roc/crates/compiler/fmt/src/expr.rs
2023-05-17 12:48:37 -03:00

1667 lines
55 KiB
Rust

use crate::annotation::{except_last, is_collection_multiline, Formattable, Newlines, Parens};
use crate::collection::{fmt_collection, Braces};
use crate::def::fmt_defs;
use crate::pattern::fmt_pattern;
use crate::spaces::{
count_leading_newlines, fmt_comments_only, fmt_spaces, fmt_spaces_no_blank_lines, NewlineAt,
INDENT,
};
use crate::Buf;
use roc_module::called_via::{self, BinOp};
use roc_parse::ast::{
AssignedField, Base, Collection, CommentOrNewline, Expr, ExtractSpaces, Pattern,
RecordBuilderField, WhenBranch,
};
use roc_parse::ast::{StrLiteral, StrSegment};
use roc_parse::ident::Accessor;
use roc_region::all::Loc;
impl<'a> Formattable for Expr<'a> {
fn is_multiline(&self) -> bool {
use roc_parse::ast::Expr::*;
// TODO cache these answers using a Map<Pointer, bool>, so
// we don't have to traverse subexpressions repeatedly
match self {
// Return whether these spaces contain any Newlines
SpaceBefore(_sub_expr, spaces) | SpaceAfter(_sub_expr, spaces) => {
debug_assert!(!spaces.is_empty());
// "spaces" always contain either a newline or comment, and comments have newlines
true
}
// These expressions never have newlines
Float(..)
| Num(..)
| NonBase10Int { .. }
| SingleQuote(_)
| RecordAccess(_, _)
| AccessorFunction(_)
| TupleAccess(_, _)
| Var { .. }
| Underscore { .. }
| MalformedIdent(_, _)
| MalformedClosure
| Tag(_)
| OpaqueRef(_)
| IngestedFile(_, _)
| Crash => false,
// These expressions always have newlines
Defs(_, _) | When(_, _) => true,
List(items) => is_collection_multiline(items),
Str(literal) => is_str_multiline(literal),
Apply(loc_expr, args, _) => {
loc_expr.is_multiline() || args.iter().any(|loc_arg| loc_arg.is_multiline())
}
Expect(condition, continuation) => {
condition.is_multiline() || continuation.is_multiline()
}
Dbg(condition, continuation) => condition.is_multiline() || continuation.is_multiline(),
If(branches, final_else) => {
final_else.is_multiline()
|| branches
.iter()
.any(|(c, t)| c.is_multiline() || t.is_multiline())
}
BinOps(lefts, loc_right) => {
lefts.iter().any(|(loc_expr, _)| loc_expr.is_multiline())
|| loc_right.is_multiline()
}
UnaryOp(loc_subexpr, _)
| PrecedenceConflict(roc_parse::ast::PrecedenceConflict {
expr: loc_subexpr, ..
})
| MultipleRecordBuilders(loc_subexpr)
| UnappliedRecordBuilder(loc_subexpr) => loc_subexpr.is_multiline(),
ParensAround(subexpr) => subexpr.is_multiline(),
Closure(loc_patterns, loc_body) => {
// check the body first because it's more likely to be multiline
loc_body.is_multiline()
|| loc_patterns
.iter()
.any(|loc_pattern| loc_pattern.is_multiline())
}
Backpassing(loc_patterns, loc_body, loc_ret) => {
// check the body first because it's more likely to be multiline
loc_body.is_multiline()
|| loc_ret.is_multiline()
|| loc_patterns
.iter()
.any(|loc_pattern| loc_pattern.is_multiline())
}
Record(fields) => is_collection_multiline(fields),
Tuple(fields) => is_collection_multiline(fields),
RecordUpdate { fields, .. } => is_collection_multiline(fields),
RecordBuilder(fields) => is_collection_multiline(fields),
}
}
fn format_with_options(&self, buf: &mut Buf, parens: Parens, newlines: Newlines, indent: u16) {
use self::Expr::*;
let apply_needs_parens = parens == Parens::InApply;
match self {
SpaceBefore(sub_expr, spaces) => {
format_spaces(buf, spaces, newlines, indent);
sub_expr.format_with_options(buf, parens, newlines, indent);
}
SpaceAfter(sub_expr, spaces) => {
sub_expr.format_with_options(buf, parens, newlines, indent);
format_spaces(buf, spaces, newlines, indent);
}
ParensAround(sub_expr) => {
if parens == Parens::NotNeeded && !sub_expr_requests_parens(sub_expr) {
sub_expr.format_with_options(buf, Parens::NotNeeded, newlines, indent);
} else {
let should_add_newlines = match sub_expr {
Expr::Closure(..)
| Expr::SpaceBefore(..)
| Expr::SpaceAfter(Closure(..), ..) => false,
_ => sub_expr.is_multiline(),
};
buf.indent(indent);
buf.push('(');
if should_add_newlines {
buf.newline();
}
let next_indent = if starts_with_newline(sub_expr) || should_add_newlines {
match sub_expr {
Expr::Closure(..) | Expr::SpaceAfter(Closure(..), ..) => indent,
_ => indent + INDENT,
}
} else {
indent
};
sub_expr.format_with_options(
buf,
Parens::NotNeeded,
Newlines::Yes,
next_indent,
);
if !matches!(sub_expr, Expr::SpaceAfter(..)) && should_add_newlines {
buf.newline();
}
buf.indent(indent);
buf.push(')');
}
}
Str(literal) => {
fmt_str_literal(buf, *literal, indent);
}
Var { module_name, ident } => {
buf.indent(indent);
if !module_name.is_empty() {
buf.push_str(module_name);
buf.push('.');
}
buf.push_str(ident);
}
Underscore(name) => {
buf.indent(indent);
buf.push('_');
buf.push_str(name);
}
Crash => {
buf.indent(indent);
buf.push_str("crash");
}
Apply(loc_expr, loc_args, _) => {
// Sadly this assertion fails in practice. The fact that the parser produces code like this is going to
// confuse the formatter, because it depends on being able to "see" spaces that logically come before the inner
// expr in several places - which is necessarily the case when the `loc_expr` of the apply itself has
// SpaceBefore.
