ONYX shell - unix-like shell simulator

onyx.lua

----
-- ONYX shell
----
-- needs TableFS (https://gist.github.com/3925335)
----
-- unix-like shell simulator
-- by Severak 2012
-- license WTFPL
----
require "tfs"
command={}
command["ver"]=function()
	return "ONYX v 1.0"
end
command["exit"]=function() os.exit() end
command["echo"]=function(argz)
	return table.concat(argz," ")
end
command["ls"]=function(argz)
	local out={}
	local dir=argz[1] or "."
	if not(type(tfs.load(dir))=="table") then
		print(string.format("%s is not a dir.", dir))
		return ""
	end
	for file in tfs.dir(dir) do
		out[#out+1]=file
	end
	return table.concat(out,"\n")
end
command["cd"]=function(argz)
	local ok,err=tfs.chdir(argz[1] or ".")
	if not ok then
		print("-onyx: ",err)
	end
end

command["pwd"]=function(argz)
	return tfs.pwd()
end

command["mkdir"]=function(argz)
	local ok,err=tfs.mkdir(argz[1] or ".")
	if ok then
		return 0
	else
		print(err)
	end
end

command["rmrf"]=function(argz)
	if #argz>0 then
		tfs.save(argz,nil)
	end
end

function splitWords(sentence)
	local ret={}
	for word in sentence:gmatch("([^%s]+)") do
		ret[#ret+1]=word
	end
	return ret
end

local tree=tDir{
	home=tDir{
		help="Work with it as you will work with unix.",
		examples=tDir{
			a="echo ok|reverse",
			b="cat /doc/readme",
			c="ls>dir.txt",
			d="echo ok|reverse|tee reversed.txt|reverse>normal.txt"
		}
	},
	doc=tDir{
		readme="There is no readme today\n:-("
	},
	bin=tDir{},
	dev=tDir{}
}

devMT={
	__index=function(dir,file)
		if file=="random" then
			return math.random(255)
		elseif file=="null" then
			return ""
		end
	end,
	__newindex=function(dir,file,data)
		if file=="null" or file=="random" then
			return nil
		else
			rawset(dir,file,data)
		end
	end
}

setmetatable(tree["dev"],devMT)

tfs=TableFS(tree,"home")

tfs.save("/bin/cat", function(argz,input)
	local out={}
	if #argz>0 then
		for _,name in pairs(argz) do
			local data,err=tfs.load(name)
			if type(data)=="table" then
				print(string.format("cat: %s: Is directory",name))
			elseif data then
				out[#out+1]=tostring(data)
			else
				print(string.format("cat: %s: %s",name,err or "File not found!"))
			end
		end
	else	
		out[#out+1]=io.read()
	end
	return table.concat(out,"\n")
end)

tfs.save("/bin/reverse", function(argz,input)
	return string.reverse(input or "")
end)

tfs.save("/bin/tee", function(argz,input)
	for _,name in pairs(argz) do
		tfs.save(name,input)
	end
	return input
end)

tfs.save("/bin/help", function()
	print("Use it like unix.")
	print("There is no other help...")
end)

function processPipe(cmds)
	local out=""
	for input in string.gmatch(cmds,"([^|]+)") do
		local args=splitWords(input)
		local cmd=table.remove(args,1)
		if command[cmd] then
			out=command[cmd](args)
		else
			local fun=tfs.load("/bin/"..cmd)
			if type(fun)=="function" then
				out=fun(args,out)
			else
				print(string.format("An attemp to call %s (not a function)",cmd))
				break
			end
		end
	end
	return out or ""
end


function main()
	while true do
		io.write("> ")
		local outfile=false
		local input=io.read()
		if string.match(input,"(.+)>(.+)") then
			input,outfile=string.match(input,"(.+)>(.+)")
		end
		local out=processPipe(input)
		if not(out=="") then
			if outfile then
				tfs.save(outfile,out)
			else
				print(out)
			end
		end
	end
end

main()