Add replace method to query (#46)

* Add replace function

* Add next method

* Remove tostring

* Fix EmptyQuery

* add replace method

* merge conflicts

* return self in without

* Make aliases relative

* Add test

* add to changelog

.luaurc

@@ -1,6 +1,6 @@
 {
     "aliases": {
-        "jecs": "C:/Users/Marcus/Documents/packages/jecs/src",
-        "testkit": "C:/Users/Marcus/Documents/packages/jecs/testkit"
+        "jecs": "src",
+        "testkit": "testkit"
     }
 }

CHANGELOG.md

@@ -10,6 +10,11 @@ The format is based on [Keep a Changelog][kac], and this project adheres to
 
 ## [Unreleased]
 
+### Added
+
+- Added `query:replace(function(...T) return ...U end)` for replacing components in place
+  - Method is fast pathed to replacing the data to the components for each corresponding entity
+
 ### Changed
 
 - Iterator now goes backwards instead to prevent common cases of iterator invalidation
@@ -109,12 +114,3 @@ The format is based on [Keep a Changelog][kac], and this project adheres to
 [0.0.0-prototype-rc.3]: https://github.com/ukendio/jecs/releases/tag/v0.0.0-prototype.rc.3
 [0.0.0-prototype.rc.2]: https://github.com/ukendio/jecs/releases/tag/v0.0.0-prototype.rc.2
 [0.0.0-prototype-rc.1]: https://github.com/ukendio/jecs/releases/tag/v0.0.0-prototype.rc.1
-
-
-
-
-
-
-
-
-

benches/query.luau

@@ -7,6 +7,7 @@ local function TITLE(title: string)
 	print()
 	print(testkit.color.white(title))
 end
+
 local jecs = require("@jecs")
 local mirror = require("../mirror/init")
 

src/init.luau

@@ -662,16 +662,24 @@ local function noop(_self: Query, ...): () -> ()
 end
 
 local EmptyQuery = {
-	__iter = noop,
-	without = noop,
+	__iter = iterNoop,
+	next = noop,
+	replace = noop,
+	without = function(self)
+		return self
+	end
 }
-EmptyQuery.__index = EmptyQuery
-setmetatable(EmptyQuery, EmptyQuery)
 
 export type Query = typeof(EmptyQuery)
 
 type CompatibleArchetype = { archetype: Archetype, indices: { number } }
 
+local function replaceMult(row, columns, ...)
+	for i, column in columns do
+		column[row] = select(i, ...)
+	end
+end
+
 local function preparedQuery(compatibleArchetypes: { Archetype },
 	components: { i53? }, indices: { { number } })
 
@@ -783,17 +791,60 @@ local function preparedQuery(compatibleArchetypes: { Archetype },
 		return self
 	end
 
-	local it = {
-		__iter = function() 
-			lastArchetype = 1
-			archetype = compatibleArchetypes[1]
-			entities = archetype.entities
-			i = #entities
+	local function iter()
+        lastArchetype = 1
+		archetype = compatibleArchetypes[1]
+		entities = archetype.entities
+		i = #entities
 
-			return queryNext
-		end,
+		return queryNext
+	end
+
+	local function replace(_, fn)
+        for i, archetype in compatibleArchetypes do
+			local tr = indices[i]
+			local columns = archetype.columns
+
+			for row in archetype.entities do
+				if queryLength == 1 then
+					local a = columns[tr[1]]
+					local pa = fn(a[row])
+
+					a[row] = pa
+				elseif queryLength == 2 then
+					local a = columns[tr[1]]
+					local b = columns[tr[2]]
+
+					a[row], b[row] = fn(a[row], b[row])
+				elseif queryLength == 3 then
+					local a = columns[tr[1]]
+					local b = columns[tr[2]]
+					local c = columns[tr[3]]
+
+					a[row], b[row], c[row] = fn(a[row], b[row], c[row])
+				elseif queryLength == 4 then
+					local a = columns[tr[1]]
+					local b = columns[tr[2]]
+					local c = columns[tr[3]]
+					local d = columns[tr[4]]
+
+					a[row], b[row], c[row], d[row] = fn(
+						a[row], b[row], c[row], d[row])
+				else
+					for i = 1, queryLength do
+						queryOutput[i] = columns[tr[i]][row]
+					end
+					replaceMult(row, columns, fn(unpack(queryOutput)))
+				end
+			end
+		end
+	end
+
+	local it = {
+		__iter = iter,
 		next = queryNext,
-		without = without
+		without = without,
+		replace = replace
 	}
 
 	return setmetatable(it, it) :: any

tests/world.luau

@@ -449,9 +449,28 @@ TEST("world", function()
 			count += 1
 		end
 
-		print(count)
 		CHECK(count == 2)
 	end
+
+	do CASE "should replace component data"
+        local world = jecs.World.new()
+		local A = world:component()
+		local B = world:component()
+	    local C = world:component()
+
+		local e = world:entity()
+		world:set(e, A, 1)
+		world:set(e, B, true)
+		world:set(e, C, "hello ")
+
+		world:query(A, B, C):replace(function(a, b, c)
+		    return a * 2, not b, c.."world"
+		end)
+
+		CHECK(world:get(e, A) == 2)
+		CHECK(world:get(e, B) == false)
+		CHECK(world:get(e, C) == "hello world")
+	end
 end)
 
 FINISH()