ESKEES script language

The full reference is available in Japanese for now. This page is an overview. Alpha: details may change without notice.

ESKEES script describes everything from "change the expression when clicked" to small games like Tetris and Patapata. It has a Lua-like syntax with blocks closed by end, and can be edited as blocks, text or a diagram in ESKEES Studio. The same script runs in test play, the Player, showcase and ESKEES Screen.

What a script looks like

Only five kinds of things can appear at the top level: var, save, function, class and on (triggers).

var score = 0 to 999999 save          -- a number shown on screen and saved
save 記録 = { best = 0 }              -- the save-data layout

function add(a, b)                     -- a function (top level only)
  return a + b
end

class 鳥                               -- an actor class
  vy = 0
  function update(dt)
    self.y += self.vy * dt
  end
end

on press 顔                            -- a trigger
  score = add(score, 1)
end

Triggers

• on start (once when opened), on frame (every frame, dt seconds), on every 1.5
• on press / click / down / up for click areas and UI buttons (any for anywhere), on drag A to B, on tap Class
• on key Space / on keyup (keyboard and gamepad names such as PadA)
• on change var, on scene name

Statements

• Control — if, switch, loop, while, repeat n … end, repeat … until, for i = 1, n do, for k, v in pairs(t) do, for each in Class, break, wait
• Parts and animation — frame face = "smile", toggle, play, tween … to { … } in 0.25 ease "back-out"
• Actors — spawn Class at x, y, destroy, self.x, touching Class, self:overlapping("Class")
• Scenes, UI, sound — scene, ui Panel show, say Text = "…", sound, music
• Camera and stages — camera follow self, camera shake, stage "name", tile.at, self:moveBy(dx, dy)
• Scores — score total as Time lower sends a value to the leaderboard (see ESKEES Studio)

Differences from Lua

• 0 and the empty string are falsy; undefined variables are 0.
• += and -= exist; != works as well as ~=.
• Functions only at the top level — no closures, no varargs, one return value.
• Objects are class (actors) only; no metatables and no standard library such as os or io.
• wait is a statement that pauses the script — no coroutines needed.