//
// TODO: enforce in the type system that spaces must be pushed to the "outside".
// In other words, Expr::Apply should look something like the following, and there shouldn't be Expr::SpaceBefore and ::SpaceAfter.
//
// ```
// Apply(&'a SpaceAfter<Loc<Expr<'a>>>, &'a [&'a SpaceBefore<Loc<Expr<'a>>>], CalledVia),
// ```
//
// assert!(loc_expr.extract_spaces().before.is_empty(), "{:#?}", self);
buf.indent(indent);
if apply_needs_parens && !loc_args.is_empty() {
buf.push('(');
}
// should_reflow_outdentable, aka should we transform this:
//
// ```
// foo bar
// [
// 1,
// 2,
// ]
// ```
//
// Into this:
//
// ```
// foo bar [
// 1,
// 2,
// ]
// ```
let should_reflow_outdentable = loc_expr.extract_spaces().after.is_empty()
&& except_last(loc_args).all(|a| !a.is_multiline())
&& loc_args
.last()
.map(|a| {
a.extract_spaces().item.is_multiline()
&& matches!(
a.value.extract_spaces().item,
Expr::Tuple(_)
| Expr::List(_)
| Expr::Record(_)
| Expr::RecordBuilder(_)
)
&& a.extract_spaces().before == [CommentOrNewline::Newline]
})
.unwrap_or_default();
let needs_indent = !should_reflow_outdentable
&& (!loc_expr.extract_spaces().after.is_empty()
|| except_last(loc_args).any(|a| a.is_multiline())
|| loc_args
.last()
.map(|a| {
a.is_multiline()
&& (!a.extract_spaces().before.is_empty()
|| !is_outdentable(&a.value))
})
.unwrap_or_default());
let arg_indent = if needs_indent {
indent + INDENT
} else {
indent
};
let expr_needs_parens =
matches!(loc_expr.value.extract_spaces().item, Expr::Closure(..))
&& !loc_args.is_empty();
if expr_needs_parens {
buf.push('(');
}
loc_expr.format_with_options(buf, Parens::InApply, Newlines::Yes, indent);
if expr_needs_parens {
buf.indent(indent);
buf.push(')');
}
for loc_arg in loc_args.iter() {
if should_reflow_outdentable {
buf.spaces(1);
// Ignore any comments+newlines before/after.
// We checked above that there's only a single newline before the last arg,
// which we're intentionally ignoring.
let arg = loc_arg.extract_spaces();
arg.item.format_with_options(
buf,
Parens::InApply,
Newlines::Yes,
arg_indent,
);
} else if needs_indent {
let arg = loc_arg.extract_spaces();
fmt_spaces(buf, arg.before.iter(), arg_indent);
buf.ensure_ends_with_newline();
arg.item.format_with_options(
buf,
Parens::InApply,
Newlines::Yes,
arg_indent,
);
fmt_spaces(buf, arg.after.iter(), arg_indent);
} else {
buf.spaces(1);
loc_arg.format_with_options(
buf,
Parens::InApply,
Newlines::Yes,
arg_indent,
);
}
}
if apply_needs_parens && !loc_args.is_empty() {
buf.push(')');
}
}
&Num(string) => {
buf.indent(indent);
buf.push_str(string);
}
&Float(string) => {
buf.indent(indent);
buf.push_str(string);
}
Tag(string) | OpaqueRef(string) => {
buf.indent(indent);
buf.push_str(string)
}
SingleQuote(string) => {
buf.indent(indent);
format_sq_literal(buf, string);
}
&NonBase10Int {
base,
string,
is_negative,
} => {
buf.indent(indent);
if is_negative {
buf.push('-');
}
match base {
Base::Hex => buf.push_str("0x"),
Base::Octal => buf.push_str("0o"),
Base::Binary => buf.push_str("0b"),
Base::Decimal => { /* nothing */ }
}
buf.push_str(string);
}
Record(fields) => {
fmt_record_like(
buf,
None,
*fields,
indent,
format_assigned_field_multiline,
assigned_field_to_space_before,
);
}
RecordUpdate { update, fields } => {
fmt_record_like(
buf,
Some(*update),
*fields,
indent,
format_assigned_field_multiline,
assigned_field_to_space_before,
);
}
RecordBuilder(fields) => {
fmt_record_like(
buf,
None,
*fields,
indent,
format_record_builder_field_multiline,
record_builder_field_to_space_before,
);
}
Closure(loc_patterns, loc_ret) => {
fmt_closure(buf, loc_patterns, loc_ret, indent);
}
Backpassing(loc_patterns, loc_body, loc_ret) => {
fmt_backpassing(buf, loc_patterns, loc_body, loc_ret, indent);
}
Defs(defs, ret) => {
{
let indent = if parens == Parens::InOperator {
buf.indent(indent);
buf.push('(');
buf.newline();
indent + INDENT
} else {
indent
};
// It should theoretically be impossible to *parse* an empty defs list.
