/// alignment).
/// E.g., `let foo = { aaaa; bbb; ccc }.bar.baz();`, we would layout for the
/// following values of `chain_indent`:
+/// Block:
+/// ```
+/// let foo = {
+/// aaaa;
+/// bbb;
+/// ccc
+/// }.bar
+/// .baz();
+/// ```
/// Visual:
/// ```
/// let foo = {
/// .bar
/// .baz();
/// ```
-/// Inherit:
-/// ```
-/// let foo = {
-/// aaaa;
-/// bbb;
-/// ccc
-/// }
-/// .bar
-/// .baz();
-/// ```
-/// Tabbed:
-/// ```
-/// let foo = {
-/// aaaa;
-/// bbb;
-/// ccc
-/// }
-/// .bar
-/// .baz();
-/// ```
///
/// If the first item in the chain is a block expression, we align the dots with
/// the braces.
-/// Visual:
-/// ```
-/// let a = foo.bar
-/// .baz()
-/// .qux
-/// ```
-/// Inherit:
+/// Block:
/// ```
/// let a = foo.bar
-/// .baz()
-/// .qux
+/// .baz()
+/// .qux
/// ```
-/// Tabbed:
+/// Visual:
/// ```
/// let a = foo.bar
-/// .baz()
-/// .qux
+/// .baz()
+/// .qux
/// ```
-use Shape;
-use rewrite::{Rewrite, RewriteContext};
-use utils::{wrap_str, first_line_width, last_line_width};
-use expr::rewrite_call;
+use shape::Shape;
use config::IndentStyle;
+use expr::rewrite_call;
use macros::convert_try_mac;
+use rewrite::{Rewrite, RewriteContext};
+use utils::{first_line_width, last_line_extendable, last_line_width, mk_sp,
+ trimmed_last_line_width, wrap_str};
use std::cmp::min;
use std::iter;
use syntax::{ast, ptr};
-use syntax::codemap::{mk_sp, Span};
+use syntax::codemap::Span;
pub fn rewrite_chain(expr: &ast::Expr, context: &RewriteContext, shape: Shape) -> Option<String> {
debug!("rewrite_chain {:?}", shape);
if chain_only_try(&subexpr_list) {
return rewrite_try(&parent, subexpr_list.len(), context, shape);
}
- let trailing_try_num = subexpr_list
- .iter()
- .take_while(|e| match e.node {
- ast::ExprKind::Try(..) => true,
- _ => false,
- })
- .count();
+ let suffix_try_num = subexpr_list.iter().take_while(|e| is_try(e)).count();
+ let prefix_try_num = subexpr_list.iter().rev().take_while(|e| is_try(e)).count();
// Parent is the first item in the chain, e.g., `foo` in `foo.bar.baz()`.
let parent_shape = if is_block_expr(context, &parent, "\n") {
match context.config.chain_indent() {
IndentStyle::Visual => shape.visual_indent(0),
- IndentStyle::Block => shape.block(),
+ IndentStyle::Block => shape,
}
} else {
shape
};
- let parent_rewrite = try_opt!(parent.rewrite(context, parent_shape));
+ let parent_rewrite = parent
+ .rewrite(context, parent_shape)
+ .map(|parent_rw| parent_rw + &repeat_try(prefix_try_num))?;
let parent_rewrite_contains_newline = parent_rewrite.contains('\n');
+ let is_small_parent = parent_rewrite.len() <= context.config.tab_spaces();
// Decide how to layout the rest of the chain. `extend` is true if we can
// put the first non-parent item on the same line as the parent.
