logo
down
shadow

Using different string types with if else constructs in Rust


Using different string types with if else constructs in Rust

By : shawlang
Date : November 17 2020, 01:00 AM
will help you The comprehensive exploration of FizzBuzz uses a now deprecated struct called MaybeOwned. Here's the updated version, with the delightfully-named CowString:
code :
use std::borrow::Cow;

fn main() {
    for i in 1..10 {
        println!("{}", if i % 15 == 0 {
            Cow::Borrowed("Fizzbuzz")
        } else if i % 5 == 0 {
            Cow::Borrowed("Buzz")
        } else if i % 3 == 0 {
            Cow::Borrowed("Fizz")
        } else {
            Cow::Owned(i.to_string())
        });
    };
}


Share : facebook icon twitter icon
JavaScript Regex to match balanced constructs without caring about imbalanced constructs

JavaScript Regex to match balanced constructs without caring about imbalanced constructs


By : Carlos Gortaris
Date : March 29 2020, 07:55 AM
I wish did fix the issue.
So in the above example the regex should match $(foo $(bar) fizz $(buzz))
code :
matchRecursiveRegExp("$(foo $(bar) fizz $(buzz)) $(something $(else))", "\\$\\(", "\\)");
     function matchRecursiveRegExp (str, left, right, flags) {
   	        var f = flags || "",
    		g = f.indexOf("g") > -1,
    		x = new RegExp(left + "|" + right, "g" + f),
    		l = new RegExp(left, f.replace(/g/g, "")),
    		a = [],
    		t, s, m;

    	do {
    		t = 0;
    		while (m = x.exec(str)) {
    			if (l.test(m[0])) {
    				if (!t++) s = x.lastIndex;
    			} else if (t) {
    				if (!--t) {
    					a.push(str.slice(s, m.index));
    					if (!g) return a;
    				}
    			}
    		}
    	} while (t && (x.lastIndex = s));

    	return a;
    }
    document.write("$(" + matchRecursiveRegExp("$(foo $(bar) fizz $(buzz)) $(something $(else))", "\\$\\(", "\\)") + ")");
Are there language constructs that are valid for type-name but not for fundamental types?

Are there language constructs that are valid for type-name but not for fundamental types?


By : Patricia May Roxas Z
Date : March 29 2020, 07:55 AM
it helps some times I do not think you will find any other cases. If we look at the draft C++ standard Annex A Grammar summary we can see the only other locations in the grammar where type-name shows up are:
code :
nested-name-specifier:
  ::
  type-name ::
  namespace-name ::
  decltype-specifier ::
  nested-name-specifier identifier ::
  nested-name-specifier templateopt simple-template-id ::
simple-type-specifier:
  nested-name-specifieropt type-name
  [...]
pseudo-destructor-name:
  nested-name-specifieropt type-name :: ~ type-name
  nested-name-specifier template simple-template-id :: ~ type-name
  nested-name-specifieropt~ type-name
  ~ decltype-specifier 
Is it possible to replace all loop constructs in Java with stream-based constructs?

Is it possible to replace all loop constructs in Java with stream-based constructs?


By : Roman DJ ZX Gorin
Date : March 29 2020, 07:55 AM
With these it helps Just for fun (this is one horrible way to do it), neither do I know if this fits your needs:
code :
List<String> result = ",,,abc,def".codePoints()
            .boxed()
            // .parallel()
            .collect(Collector.of(
                    () -> {
                        List<StringBuilder> inner = new ArrayList<>();
                        inner.add(new StringBuilder());
                        return inner;
                    },
                    (List<StringBuilder> list, Integer character) -> {
                        StringBuilder last = list.get(list.size() - 1);
                        if (character == ',') {
                            list.add(new StringBuilder());
                        } else {
                            last.appendCodePoint(character);
                        }
                    },
                    (left, right) -> {
                        left.get(left.size() - 1).append(right.remove(0));
                        left.addAll(right);
                        return left;
                    },
                    list -> list.stream()
                            .map(StringBuilder::toString)
                            .filter(x -> !x.equals(""))
                            .collect(Collectors.toList())

    ));
How do you convert between Substrate specific types and Rust primitive types?

How do you convert between Substrate specific types and Rust primitive types?


By : Sandeep
Date : March 29 2020, 07:55 AM
This might help you For the latest in Substrate master
Substrate has removed As in favor of From/Into. An assumption is made that all types are at least u32.
code :
pub fn u32_to_balance(input: u32) -> T::Balance {
    input.into()
}
pub fn u64_to_balance_option(input: u64) -> Option<T::Balance> {
    input.try_into().ok()
}

// Note the warning above about saturated conversions
pub fn u64_to_balance_saturated(input: u64) -> T::Balance {
    input.saturated_into()
}
pub fn balance_to_u64(input: T::Balance) -> Option<u64> {
    TryInto::<u64>::try_into(input).ok()
}

// Note the warning above about saturated conversions
pub fn balance_to_u64_saturated(input: T::Balance) -> u64 {
    input.saturated_into::<u64>()
}
/// Simple trait similar to `Into`, except that it can be used to convert numerics between each
/// other.
pub trait As<T> {
    /// Convert forward (ala `Into::into`).
    fn as_(self) -> T;
    /// Convert backward (ala `From::from`).
    fn sa(_: T) -> Self;
}
impl<T: Trait> Module<T> {
    // `as_` will turn T::Balance into a u64
    pub fn balance_to_u64(input: T::Balance) -> u64 {
        input.as_()
    }

    // Being explicit, you can convert a `u64` to a T::Balance
    // using the `As` trait, with `T: u64`, and then calling `sa`
    pub fn u64_to_balance(input: u64) -> T::Balance {
        <T::Balance as As<u64>>::sa(input)
    }

    // You can also let Rust figure out what `T` is
    pub fn u64_to_balance_implied(input: u64) -> T::Balance {
        <T::Balance as As<_>>::sa(input)
    }

    // You can also let Rust figure out where `sa` is implemented
    pub fn u64_to_balance_implied_more(input: u64) -> T::Balance {
        T::Balance::sa(input)
    }
}
Does Rust formally distinguish constructs that trade compile-time checks for runtime checks?

Does Rust formally distinguish constructs that trade compile-time checks for runtime checks?


By : user2929106
Date : March 29 2020, 07:55 AM
around this issue No, there is no formal distinction.
I believe you are asking if there is an effect system. While this has been talked about by compiler developers for a while, there is no consensus about if it would truly be beneficial or detrimental in the long run.
shadow
Privacy Policy - Terms - Contact Us © ourworld-yourmove.org