initial commit

luigi/style.lua

@@ -0,0 +1,79 @@
+local ROOT = (...):gsub('[^.]*$', '')
+
+local Base = require(ROOT .. 'base')
+
+local Style = Base:extend()
+
+function Style:constructor (rules, ...)
+    self.rules = rules
+    self.lookupNames = { ... }
+end
+
+function Style:getProperty (object, property)
+    local ownProperty = rawget(object, property)
+    if ownProperty ~= nil then return ownProperty end
+    for styleDef in self:each(object) do
+        local result = self:getProperty(styleDef, property)
+        if result ~= nil then return result end
+    end
+end
+
+function Style:each (object)
+    local rules = self.rules
+    local nextStyleName = self:eachName(object)
+    return function ()
+        local styleName = nextStyleName()
+        while styleName do
+            local styleDef = rules[styleName]
+            if styleDef then return styleDef end
+            styleName = nextStyleName()
+        end
+    end
+end
+
+function Style:eachName (object)
+    local lookupNames = self.lookupNames
+    local lookupNameIndex = 0
+    local lookupPropIndex = 0
+    local lookupProp
+
+    local returnedSpecialName = {}
+
+    local function checkLookupProp()
+        if type(lookupProp) == 'table' and lookupPropIndex >= #lookupProp then
+            lookupProp = nil
+        end
+        while not lookupProp do
+            returnedSpecialName = {}
+            lookupPropIndex = 0
+            lookupNameIndex = lookupNameIndex + 1
+            if lookupNameIndex > #lookupNames then return end
+            lookupProp = rawget(object, lookupNames[lookupNameIndex])
+            if type(lookupProp) == 'string' then
+                lookupProp = { lookupProp }
+            end
+        end
+        return true
+    end
+    local function getSpecialName (...)
+        for k, name in ipairs({ ... }) do
+            if not returnedSpecialName[name] then
+                returnedSpecialName[name] = true
+                if rawget(object, name) then
+                    return lookupProp[lookupPropIndex + 1] .. '_' .. name
+                else
+                    return lookupProp[lookupPropIndex + 1] .. '_not_' .. name
+                end
+            end
+        end
+    end
+    return function ()
+        if not checkLookupProp() then return end
+        local specialName = getSpecialName('pressed', 'hovered')
+        if specialName then return specialName end
+        lookupPropIndex = lookupPropIndex + 1
+        return lookupProp[lookupPropIndex]
+    end
+end
+
+return Style