- let first_subexpr_is_try = match subexpr_list.last().unwrap().node {
- ast::ExprKind::Try(..) => true,
- _ => false,
- };
let (nested_shape, extend) = if !parent_rewrite_contains_newline && is_continuable(&parent) {
- let nested_shape = if first_subexpr_is_try {
- parent_shape.block_indent(context.config.tab_spaces())
- } else {
- chain_indent(context, shape.add_offset(parent_rewrite.len()))
- };
- (nested_shape,
- context.config.chain_indent() == IndentStyle::Visual ||
- parent_rewrite.len() <= context.config.tab_spaces())
+ (
+ chain_indent(context, shape.add_offset(parent_rewrite.len())),
+ context.config.chain_indent() == IndentStyle::Visual || is_small_parent,
+ )
} else if is_block_expr(context, &parent, &parent_rewrite) {
match context.config.chain_indent() {
// Try to put the first child on the same line with parent's last line
// brace.
IndentStyle::Visual => (parent_shape, false),
}
- } else if parent_rewrite_contains_newline {
- (chain_indent(context, parent_shape), false)
} else {
- (shape.block_indent(context.config.tab_spaces()), false)
+ (
+ chain_indent(context, shape.add_offset(parent_rewrite.len())),
+ false,
+ )
};
let other_child_shape = nested_shape.with_max_width(context.config);
let first_child_shape = if extend {
let overhead = last_line_width(&parent_rewrite);
- let offset = parent_rewrite.lines().rev().next().unwrap().trim().len();
+ let offset = trimmed_last_line_width(&parent_rewrite);
match context.config.chain_indent() {
- IndentStyle::Visual => try_opt!(parent_shape.offset_left(overhead)),
- IndentStyle::Block => try_opt!(parent_shape.block().offset_left(offset)),
+ IndentStyle::Visual => parent_shape.offset_left(overhead)?,
+ IndentStyle::Block => parent_shape.block().offset_left(offset)?,
}
} else {
other_child_shape
};
- debug!("child_shapes {:?} {:?}",
- first_child_shape,
- other_child_shape);
+ debug!(
+ "child_shapes {:?} {:?}",
+ first_child_shape,
+ other_child_shape
+ );
let child_shape_iter = Some(first_child_shape)
.into_iter()
- .chain(::std::iter::repeat(other_child_shape)
- .take(subexpr_list.len() - 1));
- let iter = subexpr_list.iter().rev().zip(child_shape_iter);
- let mut rewrites = try_opt!(iter.map(|(e, shape)| {
- rewrite_chain_subexpr(e, total_span, context, shape)
- })
- .collect::<Option<Vec<_>>>());
+ .chain(iter::repeat(other_child_shape));
+ let subexpr_num = subexpr_list.len();
+ let last_subexpr = &subexpr_list[suffix_try_num];
+ let subexpr_list = &subexpr_list[suffix_try_num..subexpr_num - prefix_try_num];
+ let iter = subexpr_list.iter().skip(1).rev().zip(child_shape_iter);
+ let mut rewrites = iter.map(|(e, shape)| {
+ rewrite_chain_subexpr(e, total_span, context, shape)
+ }).collect::<Option<Vec<_>>>()?;
// Total of all items excluding the last.
- let last_non_try_index = rewrites.len() - (1 + trailing_try_num);
- let almost_total = rewrites[..last_non_try_index]
- .iter()
- .fold(0, |a, b| a + first_line_width(b)) + parent_rewrite.len();
- let one_line_len = rewrites.iter().fold(0, |a, r| a + first_line_width(r)) +
- parent_rewrite.len();
-
- let one_line_budget = min(shape.width, context.config.chain_one_line_max());
- let veto_single_line = if one_line_len > one_line_budget {
- if rewrites.len() > 1 {
- true
- } else if rewrites.len() == 1 {
- parent_rewrite.len() > context.config.chain_one_line_max() / 2
- } else {
- false
- }
- } else if context.config.take_source_hints() && subexpr_list.len() > 1 {
- // Look at the source code. Unless all chain elements start on the same
- // line, we won't consider putting them on a single line either.
