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suffixed.rs
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/
suffixed.rs
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#![allow(clippy::manual_map)]
use bumpalo::collections::Vec;
use bumpalo::Bump;
use roc_error_macros::internal_error;
use roc_module::called_via::CalledVia;
use roc_module::ident::ModuleName;
use roc_parse::ast::Expr::{self, *};
use roc_parse::ast::{is_expr_suffixed, Pattern, ValueDef, WhenBranch};
use roc_region::all::{Loc, Region};
use std::cell::Cell;
thread_local! {
// we use a thread_local here so that tests consistently give the same pattern
static SUFFIXED_ANSWER_COUNTER: Cell<usize> = Cell::new(0);
}
/// Provide an intermediate answer expression and pattern when unwrapping a
/// (sub) expression
///
/// e.g. `x = foo (bar!)` unwraps to `x = Task.await (bar) \#!a0 -> foo #!a0`
fn next_suffixed_answer_pattern(arena: &Bump) -> (Expr, Pattern) {
// Use the thread-local counter
SUFFIXED_ANSWER_COUNTER.with(|counter| {
let count = counter.get();
counter.set(count + 1);
let answer_ident = arena.alloc(format!("#!a{}", count));
(
Expr::Var {
module_name: "",
ident: answer_ident,
},
Pattern::Identifier {
ident: answer_ident.as_str(),
},
)
})
}
#[derive(Debug)]
pub enum EUnwrapped<'a> {
UnwrappedDefExpr(&'a Loc<Expr<'a>>),
UnwrappedSubExpr {
/// the unwrapped expression argument for Task.await
sub_arg: &'a Loc<Expr<'a>>,
/// the pattern for the closure
sub_pat: &'a Loc<Pattern<'a>>,
/// the expression to replace the unwrapped
sub_new: &'a Loc<Expr<'a>>,
},
Malformed,
}
fn init_unwrapped_err<'a>(
arena: &'a Bump,
unwrapped_expr: &'a Loc<Expr<'a>>,
maybe_def_pat: Option<&'a Loc<Pattern<'a>>>,
) -> Result<&'a Loc<Expr<'a>>, EUnwrapped<'a>> {
match maybe_def_pat {
Some(..) => {
// we have a def pattern, so no need to generate a new pattern
// as this should only be created in the first call from a def
Err(EUnwrapped::UnwrappedDefExpr(unwrapped_expr))
}
None => {
let (answer_var, answer_pat) = next_suffixed_answer_pattern(arena);
let sub_new = arena.alloc(Loc::at(unwrapped_expr.region, answer_var));
let sub_pat = arena.alloc(Loc::at(unwrapped_expr.region, answer_pat));
Err(EUnwrapped::UnwrappedSubExpr {
sub_arg: unwrapped_expr,
sub_pat,
sub_new,
})
}
}
}
/// Descend through the AST and unwrap each suffixed expression
/// when an expression is unwrapped, we apply a `Task.await` and
/// then descend through the AST again until there are no more suffixed
/// expressions, or we hit an error
pub fn unwrap_suffixed_expression<'a>(
arena: &'a Bump,
loc_expr: &'a Loc<Expr<'a>>,
maybe_def_pat: Option<&'a Loc<Pattern<'a>>>,
) -> Result<&'a Loc<Expr<'a>>, EUnwrapped<'a>> {
let unwrapped_expression = {
match loc_expr.value {
Expr::TaskAwaitBang(sub_expr) => {
let unwrapped_sub_expr = arena.alloc(Loc::at(loc_expr.region, *sub_expr));
init_unwrapped_err(arena, unwrapped_sub_expr, maybe_def_pat)
}
Expr::Defs(..) => unwrap_suffixed_expression_defs_help(arena, loc_expr, maybe_def_pat),
Expr::Apply(..) => {
unwrap_suffixed_expression_apply_help(arena, loc_expr, maybe_def_pat)
}
Expr::When(..) => unwrap_suffixed_expression_when_help(arena, loc_expr, maybe_def_pat),
Expr::If(..) => {
unwrap_suffixed_expression_if_then_else_help(arena, loc_expr, maybe_def_pat)
}
Expr::Closure(..) => {
unwrap_suffixed_expression_closure_help(arena, loc_expr, maybe_def_pat)
}
Expr::ParensAround(..) => {
unwrap_suffixed_expression_parens_help(arena, loc_expr, maybe_def_pat)