// (Canonicalization can remove defs later, but that hasn't happened yet!)
debug_assert!(!defs.is_empty());
fmt_defs(buf, defs, indent);
match &ret.value {
SpaceBefore(sub_expr, spaces) => {
buf.spaces(1);
fmt_spaces(buf, spaces.iter(), indent);
buf.indent(indent);
sub_expr.format_with_options(
buf,
Parens::NotNeeded,
Newlines::Yes,
indent,
);
}
_ => {
buf.ensure_ends_with_newline();
buf.indent(indent);
// Even if there were no defs, which theoretically should never happen,
// still print the return value.
ret.format_with_options(buf, Parens::NotNeeded, Newlines::Yes, indent);
}
}
}
if parens == Parens::InOperator {
buf.ensure_ends_with_newline();
buf.indent(indent);
buf.push(')');
}
}
Expect(condition, continuation) => {
fmt_expect(buf, condition, continuation, self.is_multiline(), indent);
}
Dbg(condition, continuation) => {
fmt_dbg(buf, condition, continuation, self.is_multiline(), indent);
}
If(branches, final_else) => {
fmt_if(buf, branches, final_else, self.is_multiline(), indent);
}
When(loc_condition, branches) => fmt_when(buf, loc_condition, branches, indent),
Tuple(items) => fmt_collection(buf, indent, Braces::Round, *items, Newlines::No),
List(items) => fmt_collection(buf, indent, Braces::Square, *items, Newlines::No),
BinOps(lefts, right) => fmt_binops(buf, lefts, right, false, indent),
UnaryOp(sub_expr, unary_op) => {
buf.indent(indent);
match &unary_op.value {
called_via::UnaryOp::Negate => {
buf.push('-');
}
called_via::UnaryOp::Not => {
buf.push('!');
}
}
let needs_newline = match &sub_expr.value {
SpaceBefore(..) => true,
Str(text) => is_str_multiline(text),
_ => false,
};
let needs_parens =
needs_newline && matches!(unary_op.value, called_via::UnaryOp::Negate);
if needs_parens {
// Unary negation can't be followed by whitespace (which is what a newline is) - so
// we need to wrap the negated value in parens.
buf.push('(');
}
let inner_indent = if needs_parens {
indent + INDENT
} else {
indent
};
sub_expr.format_with_options(buf, Parens::InApply, newlines, inner_indent);
if needs_parens {
buf.push(')');
}
}
AccessorFunction(key) => {
buf.indent(indent);
buf.push('.');
match key {
Accessor::RecordField(key) => buf.push_str(key),
Accessor::TupleIndex(key) => buf.push_str(key),
}
}
RecordAccess(expr, key) => {
expr.format_with_options(buf, Parens::InApply, Newlines::Yes, indent);
buf.push('.');
buf.push_str(key);
}
TupleAccess(expr, key) => {
expr.format_with_options(buf, Parens::InApply, Newlines::Yes, indent);
buf.push('.');
buf.push_str(key);
}
MalformedIdent(str, _) => {
buf.indent(indent);
buf.push_str(str)
}
MalformedClosure => {}
PrecedenceConflict { .. } => {}
MultipleRecordBuilders { .. } => {}
UnappliedRecordBuilder { .. } => {}
IngestedFile(_, _) => {}
}
}
}
fn is_str_multiline(literal: &StrLiteral) -> bool {
use roc_parse::ast::StrLiteral::*;
match literal {
PlainLine(string) => {
// When a PlainLine contains '\n' or '"', format as a block string
string.contains('"') || string.contains('\n')
}
Line(_) => {
// If this had any newlines, it'd have parsed as Block.
false
}
Block(_) => {
// Block strings are always formatted on multiple lines,
// even if the string is only a single line.
true
}
}
}
fn needs_unicode_escape(ch: char) -> bool {
matches!(ch, '\u{0000}'..='\u{001f}' | '\u{007f}'..='\u{009f}')
}
pub(crate) fn format_sq_literal(buf: &mut Buf, s: &str) {
buf.push('\'');
for c in s.chars() {
if c == '"' {
buf.push_char_literal('"')
} else {
match c {
'"' => buf.push_str("\""),
'\'' => buf.push_str("\\\'"),
'\t' => buf.push_str("\\t"),
'\r' => buf.push_str("\\r"),
'\n' => buf.push_str("\\n"),
'\\' => buf.push_str("\\\\"),
_ => {
if needs_unicode_escape(c) {
buf.push_str(&format!("\\u({:x})", c as u32))
} else {
buf.push_char_literal(c)
}
}
}
}
}
buf.push('\'');
}
fn is_outdentable(expr: &Expr) -> bool {
matches!(
expr.extract_spaces().item,
Expr::Tuple(_)
| Expr::List(_)
| Expr::Record(_)
| Expr::RecordBuilder(_)
| Expr::Closure(..)
)
}
fn starts_with_newline(expr: &Expr) -> bool {
use roc_parse::ast::Expr::*;
match expr {
SpaceBefore(_, comment_or_newline) => {
matches!(comment_or_newline.first(), Some(CommentOrNewline::Newline))
}
_ => false,
}
}
fn format_str_segment(seg: &StrSegment, buf: &mut Buf, indent: u16) {
use StrSegment::*;
match seg {
Plaintext(string) => {
// Lines in block strings will end with Plaintext ending in "\n" to indicate
// a line break in the input string
match string.strip_suffix('\n') {
Some(string_without_newline) => {
buf.push_str_allow_spaces(string_without_newline);
buf.newline();
}
None => buf.push_str_allow_spaces(string),
}
}
Unicode(loc_str) => {
buf.push_str("\\u(");
buf.push_str(loc_str.value); // e.g. "00A0" in "\u(00A0)"
buf.push(')');
}
EscapedChar(escaped) => {
buf.push('\\');
buf.push(escaped.to_parsed_char());
}
Interpolated(loc_expr) => {
buf.push_str("\\(");
// e.g. (name) in "Hi, \(name)!"
loc_expr.value.format_with_options(
buf,
Parens::NotNeeded, // We already printed parens!
