PsychOSPackages/preproc/lib/preproc.lua

70 lines
1.9 KiB
Lua

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})