}
Expr::SpaceBefore(..) | Expr::SpaceAfter(..) => {
internal_error!(
"SpaceBefore and SpaceAfter should have been removed in desugar_expr"
);
}
Expr::BinOps(..) => {
internal_error!("BinOps should have been desugared in desugar_expr");
}
Expr::LowLevelDbg(dbg_src, arg, rest) => {
if is_expr_suffixed(&arg.value) {
// we cannot unwrap a suffixed expression within dbg
// e.g. dbg (foo! "bar")
return Err(EUnwrapped::Malformed);
}
match unwrap_suffixed_expression(arena, rest, maybe_def_pat) {
Ok(unwrapped_expr) => {
let new_dbg = arena.alloc(Loc::at(
loc_expr.region,
LowLevelDbg(dbg_src, arg, unwrapped_expr),
));
return Ok(new_dbg);
}
Err(EUnwrapped::UnwrappedDefExpr(unwrapped_expr)) => {
let new_dbg = arena.alloc(Loc::at(
loc_expr.region,
LowLevelDbg(dbg_src, arg, unwrapped_expr),
));
Err(EUnwrapped::UnwrappedDefExpr(new_dbg))
}
Err(EUnwrapped::UnwrappedSubExpr {
sub_arg: unwrapped_expr,
sub_pat,
sub_new,
}) => {
let new_dbg = arena.alloc(Loc::at(
loc_expr.region,
LowLevelDbg(dbg_src, arg, unwrapped_expr),
));
Err(EUnwrapped::UnwrappedSubExpr {
sub_arg: new_dbg,
sub_pat,
sub_new,
})
}
Err(EUnwrapped::Malformed) => Err(EUnwrapped::Malformed),
}
}
Expr::Expect(condition, continuation) => {
if is_expr_suffixed(&condition.value) {
// we cannot unwrap a suffixed expression within expect
// e.g. expect (foo! "bar")
return Err(EUnwrapped::Malformed);
}
match unwrap_suffixed_expression(arena, continuation, maybe_def_pat) {
Ok(unwrapped_expr) => {
let new_expect = arena
.alloc(Loc::at(loc_expr.region, Expect(condition, unwrapped_expr)));
return Ok(new_expect);
}
Err(EUnwrapped::UnwrappedDefExpr(unwrapped_expr)) => {
let new_expect = arena
.alloc(Loc::at(loc_expr.region, Expect(condition, unwrapped_expr)));
Err(EUnwrapped::UnwrappedDefExpr(new_expect))
}
Err(EUnwrapped::UnwrappedSubExpr {
sub_arg: unwrapped_expr,
sub_pat,
sub_new,
}) => {
let new_expect = arena
.alloc(Loc::at(loc_expr.region, Expect(condition, unwrapped_expr)));
Err(EUnwrapped::UnwrappedSubExpr {
sub_arg: new_expect,
sub_pat,
sub_new,
})
}
Err(EUnwrapped::Malformed) => Err(EUnwrapped::Malformed),
}
}
// we only need to unwrap some expressions, leave the rest as is
_ => Ok(loc_expr),
}
};
// KEEP THIS HERE FOR DEBUGGING
// USEFUL TO SEE THE UNWRAPPING
// OF AST NODES AS THEY DESCEND
// if is_expr_suffixed(&loc_expr.value) {
// dbg!(&maybe_def_pat, &loc_expr, &unwrapped_expression);
// }
unwrapped_expression
}
pub fn unwrap_suffixed_expression_parens_help<'a>(
arena: &'a Bump,
loc_expr: &'a Loc<Expr<'a>>,
_maybe_def_pat: Option<&'a Loc<Pattern<'a>>>,
) -> Result<&'a Loc<Expr<'a>>, EUnwrapped<'a>> {
match loc_expr.value {
Expr::ParensAround(sub_loc_expr) => {
// note we use `None` here as we always want to generate a new pattern from child expressions
match unwrap_suffixed_expression(arena, arena.alloc(Loc::at_zero(*sub_loc_expr)), None)
{
Ok(new_expr) => {
let new_parens = arena.alloc(Loc::at(
loc_expr.region,
ParensAround(arena.alloc(new_expr.value)),
));
Ok(new_parens)
}
Err(EUnwrapped::UnwrappedDefExpr(..)) => {
internal_error!("unreachable, child expressions from ParensAround should generate UnwrappedSubExpr instead");
}
Err(EUnwrapped::UnwrappedSubExpr {
sub_arg,
sub_pat,
sub_new,
}) => {
let new_parens = arena.alloc(Loc::at(
loc_expr.region,
ParensAround(arena.alloc(sub_new.value)),
));
Err(EUnwrapped::UnwrappedSubExpr {
sub_arg,
sub_pat,
sub_new: new_parens,
})
}
Err(err) => Err(err),
}
}
