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roc/crates/compiler/parse/src/expr.rs
Richard Feldman 0d2141d8b8
Separate out parse_loc_term_or_underscore_or_if
2022-07-24 18:15:18 -04:00

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use crate::ast::{
AssignedField, Collection, CommentOrNewline, Defs, Expr, ExtractSpaces, Has, HasAbilities,
Pattern, Spaceable, TypeAnnotation, TypeDef, TypeHeader, ValueDef,
};
use crate::blankspace::{
space0_after_e, space0_around_ee, space0_before_e, space0_before_optional_after, space0_e,
};
use crate::ident::{lowercase_ident, parse_ident, Ident};
use crate::keyword;
use crate::parser::{
self, backtrackable, optional, sep_by1, sep_by1_e, specialize, specialize_ref, then,
trailing_sep_by0, word1, word2, EExpect, EExpr, EIf, EInParens, ELambda, EList, ENumber,
EPattern, ERecord, EString, EType, EWhen, Either, ParseResult, Parser,
};
use crate::pattern::{loc_closure_param, loc_has_parser};
use crate::state::State;
use crate::type_annotation;
use bumpalo::collections::Vec;
use bumpalo::Bump;
use roc_collections::soa::Slice;
use roc_module::called_via::{BinOp, CalledVia, UnaryOp};
use roc_region::all::{Loc, Position, Region};
use crate::parser::Progress::{self, *};
fn expr_end<'a>() -> impl Parser<'a, (), EExpr<'a>> {
|_arena, state: State<'a>| {
if state.has_reached_end() {
Ok((NoProgress, (), state))
} else {
Err((NoProgress, EExpr::BadExprEnd(state.pos()), state))
}
}
}
pub fn test_parse_expr<'a>(
min_indent: u32,
arena: &'a bumpalo::Bump,
state: State<'a>,
) -> Result<Loc<Expr<'a>>, EExpr<'a>> {
let parser = skip_second!(
space0_before_e(
move |a, s| parse_loc_expr(min_indent, a, s),
min_indent,
EExpr::IndentStart,
),
expr_end()
);
match parser.parse(arena, state) {
Ok((_, expression, _)) => Ok(expression),
Err((_, fail, _)) => Err(fail),
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct ExprParseOptions {
/// Check for and accept multi-backpassing syntax
/// This is usually true, but false within list/record literals
/// because the comma separating backpassing arguments conflicts
/// with the comma separating literal elements
accept_multi_backpassing: bool,
/// Check for the `->` token, and raise an error if found
/// This is usually true, but false in if-guards
///
/// > Just foo if foo == 2 -> ...
check_for_arrow: bool,
}
impl Default for ExprParseOptions {
fn default() -> Self {
ExprParseOptions {
accept_multi_backpassing: true,
check_for_arrow: true,
}
}
}
pub fn expr_help<'a>(min_indent: u32) -> impl Parser<'a, Expr<'a>, EExpr<'a>> {
move |arena, state: State<'a>| {
parse_loc_expr(min_indent, arena, state).map(|(a, b, c)| (a, b.value, c))
}
}
fn loc_expr_in_parens_help<'a>(min_indent: u32) -> impl Parser<'a, Loc<Expr<'a>>, EInParens<'a>> {
move |arena, state| {
let (_, loc_expr, state) = loc_expr_in_parens_help_help(min_indent).parse(arena, state)?;
Ok((
MadeProgress,
Loc {
region: loc_expr.region,
value: Expr::ParensAround(arena.alloc(loc_expr.value)),
},
state,
))
}
}
fn loc_expr_in_parens_help_help<'a>(
min_indent: u32,
) -> impl Parser<'a, Loc<Expr<'a>>, EInParens<'a>> {
between!(
word1(b'(', EInParens::Open),
space0_around_ee(
specialize_ref(EInParens::Expr, move |arena, state| parse_loc_expr(
min_indent, arena, state
)),
min_indent,
EInParens::IndentOpen,
EInParens::IndentEnd,
),
word1(b')', EInParens::End)
)
}
fn loc_expr_in_parens_etc_help<'a>(min_indent: u32) -> impl Parser<'a, Loc<Expr<'a>>, EExpr<'a>> {
move |arena, state: State<'a>| {
let parser = loc!(and!(
specialize(EExpr::InParens, loc_expr_in_parens_help(min_indent)),
one_of![record_field_access_chain(), |a, s| Ok((
NoProgress,
Vec::new_in(a),
s
))]
));
let (
_,
Loc {
mut region,
value: (loc_expr, field_accesses),
},
state,
) = parser.parse(arena, state)?;
let mut value = loc_expr.value;
// if there are field accesses, include the parentheses in the region
// otherwise, don't include the parentheses
if field_accesses.is_empty() {
region = loc_expr.region;
} else {
for field in field_accesses {
// Wrap the previous answer in the new one, so we end up
// with a nested Expr. That way, `foo.bar.baz` gets represented
// in the AST as if it had been written (foo.bar).baz all along.
value = Expr::Access(arena.alloc(value), field);
}
}
let loc_expr = Loc::at(region, value);
Ok((MadeProgress, loc_expr, state))
}
}
fn record_field_access_chain<'a>() -> impl Parser<'a, Vec<'a, &'a str>, EExpr<'a>> {
|arena, state| match record_field_access().parse(arena, state) {
Ok((_, initial, state)) => {
let mut accesses = Vec::with_capacity_in(1, arena);
accesses.push(initial);
let mut loop_state = state;
loop {
match record_field_access().parse(arena, loop_state) {
Ok((_, next, state)) => {
accesses.push(next);
loop_state = state;
}
Err((MadeProgress, fail, state)) => return Err((MadeProgress, fail, state)),
Err((NoProgress, _, state)) => return Ok((MadeProgress, accesses, state)),
}
}
}
Err((MadeProgress, fail, state)) => Err((MadeProgress, fail, state)),
Err((NoProgress, _, state)) => Err((NoProgress, EExpr::Access(state.pos()), state)),
}
}
fn record_field_access<'a>() -> impl Parser<'a, &'a str, EExpr<'a>> {
skip_first!(
word1(b'.', EExpr::Access),
specialize(|_, pos| EExpr::Access(pos), lowercase_ident())
)
}
/// In some contexts we want to parse the `_` as an expression, so it can then be turned into a
/// pattern later
fn parse_loc_term_or_underscore_or_if<'a>(
min_indent: u32,
options: ExprParseOptions,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Loc<Expr<'a>>, EExpr<'a>> {
one_of!(
loc_expr_in_parens_etc_help(min_indent),
loc!(specialize(EExpr::If, if_expr_help(min_indent, options))),
loc!(specialize(EExpr::Str, string_literal_help())),
loc!(specialize(EExpr::SingleQuote, single_quote_literal_help())),
loc!(specialize(EExpr::Number, positive_number_literal_help())),
loc!(specialize(EExpr::Lambda, closure_help(min_indent, options))),
loc!(underscore_expression()),
loc!(record_literal_help(min_indent)),
loc!(specialize(EExpr::List, list_literal_help(min_indent))),
loc!(map_with_arena!(
assign_or_destructure_identifier(),
ident_to_expr
)),
)
.parse(arena, state)
}
/// In some contexts we want to parse the `_` as an expression, so it can then be turned into a
/// pattern later
fn parse_loc_term_or_underscore<'a>(
min_indent: u32,
options: ExprParseOptions,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Loc<Expr<'a>>, EExpr<'a>> {
one_of!(
loc_expr_in_parens_etc_help(min_indent),
loc!(specialize(EExpr::Str, string_literal_help())),
loc!(specialize(EExpr::SingleQuote, single_quote_literal_help())),
loc!(specialize(EExpr::Number, positive_number_literal_help())),
loc!(specialize(EExpr::Lambda, closure_help(min_indent, options))),
loc!(underscore_expression()),
loc!(record_literal_help(min_indent)),
loc!(specialize(EExpr::List, list_literal_help(min_indent))),
loc!(map_with_arena!(
assign_or_destructure_identifier(),
ident_to_expr
)),
)
.parse(arena, state)
}
fn parse_loc_term<'a>(
min_indent: u32,
options: ExprParseOptions,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Loc<Expr<'a>>, EExpr<'a>> {
one_of!(
loc_expr_in_parens_etc_help(min_indent),
loc!(specialize(EExpr::Str, string_literal_help())),
loc!(specialize(EExpr::SingleQuote, single_quote_literal_help())),
loc!(specialize(EExpr::Number, positive_number_literal_help())),
loc!(specialize(EExpr::Lambda, closure_help(min_indent, options))),
loc!(record_literal_help(min_indent)),
loc!(specialize(EExpr::List, list_literal_help(min_indent))),
loc!(map_with_arena!(
assign_or_destructure_identifier(),
ident_to_expr
)),
)
.parse(arena, state)
}
fn underscore_expression<'a>() -> impl Parser<'a, Expr<'a>, EExpr<'a>> {
move |arena: &'a Bump, state: State<'a>| {
let start = state.pos();
let (_, _, next_state) = word1(b'_', EExpr::Underscore).parse(arena, state)?;
let lowercase_ident_expr = { specialize(move |_, _| EExpr::End(start), lowercase_ident()) };
let (_, output, final_state) = optional(lowercase_ident_expr).parse(arena, next_state)?;
match output {
Some(name) => Ok((MadeProgress, Expr::Underscore(name), final_state)),
None => Ok((MadeProgress, Expr::Underscore(""), final_state)),
}
}
}
fn loc_possibly_negative_or_negated_term<'a>(
min_indent: u32,
options: ExprParseOptions,
) -> impl Parser<'a, Loc<Expr<'a>>, EExpr<'a>> {
one_of![
|arena, state: State<'a>| {
let initial = state.clone();
let (_, (loc_op, loc_expr), state) = and!(loc!(unary_negate()), |a, s| parse_loc_term(
min_indent, options, a, s
))
.parse(arena, state)?;
let loc_expr = numeric_negate_expression(arena, initial, loc_op, loc_expr, &[]);
Ok((MadeProgress, loc_expr, state))
},
// this will parse negative numbers, which the unary negate thing up top doesn't (for now)
loc!(specialize(EExpr::Number, number_literal_help())),
loc!(map_with_arena!(
and!(loc!(word1(b'!', EExpr::Start)), |a, s| {
parse_loc_term(min_indent, options, a, s)
}),
|arena: &'a Bump, (loc_op, loc_expr): (Loc<_>, _)| {
Expr::UnaryOp(arena.alloc(loc_expr), Loc::at(loc_op.region, UnaryOp::Not))
}
)),
