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chains: further simplification

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This commit is contained in:
Nick Cameron 2018-07-09 21:09:25 +12:00
parent 38e8b086e8
commit 914e750c9e
1 changed files with 33 additions and 47 deletions
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80
src/chains.rs
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@ -161,11 +161,7 @@ fn rewrite_chain_block(mut chain: Chain, context: &RewriteContext, shape: Shape)
shape.block_indent(context.config.tab_spaces())
}.with_max_width(context.config);
let extend = if !parent_rewrite_contains_newline && is_continuable(&chain.parent.expr) {
is_small_parent
} else {
parent_is_block
};
let extend = parent_is_block || (is_small_parent && !parent_rewrite_contains_newline && is_continuable(&chain.parent.expr));
let first_child_shape = if extend {
let offset = trimmed_last_line_width(&parent_rewrite) + chain.parent.tries;
@ -351,7 +347,6 @@ fn rewrite_chain_visual(mut chain: Chain, context: &RewriteContext, shape: Shape
.rewrite(context, parent_shape)
.map(|parent_rw| parent_rw + &"?".repeat(chain.parent.tries))?;
let parent_rewrite_contains_newline = parent_rewrite.contains('\n');
let is_small_parent = shape.offset + parent_rewrite.len() <= context.config.tab_spaces();
let other_child_shape = shape.visual_indent(0).with_max_width(context.config);
@ -382,16 +377,7 @@ fn rewrite_chain_visual(mut chain: Chain, context: &RewriteContext, shape: Shape
}
// Total of all items excluding the last.
let extend_last_subexpr = if is_small_parent {
rewrites.len() == 1 && last_line_extendable(&rewrites[0])
} else {
rewrites.is_empty() && last_line_extendable(&parent_rewrite)
};
let almost_total = if extend_last_subexpr {
last_line_width(&parent_rewrite)
} else {
rewrites.iter().fold(0, |a, b| a + b.len()) + parent_rewrite.len()
} + last.tries;
let almost_total = rewrites.iter().fold(0, |a, b| a + b.len()) + parent_rewrite.len() + last.tries;
let one_line_budget = if rewrites.is_empty() {
shape.width
} else {
@ -436,38 +422,48 @@ fn rewrite_chain_visual(mut chain: Chain, context: &RewriteContext, shape: Shape
// })
// ```
let (last_subexpr_str, fits_single_line) = if all_in_one_line || extend_last_subexpr {
let mut last_subexpr_str = None;
let mut fits_single_line = false;
if all_in_one_line {
// 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(shape) = parent_shape.offset_left(almost_total) {
if let Some(rw) = rewrite_chain_subexpr(&last.expr, context, shape) {
// We allow overflowing here only if both of the following conditions match:
// 1. The entire chain fits in a single line except the last child.
// 2. `last_child_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)
let could_fit_single_line = almost_total + first_line_width(&rw) <= one_line_budget;
if could_fit_single_line && line_count >= 5 {
last_subexpr_str = Some(rw);
fits_single_line = 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_chain_subexpr(&last.expr, context, last_shape) {
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)
Some(ref new_rw) if !could_fit_single_line => {
last_subexpr_str = Some(new_rw.clone());
}
Some(ref new_rw) if new_rw.lines().count() >= line_count => {
last_subexpr_str = Some(rw);
fits_single_line = could_fit_single_line;
}
new_rw @ Some(..) => {
last_subexpr_str = new_rw;
}
_ => {
last_subexpr_str = Some(rw);
fits_single_line = could_fit_single_line;
}
new_rw @ Some(..) => (new_rw, false),
_ => (Some(rw), fits_single_line),
}
}
} else {
(rewrite_chain_subexpr(&last.expr, context, last_shape), false)
}
})?
} else {
(rewrite_chain_subexpr(&last.expr, context, last_shape), false)
};
}
}
last_subexpr_str = last_subexpr_str.or_else(|| rewrite_chain_subexpr(&last.expr, context, last_shape));
rewrites.push(last_subexpr_str?);
let connector = if fits_single_line && !parent_rewrite_contains_newline {
@ -481,21 +477,11 @@ fn rewrite_chain_visual(mut chain: Chain, context: &RewriteContext, shape: Shape
other_child_shape.indent.to_string_with_newline(context.config)
};
let result = if is_small_parent && rewrites.len() > 1 {
format!(
"{}{}{}",
parent_rewrite,
rewrites[0],
join_rewrites_vis(&rewrites[1..], &connector),
)
} else {
format!(
"{}{}",
parent_rewrite,
join_rewrites_vis(&rewrites, &connector),
)
};
let result = format!("{}{}", result, "?".repeat(last.tries));
let result = format!("{}{}{}",
parent_rewrite,
join_rewrites_vis(&rewrites, &connector),
"?".repeat(last.tries),
);
wrap_str(result, context.config.max_width(), shape)
}