Newlines::No, // Interpolations can never have newlines
indent,
);
buf.push(')');
}
}
}
fn push_op(buf: &mut Buf, op: BinOp) {
match op {
called_via::BinOp::Caret => buf.push('^'),
called_via::BinOp::Star => buf.push('*'),
called_via::BinOp::Slash => buf.push('/'),
called_via::BinOp::DoubleSlash => buf.push_str("//"),
called_via::BinOp::Percent => buf.push('%'),
called_via::BinOp::Plus => buf.push('+'),
called_via::BinOp::Minus => buf.push('-'),
called_via::BinOp::Equals => buf.push_str("=="),
called_via::BinOp::NotEquals => buf.push_str("!="),
called_via::BinOp::LessThan => buf.push('<'),
called_via::BinOp::GreaterThan => buf.push('>'),
called_via::BinOp::LessThanOrEq => buf.push_str("<="),
called_via::BinOp::GreaterThanOrEq => buf.push_str(">="),
called_via::BinOp::And => buf.push_str("&&"),
called_via::BinOp::Or => buf.push_str("||"),
called_via::BinOp::Pizza => buf.push_str("|>"),
called_via::BinOp::Assignment => unreachable!(),
called_via::BinOp::IsAliasType => unreachable!(),
called_via::BinOp::IsOpaqueType => unreachable!(),
called_via::BinOp::Backpassing => unreachable!(),
}
}
pub fn fmt_str_literal(buf: &mut Buf, literal: StrLiteral, indent: u16) {
use roc_parse::ast::StrLiteral::*;
match literal {
PlainLine(string) => {
// When a PlainLine contains '\n' or '"', format as a block string
if string.contains('"') || string.contains('\n') {
buf.ensure_ends_with_newline();
buf.indent(indent);
buf.push_str("\"\"\"");
buf.push_newline_literal();
for line in string.split('\n') {
buf.indent(indent);
buf.push_str_allow_spaces(line);
buf.push_newline_literal();
}
buf.indent(indent);
buf.push_str("\"\"\"");
} else {
buf.indent(indent);
buf.push('"');
buf.push_str_allow_spaces(string);
buf.push('"');
};
}
Line(segments) => {
buf.indent(indent);
buf.push('"');
for seg in segments.iter() {
format_str_segment(seg, buf, 0)
}
buf.push('"');
}
Block(lines) => {
// Block strings will always be formatted with """ on new lines
buf.ensure_ends_with_newline();
buf.indent(indent);
buf.push_str("\"\"\"");
buf.push_newline_literal();
for segments in lines.iter() {
for seg in segments.iter() {
// only add indent if the line isn't empty
if *seg != StrSegment::Plaintext("\n") {
buf.indent(indent);
format_str_segment(seg, buf, indent);
} else {
buf.push_newline_literal();
}
}
buf.push_newline_literal();
}
buf.indent(indent);
buf.push_str("\"\"\"");
}
}
}
fn fmt_binops<'a>(
buf: &mut Buf,
lefts: &'a [(Loc<Expr<'a>>, Loc<BinOp>)],
loc_right_side: &'a Loc<Expr<'a>>,
part_of_multi_line_binops: bool,
indent: u16,
) {
let is_multiline = part_of_multi_line_binops
|| loc_right_side.value.is_multiline()
|| lefts.iter().any(|(expr, _)| expr.value.is_multiline());
for (loc_left_side, loc_binop) in lefts {
let binop = loc_binop.value;
loc_left_side.format_with_options(buf, Parens::InOperator, Newlines::No, indent);
if is_multiline {
buf.ensure_ends_with_newline();
buf.indent(indent);
} else {
buf.spaces(1);
}
push_op(buf, binop);
buf.spaces(1);
}
loc_right_side.format_with_options(buf, Parens::InOperator, Newlines::Yes, indent);
}
fn format_spaces(buf: &mut Buf, spaces: &[CommentOrNewline], newlines: Newlines, indent: u16) {
match newlines {
Newlines::Yes => {
fmt_spaces(buf, spaces.iter(), indent);
}
Newlines::No => {
fmt_comments_only(buf, spaces.iter(), NewlineAt::Bottom, indent);
}
}
}
fn is_when_patterns_multiline(when_branch: &WhenBranch) -> bool {
let patterns = when_branch.patterns;
let (first_pattern, rest) = patterns.split_first().unwrap();
let is_multiline_patterns = if let Some((last_pattern, inner_patterns)) = rest.split_last() {
!first_pattern.value.extract_spaces().after.is_empty()
|| !last_pattern.value.extract_spaces().before.is_empty()
|| inner_patterns.iter().any(|p| {
let spaces = p.value.extract_spaces();
!spaces.before.is_empty() || !spaces.after.is_empty()
})
} else {
false
};
is_multiline_patterns
}
fn fmt_when<'a>(
buf: &mut Buf,
loc_condition: &'a Loc<Expr<'a>>,
branches: &[&'a WhenBranch<'a>],
indent: u16,
) {
let is_multiline_condition = loc_condition.is_multiline();
buf.ensure_ends_with_newline();
buf.indent(indent);
buf.push_str("when");
if is_multiline_condition {
let condition_indent = indent + INDENT;
match &loc_condition.value {
Expr::SpaceBefore(expr_below, spaces_above_expr) => {
fmt_comments_only(
buf,
spaces_above_expr.iter(),
NewlineAt::Top,
condition_indent,
);
buf.newline();
match &expr_below {
Expr::SpaceAfter(expr_above, spaces_below_expr) => {
// If any of the spaces is a newline, add a newline at the top.
