一段代码告诉你面向对象和λ演算本质相同
'use strict'; //ES.next
const $ = do{
let top=this;
const init = (target, ...keys) => do{
try{
typeof target === 'function'
? target(...keys)
: target[keys[0]];
}catch(error){
console.error(error);
}
};
const isScope = target => typeof target === 'object' && target !== null || typeof target === 'function';
const new_scope = (old, new_match, value) => (...matches) =>
matches.length === 1 && matches[0] === new_match
? value
: init(old, ...matches);
const def = (...matches) => value => {
const def = (scope, value, ...matches) =>
new_scope(scope, matches[0],
matches.length > 1
? def(init(scope, matches[0]), value, ...matches.slice(1))
: value
);
top = def(top, value, ...matches);
};
def('def')(def);
match => do{
const $ = scope => (...matches) => do{
const value=init(scope, ...matches);
isScope(value)
? $(value)
: value;
};
match === undefined
? undefined
: $(top)(match);
};
};
$('Math')('sqrt')(16);
//4
$('def')('Math', 233)(1);
//undefined
$('Math')(233);
//1
$('Math')('233');
//undefined
$('Math')('sqrt')(16);
//4
$('def')('Math', 233, 'test')(2);
//undefined
$('Math')(233);
//[Function]
$('Math')(233)('test');
//2
$('Math')(233)(233);
//undefined
$('def')('Math', 'sqrt', 16)('^_^');
//undefined
$('Math')('sqrt')(16);
//^_^
$('Math')('sqrt')(54397632289);
//233233
$('def')(undefined)('T_T');
//undefined
$(undefined);
//undefined
$('def')('a')(x => x + 6);
//undefined
$('a')(660);
//666
$('def')('b')($('a'));
//undefined
$('def')('b', 660)('^_^');
//undefined
$('b')(660);
//^_^
$('a')(660);
//666
$('b')('FP is cool. +1008');
//FP is cool. +10086
16 回复
@dou4cc 我贴到了http://babeljs.io/repl/，结果出错了。楼主还是写一篇渐进点的博客吧，讲讲什么是“object的逐层getter”以及lambda演算的柯里化。
@kolujjj 这是ES6版本，可以直接运行：
'use strict'; //ES6
const λ = (()=>{
let top=this;
const init = (target, ...keys) => (()=>{
try{
return typeof target === 'function' ? target(...keys) : target[keys[0]];
}catch(error){
console.error(error);
}
})();
const isScope = target => typeof target === 'object' && target !== null || typeof target === 'function';
const new_scope = (old, new_match, value) => (...matches) =>
matches.length === 1 && matches[0] === new_match ? value : init(old, ...matches);
const def = (...matches) => value => {
const def = (scope, value, ...matches) =>
new_scope(scope, matches[0],
matches.length > 1 ? def(init(scope, matches[0]), value, ...matches.slice(1)) : value
);
top = def(top, value, ...matches);
};
def('def')(def);
return match => (()=>{
const $ = scope => (...matches) => (()=>{
const value=init(scope, ...matches);
return isScope(value) ? $(value) : value;
})();
return match === undefined ? undefined : $(top)(match);
})();
})();
λ('Math')('sqrt')(16);
//4
λ('def')('Math', 233)(1);
//undefined
λ('Math')(233);
//1
λ('Math')('233');
//undefined
λ('Math')('sqrt')(16);
//4
λ('def')('Math', 233, 'test')(2);
//undefined
λ('Math')(233);
//[Function]
λ('Math')(233)('test');
//2
λ('Math')(233)(233);
//undefined
λ('def')('Math', 'sqrt', 16)('^_^');
//undefined
λ('Math')('sqrt')(16);
//^_^
λ('Math')('sqrt')(54397632289);
//233233
λ('def')(undefined)('T_T');
//undefined
λ(undefined);
//undefined
λ('def')('a')(x => x + 6);
//undefined
λ('a')(660);
//666
λ('def')('b')(λ('a'));
//undefined
λ('def')('b', 660)('^_^');
//undefined
λ('b')(660);
//^_^
λ('a')(660);
//666
λ('b')('FP is cool. +1008');
//FP is cool. +10086
