# A list links up multiple objects together to make them easier to manage.
#
# The objects must be of the same type. If you want to store multiple types in
# a single list, use an exclusive-container.
container list:_elem [
value:_elem
next:address:list:_elem
]
def push x:_elem, in:address:list:_elem -> result:address:list:_elem [
local-scope
load-ingredients
result <- new {(list _elem): type}
*result <- merge x, in
]
def first in:address:list:_elem -> result:_elem [
local-scope
load-ingredients
result <- get *in, value:offset
]
def rest in:address:list:_elem -> result:address:list:_elem/contained-in:in [
local-scope
load-ingredients
result <- get *in, next:offset
]
scenario list-handling [
run [
local-scope
x:address:list:number <- push 3, 0
x <- push 4, x
x <- push 5, x
10:number/raw <- first x
x <- rest x
11:number/raw <- first x
x <- rest x
12:number/raw <- first x
20:address:list:number/raw <- rest x
]
memory-should-contain [
10 <- 5
11 <- 4
12 <- 3
20 <- 0 # nothing left
]
]
def length l:address:list:_elem -> result:number [
local-scope
load-ingredients
return-unless l, 0
rest:address:list:_elem <- rest l
length-of-rest:number <- length rest
result <- add length-of-rest, 1
]
def to-text in:address:list:_elem -> result:address:array:character [
local-scope
load-ingredients
buf:address:buffer <- new-buffer 80
buf <- to-buffer in, buf
result <- buffer-to-array buf
]
# variant of 'to-text' which stops printing after a few elements (and so is robust to cycles)
def to-text-line in:address:list:_elem -> result:address:array:character [
local-scope
load-ingredients
buf:address:buffer <- new-buffer 80
buf <- to-buffer in, buf, 6 # max elements to display
result <- buffer-to-array buf
]
def to-buffer in:address:list:_elem, buf:address:buffer -> buf:address:buffer [
local-scope
load-ingredients
{
break-if in
buf <- append buf, 48/0
return
}
# append in.value to buf
val:_elem <- get *in, value:offset
buf <- append buf, val
# now prepare next
next:address:list:_elem <- rest in
nextn:number <- copy next
return-unless next
buf <- append buf, [ -> ]
# and recurse
remaining:number, optional-ingredient-found?:boolean <- next-ingredient
{
break-if optional-ingredient-found?
# unlimited recursion
buf <- to-buffer next, buf
return
}
{
break-unless remaining
# limited recursion
remaining <- subtract remaining, 1
buf <- to-buffer next, buf, remaining
return
}
# past recursion depth; insert ellipses and stop
append buf, [...]
]