_ => internal_error!("unreachable, expected a ParensAround node to be passed into unwrap_suffixed_expression_parens_help"),
}
}
pub fn unwrap_suffixed_expression_closure_help<'a>(
arena: &'a Bump,
loc_expr: &'a Loc<Expr<'a>>,
_maybe_def_pat: Option<&'a Loc<Pattern<'a>>>,
) -> Result<&'a Loc<Expr<'a>>, EUnwrapped<'a>> {
match loc_expr.value {
Expr::Closure(closure_args, closure_loc_ret) => {
// note we use `None` here as we don't want to pass a DefExpr up and
// unwrap the definition pattern for the closure
match unwrap_suffixed_expression(arena, closure_loc_ret, None) {
Ok(unwrapped_expr) => {
let new_closure = arena.alloc(Loc::at(loc_expr.region, Expr::Closure(closure_args, unwrapped_expr)));
Ok(new_closure)
}
Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new }) => {
let new_closure_loc_ret = apply_task_await(arena, loc_expr.region, sub_arg, sub_pat, sub_new);
let new_closure = arena.alloc(Loc::at(loc_expr.region, Expr::Closure(closure_args, new_closure_loc_ret)));
Ok(new_closure)
}
Err(err) => {
debug_assert!(false,"the closure Defs was malformd, got {:#?}", err);
Err(EUnwrapped::Malformed)
}
}
}
_ => internal_error!("unreachable, expected a Closure node to be passed into unwrap_suffixed_expression_closure_help"),
}
}
pub fn unwrap_suffixed_expression_apply_help<'a>(
arena: &'a Bump,
loc_expr: &'a Loc<Expr<'a>>,
maybe_def_pat: Option<&'a Loc<Pattern<'a>>>,
) -> Result<&'a Loc<Expr<'a>>, EUnwrapped<'a>> {
match loc_expr.value {
Expr::Apply(function, apply_args, called_via) => {
// Any suffixed arguments will be innermost, therefore we unwrap those first
let local_args = arena.alloc_slice_copy(apply_args);
for arg in local_args.iter_mut() {
// Args are always expressions, don't pass `maybe_def_pat`
match unwrap_suffixed_expression(arena, arg, None) {
Ok(new_arg) => {
*arg = new_arg;
}
Err(EUnwrapped::UnwrappedDefExpr(..)) => {
internal_error!("unreachable, unwrapped arg cannot be def expression as `None` was passed as pattern");
}
Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new: new_arg }) => {
*arg = new_arg;
let new_apply = arena.alloc(Loc::at(loc_expr.region, Apply(function, local_args, called_via)));
return Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new: new_apply});
}
Err(err) => return Err(err),
}
}
// special case for when our Apply function is a suffixed Var (but not multiple suffixed)
if let Expr::TaskAwaitBang(sub_expr) = function.value {
let unwrapped_function = arena.alloc(Loc::at(
loc_expr.region,
*sub_expr,
));
let new_apply = arena.alloc(Loc::at(loc_expr.region, Expr::Apply(unwrapped_function, local_args, called_via)));
return init_unwrapped_err(arena, new_apply, maybe_def_pat);
}
// function is another expression
match unwrap_suffixed_expression(arena, function, maybe_def_pat) {
Ok(new_function) => {
let new_apply = arena.alloc(Loc::at(loc_expr.region, Expr::Apply(new_function, local_args, called_via)));
Ok(new_apply)
}
Err(EUnwrapped::UnwrappedDefExpr(unwrapped_function)) => {
let new_apply = arena.alloc(Loc::at(loc_expr.region, Expr::Apply(unwrapped_function, local_args, called_via)));
Err(EUnwrapped::UnwrappedDefExpr(new_apply))
}
Err(EUnwrapped::UnwrappedSubExpr { sub_arg: unwrapped_function, sub_pat, sub_new }) => {
let new_apply = arena.alloc(Loc::at(loc_expr.region, Expr::Apply(sub_new, local_args, called_via)));
Err(EUnwrapped::UnwrappedSubExpr { sub_arg: unwrapped_function, sub_pat, sub_new:new_apply})
}
Err(err) => Err(err)
}
}
_ => internal_error!("unreachable, expected an Apply node to be passed into unwrap_suffixed_expression_apply_help"),
