From 1754e50d7a7d66336cce2650aa0706b416e7631c Mon Sep 17 00:00:00 2001
From: Signal <signal@noreply.localhost>
Date: Sat, 10 Jan 2026 02:43:00 +0000
Subject: [PATCH] Initial commit.

---
 init.lua | 602 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 602 insertions(+)
 create mode 100644 init.lua

diff --git a/init.lua b/init.lua
new file mode 100644
index 0000000..2ef7414
--- /dev/null
+++ b/init.lua
@@ -0,0 +1,602 @@
+local ns = {
+    contexts = {}
+}
+
+local fe = minetest.formspec_escape
+local hte = minetest.hypertext_escape
+
+local ctx
+
+local observers = {}
+local State = {
+    get = function(e)
+        local observer = observers[#observers]
+        if observer then
+            observer[e] = true  -- Add this base state as a dep (using table for set-like uniqueness)
+        end
+        return e._val
+    end,
+    set = function(e, val)
+        if val == nil then error "!" end
+        e._oldVal = e._val
+        e._val = val
+        for _, x in pairs(e._getters) do
+            x:update()
+        end
+    end,
+    __call = function(e, val)
+        if val == nil then -- Getter
+            return e:get()
+        else -- Setter
+            return e:set(val)
+        end
+    end
+}
+State.__index = State
+
+function state(val)
+    local state = {_getters = {}, _val = val}
+    setmetatable(state, State)
+    
+    return state
+end
+
+local DerivedState = {
+    get = function(e)
+        if e._stale then
+            e:update()
+        end
+        return e._val
+    end,
+    update = function(e)
+        for dep in pairs(e._deps) do
+            dep._getters[e.__id] = nil
+            e._deps[dep] = nil
+        end
+        
+        local tracker = e._deps
+        table.insert(observers, tracker)
+        
+        local val = e._fn()
+        
+        table.remove(observers)
+        
+        e._val = val
+        
+        for dep in pairs(e._deps) do
+            dep._getters[e.__id] = e
+        end
+        
+        -- Don't propagate updates on initial computation to avoid stack overflow.
+        if not e._stale then
+            for _, x in pairs(e._getters) do
+                x:update()
+            end
+        end
+        e._stale = false
+    end,
+    __call = function(e)
+        return e:get()
+    end
+}
+DerivedState.__index = DerivedState
+
+function derive(fn)
+    return setmetatable({_fn = fn, _stale = true, _getters = {}, _deps = {}, __id = minetest.get_us_time()}, DerivedState)
+end
+
+local function get(e, x)
+    local item = e[x]
+    local mt = getmetatable(item)
+    if mt == State or mt == DerivedState then
+        return fe(item())
+    end
+    return fe(item)
+end
+
+-- MARK: Elements
+
+local fs_style = {
+    render = function(e)
+        local props = {}
+        for k, v in pairs(e.props) do
+            props[#props +1] = ";"
+            props[#props +1] = k
+            props[#props +1] = "="
+            props[#props +1] = tostring(v)
+        end
+        return string.format("style[%s%s]", e.name, table.concat(props))
+    end
+}
+fs_style.__index = fs_style
+setmetatable(fs_style, {
+    __call = function(_, name, props, internal)
+        local e = {name = name, props = props}
+        setmetatable(e, fs_style)
+        if not internal then table.insert(ctx, e) end
+        return e
+    end
+})
+
+local fs_label = {
+    render = function(e)
+        return string.format("label[%f,%f;%s]", get(e, "x"), get(e, "y"), get(e, "txt"))
+    end
+}
+fs_label.__index = fs_label
+setmetatable(fs_label, {
+    __call = function(_, x, y, txt)
+        local e = {x = x, y = y, txt = txt}
+        setmetatable(e, fs_label)
+        table.insert(ctx, e)
+        return e
+    end
+})
+
+local fs_arealabel = {
+    render = function(e)
+        if e._scrollable then
+            return string.format("textarea[%f,%f;%f,%f;;;%s]", get(e, "x"), get(e, "y"), get(e, "w"), get(e, "h"), get(e, "txt"))
+        else
+            return string.format("label[%f,%f;%f,%f;%s]", get(e, "x"), get(e, "y"), get(e, "w"), get(e, "h"), get(e, "txt"))
+        end
+    end,
+    scrollable = function(e)
+        e._scrollable = true
+        return e
+    end,
+}
+fs_arealabel.__index = fs_arealabel
