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error message for when
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Folkert
parent
3a35bcb3cb
commit
9edbf322c0
5 changed files with 454 additions and 80 deletions
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@ -2,8 +2,8 @@ use crate::ast::{
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AssignedField, Attempting, CommentOrNewline, Def, Expr, Pattern, Spaceable, TypeAnnotation,
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};
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use crate::blankspace::{
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line_comment, space0, space0_after, space0_around, space0_around_e, space0_before,
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space0_before_e, space1, space1_around, space1_before, spaces_exactly,
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line_comment, space0, space0_after, space0_after_e, space0_around, space0_around_e,
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space0_before, space0_before_e, space0_e, space1, space1_around, space1_before, spaces_exactly,
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};
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use crate::ident::{global_tag_or_ident, ident, lowercase_ident, Ident};
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use crate::keyword;
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@ -1019,27 +1019,34 @@ mod when {
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/// Parser for when expressions.
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pub fn expr<'a>(min_indent: u16) -> impl Parser<'a, Expr<'a>, SyntaxError<'a>> {
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specialize(
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|e, r, c| SyntaxError::Expr(EExpr::When(e, r, c)),
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expr_help(min_indent),
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)
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}
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pub fn expr_help<'a>(min_indent: u16) -> impl Parser<'a, Expr<'a>, When<'a>> {
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then(
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and!(
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when_with_indent(min_indent),
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attempt!(
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Attempting::WhenCondition,
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skip_second!(
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space1_around(
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loc!(move |arena, state| parse_expr(min_indent, arena, state)),
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min_indent,
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),
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parser::keyword(keyword::IS, min_indent)
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)
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when_with_indent(),
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skip_second!(
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space0_around_e(
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loc!(specialize_ref(
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When::Syntax,
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move |arena, state| parse_expr(min_indent, arena, state)
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)),
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min_indent,
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When::Space,
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When::IndentCondition
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),
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parser::keyword_e(keyword::IS, When::Is)
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)
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),
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move |arena, state, progress, (case_indent, loc_condition)| {
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if case_indent < min_indent {
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return Err((
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progress,
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SyntaxError::NotYetImplemented(
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"TODO case wasn't indented enough".to_string(),
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),
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// TODO maybe pass case_indent here?
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When::PatternAlignment(5, state.line, state.column),
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state,
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));
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}
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@ -1047,8 +1054,7 @@ mod when {
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// Everything in the branches must be indented at least as much as the case itself.
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let min_indent = case_indent;
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let (p1, branches, state) =
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attempt!(Attempting::WhenBranch, branches(min_indent)).parse(arena, state)?;
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let (p1, branches, state) = branches(min_indent).parse(arena, state)?;
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Ok((
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progress.or(p1),
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@ -1060,18 +1066,15 @@ mod when {
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}
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/// Parsing when with indentation.
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fn when_with_indent<'a>(min_indent: u16) -> impl Parser<'a, u16, SyntaxError<'a>> {
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fn when_with_indent<'a>() -> impl Parser<'a, u16, When<'a>> {
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move |arena, state: State<'a>| {
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parser::keyword(keyword::WHEN, min_indent)
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parser::keyword_e(keyword::WHEN, When::When)
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.parse(arena, state)
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.map(|(progress, (), state)| (progress, state.indent_col, state))
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}
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}
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/// Parsing branches of when conditional.
