NEP16 Comment character - ghewgill/neon-lang GitHub Wiki

This proposal changes the comment character from # to -- (see also NEP10 Comment character).

History

The (single-line) comment character was originally %. NEP10 Comment character changed this to #. However, both these character glyphs occupy the same shape as upper case characters, which can visually conflict with Neon keywords, making code harder to read.

Proposal

This proposal has two parts:

• Change the single comment character to --
• Change the multiline comment characters to /* and */

The -- comment style is used by venerable languages such as Ada, Eiffel, Haskell, Lua, SQL, and VHDL. It would look like this in Neon code:

-- File: fizzbuzz.neon
--
-- For each integer from 1 to 100, print "Fizz" if the number
-- is divisible by 3, or "Buzz" if the number is divisible
-- by 5, or "FizzBuzz" if the number is divisible by both.
-- Otherwise, print the number itself.

FOR i := 1 TO 100 DO
    -- Check divisibility of number.
    IF i MOD 15 = 0 THEN
        -- Divisible by both 3 and 5.
        print("FizzBuzz")
    ELSIF i MOD 3 = 0 THEN
        -- Divisible by 3.
        print("Fizz")
    ELSIF i MOD 5 = 0 THEN
        -- Divisible by 5.
        print("Buzz")
    ELSE
        -- Not divisible by 3 or 5, print just the number.
        print(i.toString())
    END IF
END FOR

Comment styles are by nature mostly subjective, but this style does have one objective advantage:

• Consistency with embedded SQL (which also uses -- and /* */).

Some subjective advantages are:

• Clean visual style.
• Easy to type single line comments without having to use shift key.

One disadvantage is we would have to reintroduce the grammar special case that allows the #! shebang at the start of the file, but this is minor.