List Operations

The UCG list modules can be imported like so let l = import "std/lists.ucg"; It has a number of useful operations.

reverse

The reverse module reverses a list. It has a single required parameter:

list the list to reverse.

let l = import "std/lists.ucg";
l.reverse{list=[1, 2, 3]} == [3, 2, 1];

str_join

The str_join module joins a list with the string representation of each element. It has two parameters:

list which is required. The list to reverse.
sep which is optional and defines the separater to use when joining the elements. Defaults to a single space

let l = import "std/lists.ucg";
l.str_join{
    sep=" ",
    list=[1, 2, 3]
} == "1,2,3";

len

The len function returns the length of a list. It has a single required parameter.

list The list to reverse.

let l = import "std/lists.ucg";
l.len{list=[0, 1, 2, 3]} == 4;

head and tail

The tail function returns the tail of a list minus it's head.

let l = import "std/lists.ucg";
let tail = l.tail([0,1,2,3]);
tail == [1,2,3];

The head function returns the head of the list as a list of one item.

let l = import "std/lists.ucg";
let hd = l.head([0,1,2,3]);
tail == [0];

slice

The slice module returns a slice of the input list. The slice module takes three parameters.

start which is optional and defaults to 0
end which is optional and defaults the length of the list
list which is required and must be a list.

list.slice{start=0, end=2, list=[0,1,2,3]} == [0,1,2];

enumerate

The enumerate module enumerates the elements of a list. It has three parameters.

list which is required and is the list to enumerate.
start which is optional and defines the start number of the enumeration. (defaults to 0)
step which is optional and defines the step amount for the enumeration. (defaults to 1)

let l = import "std/lists.ucg";

// with defaults
l.enumerate{list=[1, 2, 3]} == [[0, 1], [1, 2], [3, 4]];

// With all parameters
l.enumerate{
    start=1,
    step=2,
    list=["foo", "bar", "foobar"],
} == [[1, "foo"], [3, "bar"], [5, "foobar"]];