More work on swizzle.

tests/bench_swizzle.nim

@@ -0,0 +1,31 @@
+import benchy, vmath
+
+block:
+  var
+    a = vec2(1, 10)
+    b = vec2(2, 20)
+    c = vec2(3, 30)
+  timeIt "xy":
+    for i in 0 ..< 1_000_000:
+      c.yx = a.xy + b.rg + c.xy
+  echo c.xy
+
+block:
+  var
+    a = vec3(1, 10, 100)
+    b = vec3(2, 20, 200)
+    c = vec3(3, 30, 300)
+  timeIt "xyz":
+    for i in 0 ..< 1_000_000:
+      c.zyx = a.xyz + b.rgb + c.xyz
+  echo c.xyz
+
+block:
+  var
+    a = vec4(1, 10, 100, -1)
+    b = vec4(2, 20, 200, -1)
+    c = vec4(3, 30, 300, -1)
+  timeIt "xyzw":
+    for i in 0 ..< 1_000_000:
+      c.wzyx = a.xyzw + b.rgba + c.xyzw
+  echo c.xyzw

tests/test.nim

@@ -356,11 +356,45 @@ block:
 
   var b = dvec4(1, 2, 3, 4)
   doAssert b == dvec4(1, 2, 3, 4)
-  b.wzyx = b
-  doAssert b == dvec4(4, 3, 2, 1)
 
   b.g = 123
-  doAssert b == dvec4(4.0, 123.0, 2.0, 1.0)
+  doAssert b == dvec4(1.0, 123.0, 3.0, 4.0)
+
+block:
+  # test swizzle self-assignment
+  var a = dvec2(1, 2)
+  a.yx = a
+  doAssert a == dvec2(2, 1)
+
+  var b = dvec3(1, 2, 3)
+  b.zyx = b
+  doAssert b == dvec3(3, 2, 1)
+
+  var c = dvec4(1, 2, 3, 4)
+  c.wzyx = c
+  doAssert c == dvec4(4, 3, 2, 1)
+
+block:
+   # Test swizzle calls only once
+  var callCount = 0
+  proc countsCalls(): Vec2 =
+    inc callCount
+
+  doAssert countsCalls().yx == vec2(0, 0)
+  doAssert callCount == 1
+
+  callCount = 0
+  doAssert vec2(0, 0) == countsCalls().yx
+  doAssert callCount == 1
+
+  var tmp: Vec2
+  proc countsCalls2(): var Vec2 =
+    inc callCount
+    return tmp
+
+  callCount = 0
+  countsCalls2().yx = vec2(0, 0)
+  doAssert callCount == 1
 
 block:
   # Test swizzle with complex expressions

tools/genswizzle.nim

@@ -1,47 +1,49 @@
 import strformat
 
-var swizzles = @["xyzw", "rgba", "stpq"]
+var
+  swizzles = @["xyzw", "rgba", "stpq"]
+  code = ""
 
-echo "# Generated by tools/gensswizzle"
+code.add "# Generated by tools/gensswizzle - don't edit manually.\n"
 
 for swizzle in swizzles[1 .. ^1]:
-  echo "\n# 1 x ", swizzle
+  code.add "\n# 1 x " & swizzle & "\n"
   for i1, s1 in swizzle:
-    echo &"template {s1}*[T](a: GVec234[T]): T = a[{i1}]"
+    code.add &"proc {s1}*[T](a: GVec234[T]): T = a[{i1}]\n"
-    echo &"template `{s1}=`*[T](a: var GVec234[T], b: T) = a[{i1}] = b"
+  for i1, s1 in swizzle:
+    code.add &"proc `{s1}=`*[T](a: var GVec234[T], b: T) = a[{i1}] = b\n"
 