// Otherwise leave it as just a comment.
let newline_at = if spaces_below_expr
.iter()
.any(|spaces| matches!(spaces, CommentOrNewline::Newline))
{
NewlineAt::Top
} else {
NewlineAt::None
};
expr_above.format(buf, condition_indent);
fmt_comments_only(
buf,
spaces_below_expr.iter(),
newline_at,
condition_indent,
);
buf.newline();
}
_ => {
expr_below.format(buf, condition_indent);
}
}
}
_ => {
buf.newline();
loc_condition.format(buf, condition_indent);
buf.newline();
}
}
buf.indent(indent);
} else {
buf.spaces(1);
loc_condition.format(buf, indent);
buf.spaces(1);
}
buf.push_str("is");
buf.newline();
let mut prev_branch_was_multiline = false;
for (branch_index, branch) in branches.iter().enumerate() {
let expr = &branch.value;
let patterns = &branch.patterns;
let is_multiline_expr = expr.is_multiline();
let is_multiline_patterns = is_when_patterns_multiline(branch);
for (pattern_index, pattern) in patterns.iter().enumerate() {
if pattern_index == 0 {
match &pattern.value {
Pattern::SpaceBefore(sub_pattern, spaces) => {
let added_blank_line;
if branch_index > 0 // Never render newlines before the first branch.
&& matches!(spaces.first(), Some(CommentOrNewline::Newline))
{
if prev_branch_was_multiline {
// Multiline branches always get a full blank line after them.
buf.ensure_ends_with_blank_line();
added_blank_line = true;
} else {
buf.ensure_ends_with_newline();
added_blank_line = false;
}
} else {
added_blank_line = false;
}
// Write comments (which may have been attached to the previous
// branch's expr, if there was a previous branch).
fmt_comments_only(buf, spaces.iter(), NewlineAt::Bottom, indent + INDENT);
if branch_index > 0 {
if prev_branch_was_multiline && !added_blank_line {
// Multiline branches always get a full blank line after them
// (which we may already have added before a comment).
buf.ensure_ends_with_blank_line();
} else {
buf.ensure_ends_with_newline();
}
}
fmt_pattern(buf, sub_pattern, indent + INDENT, Parens::NotNeeded);
}
other => {
if branch_index > 0 {
if prev_branch_was_multiline {
// Multiline branches always get a full blank line after them.
buf.ensure_ends_with_blank_line();
} else {
buf.ensure_ends_with_newline();
}
}
fmt_pattern(buf, other, indent + INDENT, Parens::NotNeeded);
}
}
} else {
if is_multiline_patterns {
buf.ensure_ends_with_newline();
buf.indent(indent + INDENT);
buf.push('|');
} else {
buf.push_str(" |");
}
buf.spaces(1);
fmt_pattern(buf, &pattern.value, indent + INDENT, Parens::NotNeeded);
}
}
if let Some(guard_expr) = &branch.guard {
buf.push_str(" if");
buf.spaces(1);
guard_expr.format_with_options(buf, Parens::NotNeeded, Newlines::Yes, indent + INDENT);
}
buf.push_str(" ->");
match expr.value {
Expr::SpaceBefore(nested, spaces) => {
fmt_spaces_no_blank_lines(buf, spaces.iter(), indent + (INDENT * 2));
if is_multiline_expr {
buf.ensure_ends_with_newline();
} else {
buf.spaces(1);
}
nested.format_with_options(
buf,
Parens::NotNeeded,
Newlines::Yes,
indent + 2 * INDENT,
);
}
_ => {
if is_multiline_expr {
buf.ensure_ends_with_newline();
} else {
buf.spaces(1);
}
expr.format_with_options(
buf,
Parens::NotNeeded,
Newlines::Yes,
indent + 2 * INDENT,
);
}
}
prev_branch_was_multiline = is_multiline_expr || is_multiline_patterns;
}
}
fn fmt_dbg<'a>(
buf: &mut Buf,
condition: &'a Loc<Expr<'a>>,
continuation: &'a Loc<Expr<'a>>,
is_multiline: bool,
indent: u16,
) {
buf.ensure_ends_with_newline();
buf.indent(indent);
buf.push_str("dbg");
let return_indent = if is_multiline {
buf.newline();
indent + INDENT
} else {
buf.spaces(1);
indent
};
condition.format(buf, return_indent);
// Always put a blank line after the `dbg` line(s)
buf.ensure_ends_with_blank_line();
continuation.format(buf, indent);
}
fn fmt_expect<'a>(
buf: &mut Buf,
condition: &'a Loc<Expr<'a>>,
continuation: &'a Loc<Expr<'a>>,
is_multiline: bool,
indent: u16,
) {
buf.ensure_ends_with_newline();
buf.indent(indent);
buf.push_str("expect");
let return_indent = if is_multiline {
buf.newline();
indent + INDENT
} else {
buf.spaces(1);
indent
};
condition.format(buf, return_indent);
// Always put a blank line after the `expect` line(s)
buf.ensure_ends_with_blank_line();
continuation.format(buf, indent);
}
fn fmt_if<'a>(
buf: &mut Buf,
branches: &'a [(Loc<Expr<'a>>, Loc<Expr<'a>>)],
final_else: &'a Loc<Expr<'a>>,
is_multiline: bool,
indent: u16,
) {
// let is_multiline_then = loc_then.is_multiline();
// let is_multiline_else = final_else.is_multiline();
// let is_multiline_condition = loc_condition.is_multiline();
// let is_multiline = is_multiline_then || is_multiline_else || is_multiline_condition;
let return_indent = if is_multiline {
indent + INDENT
} else {
indent
};
for (i, (loc_condition, loc_then)) in branches.iter().enumerate() {
let is_multiline_condition = loc_condition.is_multiline();
buf.indent(indent);
if i > 0 {
buf.push_str("else");
buf.spaces(1);
}
buf.push_str("if");
if is_multiline_condition {
match &loc_condition.value {
Expr::SpaceBefore(expr_below, spaces_before_expr) => {
fmt_comments_only(
buf,
spaces_before_expr.iter(),
NewlineAt::Top,
return_indent,
);
buf.newline();
match &expr_below {
Expr::SpaceAfter(expr_above, spaces_after_expr) => {
expr_above.format(buf, return_indent);
// If any of the spaces is a newline, add a newline at the top.
