modify router macro

[jaemk]

issue #155

• Modify router! to take a string expr url instead of a token sequence.
  • Allows arbitrary routes with numbers/periods/non-token-types
• Url parameters must be specified in the url string and in a trailing identity: type pair.
• Update usage/tests and examples

problems:

• Uses a HashMap when pulling url params out of the url string so it's definitely slower than the current implementation. (only routes with url params)
• ~~Still need to get multiple param parsing working e.g. (GET) ("/add/{a}/plus/{b}", a: u32, b: u32) .... The meat of the macro should work, but pattern matching that section is finicky and would likely require an ugly trailing separator for the no param variant: e.g. (GET) ("/home",) ...~~

[jaemk]

Alright, so the router! macro should now support things like:

(GET) ("/float/5.0") => { ... },
(GET) ("/add/{a}/plus/{b}", a: u32, b: u32) => { ... },
(GET) ("/favicon.ico") => { ... },

Url parameters do have runtime parsing overhead, but normal urls should only do a string comparison.

If you wanted to also support intermixed ident urls, the router! macro would probably need to be broken up into a second macro that just matches a single route:

router!(request,
    rt!(GET, ("/number/5/{name}", name: String) => { ... }),
    rt!(GET, (/old/version/{num: u32}) => { ... }),
)

[jaemk]

Pretty sure I can replace the HashMap with a struct. I'll see what I can do.

[tomaka]

I don't want to break backwards compatibility. If you can accept both the old and new syntaxes then it would be good.

[jaemk]

Would it be acceptable if router! was "all-in" either old or new? Meaning you can't mix old and new style routes. So if you have a router with the current syntax it will continue to work, but if you want to use the new syntax you will have to update all your route definitions to the new style.

[jaemk]

So it seems like there's issues supporting both old and new macro patterns for rust versions prior to 1.20, the new pattern captures everything. I'm not sure why that is.

[jaemk]

We can get around the parsing problems (for rustc < 1.20) by changing the surrounding parens in the new router syntax to one of the following:

// option 1 (current)
(GET) ["/user/{id}", id: u32] => { ... },

// option 2
[GET] ("/user/{id}", id: u32) => { ... },

// option 3
[GET] ["/user/{id}", id: u32] => { ... },

// option 4
|GET| ("/user/{id}", id: u32) => { ... },

Have a preference? Option 1 is probably the least obstructive to change to since you'd need to update that section anyway if you were migrating.

[jaemk]

Pinging @tomaka , can you review this latest version? router! will accept both old and new syntaxes so this shouldn't break any existing usage. If you choose to use the new syntax, all url definitions will need to be updated (can't mix old and new syntaxes in the same router! invocation)

// new
(GET) ["/user/{id}", id: u32] => { ... },

// old
(GET) (/usr/{id: u32}) => { ... },

[tomaka]

I'm ok with the change, but I don't think it should replace the existing style yet. In other words I don't think we should change the examples just yet.

[jaemk]

Alright, I reverted the docs and examples to the existing style

[tomaka]

Looks good, thanks!