lua-users home
lua-l archive

[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index] [Thread Index]

On 1-Dec-07, at 4:11 PM, Fabien wrote:

You can get rid of the "then" without adding ambiguity for the compiler. Ditto for the "do" in "while/do/end" and "for/do/end". There is a patch somewhere allowing this.

Yes but it is not always unambiguous. Consider:

  if x or y (x or y)() end

The only way to write that without 'then' would be to use a semicolon, but that's currently ungrammatical (there are no empty statements in Lua) and in any event not
particularly readable.

The case of making 'do' optional is even worse. Consider:

local result = {}
for k, v in pairs(t) -- do --
  do local x = make_a_huge_object(v)
     result[#result + 1] = summary(x)

The first do (the one commented out) must be either required or prohibited. If it is optional, the above loop cannot be parsed correctly with a limited lookahead parser. If it is prohibited, you'll end up with the same ambiguity as in the if statement above.

But if you want to save a couple of keystrokes, don't suppress keyword; pick a proper editor and customize its macros. The main interest of a well designed syntax is to improve code readability, and thus maintainability. It's always at least partially a matter of taste, but I'd guess most people would find "if foo then bar end" more readable than "if foo bar end". I definitely would, at least.

Me too. You might even just customize your editor's tab-completion, if it has such a feature.