = io.open(sourcedir .. file)
         local text = f:read("*all")
         f:close()
         local name, ext = basename(file)
 
+        -- preprocess, strip all commented lines
+        text = text:gsub("\n%%[^\n]*\n","")
+
         -- extract all code examples
         local matches = extractor:match(text) or {}
 
         -- write code examples to separate files
+        local setup_code = ""
         for n, e in ipairs(matches) do
             local options = e[1]
             local content = e[2]
 
+            -- If the snippet is marked as setup code, we have to put it before
+            -- every other snippet in the same file
+            if options["setup code"] then
+                setup_code = setup_code .. strip(content) .. "\n"
+            end
+
             -- Skip those that say "code only"
             if not options["code only"] then
                 local newname = name .. "-" .. n .. "." .. ext
-
                 local examplefile = io.open(targetdir .. newname, "w")
 
-                -- TODO: Use options to convert to MWE
-                examplefile:write("===Options===\n")
-                for key, value in pairs(options) do
-                    examplefile:write(key)
-                    if value ~= invalid then
-                        examplefile:write("=" .. value)
-                    end
-                    examplefile:write("\n")
+                examplefile:write"\\documentclass{article}\n"
+                examplefile:write"\\usepackage{fp,pgf,tikz,xcolor}\n"
+                examplefile:write(preamble)
+                examplefile:write"\\begin{document}\n"
+                examplefile:write"\\makeatletter\n" -- TODO: this has to go
+                examplefile:write(setup_code)
+                examplefile:write(options["pre"] and options["pre"] .. "\n" or "")
+                if options["render instead"] then
+                    examplefile:write(options["render instead"] .. "\n")
+                else
+                    examplefile:write(strip(content) .. "\n")
                 end
-                examplefile:write("===Content===\n")
-                examplefile:write(strip(content))
+                examplefile:write(options["post"] and options["post"] .. "\n" or "")
+                examplefile:write"\\end{document}\n"
 
                 examplefile:close()
             end