- let last_span = context.snippet(mk_sp(subexpr_list[1].span.hi, total_span.hi));
- let first_span = context.snippet(subexpr_list[1].span);
- let last_iter = last_span.chars().take_while(|c| c.is_whitespace());
-
- first_span.chars().chain(last_iter).any(|c| c == '\n')
+ let extend_last_subexr = last_line_extendable(&parent_rewrite) && rewrites.is_empty();
+ let almost_total = if extend_last_subexr {
+ last_line_width(&parent_rewrite)
} else {
- false
+ rewrites.iter().fold(0, |a, b| a + b.len()) + parent_rewrite.len()
+ } + suffix_try_num;
+ let one_line_budget = if rewrites.is_empty() && !context.config.chain_split_single_child() {
+ shape.width
+ } else {
+ min(shape.width, context.config.chain_one_line_max())
};
-
- let mut fits_single_line = !veto_single_line && almost_total <= shape.width;
- if fits_single_line {
- let len = rewrites.len();
- let (init, last) = rewrites.split_at_mut(len - (1 + trailing_try_num));
- fits_single_line = init.iter().all(|s| !s.contains('\n'));
-
- if fits_single_line {
- fits_single_line = match expr.node {
- ref e @ ast::ExprKind::MethodCall(..) => {
- if rewrite_method_call_with_overflow(e,
- &mut last[0],
- almost_total,
- total_span,
- context,
- shape) {
- // If the first line of the last method does not fit into a single line
- // after the others, allow new lines.
- almost_total + first_line_width(&last[0]) < context.config.max_width()
- } else {
- false
+ let all_in_one_line = !parent_rewrite_contains_newline
+ && rewrites.iter().all(|s| !s.contains('\n'))
+ && almost_total < one_line_budget;
+ let last_shape = match context.config.chain_indent() {
+ IndentStyle::Visual => other_child_shape.sub_width(shape.rhs_overhead(context.config))?,
+ IndentStyle::Block => other_child_shape,
+ };
+ let last_shape = last_shape.sub_width(suffix_try_num)?;
+
+ // Rewrite the last child. The last child of a chain requires special treatment. We need to
+ // know whether 'overflowing' the last child make a better formatting:
+ //
+ // A chain with overflowing the last child:
+ // ```
+ // parent.child1.child2.last_child(
+ // a,
+ // b,
+ // c,
+ // )
+ // ```
+ //
+ // A chain without overflowing the last child (in vertical layout):
+ // ```
+ // parent
+ // .child1
+ // .child2
+ // .last_child(a, b, c)
+ // ```
+ //
+ // In particular, overflowing is effective when the last child is a method with a multi-lined
+ // block-like argument (e.g. closure):
+ // ```
+ // parent.child1.chlid2.last_child(|a, b, c| {
+ // let x = foo(a, b, c);
+ // let y = bar(a, b, c);
+ //
+ // // ...
+ //
+ // result
+ // })
+ // ```
+
+ // `rewrite_last` rewrites the last child on its own line. We use a closure here instead of
+ // directly calling `rewrite_chain_subexpr()` to avoid exponential blowup.
+ let rewrite_last = || rewrite_chain_subexpr(last_subexpr, total_span, context, last_shape);
+ let (last_subexpr_str, fits_single_line) = if all_in_one_line || extend_last_subexr {
+ // First we try to 'overflow' the last child and see if it looks better than using
+ // vertical layout.
+ parent_shape.offset_left(almost_total).map(|shape| {
+ if let Some(rw) = rewrite_chain_subexpr(last_subexpr, total_span, context, shape) {
+ // We allow overflowing here only if both of the following conditions match:
+ // 1. The entire chain fits in a single line expect the last child.
+ // 2. `last_chlid_str.lines().count() >= 5`.
+ let line_count = rw.lines().count();
+ let fits_single_line = almost_total + first_line_width(&rw) <= one_line_budget;
+ if fits_single_line && line_count >= 5 {
+ (Some(rw), true)
+ } else {
+ // We could not know whether overflowing is better than using vertical layout,
+ // just by looking at the overflowed rewrite. Now we rewrite the last child
+ // on its own line, and compare two rewrites to choose which is better.
