for example
child.stdout.on \data (buffer) ->
result.stdout += buffer
-->
child.stdout.on('data', function(buffer){
return result.stdout += buffer;
});
and I need it without return. In F# I can add |> ignore how can I handle it in livescript?
You can prepend an ! to the definition of the function:
!(buffer) -> result.stdout += buffer
Alternatively, return void
child.stdout.on \data (buffer) ->
result.stdout += buffer
void
In JavaScript, when you return undefined (void), it is the same as not returning anything.
Related
When I call the precompiled contract, it always returns 0.
Of course, there is more likely to be a problem with my code.
my code:
struct G1Point {
uint256[2] X;
uint256[2] Y;
}
function addition(G1Point memory p1, G1Point memory p2)
internal
view
returns (G1Point memory r)
{
uint256[8] memory input;
input[0] = p1.X[0];
input[1] = p1.X[1];
input[2] = p1.Y[0];
input[3] = p1.Y[1];
input[4] = p2.X[0];
input[5] = p2.X[1];
input[6] = p2.Y[0];
input[7] = p2.Y[1];
bool success;
assembly {
success := staticcall(gas(), 0x0b, input, 256 , r, 0x80)
switch success
case 0 {
invalid()
}
}
require(success, "pairing-add-failed");
}
My English is not good. I hope I have clearly explained the problems I have encountered
I am writing a function that gets an initial length of a vector then reads input until the vector is filled. Things go wrong when I convert the input string into an integer.
fn read_to_vector(prompt: &str) -> Vec<String> {
println!("Enter the number of inital values: ");
let length_string:String = read_value();
let length = length_string.parse::<i32>().unwrap();
println!("{}", prompt);
let mut buffer_vector:Vec<String> = Vec::new();
for _i in 1..(length + 1) {
let buffer_str:String = read_value();
buffer_vector.push(buffer_str);
}
return buffer_vector;
}
fn read_value() -> String {
use std::io;
let mut buf:String = String::new();
io::stdin().read_line(&mut buf).expect("Failed to get input");
return buf;
}
Here is the error message:
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: ParseIntError { kind: InvalidDigit }', src/main.rs:8:47
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
I searched online but I could not find anything related.
read_line() does not trim any whitespace. There is probably a newline character at the end of the string, which indeed is not a digit, and this causes parsing to fail. To fix this, trim whitespace from the end of the string before returning it:
return buf.trim_end().to_string();
To save an allocation, you can combine trim_end() with truncate() on the owned string:
let new_len = buf.trim_end().len();
buf.truncate(new_len);
return buf;
I want to do something like below. In the Mono.fromCallable I run some block logic, then based on the value I either return Mono.empty() or the value so that it will either trigger the map or defaultIfEmpty.
Mono.fromCallable(() -> {
double number = Math.random();
if (number < 0.5) {
return Mono.empty();
}
return number;
})
.map(number -> 1)
.defaultIfEmpty(0)
This give an error since Mono.fromCallable expect a consistent return value. How do I adjust the code to make it work?
Although returning null is usually prohibited in Reactor APIs, it is a valid value that Callable may return, and Reactor handles it correctly by transforming into an empty Mono:
Mono.fromCallable(() -> {
double number = Math.random();
if (number < 0.5) {
return null;
}
return number;
})
I am doing a project for nand2tetris. We write a program in Jack and test it on VMEmulator. The class looks like this:
class List {
field int data;
field List next;
/* Creates a new List object. */
constructor List new(int car, List cdr) {
let data = car;
let next = cdr;
return this;
}
/* Disposes this List by recursively disposing its tail. */
method void dispose() {
if (~(next = null)) {
do next.dispose();
}
// Use an OS routine to recycle the memory held by this object.
