language-servers/roc
1
0
Fork 0
mirror of https://github.com/roc-lang/roc.git synced 2025-09-30 07:14:46 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 6

adds List.last

Browse source
This commit is contained in:
Celso Bonutti Filho 2020-12-21 19:44:24 -03:00
parent b5dcde267a
commit 51a302957f
6 changed files with 198 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

99
compiler/can/src/builtins.rs
View file

@ -64,6 +64,7 @@ pub fn builtin_defs_map(symbol: Symbol, var_store: &mut VarStore) -> Option<Def>
LIST_SET => list_set,
LIST_APPEND => list_append,
LIST_FIRST => list_first,
LIST_LAST => list_last,
LIST_IS_EMPTY => list_is_empty,
LIST_SINGLE => list_single,
LIST_REPEAT => list_repeat,
@ -152,6 +153,7 @@ pub fn builtin_defs(var_store: &mut VarStore) -> MutMap<Symbol, Def> {
Symbol::LIST_SET => list_set,
Symbol::LIST_APPEND => list_append,
Symbol::LIST_FIRST => list_first,
Symbol::LIST_LAST => list_last,
Symbol::LIST_IS_EMPTY => list_is_empty,
Symbol::LIST_SINGLE => list_single,
Symbol::LIST_REPEAT => list_repeat,
@ -1897,6 +1899,103 @@ fn list_first(symbol: Symbol, var_store: &mut VarStore) -> Def {
)
}
/// List.last : List elem -> Result elem [ ListWasEmpty ]*
///
/// List.last :
/// Attr (* | u) (List (Attr u a)),
/// -> Attr * (Result (Attr u a) (Attr * [ OutOfBounds ]*))
fn list_last(symbol: Symbol, var_store: &mut VarStore) -> Def {
let arg_var = var_store.fresh();
let bool_var = var_store.fresh();
let list_var = var_store.fresh();
let len_var = var_store.fresh();
let num_var = var_store.fresh();
let list_elem_var = var_store.fresh();
let ret_var = var_store.fresh();
// Perform a bounds check. If it passes, delegate to List.getUnsafe.
let body = If {
cond_var: bool_var,
branch_var: var_store.fresh(),
branches: vec![(
// if-condition
no_region(
// List.len list != 0
RunLowLevel {
op: LowLevel::NotEq,
args: vec![
(len_var, Int(num_var, 0)),
(
len_var,
RunLowLevel {
op: LowLevel::ListLen,
args: vec![(list_var, Var(Symbol::ARG_1))],
ret_var: len_var,
},
),
],
ret_var: bool_var,
},
),
// list was not empty
no_region(
// Ok (List.#getUnsafe list 0)
tag(
"Ok",
vec![
// List.#getUnsafe list 0
RunLowLevel {
op: LowLevel::ListGetUnsafe,
args: vec![
(list_var, Var(Symbol::ARG_1)),
(
len_var,
RunLowLevel {
op: LowLevel::NumSub,
args: vec![
(
arg_var,
RunLowLevel {
op: LowLevel::ListLen,
args: vec![(list_var, Var(Symbol::ARG_1))],
ret_var: len_var,
},
),
(arg_var, Int(num_var, 1)),
],
ret_var: len_var,
},
),
],
ret_var: list_elem_var,
},
],
var_store,
),
),
)],
final_else: Box::new(
// list was empty
no_region(
// Err ListWasEmpty
tag(
"Err",
vec![tag("ListWasEmpty", Vec::new(), var_store)],
var_store,
),
),
),
};
defn(
symbol,
vec![(list_var, Symbol::ARG_1)],
var_store,
body,
ret_var,
)
}
#[inline(always)]
fn no_region<T>(value: T) -> Located<T> {
Located {