+setmetatable(fs_arealabel, {
+    __call = function(_, x, y, w, h, txt)
+        local e = {x = x, y = y, w = w, h = h, txt = txt}
+        setmetatable(e, fs_arealabel)
+        table.insert(ctx, e)
+        return e
+    end
+})
+
+local fs_hypertext = {
+    render = function(e)
+        return string.format("hypertext[%f,%f;%f,%f;%s]", get(e, "x"), get(e, "y"), get(e, "w"), get(e, "h"), hte(get(e, "txt")))
+    end,
+    onaction = function(e, fn)
+        ctx._events.on_click[e.__id] = fn
+        return e
+    end
+}
+fs_hypertext.__index = fs_hypertext
+setmetatable(fs_hypertext, {
+    __call = function(_, x, y, w, h, txt)
+        local e = {x = x, y = y, w = w, h = h, txt = txt}
+        e.__id = "_"..minetest.get_us_time().."_"..math.random(1, 100000)
+        setmetatable(e, fs_hypertext)
+        table.insert(ctx, e)
+        return e
+    end
+})
+
+local fs_image = {
+    render = function(e)
+        return string.format("label[%f,%f;%f,%f;%s;%s]", get(e, "x"), get(e, "y"), get(e, "w"), get(e, "h"), get(e, "texture"), get(e, "middle"))
+    end
+}
+fs_image.__index = fs_image
+setmetatable(fs_image, {
+    __call = function(_, x, y, w, h, texture, middle)
+        local e = {x = x, y = y, w = w, h = h, texture = texture, middle = middle or ""}
+        setmetatable(e, fs_image)
+        table.insert(ctx, e)
+        return e
+    end
+})
+
+local fs_button = {
+    render = function(e)
+        local out = {}
+        for _, x in pairs(e._styles) do
+            out[#out +1] = x:render()
+        end
+        out[#out +1] = string.format("button[%f,%f;%f,%f;%s;%s]", get(e, "x"), get(e, "y"), get(e, "w"), get(e, "h"), e.__id, get(e, "label"))
+        return table.concat(out)
+    end,
+    style = function(e, state, props)
+        -- Allow omitting the state while keeping the properties the last argument.
+        if not props then
+            props = state
+            state = "default"
+        end
+        e._styles[state] = fs_style(e.__id..":"..state, props, true)
+        return e
+    end,
+    onclick = function(e, fn)
+        ctx._events.on_click[e.__id] = fn
+        return e
+    end
+}
+fs_button.__index = fs_button
+setmetatable(fs_button, {
+    __call = function(_, x, y, w, h, label)
+        local e = {x = x, y = y, w = w, h = h, label = label, _styles = {}}
+        e.__id = "_"..minetest.get_us_time().."_"..math.random(1, 100000)
+        setmetatable(e, fs_button)
+        table.insert(ctx, e)
+        return e
+    end
+})
+
+local fs_field = {
+    render = function(e)
+        local out = {}
+        for _, x in pairs(e._styles) do
+            out[#out +1] = x:render()
+        end
+        out[#out +1] = string.format("%s[%f,%f;%f,%f;%s;%s;%s]", e._textarea and "textarea" or "field", get(e, "x"), get(e, "y"), get(e, "w"), get(e, "h"), e.__id, get(e, "label"), get(e, "value"))
+        
+        if not e._textarea and not e._close_on_enter then
+            out[#out +1] = string.format("field_close_on_enter[%s;false]", e.__id)
+        end
+        
+        return table.concat(out)
+    end,
+    style = function(e, state, props)
+        -- Allow omitting the state while keeping the properties the last argument.
+        if not props then
+            props = state
+            state = "default"
+        end
+        e._styles[state] = fs_style(e.__id..":"..state, props, true)
+        return e
+    end,
+    onenter = function(e, fn)
+        ctx._events.on_enter[e.__id] = fn
+        return e
+    end,
+    onchange = function(e, fn)
+        ctx._events.on_change[e.__id] = fn
+        return e
+    end,
+    close_on_enter = function(e)
+        e._close_on_enter = true
+        return e
+    end,
+    multiline = function(e)
+        e._textarea = true
+        return e
+    end
+}
+fs_field.__index = fs_field
+setmetatable(fs_field, {
+    __call = function(_, x, y, w, h, label, value)
+        local e = {x = x, y = y, w = w, h = h, label = label or "", value = value or label or "", _styles = {}}
+        e.__id = "_"..minetest.get_us_time().."_"..math.random(1, 100000)
+        setmetatable(e, fs_field)
+        table.insert(ctx, e)
+        return e
+    end
+})
+
+function fs_textarea(...)
+    return fs_field(...)
