
I was thinking the same thing. If I remember correctly, RWH does a parser in
an applicative style, but I'll have to look when I get home to be sure. If
so, then maybe we could try doing the same thing in a monadic style, for
comparison and contrast purposes.
On Thu, Mar 12, 2009 at 11:29 AM, Jeff Heard
Come to think of it, I've never seen an applicative tutorial of Parsec, only a monadic one. Does such a beast exist, and if so, maybe we could merge the two together, work the same example in both, and thus help the programmer make the shift from monadic to applicative, from order of parsing to describing the grammar.
-- Jeff
Thank you Bob! I'll throw in another 2 cents:
Yes, *one* aspect of Haskell is that it's a power tool for imperative programming -- a clever way to keep plugging away at the old sequential von Neumann paradigm. C++++.
I'd rather we strongly encourage Haskell-newbies toward shifting out of
imperative paradigm to thinking and programming *functionally*. It's a big shift, to make, and imperative-Haskell is a relatively easy substitute.
- Conal
On Thu, Mar 12, 2009 at 7:28 AM, Thomas Davie
wrote: On 12 Mar 2009, at 15:16, Andrew Wagner wrote:
Can you expand on this a bit? I'm curious why you think this.
For two reasons:
Firstly, I often find that people use the Monadic interface when one of the less powerful ones is both powerful enough and more convenient,
2009/3/12 Conal Elliott
: the parsec is a wonderful example of this. When the applicative instance is used instead of the monadic one, programs rapidly become more readable, because they stop describing the order in which things should be parsed, and start describing the grammar of the language being parsed instead.
Secondly, It seems relatively common now for beginners to be told about the IO monad, and start writing imperative code in it, and thinking that this is what Haskell programming is. I have no problem with people writing imperative code in Haskell, it's an excellent imperative language. However, beginners seeing this, and picking it up is usually counter productive – they never learn how to write things in a functional way, and miss out on most of the benefits of doing so.
Hope that clarifies what I meant :)
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