Macro route 

macro_rules! route {
    (/ => $callback:ident) => { ... };
    (/?$($expected_query:tt)+ => $callback:ident) => { ... };
    (/$($expected_segment:tt)/+ => $callback:ident) => { ... };
    (/$($expected_segment:tt)/+?$($expected_query:tt)&+ => $callback: ident) => { ... };
    (@try $callback:ident [$($expected_segment:tt)*] [$($expected_query:tt)*] $uri:ident) => { ... };
    (@parse_segments [$($expected_segment:tt)*] $path:ident) => { ... };
    (@parse_segment ($name:tt : $type:ty) $data:expr) => { ... };
    (@parse_segment $name:tt $data:ident) => { ... };
    (@segment_pattern ($name:tt : $type:ty)) => { ... };
    (@segment_pattern $name:tt) => { ... };
    (@parse_queries [$($expected_query:tt)*] $query_string:ident) => { ... };
    (@query_name ($name:tt : $type:ty)) => { ... };
    (@query_name $name:tt) => { ... };
    (@query_type ($name:tt : $type:ty)) => { ... };
    (@query_type $name:tt) => { ... };
    (@parse_query ($name:tt : $type:ty) $data:ident) => { ... };
    (@parse_query $name:tt $data:ident) => { ... };
}

Build a route from a pattern and a callback.

route!(pattern => callback) is a function from &str to Option<T>. The input represents a URL’s path and query string. If the input matches the pattern, its segments and query parameters can be captured and exposed as parameters of the callback.

A pattern is defined with the following grammar:

pattern := path | path ? query_string
path := root | root some_segments
root := /
some_segments := segment | segment / some_segments
segment := ident | (ident: type)
query_string := query | query & query_string
query := ident | (ident: type)

The callback is a function from captured segments and query parameters to T. Captured segments are passed to the callback. All query parameters are captured. Query parameters without type annotation are passed as Option<()>, query parameters with type annotation are passed as Option<U>. Any type U can be captured as long as they implement the FromStr trait.

Examples:

• Matches /[?query_string], captures nothing and calls callback():

route!(/ => callback)

• Matches /help[?query_string], captures nothing and calls callback():

route!(/help => callback)

• Matches /sum/<a: u32>/<b: u32>[?query_string], captures a and b as u32s and calls callback(a: u32, b: u32):

route!(/sum/(a: u32)/(b: u32) => callback)

• Matches /maps/<lon: f64>/<lat: f64>?show_marker&color=<Color>, captures lon and lat as f64s, show_marker as Option<()> and color as Option<Color>, and calls callback(lon: f64, lat: f64, show_marker: Option<()>, color: Option<Color>):

route!(/maps/(lon: f64)/(lat: f64)?show_marker&(color: Color) => callback)