Levi Stephen wrote:
Hi,
I'm was wondering how most people work during when designing a functional program. Do you create data structures/types first? Do you work from some type signatures?
For example, take a blog. Is the first step likely to be something like:
data BlogEntry = BlogEntry { title::String,content::String,comments::[Comment] } type Blog = [BlogEntry]
or more likely thinking about what functions will be required:
addEntry :: BlogEntry -> Blog -> Blog displayBlog :: Blog -> HTML displayEntry :: BlogEntry -> HTML
I think you can work either way around, or both, or a mixture. If I had to choose between the two, I would *definitely* choose the second. Writing a program is like defining a custom language. Start by defining your primitives (functions). The data types are just "whatever you need to make it work". YMMV :) Jules