// Otherwise leave it as just a comment.
let newline_at = if spaces_after_expr
.iter()
.any(|spaces| matches!(spaces, CommentOrNewline::Newline))
{
NewlineAt::Top
} else {
NewlineAt::None
};
fmt_comments_only(
buf,
spaces_after_expr.iter(),
newline_at,
return_indent,
);
buf.newline();
}
_ => {
expr_below.format(buf, return_indent);
}
}
}
Expr::SpaceAfter(expr_above, spaces_below_expr) => {
buf.newline();
expr_above.format(buf, return_indent);
fmt_comments_only(buf, spaces_below_expr.iter(), NewlineAt::Top, return_indent);
buf.newline();
}
_ => {
buf.newline();
loc_condition.format(buf, return_indent);
buf.newline();
}
}
buf.indent(indent);
} else {
buf.spaces(1);
loc_condition.format_with_options(buf, Parens::NotNeeded, Newlines::Yes, indent);
buf.spaces(1);
}
buf.push_str("then");
if is_multiline {
match &loc_then.value {
Expr::SpaceBefore(expr_below, spaces_below) => {
// we want exactly one newline, user-inserted extra newlines are ignored.
buf.newline();
fmt_comments_only(buf, spaces_below.iter(), NewlineAt::Bottom, return_indent);
match &expr_below {
Expr::SpaceAfter(expr_above, spaces_above) => {
expr_above.format(buf, return_indent);
// If any of the spaces is a newline, add a newline at the top.
// Otherwise leave it as just a comment.
let newline_at = if spaces_above
.iter()
.any(|spaces| matches!(spaces, CommentOrNewline::Newline))
{
NewlineAt::Top
} else {
NewlineAt::None
};
fmt_comments_only(buf, spaces_above.iter(), newline_at, return_indent);
buf.newline();
}
_ => {
expr_below.format(buf, return_indent);
}
}
}
_ => {
buf.newline();
loc_then.format(buf, return_indent);
buf.newline();
}
}
} else {
buf.push_str("");
buf.spaces(1);
loc_then.format(buf, return_indent);
}
}
buf.indent(indent);
if is_multiline {
buf.push_str("else");
buf.newline();
} else {
buf.push_str(" else");
buf.spaces(1);
}
final_else.format(buf, return_indent);
}
fn fmt_closure<'a>(
buf: &mut Buf,
loc_patterns: &'a [Loc<Pattern<'a>>],
loc_ret: &'a Loc<Expr<'a>>,
indent: u16,
) {
use self::Expr::*;
buf.indent(indent);
buf.push('\\');
let arguments_are_multiline = loc_patterns
.iter()
.any(|loc_pattern| loc_pattern.is_multiline());
// If the arguments are multiline, go down a line and indent.
let indent = if arguments_are_multiline {
indent + INDENT
} else {
indent
};
let mut it = loc_patterns.iter().peekable();
while let Some(loc_pattern) = it.next() {
loc_pattern.format(buf, indent);
if it.peek().is_some() {
buf.indent(indent);
if arguments_are_multiline {
buf.push(',');
buf.newline();
} else {
buf.push_str(",");
buf.spaces(1);
}
}
}
if arguments_are_multiline {
buf.newline();
buf.indent(indent);
} else {
buf.spaces(1);
}
buf.push_str("->");
let is_multiline = loc_ret.value.is_multiline();
// If the body is multiline, go down a line and indent.
let body_indent = if is_multiline {
indent + INDENT
} else {
indent
};
// the body of the Closure can be on the same line, or
// on a new line. If it's on the same line, insert a space.
match &loc_ret.value {
SpaceBefore(_, _) => {
// the body starts with (first comment and then) a newline
// do nothing
}
_ => {
// add a space after the `->`
buf.spaces(1);
}
};
if is_multiline {
match &loc_ret.value {
SpaceBefore(sub_expr, spaces) => {
let should_outdent = match sub_expr {
Record { .. } | List { .. } => {
let is_only_newlines = spaces.iter().all(|s| s.is_newline());
is_only_newlines && sub_expr.is_multiline()
}
_ => false,
};
if should_outdent {
buf.spaces(1);
sub_expr.format_with_options(buf, Parens::NotNeeded, Newlines::Yes, indent);
} else {
loc_ret.format_with_options(buf, Parens::NotNeeded, Newlines::Yes, body_indent);
}
}
Record { .. } | List { .. } => {
loc_ret.format_with_options(buf, Parens::NotNeeded, Newlines::Yes, indent);
}
_ => {
loc_ret.format_with_options(buf, Parens::NotNeeded, Newlines::Yes, body_indent);
}
}
} else {
loc_ret.format_with_options(buf, Parens::NotNeeded, Newlines::Yes, body_indent);
}
}
fn fmt_backpassing<'a>(
buf: &mut Buf,
loc_patterns: &'a [Loc<Pattern<'a>>],
loc_body: &'a Loc<Expr<'a>>,
loc_ret: &'a Loc<Expr<'a>>,
indent: u16,
) {
use self::Expr::*;
let arguments_are_multiline = loc_patterns
.iter()
.any(|loc_pattern| loc_pattern.is_multiline());
// If the arguments are multiline, go down a line and indent.
