+ LuaMacro

1 files changed, 31 insertions, 0 deletions

diff --git a/Tools/LuaMacro/macro/with.lua b/Tools/LuaMacro/macro/with.lua
new file mode 100644
index 0000000..de51590
--- /dev/null
+++ b/Tools/LuaMacro/macro/with.lua
@@ -0,0 +1,31 @@
+--[[--
+A `with` statement. This works more like the Visual Basic statement than the
+Pascal one; fields have an explicit period to indicate that they are special.
+This makes variable scoping explcit.
+
+    aLongTableName = {}
+    with aLongTableName do
+      .a = 1
+      .b = {{x=1},{x=2}}
+      .c = {f = 2}
+      print(.a,.c.f,.b[1].x)
+    end
+
+Fields that follow an identifier or a `}` are passed as-is.
+
+@module macro.with
+]]
+local M = require 'macro'
+
+M.define('with',function(get,put)
+  M.define_scoped('.',function()
+    local lt,lv = get:peek(-1,true) --  peek before the period...
+    if lt ~= 'iden' and lt ~= ']' then
+      return '_var.'
+    else
+      return nil,true -- pass through
+    end
+  end)
+  local expr = get:upto 'do'
+  return 'do local _var = '..tostring(expr)..'; '
+end)