L/loop keyword



There are 5 forms of loops in 11l.


1. The infinite loop.


L
   print("\a")
   sleep(1)


2. A "while" loop.


L <condition>
   ...

Keep executing a loop body as long the given condition evaluates to true (1B).

Note: if 
<condition>
is just a single identifier, like in 
L ok {...}
, then please write this: 
L ok == 1B {...}
.


3. Loop a specified number of times.


L <number>
   ...

Example:
L 3
   print("ABC")
will print 
"ABC"
3 times.

Note: only integer literals/constants are considered so far as 
<number>
{…}.


4. A "for in" loop.


L(<variable>) <iterable>
   ...

Examples:
L(x) 1..10 {print(x)}
will print 
1
through 
10
.
L(c) "str" {print(c)}
will print 
"s"
, 
"t"
and 
"r"
.
L(n) [9,7] {print(n)}
will print 
9
and 
7
.
L(k, v) [‘k’ = 1] {print(k‘=’v)}
will print 
k=1
.

If you want to modify the items/elements of the iterating container, then prefix 
<variable>
with 
&
:
V arr = [1, 2, 3]
L(&el) arr
   el++
print(arr) // prints `[2, 3, 4]`

Rarely useful stuff

5. A range loop.


L <range>
   ...

Examples:
L 1..n {print("ABC")}
will print 
"ABC"
n times.
L 0.<n {print("ABC")}
will print 
"ABC"
n times.


L/loop subkeywords



The 
L.break
/
loop.break
statement terminates the current loop.
By default 
L.break
/
loop.break
will apply to innermost loop. In a situation where you would like to a break for one of the outer loops, you can specify which loop the break statement applies to:
L(y) 0..10
   L(x) 0..10
      I a[y][x] == 1
         L(y).break // breaks out of outer loop over `y`
Or you can use 
^L.break
, 
^^L.break
, etc.


The 
L.continue
/
loop.continue
statement terminates execution of the statements in the current iteration of the current loop, and continues execution of the loop with the next iteration.


The 
L.remove_current_element_and_continue
statement removes current element of iterating collection. For example, this code removes all even numbers in 
array
:
L(i) array
   I i % 2 == 0
      L.remove_current_element_and_continue


Statements under 
L.was_no_break
/
loop.was_no_break
are executed only when loop was successfully finished without 
L.break
/
loop.break
(just like else in Python):
L(test) tests
   I !test.ok()
      L.break

L.was_no_break
   print(‘All tests are ok!’)



L.index
/
loop.index
can be used to get the index of the current iteration of the loop.


L.first_iteration
/
loop.first_iteration
evaluates to true (1B) on the first iteration of the loop, and evaluates to false (0B) otherwise.

L.last_iteration
/
loop.last_iteration
evaluates to true (1B) if ‘current element of the iterating container’/‘current iteration’ is the last one.


L.prev
/
loop.prev
and 
L.next
/
loop.next
are not supported now.