Macro bio_code 

macro_rules! bio_code {
    ($fn_name:ident, $name_start:ident, $name_end:ident, $($item:expr),*) => { ... };
}

This macro takes three identifiers and assembly code:

• name of the function to call to retrieve the assembled code
• a unique identifier that serves as label name for the start of the code
• a unique identifier that serves as label name for the end of the code
• a comma separated list of strings that form the assembly itself

*** The comma separated list must not end in a comma. ***

The macro is unable to derive names of functions or identifiers for labels due to the partially hygienic macro rules of Rust, so you have to come up with a list of unique names by yourself.