}
}
/// Unwrap if-then-else statements
pub fn unwrap_suffixed_expression_if_then_else_help<'a>(
arena: &'a Bump,
loc_expr: &'a Loc<Expr<'a>>,
maybe_def_pat: Option<&'a Loc<Pattern<'a>>>,
) -> Result<&'a Loc<Expr<'a>>, EUnwrapped<'a>> {
match loc_expr.value {
Expr::If(if_thens, final_else_branch) => {
for (index, if_then) in if_thens.iter().enumerate() {
let (current_if_then_statement, current_if_then_expression) = if_then;
// unwrap suffixed (innermost) expressions e.g. `if true then doThing! then ...`
if is_expr_suffixed(¤t_if_then_expression.value) {
// split if_thens around the current index
let (before, after) = roc_parse::ast::split_around(if_thens, index);
match unwrap_suffixed_expression(arena, current_if_then_expression, None) {
Ok(unwrapped_expression) => {
let mut new_if_thens = Vec::new_in(arena);
new_if_thens.extend(before);
new_if_thens.push((*current_if_then_statement, *unwrapped_expression));
new_if_thens.extend(after);
let new_if = arena.alloc(Loc::at(
loc_expr.region,
Expr::If(
arena.alloc_slice_copy(new_if_thens.as_slice()),
final_else_branch,
),
));
return unwrap_suffixed_expression(arena, new_if, maybe_def_pat);
}
Err(EUnwrapped::UnwrappedDefExpr(..)) => {
internal_error!("unexpected, unwrapped if-then-else Def expr should have intermediate answer as `None` was passed as pattern");
}
Err(EUnwrapped::UnwrappedSubExpr {
sub_arg,
sub_pat,
sub_new,
}) => {
let unwrapped_expression =
apply_task_await(arena, sub_arg.region, sub_arg, sub_pat, sub_new);
let mut new_if_thens = Vec::new_in(arena);
new_if_thens.extend(before);
new_if_thens.push((*current_if_then_statement, *unwrapped_expression));
new_if_thens.extend(after);
let new_if = arena.alloc(Loc::at(
loc_expr.region,
Expr::If(
arena.alloc_slice_copy(new_if_thens.as_slice()),
final_else_branch,
),
));
return unwrap_suffixed_expression(arena, new_if, maybe_def_pat);
}
Err(EUnwrapped::Malformed) => return Err(EUnwrapped::Malformed),
}
}
// unwrap suffixed statements e.g. `if isThing! then ...`
// note we want to split and nest if-then's so we only run Task's
// that are required
if is_expr_suffixed(¤t_if_then_statement.value) {
// split if_thens around the current index
let (before, after) = roc_parse::ast::split_around(if_thens, index);
match unwrap_suffixed_expression(arena, current_if_then_statement, None) {
Ok(unwrapped_statement) => {
let mut new_if_thens = Vec::new_in(arena);
new_if_thens.push((*unwrapped_statement, *current_if_then_expression));
new_if_thens.extend(after);
let new_if = arena.alloc(Loc::at(
loc_expr.region,
Expr::If(
arena.alloc_slice_copy(new_if_thens.as_slice()),
final_else_branch,
),
));
return unwrap_suffixed_expression(arena, new_if, maybe_def_pat);
}
Err(EUnwrapped::UnwrappedDefExpr(..)) => {
internal_error!("unexpected, unwrapped if-then-else Def expr should have intermediate answer as `None` was passed as pattern");
}
Err(EUnwrapped::UnwrappedSubExpr {
sub_arg,
sub_pat,
sub_new,
}) => {
if before.is_empty() {
let mut new_if_thens = Vec::new_in(arena);
new_if_thens.extend(before);
new_if_thens.push((*sub_new, *current_if_then_expression));
new_if_thens.extend(after);
let new_if = arena.alloc(Loc::at(
loc_expr.region,
Expr::If(
arena.alloc_slice_copy(new_if_thens.as_slice()),
final_else_branch,
),
));
let unwrapped_if_then = apply_task_await(
arena,
sub_arg.region,
sub_arg,
sub_pat,
new_if,
);
return unwrap_suffixed_expression(
arena,
unwrapped_if_then,
maybe_def_pat,
);
} else {
