# 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
]
recipe push x:_elem, in:address:list:_elem -> in:address:list:_elem [
local-scope
load-ingredients
result:address:list:_elem <- new {(list _elem): type}
val:address:_elem <- get-address *result, value:offset
*val <- copy x
next:address:address:list:_elem <- get-address *result, next:offset
*next <- copy in
reply result # needed explicitly because we need to replace 'in' with 'result'
]
recipe first in:address:list:_elem -> result:_elem [
local-scope
load-ingredients
result <- get *in, value:offset
]
recipe 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 [
1:address:list:number <- push 3, 0
1:address:list:number <- push 4, 1:address:list:number
1:address:list:number <- push 5, 1:address:list:number
2:number <- first 1:address:list:number
1:address:list:number <- rest 1:address:list:number
3:number <- first 1:address:list:number
1:address:list:number <- rest 1:address:list:number
4:number <- first 1:address:list:number
1:address:list:number <- rest 1:address:list:number
]
memory-should-contain [
1 <- 0 # empty to empty, dust to dust..
2 <- 5
3 <- 4
4 <- 3
]
]
recipe to-text in:address:list:_elem -> result:address:array:character [
local-scope
#? $print [to text: list], 10/newline
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)
recipe to-text-line in:address:list:_elem -> result:address:array:character [
local-scope
#? $print [to text line: list], 10/newline
load-ingredients
buf:address:buffer <- new-buffer 80
buf <- to-buffer in, buf, 6 # max elements to display
result <- buffer-to-array buf
]
recipe to-buffer in:address:list:_elem, buf:address:buffer -> buf:address:buffer [
local-scope
#? $print [to buffer: list], 10/newline
load-ingredients
{
break-if in
buf <- append buf, 48/0
reply
}
# 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
#? buf <- append buf, nextn
reply-unless next
space:character <- copy 32/space
buf <- append buf, space:character
s:address:array:character <- new [-> ]
n:number <- length *s
buf <- append buf, s
# and recurse
remaining:number, optional-ingredient-found?:boolean <- next-ingredient
{
break-if optional-ingredient-found?
# unlimited recursion
buf <- to-buffer next, buf
reply
}
{
break-unless remaining
# limited recursion
remaining <- subtract remaining, 1
buf <- to-buffer next, buf, remaining
reply
}
# past recursion depth; insert ellipses and stop
s:address:array:character <- new [...]
append buf, s
]
scenario stash-on-list-converts-to-text [
run [
x:address:list:number <- push 4, 0
x <- push 5, x
x <- push 6, x
stash [foo foo], x
]
trace-should-contain [
app: foo foo 6 -> 5 -> 4
]
]
scenario stash-handles-list-with-cycle [
run [
x:address:list:number <- push 4, 0
y:address:address:list:number <- get-address *x, next:offset
*y <- copy x
stash [foo foo], x
]
trace-should-contain [
app: foo foo 4 -> 4 -> 4 -> 4 -> 4 -> 4 -> 4 -> ...
]
]