|arena, state| { parse_loc_term_or_underscore_or_if(min_indent, options, arena, state) }
]
}
fn fail_expr_start_e<'a, T: 'a>() -> impl Parser<'a, T, EExpr<'a>> {
|_arena, state: State<'a>| Err((NoProgress, EExpr::Start(state.pos()), state))
}
fn unary_negate<'a>() -> impl Parser<'a, (), EExpr<'a>> {
move |_arena: &'a Bump, state: State<'a>| {
// a minus is unary iff
//
// - it is preceded by whitespace (spaces, newlines, comments)
// - it is not followed by whitespace
let followed_by_whitespace = state
.bytes()
.get(1)
.map(|c| c.is_ascii_whitespace() || *c == b'#')
.unwrap_or(false);
if state.bytes().starts_with(b"-") && !followed_by_whitespace {
// the negate is only unary if it is not followed by whitespace
let state = state.advance(1);
Ok((MadeProgress, (), state))
} else {
// this is not a negated expression
Err((NoProgress, EExpr::UnaryNot(state.pos()), state))
}
}
}
fn parse_expr_start<'a>(
min_indent: u32,
options: ExprParseOptions,
start_column: u32,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Loc<Expr<'a>>, EExpr<'a>> {
one_of![
loc!(specialize(EExpr::If, if_expr_help(min_indent, options))),
loc!(specialize(
EExpr::When,
when::expr_help(min_indent, options)
)),
loc!(specialize(EExpr::Expect, expect_help(min_indent, options))),
loc!(specialize(EExpr::Lambda, closure_help(min_indent, options))),
loc!(move |a, s| parse_expr_operator_chain(min_indent, options, start_column, a, s)),
fail_expr_start_e()
]
.parse(arena, state)
}
fn parse_expr_operator_chain<'a>(
min_indent: u32,
options: ExprParseOptions,
start_column: u32,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Expr<'a>, EExpr<'a>> {
let (_, expr, state) =
loc_possibly_negative_or_negated_term(min_indent, options).parse(arena, state)?;
let initial = state.clone();
let end = state.pos();
match space0_e(min_indent, EExpr::IndentEnd).parse(arena, state) {
Err((_, _, state)) => Ok((MadeProgress, expr.value, state)),
Ok((_, spaces_before_op, state)) => {
let expr_state = ExprState {
operators: Vec::new_in(arena),
arguments: Vec::new_in(arena),
expr,
spaces_after: spaces_before_op,
initial,
end,
};
parse_expr_end(min_indent, options, start_column, expr_state, arena, state)
}
}
}
#[derive(Debug)]
struct ExprState<'a> {
operators: Vec<'a, (Loc<Expr<'a>>, Loc<BinOp>)>,
arguments: Vec<'a, &'a Loc<Expr<'a>>>,
expr: Loc<Expr<'a>>,
spaces_after: &'a [CommentOrNewline<'a>],
initial: State<'a>,
end: Position,
}
impl<'a> ExprState<'a> {
fn consume_spaces(&mut self, arena: &'a Bump) {
if !self.spaces_after.is_empty() {
if let Some(last) = self.arguments.pop() {
let new = last.value.with_spaces_after(self.spaces_after, last.region);
self.arguments.push(arena.alloc(new));
} else {
let region = self.expr.region;
let mut value = Expr::Num("");
std::mem::swap(&mut self.expr.value, &mut value);
self.expr = arena
.alloc(value)
.with_spaces_after(self.spaces_after, region);
};
self.spaces_after = &[];
}
}
fn validate_assignment_or_backpassing<F>(
mut self,
arena: &'a Bump,
loc_op: Loc<BinOp>,
argument_error: F,
) -> Result<Loc<Expr<'a>>, EExpr<'a>>
where
F: Fn(Region, Position) -> EExpr<'a>,
{
if !self.operators.is_empty() {
// this `=` or `<-` likely occurred inline; treat it as an invalid operator
let opchar = match loc_op.value {
BinOp::Assignment => "=",
BinOp::Backpassing => "<-",
_ => unreachable!(),
};
let fail = EExpr::BadOperator(opchar, loc_op.region.start());
Err(fail)
} else if !self.expr.value.is_tag() && !self.arguments.is_empty() {
let region = Region::across_all(self.arguments.iter().map(|v| &v.region));
Err(argument_error(region, loc_op.region.start()))
} else {
self.consume_spaces(arena);
Ok(to_call(arena, self.arguments, self.expr))
}
}
fn validate_is_type_def(
mut self,
arena: &'a Bump,
loc_op: Loc<BinOp>,
kind: AliasOrOpaque,
) -> Result<(Loc<Expr<'a>>, Vec<'a, &'a Loc<Expr<'a>>>), EExpr<'a>> {
debug_assert_eq!(
loc_op.value,
match kind {
AliasOrOpaque::Alias => BinOp::IsAliasType,
AliasOrOpaque::Opaque => BinOp::IsOpaqueType,
}
);
if !self.operators.is_empty() {
// this `:`/`:=` likely occurred inline; treat it as an invalid operator
let op = match kind {
AliasOrOpaque::Alias => ":",
AliasOrOpaque::Opaque => ":=",
};
let fail = EExpr::BadOperator(op, loc_op.region.start());
Err(fail)
} else {
self.consume_spaces(arena);
Ok((self.expr, self.arguments))
}
}
}
#[allow(clippy::unnecessary_wraps)]
fn parse_expr_final<'a>(
expr_state: ExprState<'a>,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Expr<'a>, EExpr<'a>> {
let right_arg = to_call(arena, expr_state.arguments, expr_state.expr);
let expr = if expr_state.operators.is_empty() {
right_arg.value
} else {
Expr::BinOps(
expr_state.operators.into_bump_slice(),
arena.alloc(right_arg),
)
};
Ok((MadeProgress, expr, state))
}
fn to_call<'a>(
arena: &'a Bump,
mut arguments: Vec<'a, &'a Loc<Expr<'a>>>,
loc_expr1: Loc<Expr<'a>>,
) -> Loc<Expr<'a>> {
if arguments.is_empty() {
loc_expr1
} else {
let last = arguments.last().map(|x| x.region).unwrap_or_default();
let region = Region::span_across(&loc_expr1.region, &last);
let spaces = if let Some(last) = arguments.last_mut() {
let spaces = last.value.extract_spaces();
if spaces.after.is_empty() {
&[]
} else {
let inner = if !spaces.before.is_empty() {
arena.alloc(spaces.item).before(spaces.before)
} else {
spaces.item
};
*last = arena.alloc(Loc::at(last.region, inner));
spaces.after
}
} else {
&[]
};
let mut apply = Expr::Apply(
arena.alloc(loc_expr1),
arguments.into_bump_slice(),
CalledVia::Space,
);
if !spaces.is_empty() {
apply = arena.alloc(apply).after(spaces)
}
Loc::at(region, apply)
}
}
fn numeric_negate_expression<'a, T>(
arena: &'a Bump,
state: State<'a>,
loc_op: Loc<T>,
expr: Loc<Expr<'a>>,
spaces: &'a [CommentOrNewline<'a>],
) -> Loc<Expr<'a>> {
debug_assert_eq!(state.bytes().get(0), Some(&b'-'));
// for overflow reasons, we must make the unary minus part of the number literal.
let start = state.pos();
let region = Region::new(start, expr.region.end());
let new_expr = match expr.value {
Expr::Num(string) => {
let new_string =
unsafe { std::str::from_utf8_unchecked(&state.bytes()[..string.len() + 1]) };
Expr::Num(new_string)
}
Expr::Float(string) => {
let new_string =
unsafe { std::str::from_utf8_unchecked(&state.bytes()[..string.len() + 1]) };
Expr::Float(new_string)
}
Expr::NonBase10Int {
string,
base,
is_negative,
} => {
// don't include the minus sign here; it will not be parsed right
Expr::NonBase10Int {
is_negative: !is_negative,
string,
base,
}
}
_ => Expr::UnaryOp(arena.alloc(expr), Loc::at(loc_op.region, UnaryOp::Negate)),
};
let new_loc_expr = Loc::at(region, new_expr);
if spaces.is_empty() {
new_loc_expr
} else {
arena
.alloc(new_loc_expr.value)
.with_spaces_before(spaces, new_loc_expr.region)
}
}
fn parse_defs_end<'a>(
_options: ExprParseOptions,
start_column: u32,
mut defs: Defs<'a>,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Defs<'a>, EExpr<'a>> {
let min_indent = start_column;
let mut global_state = state;
loop {
let state = global_state;
let initial = state.clone();
let mut spaces_before_current = &[] as &[_];
let spaces_before_current_start = state.pos();
let state = match space0_e(min_indent, EExpr::IndentStart).parse(arena, state) {
Err((MadeProgress, _, s)) => {
return Err((MadeProgress, EExpr::DefMissingFinalExpr(s.pos()), s));
}
Ok((_, spaces, state)) => {
spaces_before_current = spaces;
state
}
Err((NoProgress, _, state)) => state,
};
let start = state.pos();
match space0_after_e(
crate::pattern::loc_pattern_help(min_indent),
min_indent,
EPattern::IndentEnd,
)
.parse(arena, state.clone())
{
Err((NoProgress, _, _)) => {
match crate::parser::keyword_e(crate::keyword::EXPECT, EExpect::Expect)
.parse(arena, state)
{
Err((_, _, _)) => {
// a hacky way to get expression-based error messages. TODO fix this
return Ok((NoProgress, defs, initial));
}
Ok((_, _, state)) => {
let parse_def_expr = space0_before_e(
move |a, s| parse_loc_expr(min_indent + 1, a, s),
min_indent,
EExpr::IndentEnd,
);
let (_, loc_def_expr, state) = parse_def_expr.parse(arena, state)?;
let end = loc_def_expr.region.end();
let region = Region::new(start, end);
// drop newlines before the preceding comment
let spaces_before_start = spaces_before_current_start.offset as usize;
let spaces_before_end = start.offset as usize;
let mut spaces_before_current_start = spaces_before_current_start;
for byte in &state.original_bytes()[spaces_before_start..spaces_before_end]
{
match byte {
b' ' | b'\n' => {
spaces_before_current_start.offset += 1;
}
_ => break,
}
}
let preceding_comment = Region::new(spaces_before_current_start, start);
let value_def = ValueDef::Expect {
condition: arena.alloc(loc_def_expr),
preceding_comment,
};
defs.push_value_def(value_def, region, spaces_before_current, &[]);
global_state = state;
continue;
}
}
}
Err((MadeProgress, _, _)) => {
// a hacky way to get expression-based error messages. TODO fix this
return Ok((NoProgress, defs, initial));
}
Ok((_, loc_pattern, state)) => {
// First let's check whether this is an ability definition.