+ match rewrite_last() {
+ Some(ref new_rw) if !fits_single_line => (Some(new_rw.clone()), false),
+ Some(ref new_rw) if new_rw.lines().count() >= line_count => {
+ (Some(rw), fits_single_line)
+ }
+ new_rw @ Some(..) => (new_rw, false),
+ _ => (Some(rw), fits_single_line),
}
}
- _ => !last[0].contains('\n'),
+ } else {
+ (rewrite_last(), false)
}
- }
- }
-
- // Try overflowing the last element if we are using block indent.
- if !fits_single_line && context.config.fn_call_style() == IndentStyle::Block {
- let (init, last) = rewrites.split_at_mut(last_non_try_index);
- let almost_single_line = init.iter().all(|s| !s.contains('\n'));
- if almost_single_line {
- let overflow_shape = Shape {
- width: one_line_budget,
- ..parent_shape
- };
- fits_single_line = rewrite_last_child_with_overflow(context,
- &subexpr_list[trailing_try_num],
- overflow_shape,
- total_span,
- almost_total,
- one_line_budget,
- &mut last[0]);
- }
- }
+ })?
+ } else {
+ (rewrite_last(), false)
+ };
+ rewrites.push(last_subexpr_str?);
let connector = if fits_single_line && !parent_rewrite_contains_newline {
// Yay, we can put everything on one line.
String::new()
} else {
// Use new lines.
+ if context.force_one_line_chain {
+ return None;
+ }
format!("\n{}", nested_shape.indent.to_string(context.config))
};
- let first_connector = if subexpr_list.is_empty() {
+ let first_connector = if is_small_parent || fits_single_line
+ || last_line_extendable(&parent_rewrite)
+ || context.config.chain_indent() == IndentStyle::Visual
+ {
""
- } else if extend || first_subexpr_is_try {
- // 1 = ";", being conservative here.
- if last_line_width(&parent_rewrite) + first_line_width(&rewrites[0]) + 1 <=
- context.config.max_width() {
+ } else {
+ connector.as_str()
+ };
+
+ let result = if is_small_parent && rewrites.len() > 1 {
+ let second_connector = if fits_single_line || rewrites[1] == "?"
+ || last_line_extendable(&rewrites[0])
+ || context.config.chain_indent() == IndentStyle::Visual
+ {
""
} else {
- &*connector
- }
+ &connector
+ };
+ format!(
+ "{}{}{}{}{}",
+ parent_rewrite,
+ first_connector,
+ rewrites[0],
+ second_connector,
+ join_rewrites(&rewrites[1..], &connector)
+ )
} else {
- &*connector
+ format!(
+ "{}{}{}",
+ parent_rewrite,
+ first_connector,
+ join_rewrites(&rewrites, &connector)
+ )
};
-
- wrap_str(format!("{}{}{}",
- parent_rewrite,
- first_connector,
- join_rewrites(&rewrites, &subexpr_list, &connector)),
- context.config.max_width(),
- shape)
+ let result = format!("{}{}", result, repeat_try(suffix_try_num));
+ if context.config.chain_indent() == IndentStyle::Visual {
+ wrap_str(result, context.config.max_width(), shape)
+ } else {
+ Some(result)
+ }
}
// True if the chain is only `?`s.
fn chain_only_try(exprs: &[ast::Expr]) -> bool {
exprs.iter().all(|e| if let ast::ExprKind::Try(_) = e.node {
- true
- } else {
- false
- })
+ true
+ } else {
+ false
+ })
}
// Try to rewrite and replace the last non-try child. Return `true` if
// replacing succeeds.
