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Date: Wed, 08 Feb 2012 13:09:48 +0000
From: David House <dhouse@janestreet.com>
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Subject: Re: [Caml-list] syntactic detail

On 02/08/2012 12:54 PM, Gabriel Scherer wrote:
> There is no purpose, it's just an edge case of the simple lexical
> specification you can find at:
> http://caml.inria.fr/pub/docs/manual-ocaml/lex.html#float-literal
>
> Everywhere digits are allowed, you can insert extraneous underscores.
> There is no restriction that there must be at least one digit for
> underscores to be valid. I don't see why there should be.

I would actually prefer a slightly more constrained format. It is very 
easy to typo large numbers like:

   let ten_million = 10_000_0000 in

When eyeballing this, it is extremely easy to mistake this as 10^7, when 
it actual fact it is 10^8.

I would prefer a syntax rule that only allows underscore every three 
characters (starting at the RHS of the number, i.e. complying to the 
usual convention). Well, certainly that for decimal literals. For hex 
literals you probably want to enforce the same, but every four characters.