let mut after_if_thens = Vec::new_in(arena);
after_if_thens.push((*sub_new, *current_if_then_expression));
after_if_thens.extend(after);
let after_if = arena.alloc(Loc::at(
loc_expr.region,
Expr::If(
arena.alloc_slice_copy(after_if_thens.as_slice()),
final_else_branch,
),
));
let after_if_then = apply_task_await(
arena,
sub_arg.region,
sub_arg,
sub_pat,
after_if,
);
let before_if_then = arena.alloc(Loc::at(
loc_expr.region,
Expr::If(before, after_if_then),
));
return unwrap_suffixed_expression(
arena,
before_if_then,
maybe_def_pat,
);
}
}
Err(EUnwrapped::Malformed) => return Err(EUnwrapped::Malformed),
}
}
}
// check the final_else_branch
match unwrap_suffixed_expression(arena, final_else_branch, None) {
Ok(unwrapped_final_else) => {
return Ok(arena.alloc(Loc::at(
loc_expr.region,
Expr::If(if_thens, unwrapped_final_else),
)));
}
Err(EUnwrapped::UnwrappedDefExpr(..)) => {
internal_error!("unexpected, unwrapped if-then-else Def expr should have intermediate answer as `None` was passed as pattern");
}
Err(EUnwrapped::UnwrappedSubExpr {
sub_arg,
sub_pat,
sub_new,
}) => {
let unwrapped_final_else =
apply_task_await(arena, sub_arg.region, sub_arg, sub_pat, sub_new);
let new_if = arena.alloc(Loc::at(
loc_expr.region,
Expr::If(if_thens, unwrapped_final_else),
));
return unwrap_suffixed_expression(arena, new_if, maybe_def_pat);
}
Err(EUnwrapped::Malformed) => Err(EUnwrapped::Malformed),
}
}
_ => internal_error!("unreachable, expected an If expression to desugar"),
}
}
pub fn unwrap_suffixed_expression_when_help<'a>(
arena: &'a Bump,
loc_expr: &'a Loc<Expr<'a>>,
maybe_def_pat: Option<&'a Loc<Pattern<'a>>>,
) -> Result<&'a Loc<Expr<'a>>, EUnwrapped<'a>> {
match loc_expr.value {
Expr::When(condition, branches) => {
// first unwrap any when branches values
// e.g.
// when foo is
// [] -> line! "bar"
// _ -> line! "baz"
for (branch_index, WhenBranch{value: branch_loc_expr,patterns, guard}) in branches.iter().enumerate() {
// if the branch isn't suffixed we can leave it alone
if is_expr_suffixed(&branch_loc_expr.value) {
let unwrapped_branch_value = match unwrap_suffixed_expression(arena, branch_loc_expr, None) {
Ok(unwrapped_branch_value) => unwrapped_branch_value,
Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new }) => apply_task_await(arena, branch_loc_expr.region, sub_arg, sub_pat, sub_new),
Err(..) => return Err(EUnwrapped::Malformed),
};
// TODO: unwrap guard
let new_branch = WhenBranch{value: *unwrapped_branch_value, patterns, guard: *guard};
let mut new_branches = Vec::new_in(arena);
let (before, rest) = branches.split_at(branch_index);
let after = &rest[1..];
new_branches.extend_from_slice(before);
new_branches.push(arena.alloc(new_branch));
new_branches.extend_from_slice(after);
let new_when = arena.alloc(Loc::at(loc_expr.region, Expr::When(condition, arena.alloc_slice_copy(new_branches.as_slice()))));
return unwrap_suffixed_expression(arena, new_when, maybe_def_pat);
}
}
// then unwrap the when condition
match unwrap_suffixed_expression(arena, condition, None) {
Ok(unwrapped_condition) => {
let new_when = arena.alloc(Loc::at(loc_expr.region, Expr::When(unwrapped_condition, branches)));
Ok(new_when)
}
Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new }) => {
let new_when = arena.alloc(Loc::at(loc_expr.region, Expr::When(sub_new, branches)));
let applied_task_await = apply_task_await(arena,loc_expr.region,sub_arg,sub_pat,new_when);
Ok(applied_task_await)
}
Err(EUnwrapped::UnwrappedDefExpr(..))
