Set up ldoc and lua-language-server, write some module stubs

.luarc.json

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+{
+  "$schema": "https://raw.githubusercontent.com/sumneko/vscode-lua/master/setting/schema.json",
+  "workspace.library": ["lib/luavgl/src", "src/lua/stubs"],
+  "runtime.version": "Lua 5.4",
+}
+

config.ld

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+file = {'src/lua/stubs'}
+project = "Tangara"
+description = "Lua modules provided by Tangara's firmware"

src/lua/stubs/bluetooth.lua

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+--- Properties and functions for handling Bluetooth connectivity
+-- @module bluetooth
+
+local bluetooth = {}
+
+-- Whether or not the Bluetooth stack is currently enabled. This property is writeable, and can be used to enable or disable Bluetooth.
+-- @treturn types.Property a boolean property
+function bluetooth.enabled() end
+
+--- Whether or not there is an active connection to another Bluetooth device.
+-- @treturn types.Property a boolean property
+function bluetooth.connected() end
+
+return bluetooth

src/lua/stubs/playback.lua

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+--- Properties for interacting with the audio playback system
+-- @module playback
+
+local playback = {}
+
+--- Whether or not any audio is *allowed* to be played. If there is a current track, then this is essentially an indicator of whether playback is paused or unpaused.
+--- This value isn't meaningful if there is no current track.
+-- @treturn types.Property a boolean property
+function playback.playing() end
+
+return playback

src/lua/stubs/power.lua

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+--- Properties and functions that deal with the device's battery and power state
+-- @module power
+
+local power = {}
+
+--- battery_pct returns the battery's current charge as a percentage
+-- @treturn types.Property an integer property, from 0 to 100
+function power.battery_pct() end
+
+--- battery_millivolts returns the battery's current voltage in millivolts
+-- @treturn types.Property an integer property, typically from about 3000 to about 4200.
+function power.battery_millivolts() end
+
+--- plugged_in returns whether or not the device is currently receiving external power
+-- @treturn types.Property a boolean property
+function power.plugged_in() end
+
+return power

src/lua/stubs/types.lua

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+--- Userdata-based types used throughout the rest of the API. These types are
+--- not generally constructable within Lua code.
+-- @module types
+
+--- A value sourced from the C++ firmware.
+-- @type Property
+local Property = {}
+
+--- Gets the current value
+-- @return The property's current value.
+function Property:get() end
+
+--- Sets a new value. Not all properties may be set from within Lua code. For
+--- example, it makes little sense to attempt to override the current battery
+--- level.
+-- @param val The new value. This should generally be of the same type as the existing value.
+-- @return true if the new value was applied, or false if the backing C++ code rejected the new value (e.g. if it was out of range, or the wrong type).
+function Property:set(val) end
+
+--- Invokes the given function once immediately with the current value, and then again whenever the value changes.
+--- The function is invoked for *all* changes; both from the underlying C++ data, and from calls to `set` (if this is a Lua-writeable property).
+--- The binding will be active **only** so long as the given function remains in scope.
+-- @param fn callback function to apply property values. Must accept one argument; the updated value.
+-- @return fn, for more ergonmic use with anonymous closures.
+function Property:bind(fn) end
+
+return Property