let opt_tag_and_args: Option<(&str, Region, &[Loc<Pattern>])> =
match loc_pattern.value {
Pattern::Apply(
Loc {
value: Pattern::Tag(name),
region,
},
args,
) => Some((name, *region, args)),
Pattern::Tag(name) => Some((name, loc_pattern.region, &[])),
_ => None,
};
if let Some((name, name_region, args)) = opt_tag_and_args {
if let Ok((_, loc_has, state)) =
loc_has_parser(min_indent).parse(arena, state.clone())
{
let (_, (type_def, def_region), state) = finish_parsing_ability_def_help(
start_column,
Loc::at(name_region, name),
args,
loc_has,
arena,
state,
)?;
defs.push_type_def(type_def, def_region, spaces_before_current, &[]);
global_state = state;
continue;
}
}
// Otherwise, this is a def or alias.
match operator().parse(arena, state) {
Ok((_, BinOp::Assignment, state)) => {
let parse_def_expr = space0_before_e(
move |a, s| parse_loc_expr(min_indent + 1, a, s),
min_indent,
EExpr::IndentEnd,
);
let (_, loc_def_expr, state) = parse_def_expr.parse(arena, state)?;
{
let region =
Region::span_across(&loc_pattern.region, &loc_def_expr.region);
if spaces_before_current.len() <= 1 {
let comment = match spaces_before_current.get(0) {
Some(CommentOrNewline::LineComment(s)) => Some(*s),
Some(CommentOrNewline::DocComment(s)) => Some(*s),
_ => None,
};
match defs.last() {
Some(Err(ValueDef::Annotation(ann_pattern, ann_type))) => {
// join this body with the preceding annotation
let value_def = ValueDef::AnnotatedBody {
ann_pattern: arena.alloc(*ann_pattern),
ann_type: arena.alloc(*ann_type),
comment,
body_pattern: arena.alloc(loc_pattern),
body_expr: &*arena.alloc(loc_def_expr),
};
let region =
Region::span_across(&ann_pattern.region, &region);
defs.replace_with_value_def(
defs.tags.len() - 1,
value_def,
region,
)
}
Some(Ok(TypeDef::Alias {
header,
ann: ann_type,
})) => {
// This is a case like
// UserId x : [UserId Int]
// UserId x = UserId 42
// We optimistically parsed the first line as an alias; we now turn it
// into an annotation.
let loc_name =
arena.alloc(header.name.map(|x| Pattern::Tag(x)));
let ann_pattern = Pattern::Apply(loc_name, header.vars);
let vars_region = Region::across_all(
header.vars.iter().map(|v| &v.region),
);
let region_ann_pattern =
Region::span_across(&loc_name.region, &vars_region);
let loc_ann_pattern =
Loc::at(region_ann_pattern, ann_pattern);
let value_def = ValueDef::AnnotatedBody {
ann_pattern: arena.alloc(loc_ann_pattern),
ann_type: arena.alloc(*ann_type),
comment,
body_pattern: arena.alloc(loc_pattern),
body_expr: &*arena.alloc(loc_def_expr),
};
let region =
Region::span_across(&header.name.region, &region);
defs.replace_with_value_def(
defs.tags.len() - 1,
value_def,
region,
)
}
_ => {
// the previous and current def can't be joined up
let value_def = ValueDef::Body(
arena.alloc(loc_pattern),
&*arena.alloc(loc_def_expr),
);
defs.push_value_def(
value_def,
region,
spaces_before_current,
&[],
)
}
}
} else {
// the previous and current def can't be joined up
let value_def = ValueDef::Body(
arena.alloc(loc_pattern),
&*arena.alloc(loc_def_expr),
);
defs.push_value_def(value_def, region, spaces_before_current, &[])
}
};
global_state = state;
continue;
}
Ok((_, BinOp::IsAliasType, state)) => {
let (_, ann_type, state) =
alias_signature_with_space_before(min_indent + 1)
.parse(arena, state)?;
let region = Region::span_across(&loc_pattern.region, &ann_type.region);
// the previous and current def can't be joined up
match &loc_pattern.value {
Pattern::Apply(
Loc {
value: Pattern::Tag(name),
..
},
alias_arguments,
) => {
let name = Loc::at(loc_pattern.region, *name);
let header = TypeHeader {
name,
vars: alias_arguments,
};
let type_def = TypeDef::Alias {
header,
ann: ann_type,
};
defs.push_type_def(type_def, region, spaces_before_current, &[]);
}
Pattern::Tag(name) => {
let name = Loc::at(loc_pattern.region, *name);
let pattern_arguments: &'a [Loc<Pattern<'a>>] = &[];
let header = TypeHeader {
name,
vars: pattern_arguments,
};
let type_def = TypeDef::Alias {
header,
ann: ann_type,
};
defs.push_type_def(type_def, region, spaces_before_current, &[]);
}
_ => {
let value_def = ValueDef::Annotation(loc_pattern, ann_type);
defs.push_value_def(value_def, region, spaces_before_current, &[]);
}
};
global_state = state;
continue;
}
Ok((_, BinOp::IsOpaqueType, state)) => {
let (_, (signature, derived), state) =
opaque_signature_with_space_before(min_indent + 1)
.parse(arena, state)?;
let region = Region::span_across(&loc_pattern.region, &signature.region);
// the previous and current def can't be joined up
match &loc_pattern.value {
Pattern::Apply(
Loc {
value: Pattern::Tag(name),
..
},
alias_arguments,
) => {
let name = Loc::at(loc_pattern.region, *name);
let header = TypeHeader {
name,
vars: alias_arguments,
};
let type_def = TypeDef::Opaque {
header,
typ: signature,
derived,
};
defs.push_type_def(type_def, region, spaces_before_current, &[]);
}
Pattern::Tag(name) => {
let name = Loc::at(loc_pattern.region, *name);
let pattern_arguments: &'a [Loc<Pattern<'a>>] = &[];
let header = TypeHeader {
name,
vars: pattern_arguments,
};
let type_def = TypeDef::Opaque {
header,
typ: signature,
derived,
};
defs.push_type_def(type_def, region, spaces_before_current, &[]);
}
_ => {
let value_def = ValueDef::Annotation(loc_pattern, signature);
defs.push_value_def(value_def, region, spaces_before_current, &[]);
}
};
global_state = state;
continue;
}
_ => return Ok((MadeProgress, defs, initial)),
}
}
}
}
}
fn parse_defs_expr<'a>(
options: ExprParseOptions,
start_column: u32,
defs: Defs<'a>,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Expr<'a>, EExpr<'a>> {
let min_indent = start_column;
match parse_defs_end(options, start_column, defs, arena, state) {
Err(bad) => Err(bad),
Ok((_, def_state, state)) => {
// this is no def, because there is no `=` or `:`; parse as an expr
let parse_final_expr = space0_before_e(
move |a, s| parse_loc_expr(min_indent, a, s),
min_indent,
EExpr::IndentEnd,
);
match parse_final_expr.parse(arena, state) {
Err((_, fail, state)) => {
return Err((
MadeProgress,
EExpr::DefMissingFinalExpr2(arena.alloc(fail), state.pos()),
state,
));
}
Ok((_, loc_ret, state)) => {
return Ok((
MadeProgress,
Expr::Defs(arena.alloc(def_state), arena.alloc(loc_ret)),
state,
));
}
}
}
}
}
fn alias_signature_with_space_before<'a>(
min_indent: u32,
) -> impl Parser<'a, Loc<TypeAnnotation<'a>>, EExpr<'a>> {
specialize(
EExpr::Type,
space0_before_e(
type_annotation::located(min_indent + 1, false),
min_indent + 1,
EType::TIndentStart,
),
)
}
fn opaque_signature_with_space_before<'a>(
min_indent: u32,
) -> impl Parser<'a, (Loc<TypeAnnotation<'a>>, Option<Loc<HasAbilities<'a>>>), EExpr<'a>> {
and!(
specialize(
EExpr::Type,
space0_before_e(
type_annotation::located_opaque_signature(min_indent, true),
min_indent,
EType::TIndentStart,
),
),
optional(specialize(
EExpr::Type,
space0_before_e(
type_annotation::has_abilities(min_indent),
min_indent,
EType::TIndentStart,
),
))
)
}
#[derive(Copy, Clone, PartialEq, Eq)]
enum AliasOrOpaque {
Alias,
Opaque,
}
#[allow(clippy::too_many_arguments)]
fn finish_parsing_alias_or_opaque<'a>(
min_indent: u32,
options: ExprParseOptions,
start_column: u32,
expr_state: ExprState<'a>,
loc_op: Loc<BinOp>,
arena: &'a Bump,
state: State<'a>,
spaces_after_operator: &'a [CommentOrNewline<'a>],
kind: AliasOrOpaque,
) -> ParseResult<'a, Expr<'a>, EExpr<'a>> {
let expr_region = expr_state.expr.region;
let indented_more = start_column + 1;
let (expr, arguments) = expr_state
.validate_is_type_def(arena, loc_op, kind)
.map_err(|fail| (MadeProgress, fail, state.clone()))?;
let mut defs = Defs::default();
let state = match &expr.value {
Expr::Tag(name) => {
let mut type_arguments = Vec::with_capacity_in(arguments.len(), arena);
for argument in arguments {
match expr_to_pattern_help(arena, &argument.value) {
Ok(good) => {
type_arguments.push(Loc::at(argument.region, good));
}
Err(_) => panic!(),
}
}
match kind {
AliasOrOpaque::Alias => {
let (_, signature, state) =
alias_signature_with_space_before(indented_more).parse(arena, state)?;
let def_region = Region::span_across(&expr.region, &signature.region);
let header = TypeHeader {
name: Loc::at(expr.region, name),
vars: type_arguments.into_bump_slice(),
};
let def = TypeDef::Alias {
header,
ann: signature,
};
defs.push_type_def(def, def_region, &[], &[]);
state
}
AliasOrOpaque::Opaque => {
let (_, (signature, derived), state) =
opaque_signature_with_space_before(indented_more).parse(arena, state)?;
let def_region = Region::span_across(&expr.region, &signature.region);
let header = TypeHeader {
name: Loc::at(expr.region, name),
vars: type_arguments.into_bump_slice(),
};
let def = TypeDef::Opaque {
header,
typ: signature,
derived,
};
defs.push_type_def(def, def_region, &[], &[]);
state
}
}
}
_ => {
let call = to_call(arena, arguments, expr);
match expr_to_pattern_help(arena, &call.value) {
Ok(good) => {
let parser = specialize(
EExpr::Type,
space0_before_e(
type_annotation::located(indented_more, false),
min_indent,
EType::TIndentStart,
),
);
match parser.parse(arena, state) {
Err((_, fail, state)) => return Err((MadeProgress, fail, state)),
Ok((_, mut ann_type, state)) => {
// put the spaces from after the operator in front of the call
if !spaces_after_operator.is_empty() {
ann_type = arena
.alloc(ann_type.value)
.with_spaces_before(spaces_after_operator, ann_type.region);
}
let def_region = Region::span_across(&call.region, &ann_type.region);
let value_def =
ValueDef::Annotation(Loc::at(expr_region, good), ann_type);
defs.push_value_def(value_def, def_region, &[], &[]);
state
}
}
}
Err(_) => {
// this `:`/`:=` likely occurred inline; treat it as an invalid operator
let op = match kind {
AliasOrOpaque::Alias => ":",
AliasOrOpaque::Opaque => ":=",
};
let fail = EExpr::BadOperator(op, loc_op.region.start());
return Err((MadeProgress, fail, state));
}
}
}
};
parse_defs_expr(options, start_column, defs, arena, state)
}
mod ability {
use super::*;
use crate::{
ast::{AbilityMember, Spaceable, Spaced},
parser::EAbility,
};
/// Parses a single ability demand line; see `parse_demand`.
