cleanup

1 files changed, 56 insertions, 0 deletions

diff --git a/script/vm/node.lua b/script/vm/node.lua
new file mode 100644
index 00000000..79a4d2cb
--- /dev/null
+++ b/script/vm/node.lua
@@ -0,0 +1,56 @@
+local union      = require 'vm.union'
+
+---@alias vm.node parser.object | vm.node.union | vm.node.global | vm.node.generic
+
+local m = {}
+
+---@type table<parser.object, vm.node>
+m.nodeCache = {}
+
+---@param a vm.node
+---@param b vm.node
+function m.mergeNode(a, b)
+    if not b then
+        return a
+    end
+    if a.type == 'union' then
+        a:merge(b)
+        return a
+    end
+    return union(a, b)
+end
+
+function m.setNode(source, node)
+    if not node then
+        return
+    end
+    local me = m.nodeCache[source]
+    if not me then
+        m.nodeCache[source] = node
+        return
+    end
+    if me == node then
+        return
+    end
+    m.nodeCache[source] = m.mergeNode(me, node)
+end
+
+function m.eachNode(node)
+    if node.type == 'union' then
+        return node:eachNode()
+    end
+    local first = true
+    return function ()
+        if first then
+            first = false
+            return node
+        end
+        return nil
+    end
+end
+
+function m.clearNodeCache()
+    m.nodeCache = {}
+end
+
+return m