+               :multiline()
+end
+
+local fs_scrollbar = {
+    render = function(e)
+        local out = {}
+        if e._options then
+            out[#out +1] = "scrollbaroptions["
+            local first = true
+            for k, v in pairs(options) do
+                if not first then
+                    out[#out +1] = ";"
+                end
+                out[#out +1] = k
+                out[#out +1] = "="
+                out[#out +1] = v
+                first = nil
+            end
+            out[#out +1] = "]"
+        end
+        
+        out[#out +1] = string.format("scrollbar[%f,%f;%f,%f;%s;%s;%s]", get(e, "x"), get(e, "y"), get(e, "w"), get(e, "h"), get(e, "orientation"), e.__id, get(e, "value"))
+        
+        return table.concat(out)
+    end,
+    style = function(e, state, props)
+        -- Allow omitting the state while keeping the properties the last argument.
+        if not props then
+            props = state
+            state = "default"
+        end
+        e._styles[state] = fs_style(e.__id..":"..state, props, true)
+        return e
+    end,
+    options = function(e, props)
+        return e
+    end,
+    onchange = function(e, fn)
+        ctx._events.on_scrollbar_event[e.__id] = fn
+        return e
+    end,
+}
+fs_scrollbar.__index = fs_scrollbar
+setmetatable(fs_scrollbar, {
+    __call = function(_, x, y, w, h, orientation, value)
+        local e = {x = x, y = y, w = w, h = h, orientation = orientation or "vertical", value = value or "", _styles = {}}
+        e.__id = "_"..minetest.get_us_time().."_"..math.random(1, 100000)
+        setmetatable(e, fs_scrollbar)
+        table.insert(ctx, e)
+        return e
+    end
+})
+
+local fs_scroll_container = {
+    render = function(e)
+        local out = {string.format("scroll_container[%f,%f;%f,%f;%s;%s;%s;%s]", get(e, "x"), get(e, "y"), get(e, "w"), get(e, "h"), e.__id, get(e, "orientation"), get(e, "factor"), get(e, "padding"))}
+        for _, x in ipairs(e) do
+            out[#out +1] = x:render()
+        end
+        out[#out +1] = "scroll_container_end[]"
+        
+        if e._scrollbar then
+            e._scrollbar.value = e._scroll_pos or ""
+            out[#out +1] = e._scrollbar:render()
+        else
+            local v = e.__fs._ctx.fields[e.__id]
+            out[#out +1] = string.format("scrollbar[-800,-800;0,0;%s;%s;%s]", get(e, "orientation"), e.__id, v and v:sub(5) or "")
+        end
+        
+        return table.concat(out)
+    end,
+    scrollbar = function(e, ...)
+        e._scrollbar = fs_scrollbar(..., e.__id, e._scroll_pos or "")
+        return e
+    end,
+    -- A non-transient name is required in order to preserve scroll position upon a rebuild.
+    named = function(e, name)
+        e.__id = name
+    end
+    
+}
+fs_scroll_container.__index = fs_scroll_container
+setmetatable(fs_scroll_container, {
+    __call = function(_, x, y, w, h, orientation, factor, padding)
+        local e = {x = x, y = y, w = w, h = h, orientation = orientation or "vertical", factor = factor or "", padding = padding or "0", _styles = {}, __parent = ctx, _events = setmetatable({}, {__index = ctx._events, __newindex = ctx._events}), __fs = ctx.__parent or ctx}
+        e.__id = "_"..minetest.get_us_time().."_"..math.random(1, 100000)
+        setmetatable(e, fs_scroll_container)
+        table.insert(ctx, e)
+        ctx = e
+        return e
+    end
+})
+
+function fs_scroll_container_end()
+    ctx = ctx.__parent
+end
+
+
+-- MARK: Building
+
+local Fs = {
+    render = function(e)
+        local out = {
+            "formspec_version[10]",
+            string.format("size[%f,%f]", e.width, e.height)
+        }
+
+        if e._no_prepend then
+            out[#out +1] = "no_prepend[]"
+        end
+        
+        if e._position then
+            out[#out +1] = string.format("position[%f,%f]", e._position.x, e._position.y)
+        end
+
+        if e._anchor then
+            out[#out +1] = string.format("anchor[%f,%f]", e._anchor.x, e._anchor.y)
+        end
+
+        if e._padding then
+            out[#out +1] = string.format("padding[%f,%f]", e._padding.x, e._padding.y)
+        end
+        
+        if e._modal then
+            out[#out +1] = "allow_close[false]"
+        end
+        
+        for _, x in ipairs(e) do
+            out[#out +1] = x:render()
+        end
+        return table.concat(out)
+    end,
+    no_prepend = function(e)
+        e._no_prepend = true
+        return e
+    end,
+    position = function(e, x, y)
+        e._position = {x = x, y = y}
+        return e