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fn branches<'a>(
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min_indent: u16,
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) -> impl Parser<'a, Vec<'a, &'a WhenBranch<'a>>, SyntaxError<'a>> {
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fn branches<'a>(min_indent: u16) -> impl Parser<'a, Vec<'a, &'a WhenBranch<'a>>, When<'a>> {
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move |arena, state| {
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let mut branches: Vec<'a, &'a WhenBranch<'a>> = Vec::with_capacity_in(2, arena);
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@ -1100,17 +1103,13 @@ mod when {
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then(
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branch_alternatives(min_indent),
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move |_arena, state, _, (loc_patterns, loc_guard)| {
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if alternatives_indented_correctly(&loc_patterns, original_indent) {
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Ok((MadeProgress, (loc_patterns, loc_guard), state))
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} else {
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Err((
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MadeProgress,
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SyntaxError::NotYetImplemented(
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"TODO additional branch didn't have same indentation as first branch".to_string(),
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),
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match alternatives_indented_correctly(&loc_patterns, original_indent) {
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Ok(()) => Ok((MadeProgress, (loc_patterns, loc_guard), state)),
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Err(indent) => Err((
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MadeProgress,
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When::PatternAlignment(indent, state.line, state.column),
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state,
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))
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)),
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}
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},
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),
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@ -1133,7 +1132,10 @@ mod when {
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branches.push(arena.alloc(next_output));
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}
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Err((_, _, old_state)) => {
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Err((MadeProgress, problem, old_state)) => {
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return Err((MadeProgress, problem, old_state));
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}
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Err((NoProgress, _, old_state)) => {
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state = old_state;
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break;
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@ -1148,27 +1150,33 @@ mod when {
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/// Parsing alternative patterns in when branches.
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fn branch_alternatives<'a>(
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min_indent: u16,
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) -> impl Parser<'a, (Vec<'a, Located<Pattern<'a>>>, Option<Located<Expr<'a>>>), SyntaxError<'a>>
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{
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specialize(
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|e, r, c| SyntaxError::Expr(EExpr::When(e, r, c)),
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branch_alternatives_help(min_indent),
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)
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}
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fn branch_alternatives_help<'a>(
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min_indent: u16,
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) -> impl Parser<'a, (Vec<'a, Located<Pattern<'a>>>, Option<Located<Expr<'a>>>), When<'a>> {
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and!(
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sep_by1(
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word1(b'|', When::Bar),
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space0_around_e(
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sep_by1(word1(b'|', When::Bar), |arena, state| {
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let (_, spaces, state) =
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backtrackable(space0_e(min_indent, When::Space, When::IndentPattern))
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.parse(arena, state)?;
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let (_, loc_pattern, state) = space0_after_e(
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specialize(When::Pattern, crate::pattern::loc_pattern_help(min_indent)),
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min_indent,
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When::Space,
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When::IndentPattern
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),
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),
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When::IndentPattern,
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)
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.parse(arena, state)?;
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Ok((
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MadeProgress,
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if spaces.is_empty() {
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loc_pattern
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} else {
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arena
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.alloc(loc_pattern.value)
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.with_spaces_before(spaces, loc_pattern.region)
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},
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state,
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))
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}),
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one_of![
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map!(
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skip_first!(
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@ -1194,24 +1202,23 @@ mod when {
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fn alternatives_indented_correctly<'a>(
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loc_patterns: &'a Vec<'a, Located<Pattern<'a>>>,
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original_indent: u16,
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) -> bool {
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) -> Result<(), u16> {
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let (first, rest) = loc_patterns.split_first().unwrap();
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let first_indented_correctly = first.region.start_col == original_indent;
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let rest_indented_correctly = rest
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.iter()
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.all(|when_pattern| when_pattern.region.start_col >= original_indent);
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first_indented_correctly && rest_indented_correctly
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if first_indented_correctly {
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for when_pattern in rest.iter() {
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if when_pattern.region.start_col < original_indent {
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return Err(original_indent - when_pattern.region.start_col);
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}
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}
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Ok(())
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} else {
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Err(original_indent - first.region.start_col)
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}
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}
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/// Parsing the righthandside of a branch in a when conditional.
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fn branch_result<'a>(indent: u16) -> impl Parser<'a, Located<Expr<'a>>, SyntaxError<'a>> {
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specialize(
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|e, r, c| SyntaxError::Expr(EExpr::When(e, r, c)),
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branch_result_help(indent),
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)
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}
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fn branch_result_help<'a>(indent: u16) -> impl Parser<'a, Located<Expr<'a>>, When<'a>> {
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fn branch_result<'a>(indent: u16) -> impl Parser<'a, Located<Expr<'a>>, When<'a>> {
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skip_first!(
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word2(b'-', b'>', When::Arrow),
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space0_before_e(
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