-fn rewrite_last_child_with_overflow(context: &RewriteContext,
- expr: &ast::Expr,
- shape: Shape,
- span: Span,
- almost_total: usize,
- one_line_budget: usize,
- last_child: &mut String)
- -> bool {
- if let Some(shape) = shape.shrink_left(almost_total) {
- if let Some(ref mut rw) = rewrite_chain_subexpr(expr, span, context, shape) {
- if almost_total + first_line_width(rw) <= one_line_budget {
- ::std::mem::swap(last_child, rw);
- return true;
- }
- }
- }
- false
+fn repeat_try(try_count: usize) -> String {
+ iter::repeat("?").take(try_count).collect::<String>()
}
-pub fn rewrite_try(expr: &ast::Expr,
- try_count: usize,
- context: &RewriteContext,
- shape: Shape)
- -> Option<String> {
- let sub_expr = try_opt!(expr.rewrite(context, try_opt!(shape.sub_width(try_count))));
- Some(format!("{}{}",
- sub_expr,
- iter::repeat("?").take(try_count).collect::<String>()))
+fn rewrite_try(
+ expr: &ast::Expr,
+ try_count: usize,
+ context: &RewriteContext,
+ shape: Shape,
+) -> Option<String> {
+ let sub_expr = expr.rewrite(context, shape.sub_width(try_count)?)?;
+ Some(format!("{}{}", sub_expr, repeat_try(try_count)))
}
-fn join_rewrites(rewrites: &[String], subexps: &[ast::Expr], connector: &str) -> String {
+fn join_rewrites(rewrites: &[String], connector: &str) -> String {
let mut rewrite_iter = rewrites.iter();
let mut result = rewrite_iter.next().unwrap().clone();
- let mut subexpr_iter = subexps.iter().rev();
- subexpr_iter.next();
- for (rewrite, expr) in rewrite_iter.zip(subexpr_iter) {
- match expr.node {
- ast::ExprKind::Try(_) => (),
- _ => result.push_str(connector),
- };
+ for rewrite in rewrite_iter {
+ if rewrite != "?" {
+ result.push_str(connector);
+ }
result.push_str(&rewrite[..]);
}
// parens, braces, and brackets in its idiomatic formatting.
fn is_block_expr(context: &RewriteContext, expr: &ast::Expr, repr: &str) -> bool {
match expr.node {
- ast::ExprKind::Call(..) => {
- context.config.fn_call_style() == IndentStyle::Block && repr.contains('\n')
+ ast::ExprKind::Mac(..) | ast::ExprKind::Call(..) => {
+ context.use_block_indent() && repr.contains('\n')
}
ast::ExprKind::Struct(..) |
ast::ExprKind::While(..) |
fn chain_indent(context: &RewriteContext, shape: Shape) -> Shape {
match context.config.chain_indent() {
IndentStyle::Visual => shape.visual_indent(0),
- IndentStyle::Block => shape.block_indent(context.config.tab_spaces()),
- }
-}
-
-fn rewrite_method_call_with_overflow(expr_kind: &ast::ExprKind,
- last: &mut String,
- almost_total: usize,
- total_span: Span,
- context: &RewriteContext,
- shape: Shape)
- -> bool {
- if let &ast::ExprKind::MethodCall(ref method_name, ref types, ref expressions) = expr_kind {
- let shape = match shape.shrink_left(almost_total) {
- Some(b) => b,
- None => return false,
- };
- let mut last_rewrite = rewrite_method_call(method_name.node,
- types,
- expressions,
- total_span,
- context,
- shape);
-
- if let Some(ref mut s) = last_rewrite {
- ::std::mem::swap(s, last);
- true
- } else {
- false
- }
- } else {
- unreachable!();
+ IndentStyle::Block => shape
+ .block_indent(context.config.tab_spaces())
+ .with_max_width(context.config),
}
}
// is a try! macro, we'll convert it to shorthand when the option is set.
fn pop_expr_chain(expr: &ast::Expr, context: &RewriteContext) -> Option<ast::Expr> {
match expr.node {
- ast::ExprKind::MethodCall(_, _, ref expressions) => {
+ ast::ExprKind::MethodCall(_, ref expressions) => {
Some(convert_try(&expressions[0], context))
}
ast::ExprKind::TupField(ref subexpr, _) |
// Rewrite the last element in the chain `expr`. E.g., given `a.b.c` we rewrite
// `.c`.