fn parse_demand_help<'a>(
start_column: u32,
) -> impl Parser<'a, AbilityMember<'a>, EAbility<'a>> {
map!(
and!(
specialize(|_, pos| EAbility::DemandName(pos), loc!(lowercase_ident())),
skip_first!(
and!(
// TODO: do we get anything from picking up spaces here?
space0_e(start_column, EAbility::DemandName),
word1(b':', EAbility::DemandColon)
),
specialize(
EAbility::Type,
// Require the type to be more indented than the name
type_annotation::located(start_column + 1, true)
)
)
),
|(name, typ): (Loc<&'a str>, Loc<TypeAnnotation<'a>>)| {
AbilityMember {
name: name.map_owned(Spaced::Item),
typ,
}
}
)
}
pub enum IndentLevel {
PendingMin(u32),
Exact(u32),
}
/// Parses an ability demand like `hash : a -> U64 | a has Hash`, in the context of a larger
/// ability definition.
/// This is basically the same as parsing a free-floating annotation, but with stricter rules.
pub fn parse_demand<'a>(
indent: IndentLevel,
) -> impl Parser<'a, (u32, AbilityMember<'a>), EAbility<'a>> {
move |arena, state: State<'a>| {
let initial = state.clone();
// Put no restrictions on the indent after the spaces; we'll check it manually.
match space0_e(0, EAbility::DemandName).parse(arena, state) {
Err((MadeProgress, fail, _)) => Err((NoProgress, fail, initial)),
Err((NoProgress, fail, _)) => Err((NoProgress, fail, initial)),
Ok((_progress, spaces, state)) => {
match indent {
IndentLevel::PendingMin(min_indent) if state.column() < min_indent => {
let indent_difference = state.column() as i32 - min_indent as i32;
Err((
MadeProgress,
EAbility::DemandAlignment(indent_difference, state.pos()),
initial,
))
}
IndentLevel::Exact(wanted) if state.column() < wanted => {
// This demand is not indented correctly
let indent_difference = state.column() as i32 - wanted as i32;
Err((
// Rollback because the deindent may be because there is a next
// expression
NoProgress,
EAbility::DemandAlignment(indent_difference, state.pos()),
initial,
))
}
IndentLevel::Exact(wanted) if state.column() > wanted => {
// This demand is not indented correctly
let indent_difference = state.column() as i32 - wanted as i32;
Err((
MadeProgress,
EAbility::DemandAlignment(indent_difference, state.pos()),
initial,
))
}
_ => {
let indent_column = state.column();
let parser = parse_demand_help(indent_column);
match parser.parse(arena, state) {
Err((MadeProgress, fail, state)) => {
Err((MadeProgress, fail, state))
}
Err((NoProgress, fail, _)) => {
// We made progress relative to the entire ability definition,
// so this is an error.
Err((MadeProgress, fail, initial))
}
Ok((_, mut demand, state)) => {
// Tag spaces onto the parsed demand name
if !spaces.is_empty() {
demand.name = arena
.alloc(demand.name.value)
.with_spaces_before(spaces, demand.name.region);
}
Ok((MadeProgress, (indent_column, demand), state))
}
}
}
}
}
}
}
}
}
fn finish_parsing_ability_def_help<'a>(
start_column: u32,
name: Loc<&'a str>,
args: &'a [Loc<Pattern<'a>>],
loc_has: Loc<Has<'a>>,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, (TypeDef<'a>, Region), EExpr<'a>> {
let mut demands = Vec::with_capacity_in(2, arena);
let min_indent_for_demand = start_column + 1;
// Parse the first demand. This will determine the indentation level all the
// other demands must observe.
let (_, (demand_indent_level, first_demand), mut state) =
ability::parse_demand(ability::IndentLevel::PendingMin(min_indent_for_demand))
.parse(arena, state)
.map_err(|(progress, err, state)| {
(progress, EExpr::Ability(err, state.pos()), state)
})?;
demands.push(first_demand);
let demand_indent = ability::IndentLevel::Exact(demand_indent_level);
let demand_parser = ability::parse_demand(demand_indent);
loop {
match demand_parser.parse(arena, state.clone()) {
Ok((_, (_indent, demand), next_state)) => {
state = next_state;
demands.push(demand);
}
Err((MadeProgress, problem, old_state)) => {
return Err((
MadeProgress,
EExpr::Ability(problem, old_state.pos()),
old_state,
));
}
Err((NoProgress, _, old_state)) => {
state = old_state;
break;
}
}
}
let def_region = Region::span_across(&name.region, &demands.last().unwrap().typ.region);
let type_def = TypeDef::Ability {
header: TypeHeader { name, vars: args },
loc_has,
members: demands.into_bump_slice(),
};
Ok((MadeProgress, (type_def, def_region), state))
}
fn parse_expr_operator<'a>(
min_indent: u32,
options: ExprParseOptions,
start_column: u32,
mut expr_state: ExprState<'a>,
loc_op: Loc<BinOp>,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Expr<'a>, EExpr<'a>> {
let (_, spaces_after_operator, state) =
space0_e(min_indent, EExpr::IndentEnd).parse(arena, state)?;
// a `-` is unary if it is preceded by a space and not followed by a space
let op = loc_op.value;
let op_start = loc_op.region.start();
let op_end = loc_op.region.end();
let new_start = state.pos();
match op {
BinOp::Minus if expr_state.end != op_start && op_end == new_start => {
// negative terms
let (_, negated_expr, state) = parse_loc_term(min_indent, options, arena, state)?;
let new_end = state.pos();
let arg = numeric_negate_expression(
arena,
expr_state.initial,
loc_op,
negated_expr,
expr_state.spaces_after,
);
expr_state.initial = state.clone();
let (spaces, state) = match space0_e(min_indent, EExpr::IndentEnd).parse(arena, state) {
Err((_, _, state)) => (&[] as &[_], state),
Ok((_, spaces, state)) => (spaces, state),
};
expr_state.arguments.push(arena.alloc(arg));
expr_state.spaces_after = spaces;
expr_state.end = new_end;
parse_expr_end(min_indent, options, start_column, expr_state, arena, state)
}
BinOp::Assignment => {
let expr_region = expr_state.expr.region;
let indented_more = start_column + 1;
let call = expr_state
.validate_assignment_or_backpassing(arena, loc_op, EExpr::ElmStyleFunction)
.map_err(|fail| (MadeProgress, fail, state.clone()))?;
let (value_def, def_region, state) = {
match expr_to_pattern_help(arena, &call.value) {
Ok(good) => {
let (_, mut body, state) = parse_loc_expr(indented_more, arena, state)?;
// put the spaces from after the operator in front of the call
if !spaces_after_operator.is_empty() {
body = arena
.alloc(body.value)
.with_spaces_before(spaces_after_operator, body.region);
}
let body_region = Region::span_across(&call.region, &body.region);
let alias = ValueDef::Body(
arena.alloc(Loc::at(expr_region, good)),
arena.alloc(body),
);
(alias, body_region, state)
}
Err(_) => {
// this `=` likely occurred inline; treat it as an invalid operator
let fail = EExpr::BadOperator(arena.alloc("="), loc_op.region.start());
return Err((MadeProgress, fail, state));
}
}
};
let mut defs = Defs::default();
defs.push_value_def(value_def, def_region, &[], &[]);
parse_defs_expr(options, start_column, defs, arena, state)
}
BinOp::Backpassing => {
let expr_region = expr_state.expr.region;
let indented_more = start_column + 1;
let call = expr_state
.validate_assignment_or_backpassing(arena, loc_op, |_, pos| {
EExpr::BadOperator("<-", pos)
})
.map_err(|fail| (MadeProgress, fail, state.clone()))?;
let (loc_pattern, loc_body, state) = {
match expr_to_pattern_help(arena, &call.value) {
Ok(good) => {
let (_, mut ann_type, state) = parse_loc_expr(indented_more, arena, state)?;
// put the spaces from after the operator in front of the call
if !spaces_after_operator.is_empty() {
ann_type = arena
.alloc(ann_type.value)
.with_spaces_before(spaces_after_operator, ann_type.region);
}
(Loc::at(expr_region, good), ann_type, state)
}
Err(_) => {
// this `=` likely occurred inline; treat it as an invalid operator
let fail = EExpr::BadOperator("=", loc_op.region.start());
return Err((MadeProgress, fail, state));
}
}
};
let parse_cont = space0_before_e(
move |a, s| parse_loc_expr(min_indent, a, s),
min_indent,
EExpr::IndentEnd,
);
let (_, loc_cont, state) = parse_cont.parse(arena, state)?;
let ret = Expr::Backpassing(
arena.alloc([loc_pattern]),
arena.alloc(loc_body),
arena.alloc(loc_cont),
);
Ok((MadeProgress, ret, state))
}
BinOp::IsAliasType | BinOp::IsOpaqueType => finish_parsing_alias_or_opaque(
min_indent,
options,
start_column,
expr_state,
loc_op,
arena,
state,
spaces_after_operator,
match op {
BinOp::IsAliasType => AliasOrOpaque::Alias,
BinOp::IsOpaqueType => AliasOrOpaque::Opaque,
_ => unreachable!(),
},
),
_ => match loc_possibly_negative_or_negated_term(min_indent, options).parse(arena, state) {
Err((MadeProgress, f, s)) => Err((MadeProgress, f, s)),
Ok((_, mut new_expr, state)) => {
let new_end = state.pos();
expr_state.initial = state.clone();
// put the spaces from after the operator in front of the new_expr
if !spaces_after_operator.is_empty() {
new_expr = arena
.alloc(new_expr.value)
.with_spaces_before(spaces_after_operator, new_expr.region);
}
match space0_e(min_indent, EExpr::IndentEnd).parse(arena, state) {
Err((_, _, state)) => {
let args = std::mem::replace(&mut expr_state.arguments, Vec::new_in(arena));
let call = to_call(arena, args, expr_state.expr);
expr_state.operators.push((call, loc_op));
expr_state.expr = new_expr;
expr_state.end = new_end;
expr_state.spaces_after = &[];
parse_expr_final(expr_state, arena, state)
}
Ok((_, spaces, state)) => {
let args = std::mem::replace(&mut expr_state.arguments, Vec::new_in(arena));
let call = to_call(arena, args, expr_state.expr);
expr_state.operators.push((call, loc_op));
expr_state.expr = new_expr;
expr_state.end = new_end;
expr_state.spaces_after = spaces;
// TODO new start?
