Add a generalized version of `word` to Derived.hs

[sid-kap]

Follow-up to #21.

I'm not sure if it's better to replace word altogether with this generalized version, or to simply add a new function word'.

I believe there wouldn't be problems with replacing word with word' with string literals and OverloadedStrings, because when the compiler sees word' "hello", I think it assumes "hello" is a String by default, which is a reasonable behavior here. Anyhow, I had no errors compiling the tests after adding OverloadedStrings and replacing word with word' in the tests.

(By the way, if we choose to keep both functions, we can simplify the implementation of word' to

word' = word . ListLike.toList

)

[ollef]

Hey! Some comments:

• The new function should return an i.
• The tests (and examples) aren't a very good benchmark of whether this will work with OverloadedStrings since there's only one usage of word, where its type is pinned down by the return type of the parser. A better experiment is someProd <* word' "abc", which yields No instance for ListLike....
• Can we come up with a better name than word'?

[sboosali]

naming: item, token, term

On Sun, Mar 6, 2016 at 8:06 PM, Olle Fredriksson notifications@github.com wrote:

Hey! Some comments:

• The new function should return an i.
• The tests (and examples) aren't a very good benchmark of whether this will work with OverloadedStrings since there's only one usage of word, where its type is pinned down by the return type of the parser. A better experiment is someProd <* word' "abc", which yields No instance for ListLike....
• Can we come up with a better name than word'?

— Reply to this email directly or view it on GitHub https://github.com/ollef/Earley/pull/22#issuecomment-192950397.

(this message was composed with dictation: charitably interpret typos)Sam Boosalis

[ollef]

I would prefer something that either reveals something about the functionality or indicates that it's a version of word for ListLikes. It was short-sighted of me to use the contextually rather vague word word in the first place, but I don't think that's worth changing now. How about just listLike?

[ollef]

Done on master.