introducing python-style list generation, and more

[zxytim]

how about adding something like:

// list generation
list := (i * i for i <- 1 to 10)
printf("%d\n", i) for i <- list

// NASTY case, complicated one
// note: two i's should be distinguished by compiler
printf("%d\n", i) for i <- (i * i if i % 3 is 0 for i <- 1 to 100, i & 1 is 0)

// or if two types of `if` reduced the consistency, you just specify that, `if` prior to `for` is not valid.
printf("%d\n", i) for i <- (i * i  for i <- 1 to 100, i & 1 is 0, i % 3 == 0)

func = (a, b) -> a + b
// or even more complicated but expressive grammar:
printf("%d\n", i) for i <- (((x) -> x * x * func(x * x, x / 2))(i) for i <- 1 to 100, i & 1 is 0, (i * i + i) % 3 == 0, func(i, i / 2) % 2 == 1)

[curimit]

I think maybe what you want is something like "map" in functional programming. I introduced a new syntax "=>" during for loop. See examples below.

Hint: Although SugarCpp support mixed usage of for and if, I suggest use just one for. Because this can both improve the fluency of coding and make code more readable.

import "iostream"
       "cstdio"
       "vector"
       "cstdlib"

using namespace std

int main()
    // due to the return value type is unknown
    // list generation maybe difficult
    // This is an alternative
    list: vector<int>
    list.push_back(i) for i <- 1 to 10

    // i => i * i
    // means map i into i*i
    printf("%d\n", i) for i <- 1 to 100, (i & 1) is 0, i % 3 == 0, i => i * i

    func := (a: int, b: int) -> a + b
    printf("%d\n", i) for i <- 1 to 100, (i & 1) is 0, (i * i + i) % 3 == 0, func(i, i / 2) % 2 == 1, i => ((x:int) -> x * x * func(x * x, x / 2))(i)

    // notice the type of i can be also changed
    printf("%d\n", i) for i <- ["12", "21"], i => atoi(i), i => i * 2

[zxytim]

Your idea seems good in my point of view. I love the substitution chain in printf("%d\n", i) for i <- ["12", "21"], i => atoi(i), i => i * 2

Type in list generation is still a problem: in list := i * i for i <- 1 to 10, list`` can be either aint *or avector```. Which one to choose? or add explicit type specification to list generation?

[curimit]

I add keyword ':' after "list generation" to specify the type of list generation. Type supports: vector list forward_list queue deque priority_queue stack set multiset unordered_set unordered_multiset map multimap unordered_map unordered_multimap But some types are not supported now: array bitset int*

import "iostream"
       "cstdio"
       "vector"
       "list"
       "forward_list"
       "queue"
       "stack"
       "set"
       "unordered_set"
       "map"
       "unordered_map"
       "tuple"

using namespace std

int main()
    a := [i for i <- 1 to 10] : vector<int>

    b := [i for i <- 1 to 10] : list<int>
    c := [i for i <- 1 to 10] : forward_list<int>

    d := [i for i <- 1 to 10] : queue<int>
    e := [i for i <- 1 to 10] : deque<int>
    f := [i for i <- 1 to 10] : priority_queue<int>

    g := [i for i <- 1 to 10] : stack<int>

    h := [i for i <- 1 to 10] : set<int>
    i := [i for i <- 1 to 10] : multiset<int>
    j := [i for i <- 1 to 10] : unordered_set<int>
    k := [i for i <- 1 to 10] : unordered_multiset<int>

    l := [[i, i*i] for i <- 1 to 10] : map<int, int>
    m := [[i, i*i] for i <- 1 to 10] : multimap<int, int>
    n := [[i, i*i] for i <- 1 to 10] : unordered_map<int, int>
    o := [[i, i*i] for i <- 1 to 10] : unordered_multimap<int, int>

    // combine list generation with for loop
    printf("%d\n", i) for i <- [i * i for i <- 1 to 100, (i & 1) is 0, (i % 3) is 0] : vector<int>

It seems that I can add more syntax like OrderBy Distinct GroupBy Foldl/Flodr in list generations....

[zxytim]

Oh great! That's pretty cool, I can not wait to give it a try!

[zxytim]

I have pulled to up-to-date version, but it does not work....

[curimit]

What is your input?