pocka/rusted

import panic from './panic';

const non_exhaustive_pattern='non-exhaustive patterns: `_` not covered';

let select_arm=function(value,pattern){
    return (value in pattern)
            ? pattern[value]
        : ('_' in pattern)
            ? pattern._
            : panic(non_exhaustive_pattern) ;
};

let match=function(value,patterns){
    let rusted=value.__rusted&&'__data' in value,
        name=rusted?value.__name:value,
        data=rusted?value.__data:value;

    if((!rusted)&&!('_' in patterns)){
        panic(non_exhaustive_pattern);
    }

    let buf=select_arm(name,patterns);

    return typeof buf==='function'
        ? buf(data)
        : buf;
};

export default match;