Function-Call.md

Stack-based way to nest function calls

Due to popular demand, nested function calls are now a feature. Here is a taste:

注曰「「辛 = 戊(甲,丁(乙,丙))」」

夫「甲」。夫「乙」。夫「丙」。取二以施「丁」。取二以施「戊」。名之曰「辛」。

More complex example for the courageous:

注曰「「壬 = 丁(己(戊(甲,丁(乙,丙))),甲,乙)」」

夫「甲」。夫「乙」。夫「丙」。取二以施「丁」。取二以施「戊」。取一以施「己」。夫「甲」。夫「乙」。取三以施「丁」。名之曰「壬」。

How it works

The original syntax of wenyan already employs a stack-like behavior. You can use 其 to refer to the previous unnamed variable, you can use 書之 to print all the unnamed variables, use 名之曰 to name them etc. Therefore, it is natural to use the same system for function calls.

Now I'll refer to the "list of unnamed variables" as the "stack" for convenience.

夫 keyword pushes a variable in into the stack. 取n marks the last n items on the stack as "usable". 以施f takes all the items marked "usable" and apply function f that takes those items as arguments, and push the result onto the stack. Finally you can use 名之曰 to take stuff from back the stack and give them names for later use.

Recap on other features that already existed before this update:

• 噫 Clears the stack, discarding everything.
• 其 Refers to the most recent item on the stack. It also clears the stack. The reason for this is not techincal, but is purely done from Classical Chinese readability standpoint: if you use multiple 其 in a row, it can be very confusing: 加其以其。乘其以其。昔之其者。今其是矣。. Hence.

More examples, showing that you can also push items of an Array, math results, and so on to stack:

注曰「「庚 = 丁(甲+乙,癸[3],癸.length)」」

加「甲」以「乙」。夫「癸」之三。夫「癸」之長。取三以施「丁」。名之曰「庚」。

You can find more examples in ./examples/nested_fun.wy

A thank you to @Lotayou and everyone for the discussion in #285 and #301. More functional programming goodies are on their way!

Automatically curried functions

functions in wenyan are now automatically curried, that is, partially applied to return a new function.

吾有一術。名之曰「丁」。欲行是術。必先得三數。曰「寅」曰「卯」曰「辰」乃行是術曰。
    乘「寅」以「卯」。加其以「辰」。乃得其。
是謂「丁」之術也。

施「丁」於一於二。名之曰「半丁」。
施「半丁」於三。書之。

compiles to

var 丁 = () => 0;
丁 = function(寅) {
    return function(卯) {
        return function(辰) {
            var _ans1 = 寅 * 卯;
            var _ans2 = _ans1 + 辰;
            return _ans2
        };
    };
};
var _ans3 = 丁(1)(2);
var 半丁 = _ans3;
var _ans4 = 半丁(3);
console.log(_ans4);