-fn rewrite_chain_subexpr(expr: &ast::Expr,
- span: Span,
- context: &RewriteContext,
- shape: Shape)
- -> Option<String> {
+fn rewrite_chain_subexpr(
+ expr: &ast::Expr,
+ span: Span,
+ context: &RewriteContext,
+ shape: Shape,
+) -> Option<String> {
let rewrite_element = |expr_str: String| if expr_str.len() <= shape.width {
Some(expr_str)
} else {
};
match expr.node {
- ast::ExprKind::MethodCall(ref method_name, ref types, ref expressions) => {
- rewrite_method_call(method_name.node, types, expressions, span, context, shape)
+ ast::ExprKind::MethodCall(ref segment, ref expressions) => {
+ let types = match segment.parameters {
+ Some(ref params) => match **params {
+ ast::PathParameters::AngleBracketed(ref data) => &data.types[..],
+ _ => &[],
+ },
+ _ => &[],
+ };
+ rewrite_method_call(segment.identifier, types, expressions, span, context, shape)
}
ast::ExprKind::Field(_, ref field) => rewrite_element(format!(".{}", field.node)),
- ast::ExprKind::TupField(_, ref field) => rewrite_element(format!(".{}", field.node)),
+ ast::ExprKind::TupField(ref expr, ref field) => {
+ let space = match expr.node {
+ ast::ExprKind::TupField(..) => " ",
+ _ => "",
+ };
+ rewrite_element(format!("{}.{}", space, field.node))
+ }
ast::ExprKind::Try(_) => rewrite_element(String::from("?")),
_ => unreachable!(),
}
}
}
-fn rewrite_method_call(method_name: ast::Ident,
- types: &[ptr::P<ast::Ty>],
- args: &[ptr::P<ast::Expr>],
- span: Span,
- context: &RewriteContext,
- shape: Shape)
- -> Option<String> {
+fn is_try(expr: &ast::Expr) -> bool {
+ match expr.node {
+ ast::ExprKind::Try(..) => true,
+ _ => false,
+ }
+}
+
+fn rewrite_method_call(
+ method_name: ast::Ident,
+ types: &[ptr::P<ast::Ty>],
+ args: &[ptr::P<ast::Expr>],
+ span: Span,
+ context: &RewriteContext,
+ shape: Shape,
+) -> Option<String> {
let (lo, type_str) = if types.is_empty() {
- (args[0].span.hi, String::new())
+ (args[0].span.hi(), String::new())
} else {
- let type_list: Vec<_> =
- try_opt!(types.iter().map(|ty| ty.rewrite(context, shape)).collect());
+ let type_list = types
+ .iter()
+ .map(|ty| ty.rewrite(context, shape))
+ .collect::<Option<Vec<_>>>()?;
- let type_str = if context.config.spaces_within_angle_brackets() && type_list.len() > 0 {
+ let type_str = if context.config.spaces_within_angle_brackets() && !type_list.is_empty() {
format!("::< {} >", type_list.join(", "))
} else {
format!("::<{}>", type_list.join(", "))
};
- (types.last().unwrap().span.hi, type_str)
+ (types.last().unwrap().span.hi(), type_str)
};
let callee_str = format!(".{}{}", method_name, type_str);
- let span = mk_sp(lo, span.hi);
+ let span = mk_sp(lo, span.hi());
rewrite_call(context, &callee_str, &args[1..], span, shape)
}
projects / rust.git / blobdiff