| Err(EUnwrapped::Malformed) => Err(EUnwrapped::Malformed)
}
}
_ => internal_error!("unreachable, expected a When node to be passed into unwrap_suffixed_expression_defs_help"),
}
}
pub fn unwrap_suffixed_expression_defs_help<'a>(
arena: &'a Bump,
loc_expr: &'a Loc<Expr<'a>>,
maybe_def_pat: Option<&'a Loc<Pattern<'a>>>,
) -> Result<&'a Loc<Expr<'a>>, EUnwrapped<'a>> {
match loc_expr.value {
Expr::Defs(defs, loc_ret) => {
let mut local_defs = defs.clone();
let tags = local_defs.tags.clone();
// try an unwrap each def, if none can be unwrapped, then try to unwrap the loc_ret
for (tag_index, type_or_value_def_index) in tags.iter().enumerate() {
use ValueDef::*;
let mut current_value_def = match type_or_value_def_index.split() {
Ok(..) => {
// ignore type definitions
continue;
},
Err(value_index) => *local_defs.value_defs.get(value_index.index()).unwrap(),
};
let maybe_suffixed_value_def = match current_value_def {
Annotation(..) | Dbg{..} | Expect{..} | ExpectFx{..} | Stmt(..) | ModuleImport{..} | IngestedFileImport(_) => None,
AnnotatedBody { body_pattern, body_expr, .. } => Some((body_pattern, body_expr)),
Body (def_pattern, def_expr, .. ) => Some((def_pattern, def_expr)),
};
match maybe_suffixed_value_def {
None => {
// We can't unwrap this def type, continue
},
Some((def_pattern, def_expr)) => {
match unwrap_suffixed_expression(arena, def_expr, Some(def_pattern)) {
Ok(unwrapped_def) => {
current_value_def.replace_expr(unwrapped_def);
local_defs.replace_with_value_def(tag_index, current_value_def, def_expr.region);
}
Err(EUnwrapped::UnwrappedDefExpr(unwrapped_expr)) => {
let split_defs = local_defs.split_defs_around(tag_index);
let before_empty = split_defs.before.is_empty();
let after_empty = split_defs.after.is_empty();
if before_empty && after_empty {
// NIL before, NIL after -> SINGLE DEF
let next_expr = match unwrap_suffixed_expression(arena,loc_ret,maybe_def_pat) {
Ok(next_expr) => next_expr,
Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new }) => {
// We need to apply Task.ok here as the defs final expression was unwrapped
apply_task_await(arena,def_expr.region,sub_arg,sub_pat,sub_new)
}
Err(EUnwrapped::UnwrappedDefExpr(..)) | Err(EUnwrapped::Malformed) => {
// TODO handle case when we have maybe_def_pat so can return an unwrapped up
return Err(EUnwrapped::Malformed);
},
};
return unwrap_suffixed_expression(arena, apply_task_await(arena,def_expr.region,unwrapped_expr,def_pattern,next_expr), maybe_def_pat);
} else if before_empty {
// NIL before, SOME after -> FIRST DEF
let new_defs = arena.alloc(Loc::at(def_expr.region, Defs(arena.alloc(split_defs.after), loc_ret)));
let next_expr = match unwrap_suffixed_expression(arena,new_defs,maybe_def_pat){
Ok(next_expr) => next_expr,
Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new }) => {
apply_task_await(arena, def_expr.region, sub_arg, sub_pat, sub_new)
}
Err(EUnwrapped::UnwrappedDefExpr(..)) | Err(EUnwrapped::Malformed) => {
// TODO handle case when we have maybe_def_pat so can return an unwrapped up
return Err(EUnwrapped::Malformed);
},
};
return unwrap_suffixed_expression(arena, apply_task_await(arena,def_expr.region,unwrapped_expr,def_pattern,next_expr), maybe_def_pat);
