JavaScript and SiC

In the past two days, the company's project has come to an end, and the school's homework is not too difficult. So I had a little leisure time, So I re-read SiCp and learned JavaScript at the same time (I saw Google suggest, Google Maps, and canyonbridge cbconnect, so I had a strong interest in Javascript ). Douglas crockford spoke well. JavaScript does have many similarities with scheme. Javascript authors must be familiar with function programming. Otherwise, it would be a coincidence that JavaScript Functions are lambda operators. For example, the Newton-Raphson algorithm used to calculate the square root in sicp1.1:

(Define (sqrt x)
(Define (good-enough? Guess)
(<(ABS (-(square guess) x) 0.001 ))
(Define (improve guess)
(Average guess (/X guess )))
(Define (SQRT-iter guess)
(If (good-enough? Guess)
Guess
(SQRT-ITER (improve guess ))))
(SQRT-iter 1.0 ))

The javascript version is almost mechanical:

// Newton's method to find/SQRT {x}
Function SQRT (x ){
Function sqrt_iter (guess ){
If (good_enough (guess )){
Return guess;
}
 
Return sqrt_iter (improve (guess ));
}

Function improve (guess ){
Return average (guess, X/guess );
}

Function average (x, y ){
Return (x + y)/2;
}

Function good_enough (guess ){
Return math. Abs (guess * Guess-x) <0.001;
}

Return sqrt_iter (1.0 );
}

Well, it seems that it is also interesting to rewrite the program in with JavaScript.

Well, it seems that it is also interesting to rewrite the program in with JavaScript.