 for swizzle in swizzles:
-  echo "\n# 2 x ", swizzle
+  code.add "\n# 2 x " & swizzle & "\n"
   for i1, s1 in swizzle:
     for i2, s2 in swizzle:
-      echo &"template {s1}{s2}*[T](a: GVec234[T]): GVec2[T] ="
+      code.add &"proc {s1}{s2}*[T](a: GVec234[T]): GVec2[T] = gvec2(a[{i1}], a[{i2}])\n"
-      echo &"  let a2 = a"
+  for i1, s1 in swizzle:
-      echo &"  gvec2(a2[{i1}], a2[{i2}])"
+    for i2, s2 in swizzle:
-      echo &"func `{s1}{s2}=`*[T](a: var GVec234[T], b: GVec2[T]) ="
+      code.add &"proc `{s1}{s2}=`*[T](a: var GVec234[T], b: GVec2[T]) = (let b = b; a[{i1}] = b.x; a[{i2}] = b.y)\n"
-      echo &"  let b2 = b"
-      echo &"  a[{i1}] = b2.x; a[{i2}] = b2.y"
 
 for swizzle in swizzles:
-  echo "\n# 3 x ", swizzle
+  code.add "\n# 3 x " & swizzle & "\n"
   for i1, s1 in swizzle:
     for i2, s2 in swizzle:
       for i3, s3 in swizzle:
-        echo &"template {s1}{s2}{s3}*[T](a: GVec234[T]): GVec3[T] ="
+        code.add &"proc {s1}{s2}{s3}*[T](a: GVec234[T]): GVec3[T] = gvec3(a[{i1}], a[{i2}], a[{i3}])\n"
-        echo &"  let a2 = a"
+  for i1, s1 in swizzle:
-        echo &"  gvec3(a2[{i1}], a2[{i2}], a2[{i3}])"
+    for i2, s2 in swizzle:
-        echo &"func `{s1}{s2}{s3}=`*[T](a: var GVec234[T], b: GVec3[T]) ="
+      for i3, s3 in swizzle:
-        echo &"  let b2 = b"
+        code.add &"proc `{s1}{s2}{s3}=`*[T](a: var GVec234[T], b: GVec3[T]) = (let b = b; a[{i1}] = b.x; a[{i2}] = b.y; a[{i3}] = b.z)\n"
-        echo &"  a[{i1}] = b2.x; a[{i2}] = b2.y; a[{i3}] = b2.z"
 
 for swizzle in swizzles:
-  echo "\n# 4 x ", swizzle
+  code.add "\n# 4 x " & swizzle & "\n"
   for i1, s1 in swizzle:
     for i2, s2 in swizzle:
       for i3, s3 in swizzle:
         for i4, s4 in swizzle:
-          echo &"template {s1}{s2}{s3}{s4}*[T](a: GVec234[T]): GVec4[T] ="
+          code.add &"proc {s1}{s2}{s3}{s4}*[T](a: GVec234[T]): GVec4[T] = gvec4(a[{i1}], a[{i2}], a[{i3}], a[{i4}])\n"
-          echo &"  let a2 = a"
+  for i1, s1 in swizzle:
-          echo &"  gvec4(a2[{i1}], a2[{i2}], a2[{i3}], a2[{i4}])"
+    for i2, s2 in swizzle:
-          echo &"func `{s1}{s2}{s3}{s4}=`*[T](a: var GVec234[T], b: GVec4[T]) ="
+      for i3, s3 in swizzle:
-          echo &"  let b2 = b"
+        for i4, s4 in swizzle:
-          echo &"  a[{i1}] = b2.x; a[{i2}] = b2.y; a[{i3}] = b2.z; a[{i4}] = b2.w"
+          code.add &"proc `{s1}{s2}{s3}{s4}=`*[T](a: var GVec234[T], b: GVec4[T]) = (let b = b; a[{i1}] = b.x; a[{i2}] = b.y; a[{i3}] = b.z; a[{i4}] = b.w)\n"
+
+writeFile("src/vmath/swizzle.nim", code)