From 29cdcb18099d58eaa2d9092f32d69ea37df144ad Mon Sep 17 00:00:00 2001
From: XeonSquared <redtailedairways@gmail.com>
Date: Wed, 3 Jun 2020 09:55:22 +1000
Subject: [PATCH] added the preproc library, meaning PsychOS is nominally
 self-hosting

---
 build.lua       |  3 +++
 build.sh        |  2 +-
 lib/preproc.lua | 69 +++++++++++++++++++++++++++++++++++++++++++++++++
 preproc.lua     |  1 +
 4 files changed, 74 insertions(+), 1 deletion(-)
 create mode 100644 build.lua
 create mode 100644 lib/preproc.lua
 create mode 120000 preproc.lua

diff --git a/build.lua b/build.lua
new file mode 100644
index 0000000..39298ff
--- /dev/null
+++ b/build.lua
@@ -0,0 +1,3 @@
+local preproc = require "preproc"
+--local tA = {...}
+preproc(...)
diff --git a/build.sh b/build.sh
index a20c7b7..1fbb833 100755
--- a/build.sh
+++ b/build.sh
@@ -2,7 +2,7 @@
 LUA=${LUA:-lua}
 rm -r target/*
 mkdir -p target/doc &>/dev/null
-$LUA luapreproc.lua module/init.lua target/init.lua
+$LUA build.lua module/init.lua target/init.lua
 echo _OSVERSION=\"PsychOS 2.0a2-$(git rev-parse --short HEAD)\" > target/version.lua
 cat target/version.lua target/init.lua > target/tinit.lua
 mv target/tinit.lua target/init.lua
diff --git a/lib/preproc.lua b/lib/preproc.lua
new file mode 100644
index 0000000..1cdac5a
--- /dev/null
+++ b/lib/preproc.lua
@@ -0,0 +1,69 @@
+local preproc = {}
+preproc.directives = {}
+
+function preproc.parsewords(line) -- string -- table -- Returns a table of words from the string *line*, parsing quotes and escapes.
+ local rt = {""}
+ local escaped, quoted = false, false
+ for c in line:gmatch(".") do
+  if escaped then
+   rt[#rt] = rt[#rt]..c
+  elseif c == '"' or c == "'" then
+   quoted = not quoted
+  elseif c == "\\" then
+   escaped = true
+  elseif c:match("%s") and not quoted and rt[#rt]:len() > 0 then
+   rt[#rt+1] = ""
+  else
+   rt[#rt] = rt[#rt]..c
+  end
+ end
+ return rt
+end
+
+function preproc.line(line) -- string -- -- Returns either a function - which can be called to get lines until it returns nil - or a string from processing *line* using preprocessor directives.
+ if line:match("^%-%-#") then
+  local directive, args = line:match("^%-%-#(%S+)%s(.+)")
+  print(directive,args)
+  local args = preproc.parsewords(args)
+  if preproc.directives[directive] then
+   return preproc.directives[directive](table.unpack(args))
+  else
+   error("unknown preprocessor directive: "..directive)
+  end
+ else
+  return line
+ end
+end
+
+function preproc.preproc(...) -- string -- string -- Returns the output from preprocessing the files listed in *...*.
+ local tA = {...}
+ local output = ""
+ for _,fname in ipairs(tA) do
+  local f,e = io.open(fname)
+  if not f then error("unable to open file "..fname..": "..e) end
+  for line in f:lines() do
+   local r = preproc.line(line)
+   if type(r) == "function" then
+    while true do
+     local rs = r()
+     if not rs then break end
+     output = output .. rs .. "\n"
+    end
+   else
+    output = output .. r .. "\n"
+   end
+  end
+ end
+ return output
+end
+
+preproc.directives.include = preproc.preproc
+
+return setmetatable(preproc,{__call=function(_,...)
+ local tA = {...}
+ local out = table.remove(tA,#tA)
+ local f,e = io.open(out,"wb")
+ if not f then error("unable to open file "..out..": "..e) end
+ f:write(preproc.preproc(table.unpack(tA)))
+ f:close()
+end})
diff --git a/preproc.lua b/preproc.lua
new file mode 120000
index 0000000..fdc06ae
--- /dev/null
+++ b/preproc.lua
@@ -0,0 +1 @@
+lib/preproc.lua
\ No newline at end of file