parse_expr_end(min_indent, options, start_column, expr_state, arena, state)
}
}
}
Err((NoProgress, expr, e)) => {
todo!("{:?} {:?}", expr, e)
}
},
}
}
fn parse_expr_end<'a>(
min_indent: u32,
options: ExprParseOptions,
start_column: u32,
mut expr_state: ExprState<'a>,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Expr<'a>, EExpr<'a>> {
let parser = skip_first!(
crate::blankspace::check_indent(min_indent, EExpr::IndentEnd),
move |a, s| parse_loc_term_or_underscore(min_indent, options, a, s)
);
match parser.parse(arena, state.clone()) {
Err((MadeProgress, f, s)) => Err((MadeProgress, f, s)),
Ok((
_,
has @ Loc {
value:
Expr::Var {
module_name: "",
ident: "has",
},
..
},
state,
)) if matches!(expr_state.expr.value, Expr::Tag(..)) => {
// This is an ability definition, `Ability arg1 ... has ...`.
let name = expr_state.expr.map_owned(|e| match e {
Expr::Tag(name) => name,
_ => unreachable!(),
});
let mut arguments = Vec::with_capacity_in(expr_state.arguments.len(), arena);
for argument in expr_state.arguments {
match expr_to_pattern_help(arena, &argument.value) {
Ok(good) => {
arguments.push(Loc::at(argument.region, good));
}
Err(_) => {
let start = argument.region.start();
let err = &*arena.alloc(EPattern::Start(start));
return Err((
MadeProgress,
EExpr::Pattern(err, argument.region.start()),
state,
));
}
}
}
// Attach any spaces to the `has` keyword
let has = if !expr_state.spaces_after.is_empty() {
arena
.alloc(Has::Has)
.with_spaces_before(expr_state.spaces_after, has.region)
} else {
Loc::at(has.region, Has::Has)
};
let args = arguments.into_bump_slice();
let (_, (type_def, def_region), state) =
finish_parsing_ability_def_help(start_column, name, args, has, arena, state)?;
let mut defs = Defs::default();
defs.push_type_def(type_def, def_region, &[], &[]);
parse_defs_expr(options, start_column, defs, arena, state)
}
Ok((_, mut arg, state)) => {
let new_end = state.pos();
// now that we have `function arg1 ... <spaces> argn`, attach the spaces to the `argn`
if !expr_state.spaces_after.is_empty() {
arg = arena
.alloc(arg.value)
.with_spaces_before(expr_state.spaces_after, arg.region);
expr_state.spaces_after = &[];
}
expr_state.initial = state.clone();
match space0_e(min_indent, EExpr::IndentEnd).parse(arena, state) {
Err((_, _, state)) => {
expr_state.arguments.push(arena.alloc(arg));
expr_state.end = new_end;
expr_state.spaces_after = &[];
parse_expr_final(expr_state, arena, state)
}
Ok((_, new_spaces, state)) => {
expr_state.arguments.push(arena.alloc(arg));
expr_state.end = new_end;
expr_state.spaces_after = new_spaces;
parse_expr_end(min_indent, options, start_column, expr_state, arena, state)
}
}
}
Err((NoProgress, _, _)) => {
let before_op = state.clone();
// try an operator
match loc!(operator()).parse(arena, state) {
Err((MadeProgress, f, s)) => Err((MadeProgress, f, s)),
Ok((_, loc_op, state)) => {
expr_state.consume_spaces(arena);
expr_state.initial = before_op;
parse_expr_operator(
min_indent,
options,
start_column,
expr_state,
loc_op,
arena,
state,
)
}
Err((NoProgress, _, mut state)) => {
// try multi-backpassing
if options.accept_multi_backpassing && state.bytes().starts_with(b",") {
state = state.advance(1);
let (_, mut patterns, state) = specialize_ref(
EExpr::Pattern,
crate::parser::sep_by0(
word1(b',', EPattern::Start),
space0_around_ee(
crate::pattern::loc_pattern_help(min_indent),
min_indent,
EPattern::Start,
EPattern::IndentEnd,
),
),
)
.parse(arena, state)?;
expr_state.consume_spaces(arena);
let call = to_call(arena, expr_state.arguments, expr_state.expr);
let loc_pattern = Loc::at(
call.region,
expr_to_pattern_help(arena, &call.value).unwrap(),
);
patterns.insert(0, loc_pattern);
match word2(b'<', b'-', EExpr::BackpassArrow).parse(arena, state) {
Err((_, fail, state)) => Err((MadeProgress, fail, state)),
Ok((_, _, state)) => {
let min_indent = start_column;
let parse_body = space0_before_e(
move |a, s| parse_loc_expr(min_indent + 1, a, s),
min_indent,
EExpr::IndentEnd,
);
let (_, loc_body, state) = parse_body.parse(arena, state)?;
let parse_cont = space0_before_e(
move |a, s| parse_loc_expr(min_indent, a, s),
min_indent,
EExpr::IndentEnd,
);
let (_, loc_cont, state) = parse_cont.parse(arena, state)?;
let ret = Expr::Backpassing(
patterns.into_bump_slice(),
arena.alloc(loc_body),
arena.alloc(loc_cont),
);
Ok((MadeProgress, ret, state))
}
}
} else if options.check_for_arrow && state.bytes().starts_with(b"->") {
Err((MadeProgress, EExpr::BadOperator("->", state.pos()), state))
} else {
// roll back space parsing
let state = expr_state.initial.clone();
parse_expr_final(expr_state, arena, state)
}
}
}
}
}
}
pub fn parse_loc_expr<'a>(
min_indent: u32,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Loc<Expr<'a>>, EExpr<'a>> {
parse_loc_expr_with_options(
min_indent,
ExprParseOptions {
accept_multi_backpassing: true,
..Default::default()
},
arena,
state,
)
}
pub fn parse_loc_expr_no_multi_backpassing<'a>(
min_indent: u32,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Loc<Expr<'a>>, EExpr<'a>> {
parse_loc_expr_with_options(
min_indent,
ExprParseOptions {
accept_multi_backpassing: false,
..Default::default()
},
arena,
state,
)
}
fn parse_loc_expr_with_options<'a>(
min_indent: u32,
options: ExprParseOptions,
arena: &'a Bump,
state: State<'a>,
) -> ParseResult<'a, Loc<Expr<'a>>, EExpr<'a>> {
let column = state.column();
parse_expr_start(min_indent, options, column, arena, state)
}
/// If the given Expr would parse the same way as a valid Pattern, convert it.