} else if after_empty {
// SOME before, NIL after -> LAST DEF
match unwrap_suffixed_expression(arena,loc_ret,maybe_def_pat){
Ok(new_loc_ret) => {
let applied_task_await = apply_task_await(arena, loc_expr.region, unwrapped_expr, def_pattern, new_loc_ret);
let new_defs = arena.alloc(Loc::at(loc_expr.region,Defs(arena.alloc(split_defs.before), applied_task_await)));
return unwrap_suffixed_expression(arena, new_defs, maybe_def_pat);
},
Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new }) => {
let new_loc_ret = apply_task_await(arena,def_expr.region,sub_arg,sub_pat,sub_new);
let applied_task_await = apply_task_await(arena, loc_expr.region, unwrapped_expr, def_pattern, new_loc_ret);
let new_defs = arena.alloc(Loc::at(loc_expr.region,Defs(arena.alloc(split_defs.before), applied_task_await)));
return unwrap_suffixed_expression(arena, new_defs, maybe_def_pat);
}
Err(EUnwrapped::UnwrappedDefExpr(..)) => {
// TODO confirm this is correct with test case
return Err(EUnwrapped::Malformed);
}
Err(EUnwrapped::Malformed) => {
return Err(EUnwrapped::Malformed);
},
}
} else {
// SOME before, SOME after -> MIDDLE DEF
let after_defs = arena.alloc(Loc::at(def_expr.region, Defs(arena.alloc(split_defs.after), loc_ret)));
match unwrap_suffixed_expression(arena,after_defs,maybe_def_pat){
Ok(new_loc_ret) => {
let applied_await = apply_task_await(arena, loc_expr.region, unwrapped_expr, def_pattern, new_loc_ret);
let new_defs = arena.alloc(Loc::at(loc_expr.region,Defs(arena.alloc(split_defs.before), applied_await)));
return unwrap_suffixed_expression(arena, new_defs, maybe_def_pat);
},
Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new }) => {
let new_loc_ret = apply_task_await(arena, def_expr.region, sub_arg, sub_pat, sub_new);
let applied_await = apply_task_await(arena, loc_expr.region, unwrapped_expr, def_pattern, new_loc_ret);
let new_defs = arena.alloc(Loc::at(loc_expr.region,Defs(arena.alloc(split_defs.before), applied_await)));
return unwrap_suffixed_expression(arena, new_defs, maybe_def_pat);
}
Err(EUnwrapped::UnwrappedDefExpr(..)) | Err(EUnwrapped::Malformed) => {
// TODO handle case when we have maybe_def_pat so can return an unwrapped up
return Err(EUnwrapped::Malformed);
},
};
}
}
Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new }) => {
let new_body_def = ValueDef::Body(def_pattern, sub_new);
local_defs.replace_with_value_def(tag_index,new_body_def, sub_new.region);
let new_defs_expr = arena.alloc(Loc::at(def_expr.region,Defs(arena.alloc(local_defs), loc_ret)));
let replaced_def = apply_task_await(arena,def_expr.region,sub_arg,sub_pat,new_defs_expr);
return unwrap_suffixed_expression(arena,replaced_def,maybe_def_pat);
}
Err(err) => return Err(err)
}
}
}
}
// try to unwrap the loc_ret
match unwrap_suffixed_expression(arena,loc_ret,maybe_def_pat){
Ok(new_loc_ret) => {
Ok(arena.alloc(Loc::at(loc_expr.region,Defs(arena.alloc(local_defs), new_loc_ret))))
},
Err(EUnwrapped::UnwrappedSubExpr { sub_arg, sub_pat, sub_new }) => {
let new_loc_ret = apply_task_await(arena, loc_expr.region,sub_arg,sub_pat,sub_new);
let new_defs = arena.alloc(Loc::at(loc_expr.region,Defs(arena.alloc(local_defs), new_loc_ret)));
