Why distinguish macro names with @?

[mbauman]

Remember that @jeff.bezanson is a lisper at heart. Here are his reasons for using the @ sigil back in 2010:

@Email thread with Jeff in 2010

As a lisper, I of course understand the ugliness of @. But I think on the balance it is worth it:

• it alerts you that something different is happening
• it prevents macro names from conflicting with other things
• it allows macros to have paren-less syntax
• it makes it easy to syntax color macros like keywords
• it makes it easier to save pre-expanded code. otherwise, it would be possible for an expression in one file to turn into a macro call as a result of a definition changing in another file (e.g. changing something from a function to a macro). with @, files stay self-contained since we know exactly which expressions to delay expanding.