let indent = if arguments_are_multiline {
indent + INDENT
} else {
indent
};
let mut it = loc_patterns.iter().peekable();
while let Some(loc_pattern) = it.next() {
let needs_parens = if pattern_needs_parens_when_backpassing(&loc_pattern.value) {
Parens::InApply
} else {
Parens::NotNeeded
};
loc_pattern.format_with_options(buf, needs_parens, Newlines::No, indent);
if it.peek().is_some() {
if arguments_are_multiline {
buf.push(',');
buf.newline();
} else {
buf.push_str(",");
buf.spaces(1);
}
}
}
if arguments_are_multiline {
buf.newline();
buf.indent(indent);
} else {
buf.spaces(1);
}
buf.push_str("<-");
let is_multiline = loc_ret.value.is_multiline();
// If the body is multiline, go down a line and indent.
let body_indent = if is_multiline {
indent + INDENT
} else {
indent
};
// the body of the Backpass can be on the same line, or
// on a new line. If it's on the same line, insert a space.
match &loc_body.value {
SpaceBefore(_, _) => {
// the body starts with (first comment and then) a newline
// do nothing
}
_ => {
// add a space after the `<-`
buf.spaces(1);
}
};
loc_body.format_with_options(buf, Parens::NotNeeded, Newlines::Yes, body_indent);
loc_ret.format_with_options(buf, Parens::NotNeeded, Newlines::Yes, indent);
}
fn pattern_needs_parens_when_backpassing(pat: &Pattern) -> bool {
match pat {
Pattern::Apply(_, _) => true,
Pattern::SpaceBefore(a, _) | Pattern::SpaceAfter(a, _) => {
pattern_needs_parens_when_backpassing(a)
}
_ => false,
}
}
fn fmt_record_like<'a, Field, Format, ToSpaceBefore>(
buf: &mut Buf,
update: Option<&'a Loc<Expr<'a>>>,
fields: Collection<'a, Loc<Field>>,
indent: u16,
format_field_multiline: Format,
to_space_before: ToSpaceBefore,
) where
Field: Formattable,
Format: Fn(&mut Buf, &Field, u16, &str),
ToSpaceBefore: Fn(&'a Field) -> Option<(&'a Field, &'a [CommentOrNewline<'a>])>,
{
let loc_fields = fields.items;
let final_comments = fields.final_comments();
buf.indent(indent);
if loc_fields.is_empty() && final_comments.iter().all(|c| c.is_newline()) && update.is_none() {
buf.push_str("{}");
} else {
buf.push('{');
match update {
None => {}
// We are presuming this to be a Var()
// If it wasnt a Var() we would not have made
// it this far. For example "{ 4 & hello = 9 }"
// doesnt make sense.
Some(record_var) => {
buf.spaces(1);
record_var.format(buf, indent);
buf.push_str(" &");
}
}
let is_multiline = loc_fields.iter().any(|loc_field| loc_field.is_multiline())
|| !final_comments.is_empty();
if is_multiline {
let field_indent = indent + INDENT;
for (index, field) in loc_fields.iter().enumerate() {
// comma addition is handled by the `format_field_multiline` function
// since we can have stuff like:
// { x # comment
// , y
// }
// In this case, we have to move the comma before the comment.
let is_first_item = index == 0;
if let Some((_sub_field, spaces)) = to_space_before(&field.value) {
let is_only_newlines = spaces.iter().all(|s| s.is_newline());
if !is_first_item
&& !is_only_newlines
&& count_leading_newlines(spaces.iter()) > 1
{
buf.newline();
}
fmt_comments_only(buf, spaces.iter(), NewlineAt::Top, field_indent);
if !is_only_newlines && count_leading_newlines(spaces.iter().rev()) > 0 {
buf.newline();
}
}
format_field_multiline(buf, &field.value, field_indent, "");
}
if count_leading_newlines(final_comments.iter()) > 1 {
buf.newline();
}
fmt_comments_only(buf, final_comments.iter(), NewlineAt::Top, field_indent);
buf.newline();
} else {
// is_multiline == false
buf.spaces(1);
let field_indent = indent;
let mut iter = loc_fields.iter().peekable();
while let Some(field) = iter.next() {
field.format_with_options(buf, Parens::NotNeeded, Newlines::No, field_indent);
if iter.peek().is_some() {
buf.push_str(",");
buf.spaces(1);
}
}
buf.spaces(1);
// if we are here, that means that `final_comments` is empty, thus we don't have
// to add a comment. Anyway, it is not possible to have a single line record with
// a comment in it.
