[New Feature] Support array:some and array:every langlib functions

[KavinduZoysa]

# Tests whether a function returns true for some member of an array.
# func` is called for each member of `arr` in order unless and until a call returns true.
# + arr - the array
# + func - function to apply to each member
# + return - true if func returns true for some member of `arr`; otherwise, false
# 
public isolated function some(Type[] arr, @isolatedParam function(Type val) returns boolean func) returns boolean = external;

# Tests whether a function returns true for every member of an array.
# `func` is called for each member of `arr` in order unless and until a call returns false.
# + arr - the array
# + func - function to apply to each member
# + return - true if func returns true for every member of `arr`; otherwise, false
# 
public isolated function every(Type[] arr, @isolatedParam function(Type val) returns boolean func) returns boolean = external;

These are the two functions we need to support (Please check spec issue ballerina-platform/ballerina-spec#1005). For both cases, we can implement ballerina functions in array.bal.

array:some

This langlib function will take an array and a function pointer as parameters and returns a boolean.
In the implementation, we have to iterate over the elements in the input array and call the input function for each element. Therefore the input of the function should be an array element and it should return a boolean. If that function returns true we have to stop the iteration and return true. Please find the below flow diagram for a clear understanding.

array:every

The signature of this function is the same as the above function.
If the input function returns false we have to stop the iteration and return false. Please find the below flow diagram for a clear understanding.

Highly appreciate your input on this discussion.

[MaryamZi]

These are the two functions we need to support (Please check spec issue ballerina-platform/ballerina-spec#1005). For both cases, we can implement ballerina functions in array.bal.

Minor detail - we "need to implement" this in array.bal (the array langlib), rather than "can implement". In the array langlib so that it is an array langlib function, in array.bal so that we are maintaining a 1:1 mapping with the spec.

index++ needs to happen before the the comparison with array length? And after incrementing needs to do call func(arr[index])?

Same comment as for array:some.

[KavinduZoysa]

Yes, that is correct

[KavinduZoysa]

Please find the progress of the array:some implementation in PR #35496

[MaryamZi]

Also see #35531 (comment) regarding array:every returning false when the list is empty.