[Haskell-cafe] Re: Precedence (Part 2)

Chris Smith cdsmith at twu.net
Thu Apr 3 18:03:08 EDT 2008

PR Stanley wrote:

Just a meta-point.

The dash-dash-space sequence introduces a signature.  If you write your 
reply after the dash-dash-space, as you did here, a lot of us won't see 
your reply because we have our mail/news clients set up to ignore 
signatures.  I had to view the original message source to see what was 
going on.

As for the main point, you can look at it as a substitution; it's just 
that you have to jump through some hoops to think of it as substituting 
plain text.  For example, put parentheses around the bit that's been 
substituted.  A slightly more accurate model would be to view things as 
substitution of parse trees.  Then one can point out that instead of 
doing straight substitution, what actually happens is that subexpressions 
are shared.  But that only effects performance; the observable behavior 
is the same as if you did substitution (of parse trees, or of text but 
adding the parentheses in the right places).

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