+    end,
+    anchor = function(e, x, y)
+        e._anchor = {x = x, y = y}
+        return e
+    end,
+    padding = function(e, x, y)
+        e._padding = {x = x, y = y}
+        return e
+    end,
+    modal = function(e)
+        e._modal = true
+        return e
+    end,
+    onclose = function(e, fn)
+        e._onclose = fn
+        return e
+    end
+}
+Fs.__index = Fs
+
+function fs_begin(w, h)
+    ctx = {_events = {on_click = {}, on_change = {}, on_scrollbar_event = {}, on_enter = {}}, width = w or 12, height = h or 10}
+    setmetatable(ctx, Fs)
+    return ctx
+end
+
+function fs_end()
+    local _ctx = ctx
+    ctx = nil
+    return _ctx
+end
+
+local Context = {
+    update = function(e)
+        if e._inert then
+            e._dirty = true
+        else
+            e:rebuild()
+        end
+    end,
+    rebuild = function(e)
+        e:clear_state_bindings()
+        
+        local tracker = e._linked_states
+        table.insert(observers, tracker)
+        
+        local fs = type(e.formspec) == "function" and e.formspec() or e.formspec
+        
+        table.remove(observers)
+        
+        fs._ctx = e
+        
+        for _, el in ipairs(fs) do
+            for _, x in pairs(el) do
+                local mt = getmetatable(x)
+                if mt == State or mt == DerivedState then
+                    x._getters[e.id] = e
+                    e._linked_states[x] = true
+                end
+            end
+        end
+        
+        e._events = fs._events
+        
+        local str = fs:render()
+        minetest.show_formspec(e.target, e.id, str)
+    end,
+    clear_state_bindings = function(e)
+        for x in pairs(e._linked_states) do
+            x._getters[e.id] = nil
+        end
+    end,
+    deinit = function(e)
+        e:clear_state_bindings()
+    end
+}
+Context.__index = Context
+
+function fs_show(target, fs)
+    local id = "form_"..minetest.get_us_time().."_"..math.random(1, 100000)
+    local ctx = setmetatable({
+        formspec = fs,
+        fields = {},
+        data = {},
+        target = target,
+        id = id,
+        _linked_states = {},
+    }, Context)
+    
+    ns.contexts[id] = ctx
+    
+    ctx:rebuild()
+end
+
+minetest.register_on_player_receive_fields(function(p, form, fields)
+    local ctx = ns.contexts[form]
+    if ctx then
+        ctx._inert = true
+        
+        if fields.key_enter_field and ctx._events.on_enter[fields.key_enter_field] then
+            ctx._events.on_enter[fields.key_enter_field](fields[fields.key_enter_field])
+        end
+        
+        for k, v in pairs(fields) do
+            if ctx._events.on_click[k] then
+                ctx._events.on_click[k](v)
+            elseif ctx._events.on_scrollbar_event[k] then
+                local ev = minetest.explode_scrollbar_event(v)
+                ctx._events.on_scrollbar_event[k](ev.type, ev.value)
+            elseif ctx.fields[k] and ctx.fields[k] ~= v and ctx._events.on_change[k] then
+                ctx._events.on_change[k](v)
+            end
+        end
+        
+        ctx.fields = fields
+        
+        ctx._inert = nil
+        
+        if fields.quit then
+            ctx:deinit()
+            ns.contexts[form] = nil
+        else
+            if ctx._dirty then
+                ctx:rebuild()
+                ctx._dirty = nil
+            end
+        end
+    end
+end)
+
+local counter = state(0)
+local str = state("")
+local pressed = state(false)
+
+local function fs()
+    fs_begin(12, 10)
+    
+    fs_label(1, 2, derive(function() return "Counter: "..counter() end))
+    fs_label(1, 3, derive(function() return "Length: "..#str end))
+    
+    if pressed() then
+        fs_label(1, 4, "Pressed!!")
+    end
+    
+    fs_button(4, 0.5, 4, 0.75, "Increment")
+        :style {
+            bgcolor = "#aaf"
+        }
+        :style("hovered", {
+            bgcolor = "#faa"
+        })
+        :style("pressed", {
+            bgcolor = "#afa"
+        })
+        :onclick(function()
+            counter(counter() +1)
+        end)
+        
+    fs_field(4, 2, 4, 0.75, "Test", str)
+        :onchange(function(value)
+            str(value)
+        end)
+        :onenter(function()
+            pressed(true)
+        end)
+    
+    fs_scroll_container(4, 3, 8, 7)
+        :named("test")
+    
+    for i = 0, 10 do
+        fs_label(0, i, i)
+    end
+    
+    fs_scroll_container_end()
+    
+    return fs_end()
+end
+
+minetest.register_chatcommand("demo", {
+    func = function(name)
+        fs_show(name, fs)
+    end
+})