unwrap_suffixed_expression(arena, new_defs, maybe_def_pat)
}
Err(EUnwrapped::UnwrappedDefExpr(..)) => {
// TODO confirm this is correct with test case
Err(EUnwrapped::Malformed)
}
Err(EUnwrapped::Malformed) => {
Err(EUnwrapped::Malformed)
},
}
},
_ => internal_error!("unreachable, expected a Defs node to be passed into unwrap_suffixed_expression_defs_help"),
}
}
/// Helper for `Task.await (loc_arg) \loc_pat -> loc_new`
pub fn apply_task_await<'a>(
arena: &'a Bump,
region: Region,
loc_arg: &'a Loc<Expr<'a>>,
loc_pat: &'a Loc<Pattern<'a>>,
loc_new: &'a Loc<Expr<'a>>,
) -> &'a Loc<Expr<'a>> {
// If the pattern and the new are the same then we don't need to unwrap anything
// e.g. `Task.await foo \{} -> Task.ok {}` is the same as `foo`
if is_matching_empty_record(loc_pat, loc_new) {
return loc_arg;
}
// If the pattern and the new are matching answers then we don't need to unwrap anything
// e.g. `Task.await foo \#!a1 -> Task.ok #!a1` is the same as `foo`
if is_matching_intermediate_answer(loc_pat, loc_new) {
return loc_arg;
}
let mut task_await_apply_args: Vec<&'a Loc<Expr<'a>>> = Vec::new_in(arena);
// apply the unwrapped suffixed expression
task_await_apply_args.push(loc_arg);
// apply the closure
let mut closure_pattern = Vec::new_in(arena);
closure_pattern.push(*loc_pat);
task_await_apply_args.push(arena.alloc(Loc::at(
region,
Closure(arena.alloc_slice_copy(closure_pattern.as_slice()), loc_new),
)));
arena.alloc(Loc::at(
region,
Apply(
arena.alloc(Loc {
region,
value: Var {
module_name: ModuleName::TASK,
ident: "await",
},
}),
arena.alloc(task_await_apply_args),
CalledVia::BangSuffix,
),
))
}
fn extract_wrapped_task_ok_value<'a>(loc_expr: &'a Loc<Expr<'a>>) -> Option<&'a Loc<Expr<'a>>> {
match loc_expr.value {
Expr::Apply(function, arguments, _) => match function.value {
Var {
module_name, ident, ..
} if module_name == ModuleName::TASK && ident == "ok" => arguments.first().copied(),
_ => None,
},
_ => None,
}
}
fn is_matching_empty_record<'a>(
loc_pat: &'a Loc<Pattern<'a>>,
loc_expr: &'a Loc<Expr<'a>>,
) -> bool {
let is_empty_record = match extract_wrapped_task_ok_value(loc_expr) {
Some(task_expr) => match task_expr.value {
Expr::Record(collection) => collection.is_empty(),
_ => false,
},
None => false,
};
let is_pattern_empty_record = match loc_pat.value {
Pattern::RecordDestructure(collection) => collection.is_empty(),
_ => false,
};
is_empty_record && is_pattern_empty_record
}
pub fn is_matching_intermediate_answer<'a>(
loc_pat: &'a Loc<Pattern<'a>>,
loc_new: &'a Loc<Expr<'a>>,
) -> bool {
let pat_ident = match loc_pat.value {
Pattern::Identifier { ident, .. } => Some(ident),
_ => None,
};
let exp_ident = match loc_new.value {
Expr::Var {
module_name, ident, ..
} if module_name.is_empty() && ident.starts_with('#') => Some(ident),
_ => None,
};
let exp_ident_in_task = match extract_wrapped_task_ok_value(loc_new) {
Some(task_expr) => match task_expr.value {
Expr::Var {
module_name, ident, ..
} if module_name.is_empty() && ident.starts_with('#') => Some(ident),
_ => None,
},
None => None,
};
match (pat_ident, exp_ident, exp_ident_in_task) {
(Some(a), Some(b), None) => a == b,
(Some(a), None, Some(b)) => a == b,
_ => false,
}
}