Add tempalte based swizzle to work around nim-lang/Nim#13063

src/vmath.nim

@@ -521,124 +521,8 @@ proc ivec4*(uvec4: Uvec4): Ivec4 {.inline.} =
 proc uvec4*(ivec4: Ivec4): Uvec4 {.inline.} =
   uvec4(ivec4.x.uint32, ivec4.y.uint32, ivec4.z.uint32, ivec4.w.uint32)
 
-{.experimental: "dotOperators".}
-proc num(letter: char, fields: NimNode): int =
-  ## Given a swizzle character gives back the location number.
-  case letter:
-  of 'x', 'r', 's': 0
-  of 'y', 'g', 't': 1
-  of 'z', 'b', 'p': 2
-  of 'w', 'a', 'q': 3
-  else:
-    error "invalid swizzle character: " & letter, fields
-    quit()
-
-proc typePrefix(node: NimNode): string =
-  ## Given a node of type GVec234 gives its prefix type.
-  ## IVec2 -> "i", DVec4 -> "d", Vec3 -> ""
-  let typeName =
-    when defined(vmathArrayBased):
-      node.getType()[2].repr
-    elif defined(vmathObjBased):
-      node.getType()[2][0].getType().repr
-    elif true or defined(vmathObjArrayBased):
-      node.getType()[2][0].getType()[2].repr
-  case typeName:
-  of "bool": "b"
-  of "int32": "i"
-  of "uint32": "u"
-  of "float32": ""
-  of "float", "float64": "d"
-  else:
-    error "invalid vector type: " & typeName, node
-    quit()
-
-macro `.`*(v: GVec234, fields: untyped): untyped =
-  ## Adds support for swizzle getter.
-  ##  x y z w
-  ##  r g b a
-  ##  s t p q
-  ## v.xyz, v.xxx, v.zyx ...
-  ## v.rgb, v.rrr, v.bgr ...
-  ## v.stp, v.sss, v.pts ...
-  let swizzle = fields.repr
-  let vec = ident(typePrefix(v) & "vec" & $swizzle.len)
-  if swizzle.len == 1:
-    let a = num(swizzle[0], fields)
-    result = quote do:
-      `v`[`a`]
-  elif swizzle.len == 2:
-    let
-      a = num(swizzle[0], fields)
-      b = num(swizzle[1], fields)
-    result = quote do:
-      `vec`(`v`[`a`], `v`[`b`])
-  elif swizzle.len == 3:
-    let
-      a = num(swizzle[0], fields)
-      b = num(swizzle[1], fields)
-      c = num(swizzle[2], fields)
-    result = quote do:
-      `vec`(`v`[`a`], `v`[`b`], `v`[`c`])
-  elif swizzle.len == 4:
-    let
-      a = num(swizzle[0], fields)
-      b = num(swizzle[1], fields)
-      c = num(swizzle[2], fields)
-      d = num(swizzle[3], fields)
-    result = quote do:
-      `vec`(`v`[`a`], `v`[`b`], `v`[`c`], `v`[`d`])
-  else:
-    error "invalid number of swizzle characters: " & swizzle, fields
-
-macro `.=`*(v: GVec234, fields: untyped, e: untyped): untyped =
-  ## Adds support for swizzle setter.
-  ##  x y z w
-  ##  r g b a
-  ##  s t p q
-  ## v.xyz, v.xxx, v.zyx ...
-  ## v.rgb, v.rrr, v.bgr ...
-  ## v.stp, v.sss, v.pts ...
-  let swizzle = fields.repr
-  if swizzle.len == 1:
-    let a = num(swizzle[0], fields)
-    result = quote do:
-      `v`[`a`] = `e`
-  elif swizzle.len == 2:
-    let
-      a = num(swizzle[0], fields)
-      b = num(swizzle[1], fields)
-    result = quote do:
-      block:
-        let tmp = `e`
-        `v`[`a`] = tmp[0]
-        `v`[`b`] = tmp[1]
-  elif swizzle.len == 3:
-    let
-      a = num(swizzle[0], fields)
-      b = num(swizzle[1], fields)
-      c = num(swizzle[2], fields)
-    result = quote do:
-      block:
-        let tmp = `e`
-        `v`[`a`] = tmp[0]
-        `v`[`b`] = tmp[1]
-        `v`[`c`] = tmp[2]
-  elif swizzle.len == 4:
-    let
-      a = num(swizzle[0], fields)
-      b = num(swizzle[1], fields)
-      c = num(swizzle[2], fields)
-      d = num(swizzle[3], fields)
-    result = quote do:
-      block:
-        let tmp = `e`
-        `v`[`a`] = tmp[0]
-        `v`[`b`] = tmp[1]
-        `v`[`c`] = tmp[2]
-        `v`[`d`] = tmp[3]
-  else:
-    error "invalid number of swizzle characters: " & swizzle, fields
+# TODO when https://github.com/nim-lang/Nim/issues/13063 is fixed use macros.
+include vmath/swizzle
 
