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@wlib
Last active December 10, 2018 18:29
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curry a js function
function _isPlaceholder(a) {
return a != null &&
typeof a === 'object' &&
a['@@functional/placeholder'] === true;
}
function _arity(n, fn) {
/* eslint-disable no-unused-vars */
switch (n) {
case 0: return function() { return fn.apply(this, arguments); };
case 1: return function(a0) { return fn.apply(this, arguments); };
case 2: return function(a0, a1) { return fn.apply(this, arguments); };
case 3: return function(a0, a1, a2) { return fn.apply(this, arguments); };
case 4: return function(a0, a1, a2, a3) { return fn.apply(this, arguments); };
case 5: return function(a0, a1, a2, a3, a4) { return fn.apply(this, arguments); };
case 6: return function(a0, a1, a2, a3, a4, a5) { return fn.apply(this, arguments); };
case 7: return function(a0, a1, a2, a3, a4, a5, a6) { return fn.apply(this, arguments); };
case 8: return function(a0, a1, a2, a3, a4, a5, a6, a7) { return fn.apply(this, arguments); };
case 9: return function(a0, a1, a2, a3, a4, a5, a6, a7, a8) { return fn.apply(this, arguments); };
case 10: return function(a0, a1, a2, a3, a4, a5, a6, a7, a8, a9) { return fn.apply(this, arguments); };
default: throw new Error('First argument to _arity must be a non-negative integer no greater than ten');
}
}
function _curry1(fn) {
return function f1(a) {
if (arguments.length === 0 || _isPlaceholder(a)) {
return f1;
} else {
return fn.apply(this, arguments);
}
};
}
function _curry2(fn) {
return function f2(a, b) {
switch (arguments.length) {
case 0:
return f2;
case 1:
return _isPlaceholder(a) ? f2
: _curry1(function(_b) { return fn(a, _b); });
default:
return _isPlaceholder(a) && _isPlaceholder(b) ? f2
: _isPlaceholder(a) ? _curry1(function(_a) { return fn(_a, b); })
: _isPlaceholder(b) ? _curry1(function(_b) { return fn(a, _b); })
: fn(a, b);
}
};
}
function _curryN(length, received, fn) {
return function() {
var combined = [];
var argsIdx = 0;
var left = length;
var combinedIdx = 0;
while (combinedIdx < received.length || argsIdx < arguments.length) {
var result;
if (combinedIdx < received.length &&
(!_isPlaceholder(received[combinedIdx]) ||
argsIdx >= arguments.length)) {
result = received[combinedIdx];
} else {
result = arguments[argsIdx];
argsIdx += 1;
}
combined[combinedIdx] = result;
if (!_isPlaceholder(result)) {
left -= 1;
}
combinedIdx += 1;
}
return left <= 0 ? fn.apply(this, combined)
: _arity(left, _curryN(length, combined, fn));
};
}
var curryN = _curry2(function curryN(length, fn) {
if (length === 1) {
return _curry1(fn);
}
return _arity(length, _curryN(length, [], fn));
});
const curry = _curry1(function curry(fn) {
return curryN(fn.length, fn);
});
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