/// Example: (foo) could be either an Expr::Var("foo") or Pattern::Identifier("foo")
fn expr_to_pattern_help<'a>(arena: &'a Bump, expr: &Expr<'a>) -> Result<Pattern<'a>, ()> {
match expr {
Expr::Var { module_name, ident } => {
if module_name.is_empty() {
Ok(Pattern::Identifier(ident))
} else {
Ok(Pattern::QualifiedIdentifier { module_name, ident })
}
}
Expr::Underscore(opt_name) => Ok(Pattern::Underscore(opt_name)),
Expr::Tag(value) => Ok(Pattern::Tag(value)),
Expr::OpaqueRef(value) => Ok(Pattern::OpaqueRef(value)),
Expr::Apply(loc_val, loc_args, _) => {
let region = loc_val.region;
let value = expr_to_pattern_help(arena, &loc_val.value)?;
let val_pattern = arena.alloc(Loc { region, value });
let mut arg_patterns = Vec::with_capacity_in(loc_args.len(), arena);
for loc_arg in loc_args.iter() {
let region = loc_arg.region;
let value = expr_to_pattern_help(arena, &loc_arg.value)?;
arg_patterns.push(Loc { region, value });
}
let pattern = Pattern::Apply(val_pattern, arg_patterns.into_bump_slice());
Ok(pattern)
}
Expr::SpaceBefore(sub_expr, spaces) => Ok(Pattern::SpaceBefore(
arena.alloc(expr_to_pattern_help(arena, sub_expr)?),
spaces,
)),
Expr::SpaceAfter(sub_expr, spaces) => Ok(Pattern::SpaceAfter(
arena.alloc(expr_to_pattern_help(arena, sub_expr)?),
spaces,
)),
Expr::ParensAround(sub_expr) => expr_to_pattern_help(arena, sub_expr),
Expr::Record(fields) => {
let patterns = fields.map_items_result(arena, |loc_assigned_field| {
let region = loc_assigned_field.region;
let value = assigned_expr_field_to_pattern_help(arena, &loc_assigned_field.value)?;
Ok(Loc { region, value })
})?;
Ok(Pattern::RecordDestructure(patterns))
}
&Expr::Float(string) => Ok(Pattern::FloatLiteral(string)),
&Expr::Num(string) => Ok(Pattern::NumLiteral(string)),
Expr::NonBase10Int {
string,
base,
is_negative,
} => Ok(Pattern::NonBase10Literal {
string,
base: *base,
is_negative: *is_negative,
}),
// These would not have parsed as patterns
Expr::AccessorFunction(_)
| Expr::Access(_, _)
| Expr::List { .. }
| Expr::Closure(_, _)
| Expr::Backpassing(_, _, _)
| Expr::BinOps { .. }
| Expr::Defs(_, _)
| Expr::If(_, _)
| Expr::When(_, _)
| Expr::Expect(_, _)
| Expr::MalformedClosure
| Expr::PrecedenceConflict { .. }
| Expr::RecordUpdate { .. }
| Expr::UnaryOp(_, _) => Err(()),
Expr::Str(string) => Ok(Pattern::StrLiteral(*string)),
Expr::SingleQuote(string) => Ok(Pattern::SingleQuote(*string)),
Expr::MalformedIdent(string, _problem) => Ok(Pattern::Malformed(string)),
}
}
fn assigned_expr_field_to_pattern_help<'a>(
arena: &'a Bump,
assigned_field: &AssignedField<'a, Expr<'a>>,
) -> Result<Pattern<'a>, ()> {
// the assigned fields always store spaces, but this slice is often empty
Ok(match assigned_field {
AssignedField::RequiredValue(name, spaces, value) => {
let pattern = expr_to_pattern_help(arena, &value.value)?;
let result = arena.alloc(Loc {
region: value.region,
value: pattern,
});
if spaces.is_empty() {
Pattern::RequiredField(name.value, result)
} else {
Pattern::SpaceAfter(
arena.alloc(Pattern::RequiredField(name.value, result)),
spaces,
)
}
}
AssignedField::OptionalValue(name, spaces, value) => {
let result = arena.alloc(Loc {
region: value.region,
value: value.value,
});
if spaces.is_empty() {
Pattern::OptionalField(name.value, result)
} else {
Pattern::SpaceAfter(
arena.alloc(Pattern::OptionalField(name.value, result)),
spaces,
)
}
}
AssignedField::LabelOnly(name) => Pattern::Identifier(name.value),
AssignedField::SpaceBefore(nested, spaces) => Pattern::SpaceBefore(
arena.alloc(assigned_expr_field_to_pattern_help(arena, nested)?),
spaces,
),
AssignedField::SpaceAfter(nested, spaces) => Pattern::SpaceAfter(
arena.alloc(assigned_expr_field_to_pattern_help(arena, nested)?),
spaces,
),
AssignedField::Malformed(string) => Pattern::Malformed(string),
})
}
pub fn toplevel_defs<'a>(min_indent: u32) -> impl Parser<'a, Defs<'a>, EExpr<'a>> {
move |arena, state: State<'a>| {
let (_, initial_space, state) =
space0_e(min_indent, EExpr::IndentEnd).parse(arena, state)?;
let start_column = state.column();
let options = ExprParseOptions {
accept_multi_backpassing: false,
check_for_arrow: true,
};
let mut output = Defs::default();
let before = Slice::extend_new(&mut output.spaces, initial_space.iter().copied());
let (_, mut output, state) = parse_defs_end(options, start_column, output, arena, state)?;
let (_, final_space, state) =
space0_e(start_column, EExpr::IndentEnd).parse(arena, state)?;
if !output.tags.is_empty() {
// add surrounding whitespace
let after = Slice::extend_new(&mut output.spaces, final_space.iter().copied());
debug_assert!(output.space_before[0].is_empty());
output.space_before[0] = before;
let last = output.tags.len() - 1;
debug_assert!(output.space_after[last].is_empty() || after.is_empty());
output.space_after[last] = after;
}
Ok((MadeProgress, output, state))
}
}
// PARSER HELPERS
fn closure_help<'a>(
min_indent: u32,
options: ExprParseOptions,
) -> impl Parser<'a, Expr<'a>, ELambda<'a>> {
map_with_arena!(
skip_first!(
// All closures start with a '\' - e.g. (\x -> x + 1)
word1(b'\\', ELambda::Start),
// Once we see the '\', we're committed to parsing this as a closure.
// It may turn out to be malformed, but it is definitely a closure.
and!(
// Parse the params
// Params are comma-separated
sep_by1_e(
word1(b',', ELambda::Comma),
space0_around_ee(
specialize(ELambda::Pattern, loc_closure_param(min_indent)),
min_indent,
ELambda::IndentArg,
ELambda::IndentArrow
),
ELambda::Arg,
),
skip_first!(
// Parse the -> which separates params from body
word2(b'-', b'>', ELambda::Arrow),
// Parse the body
space0_before_e(
specialize_ref(ELambda::Body, move |arena, state| {
parse_loc_expr_with_options(min_indent, options, arena, state)
}),
min_indent,
ELambda::IndentBody
)
)
)
),
|arena: &'a Bump, (params, loc_body)| {
let params: Vec<'a, Loc<Pattern<'a>>> = params;
let params: &'a [Loc<Pattern<'a>>] = params.into_bump_slice();
Expr::Closure(params, arena.alloc(loc_body))
}
)
}
mod when {
use super::*;
use crate::ast::WhenBranch;
/// Parser for when expressions.
pub fn expr_help<'a>(
min_indent: u32,
options: ExprParseOptions,
) -> impl Parser<'a, Expr<'a>, EWhen<'a>> {
then(
and!(
when_with_indent(),
skip_second!(
space0_around_ee(
specialize_ref(EWhen::Condition, move |arena, state| {
parse_loc_expr_with_options(min_indent, options, arena, state)
}),
min_indent,
EWhen::IndentCondition,
EWhen::IndentIs,
),
parser::keyword_e(keyword::IS, EWhen::Is)
)
),
move |arena, state, progress, (case_indent, loc_condition)| {
if case_indent < min_indent {
return Err((
progress,
// TODO maybe pass case_indent here?
EWhen::PatternAlignment(5, state.pos()),
state,
));
}
// Everything in the branches must be indented at least as much as the case itself.
let min_indent = case_indent;
let (p1, branches, state) = branches(min_indent, options).parse(arena, state)?;
Ok((
progress.or(p1),
Expr::When(arena.alloc(loc_condition), branches.into_bump_slice()),
state,
))
},
)
}
/// Parsing when with indentation.
fn when_with_indent<'a>() -> impl Parser<'a, u32, EWhen<'a>> {
move |arena, state: State<'a>| {
let min_indent = state.column();
parser::keyword_e(keyword::WHEN, EWhen::When)
.parse(arena, state)
.map(|(progress, (), state)| (progress, min_indent, state))
}
}
fn branches<'a>(
min_indent: u32,
options: ExprParseOptions,
) -> impl Parser<'a, Vec<'a, &'a WhenBranch<'a>>, EWhen<'a>> {
move |arena, state: State<'a>| {
let mut branches: Vec<'a, &'a WhenBranch<'a>> = Vec::with_capacity_in(2, arena);
// 1. Parse the first branch and get its indentation level. (It must be >= min_indent.)
// 2. Parse the other branches. Their indentation levels must be == the first branch's.
let (_, ((pattern_indent_level, loc_first_patterns), loc_first_guard), state): (
_,
((_, _), _),
State<'a>,
) = branch_alternatives(min_indent, options, None).parse(arena, state)?;
let original_indent = pattern_indent_level;
// Parse the first "->" and the expression after it.
let (_, loc_first_expr, mut state) =
branch_result(original_indent + 1).parse(arena, state)?;
// Record this as the first branch, then optionally parse additional branches.
branches.push(arena.alloc(WhenBranch {
patterns: loc_first_patterns.into_bump_slice(),
value: loc_first_expr,
guard: loc_first_guard,
}));
let branch_parser = map!(
and!(
then(
branch_alternatives(min_indent, options, Some(pattern_indent_level)),
move |_arena, state, _, ((indent_column, loc_patterns), loc_guard)| {
if pattern_indent_level == indent_column {
Ok((MadeProgress, (loc_patterns, loc_guard), state))
} else {
let indent = pattern_indent_level - indent_column;
Err((
MadeProgress,
EWhen::PatternAlignment(indent, state.pos()),
state,
))
}
},
),
branch_result(original_indent + 1)
),
|((patterns, guard), expr)| {
let patterns: Vec<'a, _> = patterns;
WhenBranch {
patterns: patterns.into_bump_slice(),
value: expr,
guard,
}
}
);
while !state.bytes().is_empty() {
match branch_parser.parse(arena, state) {
Ok((_, next_output, next_state)) => {
state = next_state;
branches.push(arena.alloc(next_output));
}
Err((MadeProgress, problem, old_state)) => {
return Err((MadeProgress, problem, old_state));
}
Err((NoProgress, _, old_state)) => {
state = old_state;
break;
}
}
}
Ok((MadeProgress, branches, state))
}
}
/// Parsing alternative patterns in `when` branches.