};
// closes the initial bracket
buf.indent(indent);
buf.push('}');
}
}
fn format_assigned_field_multiline<T>(
buf: &mut Buf,
field: &AssignedField<T>,
indent: u16,
separator_prefix: &str,
) where
T: Formattable,
{
use self::AssignedField::*;
match field {
RequiredValue(name, spaces, ann) => {
buf.newline();
buf.indent(indent);
buf.push_str(name.value);
if !spaces.is_empty() {
fmt_spaces(buf, spaces.iter(), indent);
buf.indent(indent);
}
buf.push_str(separator_prefix);
buf.push_str(":");
buf.spaces(1);
ann.value.format(buf, indent);
buf.push(',');
}
OptionalValue(name, spaces, ann) => {
buf.newline();
buf.indent(indent);
buf.push_str(name.value);
if !spaces.is_empty() {
fmt_spaces(buf, spaces.iter(), indent);
buf.indent(indent);
}
buf.push_str(separator_prefix);
buf.push_str("?");
buf.spaces(1);
ann.value.format(buf, indent);
buf.push(',');
}
LabelOnly(name) => {
buf.newline();
buf.indent(indent);
buf.push_str(name.value);
buf.push(',');
}
AssignedField::SpaceBefore(sub_field, _spaces) => {
// We have something like that:
// ```
// # comment
// field,
// ```
// we'd like to preserve this
format_assigned_field_multiline(buf, sub_field, indent, separator_prefix);
}
AssignedField::SpaceAfter(sub_field, spaces) => {
// We have something like that:
// ```
// field # comment
// , otherfield
// ```
// we'd like to transform it into:
// ```
// field,
// # comment
// otherfield
// ```
format_assigned_field_multiline(buf, sub_field, indent, separator_prefix);
fmt_comments_only(buf, spaces.iter(), NewlineAt::Top, indent);
}
Malformed(raw) => {
buf.push_str(raw);
}
}
}
fn assigned_field_to_space_before<'a, T>(
field: &'a AssignedField<'a, T>,
) -> Option<(&AssignedField<'a, T>, &'a [CommentOrNewline<'a>])> {
match field {
AssignedField::SpaceBefore(sub_field, spaces) => Some((sub_field, spaces)),
_ => None,
}
}
fn format_record_builder_field_multiline(
buf: &mut Buf,
field: &RecordBuilderField,
indent: u16,
separator_prefix: &str,
) {
use self::RecordBuilderField::*;
match field {
Value(name, spaces, ann) => {
buf.newline();
buf.indent(indent);
buf.push_str(name.value);
if !spaces.is_empty() {
fmt_spaces(buf, spaces.iter(), indent);
buf.indent(indent);
}
buf.push_str(separator_prefix);
buf.push_str(":");
if ann.value.is_multiline() {
buf.newline();
ann.value.format(buf, indent + INDENT);
} else {
buf.spaces(1);
ann.value.format(buf, indent);
}
buf.push(',');
}
ApplyValue(name, colon_spaces, arrow_spaces, ann) => {
buf.newline();
buf.indent(indent);
buf.push_str(name.value);
if !colon_spaces.is_empty() {
fmt_spaces(buf, colon_spaces.iter(), indent);
buf.indent(indent);
}
buf.push_str(separator_prefix);
buf.push(':');
buf.spaces(1);
if !arrow_spaces.is_empty() {
fmt_spaces(buf, arrow_spaces.iter(), indent);
buf.indent(indent + INDENT);
}
buf.push_str("<-");
if ann.value.is_multiline() {
buf.newline();
ann.value.format(buf, indent + INDENT);
} else {
buf.spaces(1);
ann.value.format(buf, indent);
}
buf.push(',');
}
LabelOnly(name) => {
buf.newline();
buf.indent(indent);
buf.push_str(name.value);
buf.push(',');
}
SpaceBefore(sub_field, _spaces) => {
// We have something like that:
// ```
// # comment
// field,
// ```
// we'd like to preserve this
format_record_builder_field_multiline(buf, sub_field, indent, separator_prefix);
}
SpaceAfter(sub_field, spaces) => {
// We have something like that:
// ```
// field # comment
// , otherfield
// ```
// we'd like to transform it into:
// ```
// field,
// # comment
// otherfield
// ```
format_record_builder_field_multiline(buf, sub_field, indent, separator_prefix);
fmt_comments_only(buf, spaces.iter(), NewlineAt::Top, indent);
}
Malformed(raw) => {
buf.push_str(raw);
}
}
}
fn record_builder_field_to_space_before<'a>(
field: &'a RecordBuilderField<'a>,
) -> Option<(&RecordBuilderField<'a>, &'a [CommentOrNewline<'a>])> {
match field {
RecordBuilderField::SpaceBefore(sub_field, spaces) => Some((sub_field, spaces)),
_ => None,
}
}
fn sub_expr_requests_parens(expr: &Expr<'_>) -> bool {
match expr {
Expr::BinOps(left_side, _) => {
left_side
.iter()
.any(|(_, loc_binop)| match loc_binop.value {
BinOp::Caret
| BinOp::Star
| BinOp::Slash
| BinOp::DoubleSlash
| BinOp::Percent
| BinOp::Plus
| BinOp::Minus
| BinOp::Equals
| BinOp::NotEquals
| BinOp::LessThan
| BinOp::GreaterThan
| BinOp::LessThanOrEq
| BinOp::GreaterThanOrEq
| BinOp::And
| BinOp::Or
| BinOp::Pizza => true,
BinOp::Assignment
| BinOp::IsAliasType
| BinOp::IsOpaqueType
| BinOp::Backpassing => false,
})
}
Expr::If(_, _) => true,
Expr::SpaceBefore(e, _) => sub_expr_requests_parens(e),
Expr::SpaceAfter(e, _) => sub_expr_requests_parens(e),
_ => false,
}
}