Here’s a few fun facts I collected about haXe:

• HaXe doesn’t like classes that begin with a lowercase letter.
• You can write three consecutive return statements in a haXe function. It compiles (same in Obj-C).
• haXe doesn’t allow spaces after the dot operator:
  this. foo = “bar” // doesn’t compile
• while java/C#/AS3 style annotations aren’t defined as core language features, haXe can support whatever annotation style you wish – check this link for limited supported for java style annotations.
• haXe supports multiple inheritance (but not all haXe targets do).

You can debug haXe code

At least, if you are targetting AS3, FlashDevelop 3.2.1 supports debugging haXe code, viz., setting breakpoints, checking locals and globals, even profiling.