fn branch_alternatives<'a>(
min_indent: u32,
options: ExprParseOptions,
pattern_indent_level: Option<u32>,
) -> impl Parser<'a, ((u32, Vec<'a, Loc<Pattern<'a>>>), Option<Loc<Expr<'a>>>), EWhen<'a>> {
let options = ExprParseOptions {
check_for_arrow: false,
..options
};
and!(
branch_alternatives_help(min_indent, pattern_indent_level),
one_of![
map!(
skip_first!(
parser::keyword_e(keyword::IF, EWhen::IfToken),
// TODO we should require space before the expression but not after
space0_around_ee(
specialize_ref(EWhen::IfGuard, move |arena, state| {
parse_loc_expr_with_options(min_indent + 1, options, arena, state)
}),
min_indent,
EWhen::IndentIfGuard,
EWhen::IndentArrow,
)
),
Some
),
|_, s| Ok((NoProgress, None, s))
]
)
}
fn branch_single_alternative<'a>(
min_indent: u32,
) -> impl Parser<'a, Loc<Pattern<'a>>, EWhen<'a>> {
move |arena, state| {
let (_, spaces, state) =
backtrackable(space0_e(min_indent, EWhen::IndentPattern)).parse(arena, state)?;
let (_, loc_pattern, state) = space0_after_e(
specialize(EWhen::Pattern, crate::pattern::loc_pattern_help(min_indent)),
min_indent,
EWhen::IndentPattern,
)
.parse(arena, state)?;
Ok((
MadeProgress,
if spaces.is_empty() {
loc_pattern
} else {
arena
.alloc(loc_pattern.value)
.with_spaces_before(spaces, loc_pattern.region)
},
state,
))
}
}
fn branch_alternatives_help<'a>(
min_indent: u32,
pattern_indent_level: Option<u32>,
) -> impl Parser<'a, (u32, Vec<'a, Loc<Pattern<'a>>>), EWhen<'a>> {
move |arena, state: State<'a>| {
let initial = state.clone();
// put no restrictions on the indent after the spaces; we'll check it manually
match space0_e(0, EWhen::IndentPattern).parse(arena, state) {
Err((MadeProgress, fail, _)) => Err((NoProgress, fail, initial)),
Err((NoProgress, fail, _)) => Err((NoProgress, fail, initial)),
Ok((_progress, spaces, state)) => {
match pattern_indent_level {
Some(wanted) if state.column() > wanted => {
// this branch is indented too much
Err((NoProgress, EWhen::IndentPattern(state.pos()), initial))
}
Some(wanted) if state.column() < wanted => {
let indent = wanted - state.column();
Err((
NoProgress,
EWhen::PatternAlignment(indent, state.pos()),
initial,
))
}
_ => {
let pattern_indent =
min_indent.max(pattern_indent_level.unwrap_or(min_indent));
// the region is not reliable for the indent column in the case of
// parentheses around patterns
let pattern_indent_column = state.column();
let parser = sep_by1(
word1(b'|', EWhen::Bar),
branch_single_alternative(pattern_indent),
);
match parser.parse(arena, state) {
Err((MadeProgress, fail, state)) => {
Err((MadeProgress, fail, state))
}
Err((NoProgress, fail, _)) => {
// roll back space parsing if the pattern made no progress
Err((NoProgress, fail, initial))
}
Ok((_, mut loc_patterns, state)) => {
// tag spaces onto the first parsed pattern
if !spaces.is_empty() {
if let Some(first) = loc_patterns.get_mut(0) {
*first = arena
.alloc(first.value)
.with_spaces_before(spaces, first.region);
}
}
Ok((MadeProgress, (pattern_indent_column, loc_patterns), state))
}
}
}
}
}
}
}
}
/// Parsing the righthandside of a branch in a when conditional.
fn branch_result<'a>(indent: u32) -> impl Parser<'a, Loc<Expr<'a>>, EWhen<'a>> {
skip_first!(
word2(b'-', b'>', EWhen::Arrow),
space0_before_e(
specialize_ref(EWhen::Branch, move |arena, state| parse_loc_expr(
indent, arena, state
)),
indent,
EWhen::IndentBranch,
)
)
}
}
fn if_branch<'a>(min_indent: u32) -> impl Parser<'a, (Loc<Expr<'a>>, Loc<Expr<'a>>), EIf<'a>> {
move |arena, state| {
// NOTE: only parse spaces before the expression
let (_, cond, state) = space0_around_ee(
specialize_ref(EIf::Condition, move |arena, state| {
parse_loc_expr(min_indent, arena, state)
}),
min_indent,
EIf::IndentCondition,
EIf::IndentThenToken,
)
.parse(arena, state)
.map_err(|(_, f, s)| (MadeProgress, f, s))?;
let (_, _, state) = parser::keyword_e(keyword::THEN, EIf::Then)
.parse(arena, state)
.map_err(|(_, f, s)| (MadeProgress, f, s))?;
let (_, then_branch, state) = space0_around_ee(
specialize_ref(EIf::ThenBranch, move |arena, state| {
parse_loc_expr(min_indent, arena, state)
}),
min_indent,
EIf::IndentThenBranch,
EIf::IndentElseToken,
)
.parse(arena, state)
.map_err(|(_, f, s)| (MadeProgress, f, s))?;
let (_, _, state) = parser::keyword_e(keyword::ELSE, EIf::Else)
.parse(arena, state)
.map_err(|(_, f, s)| (MadeProgress, f, s))?;
Ok((MadeProgress, (cond, then_branch), state))
}
}
fn expect_help<'a>(
min_indent: u32,
options: ExprParseOptions,
) -> impl Parser<'a, Expr<'a>, EExpect<'a>> {
move |arena: &'a Bump, state: State<'a>| {
let start_column = state.column();
let (_, _, state) =
parser::keyword_e(keyword::EXPECT, EExpect::Expect).parse(arena, state)?;
let (_, condition, state) = space0_before_e(
specialize_ref(EExpect::Condition, move |arena, state| {
parse_loc_expr_with_options(start_column + 1, options, arena, state)
}),
start_column + 1,
EExpect::IndentCondition,
)
.parse(arena, state)
.map_err(|(_, f, s)| (MadeProgress, f, s))?;
let parse_cont = specialize_ref(
EExpect::Continuation,
space0_before_e(
move |a, s| parse_loc_expr(min_indent, a, s),
min_indent,
EExpr::IndentEnd,
),
);
let (_, loc_cont, state) = parse_cont.parse(arena, state)?;
let expr = Expr::Expect(arena.alloc(condition), arena.alloc(loc_cont));
Ok((MadeProgress, expr, state))
}
}
fn if_expr_help<'a>(
min_indent: u32,
options: ExprParseOptions,
) -> impl Parser<'a, Expr<'a>, EIf<'a>> {
move |arena: &'a Bump, state| {
let (_, _, state) = parser::keyword_e(keyword::IF, EIf::If).parse(arena, state)?;
let mut branches = Vec::with_capacity_in(1, arena);
let mut loop_state = state;
let state_final_else = loop {
let (_, (cond, then_branch), state) = if_branch(min_indent).parse(arena, loop_state)?;
branches.push((cond, then_branch));
// try to parse another `if`
// NOTE this drops spaces between the `else` and the `if`
let optional_if = and!(
backtrackable(space0_e(min_indent, EIf::IndentIf)),
parser::keyword_e(keyword::IF, EIf::If)
);
match optional_if.parse(arena, state) {
Err((_, _, state)) => break state,
Ok((_, _, state)) => {
loop_state = state;
continue;
}
}
};
let (_, else_branch, state) = space0_before_e(
specialize_ref(EIf::ElseBranch, move |arena, state| {
parse_loc_expr_with_options(min_indent, options, arena, state)
}),
min_indent,
EIf::IndentElseBranch,
)
.parse(arena, state_final_else)
.map_err(|(_, f, s)| (MadeProgress, f, s))?;
let expr = Expr::If(branches.into_bump_slice(), arena.alloc(else_branch));
Ok((MadeProgress, expr, state))
}
}
/// This is a helper function for parsing function args.
/// The rules for (-) are special-cased, and they come up in function args.
///
/// They work like this:
///
/// x - y # "x minus y"
/// x-y # "x minus y"
/// x- y # "x minus y" (probably written in a rush)
/// x -y # "call x, passing (-y)"
///
/// Since operators have higher precedence than function application,
/// any time we encounter a '-' it is unary iff it is both preceded by spaces
/// and is *not* followed by a whitespace character.
/// When we parse an ident like `foo ` it could be any of these:
///
/// 1. A standalone variable with trailing whitespace (e.g. because an operator is next)
/// 2. The beginning of a function call (e.g. `foo bar baz`)
/// 3. The beginning of a definition (e.g. `foo =`)
/// 4. The beginning of a type annotation (e.g. `foo :`)
/// 5. A reserved keyword (e.g. `if ` or `case `), meaning we should do something else.
fn assign_or_destructure_identifier<'a>() -> impl Parser<'a, Ident<'a>, EExpr<'a>> {
crate::ident::parse_ident
}
#[allow(dead_code)]
fn with_indent<'a, E, T, P>(parser: P) -> impl Parser<'a, u32, E>
where
P: Parser<'a, T, E>,
E: 'a,
{
move |arena, state: State<'a>| {
let indent_column = state.column();
let (progress, _, state) = parser.parse(arena, state)?;
Ok((progress, indent_column, state))
}
}
fn ident_to_expr<'a>(arena: &'a Bump, src: Ident<'a>) -> Expr<'a> {
match src {
Ident::Tag(string) => Expr::Tag(string),
Ident::OpaqueRef(string) => Expr::OpaqueRef(string),
Ident::Access { module_name, parts } => {
let mut iter = parts.iter();
// The first value in the iterator is the variable name,
// e.g. `foo` in `foo.bar.baz`
let mut answer = match iter.next() {
Some(ident) => Expr::Var { module_name, ident },
None => {
panic!("Parsed an Ident::Access with no parts");
}
};
// The remaining items in the iterator are record field accesses,
// e.g. `bar` in `foo.bar.baz`, followed by `baz`
for field in iter {
// Wrap the previous answer in the new one, so we end up
// with a nested Expr. That way, `foo.bar.baz` gets represented
// in the AST as if it had been written (foo.bar).baz all along.
