feat: add hilbish.opts and autocd opt

this adds `hilbish.opts`, a table to set
simple options akin to shopt or setopt on
other shells. this commit specifically also
includes the autocd opt, which functions the
way you expect it to

to set opts, simply do `hilbish.opts.name = val`,
where `name` is the opt you want to set and `val`
being the opt setting.

ie: `hilbish.opts.autocd = true` to turn on autocd

nature/init.lua

@@ -6,6 +6,7 @@ package.path = package.path .. ';' .. hilbish.dataDir .. '/?/init.lua'
 
 require 'nature.commands'
 require 'nature.completions'
+require 'nature.opts'
 
 local shlvl = tonumber(os.getenv 'SHLVL')
 if shlvl ~= nil then

nature/opts/autocd.lua

@@ -0,0 +1,23 @@
+local fs = require 'fs'
+
+function cdHandle(inp)
+	local input, exit, err = hilbish.runner.lua(inp)
+
+	if not err then
+		return input, exit, err
+	end
+
+	input, exit, err = hilbish.runner.sh(inp)
+
+	if exit ~= 0 and hilbish.opts.autocd then
+		local ok, stat = pcall(fs.stat, input)
+		if ok and stat.isDir then
+			-- discard here to not append the cd, which will be in history
+			_, exit, err = hilbish.runner.sh('cd ' .. input)
+		end
+	end
+
+	return input, exit, err
+end
+
+hilbish.runner.setMode(cdHandle)

nature/opts/init.lua

@@ -0,0 +1,28 @@
+local opts = {}
+hilbish.opts = {}
+
+setmetatable(hilbish.opts, {
+	__newindex = function(_, k, v)
+		if opts[k] == nil then
+			error(string.format('opt %s does not exist', k))
+		end
+
+		opts[k] = v
+	end,
+	__index = function(_, k)
+		return opts[k]
+	end
+})
+
+local function setupOpt(name, default)
+	opts[name] = default
+	require('nature.opts.' .. name)
+end
+
+local defaultOpts = {
+	autocd = false
+}
+
+for optsName, default in pairs(defaultOpts) do
+	setupOpt(optsName, default)
+end