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parse closure

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This commit is contained in:
Folkert 2021-02-25 02:03:47 +01:00
parent f97e8ae7f3
commit 1a7fd57833
4 changed files with 110 additions and 23 deletions
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55
compiler/parse/src/expr.rs
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@ -3,7 +3,8 @@ use crate::ast::{
};
use crate::blankspace::{
line_comment, space0, space0_after, space0_after_e, space0_around, space0_around_e,
space0_before, space0_before_e, space0_e, space1, space1_around, space1_before, spaces_exactly,
space0_around_ee, space0_before, space0_before_e, space0_e, space1, space1_around,
space1_before, spaces_exactly,
};
use crate::ident::{global_tag_or_ident, ident, lowercase_ident, Ident};
use crate::keyword;
@ -11,8 +12,8 @@ use crate::number_literal::number_literal;
use crate::parser::{
self, allocated, and_then_with_indent_level, ascii_char, ascii_string, attempt, backtrackable,
fail, map, newline_char, not, not_followed_by, optional, sep_by1, specialize, specialize_ref,
then, unexpected, unexpected_eof, word1, word2, EExpr, Either, ParseResult, Parser, State,
SyntaxError, When,
then, unexpected, unexpected_eof, word1, word2, EExpr, ELambda, Either, ParseResult, Parser,
State, SyntaxError, When,
};
use crate::pattern::loc_closure_param;
use crate::type_annotation;
@ -596,7 +597,13 @@ pub fn def<'a>(min_indent: u16) -> impl Parser<'a, Def<'a>, SyntaxError<'a>> {
// PARSER HELPERS
fn pattern<'a>(min_indent: u16) -> impl Parser<'a, Located<Pattern<'a>>, SyntaxError<'a>> {
space0_after(loc_closure_param(min_indent), min_indent)
space0_after(
specialize(
|e, _, _| SyntaxError::Pattern(e),
loc_closure_param(min_indent),
),
min_indent,
)
}
fn spaces_then_comment_or_newline<'a>() -> impl Parser<'a, Option<&'a str>, SyntaxError<'a>> {
@ -971,32 +978,44 @@ fn reserved_keyword<'a>() -> impl Parser<'a, (), SyntaxError<'a>> {
}
fn closure<'a>(min_indent: u16) -> impl Parser<'a, Expr<'a>, SyntaxError<'a>> {
specialize(
|e, r, c| SyntaxError::Expr(EExpr::Lambda(e, r, c)),
closure_help(min_indent),
)
}
fn closure_help<'a>(min_indent: u16) -> impl Parser<'a, Expr<'a>, ELambda<'a>> {
map_with_arena!(
skip_first!(
// All closures start with a '\' - e.g. (\x -> x + 1)
ascii_char(b'\\'),
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.
optional(and!(
// Parse the params
attempt!(
Attempting::ClosureParams,
// Params are comma-separated
sep_by1(
ascii_char(b','),
space0_around(loc_closure_param(min_indent), min_indent)
// Params are comma-separated
sep_by1(
word1(b',', ELambda::Comma),
space0_around_ee(
specialize(ELambda::Pattern, loc_closure_param(min_indent)),
min_indent,
ELambda::Space,
ELambda::IndentArg,
ELambda::IndentArrow
)
),
skip_first!(
// Parse the -> which separates params from body
ascii_string("->"),
word2(b'-', b'>', ELambda::Arrow),
// Parse the body
attempt!(
Attempting::ClosureBody,
space0_before(
loc!(move |arena, state| parse_expr(min_indent, arena, state)),
min_indent,
)
space0_before_e(
specialize_ref(
ELambda::Syntax,
loc!(move |arena, state| parse_expr(min_indent, arena, state))
),
min_indent,
ELambda::Space,
ELambda::IndentBody
)
)
))