answer = Expr::Access(arena.alloc(answer), field);
}
answer
}
Ident::AccessorFunction(string) => Expr::AccessorFunction(string),
Ident::Malformed(string, problem) => Expr::MalformedIdent(string, problem),
}
}
fn list_literal_help<'a>(min_indent: u32) -> impl Parser<'a, Expr<'a>, EList<'a>> {
move |arena, state| {
let (_, elements, state) = collection_trailing_sep_e!(
word1(b'[', EList::Open),
specialize_ref(
EList::Expr,
move |a, s| parse_loc_expr_no_multi_backpassing(min_indent, a, s)
),
word1(b',', EList::End),
word1(b']', EList::End),
min_indent,
EList::Open,
EList::IndentEnd,
Expr::SpaceBefore
)
.parse(arena, state)?;
let elements = elements.ptrify_items(arena);
let expr = Expr::List(elements);
Ok((MadeProgress, expr, state))
}
}
pub fn record_value_field<'a>(
min_indent: u32,
) -> impl Parser<'a, AssignedField<'a, Expr<'a>>, ERecord<'a>> {
use AssignedField::*;
move |arena, state: State<'a>| {
// You must have a field name, e.g. "email"
let (progress, loc_label, state) =
specialize(|_, pos| ERecord::Field(pos), loc!(lowercase_ident()))
.parse(arena, state)?;
debug_assert_eq!(progress, MadeProgress);
let (_, spaces, state) = space0_e(min_indent, ERecord::IndentColon).parse(arena, state)?;
// Having a value is optional; both `{ email }` and `{ email: blah }` work.
// (This is true in both literals and types.)
let (_, opt_loc_val, state) = optional(and!(
either!(
word1(b':', ERecord::Colon),
word1(b'?', ERecord::QuestionMark)
),
space0_before_e(
specialize_ref(ERecord::Expr, move |a, s| {
parse_loc_expr_no_multi_backpassing(min_indent, a, s)
}),
min_indent,
ERecord::IndentEnd,
)
))
.parse(arena, state)?;
let answer = match opt_loc_val {
Some((Either::First(_), loc_val)) => {
RequiredValue(loc_label, spaces, arena.alloc(loc_val))
}
Some((Either::Second(_), loc_val)) => {
OptionalValue(loc_label, spaces, arena.alloc(loc_val))
}
// If no value was provided, record it as a Var.
// Canonicalize will know what to do with a Var later.
None => {
if !spaces.is_empty() {
SpaceAfter(arena.alloc(LabelOnly(loc_label)), spaces)
} else {
LabelOnly(loc_label)
}
}
};
Ok((MadeProgress, answer, state))
}
}
fn record_updateable_identifier<'a>() -> impl Parser<'a, Expr<'a>, ERecord<'a>> {
specialize(
|_, pos| ERecord::Updateable(pos),
map_with_arena!(parse_ident, ident_to_expr),
)
}
fn record_help<'a>(
min_indent: u32,
) -> impl Parser<
'a,
(
Option<Loc<Expr<'a>>>,
Loc<(
Vec<'a, Loc<AssignedField<'a, Expr<'a>>>>,
&'a [CommentOrNewline<'a>],
)>,
),
ERecord<'a>,
> {
skip_first!(
word1(b'{', ERecord::Open),
and!(
// You can optionally have an identifier followed by an '&' to
// make this a record update, e.g. { Foo.user & username: "blah" }.
optional(skip_second!(
space0_around_ee(
// We wrap the ident in an Expr here,
// so that we have a Spaceable value to work with,
// and then in canonicalization verify that it's an Expr::Var
// (and not e.g. an `Expr::Access`) and extract its string.
loc!(record_updateable_identifier()),
min_indent,
ERecord::IndentEnd,
ERecord::IndentAmpersand,
),
word1(b'&', ERecord::Ampersand)
)),
loc!(skip_first!(
// We specifically allow space characters inside here, so that
// `{ }` can be successfully parsed as an empty record, and then
// changed by the formatter back into `{}`.
zero_or_more!(word1(b' ', ERecord::End)),
skip_second!(
and!(
trailing_sep_by0(
word1(b',', ERecord::End),
space0_before_optional_after(
loc!(record_value_field(min_indent)),
min_indent,
ERecord::IndentEnd,
ERecord::IndentEnd
),
),
// Allow outdented closing braces
space0_e(0, ERecord::IndentEnd)
),
word1(b'}', ERecord::End)
)
))
)
)
}
fn record_literal_help<'a>(min_indent: u32) -> impl Parser<'a, Expr<'a>, EExpr<'a>> {
then(
loc!(specialize(EExpr::Record, record_help(min_indent))),
move |arena, state, _, loc_record| {
let (opt_update, loc_assigned_fields_with_comments) = loc_record.value;
// This is a record literal, not a destructure.
let mut value = match opt_update {
Some(update) => Expr::RecordUpdate {
update: &*arena.alloc(update),
fields: Collection::with_items_and_comments(
arena,
loc_assigned_fields_with_comments.value.0.into_bump_slice(),
arena.alloc(loc_assigned_fields_with_comments.value.1),
),
},
None => Expr::Record(Collection::with_items_and_comments(
arena,
loc_assigned_fields_with_comments.value.0.into_bump_slice(),
loc_assigned_fields_with_comments.value.1,
)),
};
// there can be field access, e.g. `{ x : 4 }.x`
let (_, accesses, state) = optional(record_field_access_chain()).parse(arena, state)?;
if let Some(fields) = accesses {
for field in fields {
// Wrap the previous answer in the new one, so we end up
// with a nested Expr. That way, `foo.bar.baz` gets represented
// in the AST as if it had been written (foo.bar).baz all along.
value = Expr::Access(arena.alloc(value), field);
}
}
Ok((MadeProgress, value, state))
},
)
}
fn string_literal_help<'a>() -> impl Parser<'a, Expr<'a>, EString<'a>> {
map!(crate::string_literal::parse(), Expr::Str)
}
fn single_quote_literal_help<'a>() -> impl Parser<'a, Expr<'a>, EString<'a>> {
map!(
crate::string_literal::parse_single_quote(),
Expr::SingleQuote
)
}
fn positive_number_literal_help<'a>() -> impl Parser<'a, Expr<'a>, ENumber> {
map!(
crate::number_literal::positive_number_literal(),
|literal| {
use crate::number_literal::NumLiteral::*;
match literal {
Num(s) => Expr::Num(s),
Float(s) => Expr::Float(s),
NonBase10Int {
string,
base,
is_negative,
} => Expr::NonBase10Int {
string,
base,
is_negative,
},
}
}
)
}
fn number_literal_help<'a>() -> impl Parser<'a, Expr<'a>, ENumber> {
map!(crate::number_literal::number_literal(), |literal| {
use crate::number_literal::NumLiteral::*;
match literal {
Num(s) => Expr::Num(s),
Float(s) => Expr::Float(s),
NonBase10Int {
string,
base,
is_negative,
} => Expr::NonBase10Int {
string,
base,
is_negative,
},
}
})
}
const BINOP_CHAR_SET: &[u8] = b"+-/*=.<>:&|^?%!";
const BINOP_CHAR_MASK: [bool; 125] = {
let mut result = [false; 125];
let mut i = 0;
while i < BINOP_CHAR_SET.len() {
let index = BINOP_CHAR_SET[i] as usize;
result[index] = true;
i += 1;
}
result
};
fn operator<'a>() -> impl Parser<'a, BinOp, EExpr<'a>> {
|_, state| operator_help(EExpr::Start, EExpr::BadOperator, state)
}
#[inline(always)]
fn operator_help<'a, F, G, E>(
to_expectation: F,
to_error: G,
mut state: State<'a>,
) -> ParseResult<'a, BinOp, E>
where
F: Fn(Position) -> E,
G: Fn(&'a str, Position) -> E,
E: 'a,
{
let chomped = chomp_ops(state.bytes());
macro_rules! good {
($op:expr, $width:expr) => {{
state = state.advance($width);
Ok((MadeProgress, $op, state))
}};
}
macro_rules! bad_made_progress {
($op:expr) => {{
Err((MadeProgress, to_error($op, state.pos()), state))
}};
}
match chomped {
"" => Err((NoProgress, to_expectation(state.pos()), state)),
"+" => good!(BinOp::Plus, 1),
"-" => good!(BinOp::Minus, 1),
"*" => good!(BinOp::Star, 1),
"/" => good!(BinOp::Slash, 1),
"%" => good!(BinOp::Percent, 1),
"^" => good!(BinOp::Caret, 1),
">" => good!(BinOp::GreaterThan, 1),
"<" => good!(BinOp::LessThan, 1),
"." => {
// a `.` makes no progress, so it does not interfere with `.foo` access(or)
Err((NoProgress, to_error(".", state.pos()), state))
}
"=" => good!(BinOp::Assignment, 1),
":=" => good!(BinOp::IsOpaqueType, 2),
":" => good!(BinOp::IsAliasType, 1),
"|>" => good!(BinOp::Pizza, 2),
"==" => good!(BinOp::Equals, 2),
"!=" => good!(BinOp::NotEquals, 2),
">=" => good!(BinOp::GreaterThanOrEq, 2),
"<=" => good!(BinOp::LessThanOrEq, 2),
"&&" => good!(BinOp::And, 2),
"||" => good!(BinOp::Or, 2),
"//" => good!(BinOp::DoubleSlash, 2),
"->" => {
// makes no progress, so it does not interfere with `_ if isGood -> ...`
Err((NoProgress, to_error("->", state.pos()), state))
}
"<-" => good!(BinOp::Backpassing, 2),
_ => bad_made_progress!(chomped),
}
}
fn chomp_ops(bytes: &[u8]) -> &str {
let mut chomped = 0;
for c in bytes.iter() {
if let Some(true) = BINOP_CHAR_MASK.get(*c as usize) {
chomped += 1;
} else {
break;
}
}
unsafe {
// Safe because BINOP_CHAR_SET only contains ascii chars
std::str::from_utf8_unchecked(&bytes[..chomped])
}
}
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