do Memory.deAlloc(this);
return;
}
/* Prints the list*/
method void print() {
do Output.printString(" -> ");
do Output.printInt(data);
if (~(next = null)) {
do next.print();
}
return;
}
/* Inserts the argument in the right position of the list (ascending order)*/
method void insertInOrder(int ins){
var List prev, curr, insert;
let prev = this;
let curr = prev.getnext();
while (ins > prev.getdata()){
if (ins < curr.getdata()){
let insert = List.new(ins, curr);
do prev.setnext(insert);
}
else{
let prev = prev.getnext();
let curr = prev.getnext();
}
}
return;
}
/* Searches the argument in the list, if found, it returns the corresponding List object*/
method List find(int toFind){
var List temp;
var List equal;
var boolean found;
let temp = this;
let found = false;
while (~(next = null)){
if(toFind = temp.getdata()){
let equal = temp;
let found = true;
}
let temp = temp.getnext();
}
if (found){
return equal;
}
else{
return null;
}
}
method List getnext(){
return next;
}
method void setnext(List object){
let next = object;
return;
}
method int getdata(){
return data;
}
}
It has one private variable data and a pointer next. So I wrote getter and setter method to return those values. Other methods are fine only the getdata()method is incorrect. When it runs through the VMEmulator, it shows the error Out of segment space in List.getdata.3. This shows in the VMEmulator.
0function List.getdata0
1push argument0
2pop pointer0
3push this 0
4return
the error is at the 4th line return. When I change the Jack code, the same error is still at the 4th line.
What exactly is the problem in my getter method?
When you run a VM program on the VMEmulator you must first manually set the pointers to the various segments, otherwise you may get an "Out of segment space" error.
To understand the necessary settings, look at what the corresponding .tst file does. An alternative method is to insert the proposed code inside a function, since the function call automatically makes this type of setting.
You can get this error when you try to access member data of an object which is not constructed. Could it be that the List cdr in the constructor was not properly constructed?
I am trying to work with payloads in Lucene 6 but I am having troubles. The idea is to index payloads and use them in a CustomScoreQuery to check if the payload of a query term matches the payload for the document term.
Here is my payload filter:
#Override
public final boolean incrementToken() throws IOException {
if (!this.input.incrementToken()) {
return false;
}
// get the current token
final char[] token = Arrays.copyOfRange(this.termAtt.buffer(), 0, this.termAtt.length());
String stoken = String.valueOf(token);
String[] parts = stoken.split(Constants.PAYLOAD_DELIMITER);
if (parts.length > 1 && parts.length == 2){
termAtt.setLength(parts[0].length());
// the rest is the payload
BytesRef br = new BytesRef(parts[1]);
System.out.println(br);
payloadAtt.setPayload(br);
}else if (parts.length > 1){
// skip
}else{
// no payload here
payloadAtt.setPayload(null);
}
return true;
}
It seems to be adding the payload, however when I try to access the payload in CustomScoreQuery it just keeps returning null.
public float determineBoost(int doc) throws IOException{
float boost = 1f;
LeafReader reader = this.context.reader();
System.out.println("Has payloads:" + reader.getFieldInfos().hasPayloads());
// loop through each location of the term and boost if location matches the payload
if (reader != null){
PostingsEnum posting = reader.postings(new Term(this.field, term.getTerm()), PostingsEnum.POSITIONS);
System.out.println("Term: " + term.getTerm());
if (posting != null){
// move to the document currently looking at
posting.advance(doc);
int count = 0;
while (count < posting.freq()){
BytesRef load = posting.getPayload();
System.out.println(posting);
System.out.println(posting.getClass());
System.out.println(posting.attributes());
System.out.println("Load: " + load);
// if the location matches in the term location than boos the term by the boost factor
try {
if(load != null && term.containLocation(new Payload(load))){
boost = boost * this.boost;
}
} catch (PayloadException e) {
// do not care too much, the payload is unrecognized
// this is not going to change the boost factor
}
posting.nextPosition();
count += 1;
}
}
}
return boost;
}
For my two tests it keeps stating the load is null. Any suggestions or help?