 proc `==`*[T](a, b: GVec2[T]): bool =
   a.x == b.x and a.y == b.y

src/vmath/macroswizzle.nim

@@ -0,0 +1,119 @@
+
+{.experimental: "dotOperators".}
+proc num(letter: char, fields: NimNode): int =
+  ## Given a swizzle character gives back the location number.
+  case letter:
+  of 'x', 'r', 's': 0
+  of 'y', 'g', 't': 1
+  of 'z', 'b', 'p': 2
+  of 'w', 'a', 'q': 3
+  else:
+    error "invalid swizzle character: " & letter, fields
+    quit()
+
+proc typePrefix(node: NimNode): string =
+  ## Given a node of type GVec234 gives its prefix type.
+  ## IVec2 -> "i", DVec4 -> "d", Vec3 -> ""
+  let typeName =
+    when defined(vmathArrayBased):
+      node.getType()[2].repr
+    elif defined(vmathObjBased):
+      node.getType()[2][0].getType().repr
+    elif true or defined(vmathObjArrayBased):
+      node.getType()[2][0].getType()[2].repr
+  case typeName:
+  of "bool": "b"
+  of "int32": "i"
+  of "uint32": "u"
+  of "float32": ""
+  of "float", "float64": "d"
+  else:
+    error "invalid vector type: " & typeName, node
+    quit()
+
+macro `.`*(v: GVec234, fields: untyped): untyped =
+  ## Adds support for swizzle getter.
+  ##  x y z w
+  ##  r g b a
+  ##  s t p q
+  ## v.xyz, v.xxx, v.zyx ...
+  ## v.rgb, v.rrr, v.bgr ...
+  ## v.stp, v.sss, v.pts ...
+  let swizzle = fields.repr
+  let vec = ident(typePrefix(v) & "vec" & $swizzle.len)
+  if swizzle.len == 1:
+    let a = num(swizzle[0], fields)
+    result = quote do:
+      `v`[`a`]
+  elif swizzle.len == 2:
+    let
+      a = num(swizzle[0], fields)
+      b = num(swizzle[1], fields)
+    result = quote do:
+      `vec`(`v`[`a`], `v`[`b`])
+  elif swizzle.len == 3:
+    let
+      a = num(swizzle[0], fields)
+      b = num(swizzle[1], fields)
+      c = num(swizzle[2], fields)
+    result = quote do:
+      `vec`(`v`[`a`], `v`[`b`], `v`[`c`])
+  elif swizzle.len == 4:
+    let
+      a = num(swizzle[0], fields)
+      b = num(swizzle[1], fields)
+      c = num(swizzle[2], fields)
+      d = num(swizzle[3], fields)
+    result = quote do:
+      `vec`(`v`[`a`], `v`[`b`], `v`[`c`], `v`[`d`])
+  else:
+    error "invalid number of swizzle characters: " & swizzle, fields
+
+macro `.=`*(v: GVec234, fields: untyped, e: untyped): untyped =
+  ## Adds support for swizzle setter.
+  ##  x y z w
+  ##  r g b a
+  ##  s t p q
+  ## v.xyz, v.xxx, v.zyx ...
+  ## v.rgb, v.rrr, v.bgr ...
+  ## v.stp, v.sss, v.pts ...
+  let swizzle = fields.repr
+  if swizzle.len == 1:
+    let a = num(swizzle[0], fields)
+    result = quote do:
+      `v`[`a`] = `e`
+  elif swizzle.len == 2:
+    let
+      a = num(swizzle[0], fields)
+      b = num(swizzle[1], fields)
+    result = quote do:
+      block:
+        let tmp = `e`
+        `v`[`a`] = tmp[0]
+        `v`[`b`] = tmp[1]
+  elif swizzle.len == 3:
+    let
+      a = num(swizzle[0], fields)
+      b = num(swizzle[1], fields)
+      c = num(swizzle[2], fields)
+    result = quote do:
+      block:
+        let tmp = `e`
+        `v`[`a`] = tmp[0]
+        `v`[`b`] = tmp[1]
+        `v`[`c`] = tmp[2]
+  elif swizzle.len == 4:
+    let
+      a = num(swizzle[0], fields)
+      b = num(swizzle[1], fields)
+      c = num(swizzle[2], fields)
+      d = num(swizzle[3], fields)
+    result = quote do:
+      block:
+        let tmp = `e`
+        `v`[`a`] = tmp[0]
+        `v`[`b`] = tmp[1]
+        `v`[`c`] = tmp[2]
+        `v`[`d`] = tmp[3]
+  else:
+    error "invalid number of swizzle characters: " & swizzle, fields