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Add option to vertically align enum discriminants.

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This commit is contained in:
moxian 2018-06-29 06:47:51 +00:00
parent 90692a5917
commit cc22869fb4
5 changed files with 134 additions and 3 deletions
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2
src/config/mod.rs
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@ -89,6 +89,8 @@ create_config! {
combine_control_expr: bool, true, false, "Combine control expressions with function calls";
struct_field_align_threshold: usize, 0, false, "Align struct fields if their diffs fits within \
threshold";
enum_discrim_align_threshold: usize, 0, false,
"Align enum variants discrims, if their diffs fit within threshold";
match_arm_blocks: bool, true, false, "Wrap the body of arms in blocks when it does not fit on \
the same line with the pattern of arms";
force_multiline_blocks: bool, false, false,

33
src/items.rs
View file

@ -500,6 +500,24 @@ impl<'a> FmtVisitor<'a> {
let original_offset = self.block_indent;
self.block_indent = self.block_indent.block_indent(self.config);
// If enum variants have discriminants, try to vertically align those,
// provided it does not result in too much padding
let pad_discrim_ident_to;
let diff_threshold = self.config.enum_discrim_align_threshold();
let discr_ident_lens: Vec<_> = enum_def
.variants
.iter()
.filter(|var| var.node.disr_expr.is_some())
.map(|var| rewrite_ident(&self.get_context(), var.node.ident).len())
.collect();
let shortest_w_discr = *discr_ident_lens.iter().min().unwrap_or(&0);
let longest_w_discr = *discr_ident_lens.iter().max().unwrap_or(&0);
if longest_w_discr > shortest_w_discr + diff_threshold {
pad_discrim_ident_to = 0;
} else {
pad_discrim_ident_to = longest_w_discr;
}
let itemize_list_with = |one_line_width: usize| {
itemize_list(
self.snippet_provider,
@ -514,7 +532,7 @@ impl<'a> FmtVisitor<'a> {
}
},
|f| f.span.hi(),
|f| self.format_variant(f, one_line_width),
|f| self.format_variant(f, one_line_width, pad_discrim_ident_to),
body_lo,
body_hi,
false,
@ -543,7 +561,12 @@ impl<'a> FmtVisitor<'a> {
}
// Variant of an enum.
fn format_variant(&self, field: &ast::Variant, one_line_width: usize) -> Option<String> {
fn format_variant(
&self,
field: &ast::Variant,
one_line_width: usize,
pad_discrim_ident_to: usize,
) -> Option<String> {
if contains_skip(&field.node.attrs) {
let lo = field.node.attrs[0].span.lo();
let span = mk_sp(lo, field.span.hi());
@ -570,7 +593,11 @@ impl<'a> FmtVisitor<'a> {
)?,
ast::VariantData::Unit(..) => {
if let Some(ref expr) = field.node.disr_expr {
let lhs = format!("{} =", rewrite_ident(&context, field.node.ident));
let lhs = format!(
"{:1$} =",
rewrite_ident(&context, field.node.ident),
pad_discrim_ident_to
);
rewrite_assign_rhs(&context, lhs, &*expr.value, shape)?
} else {
rewrite_ident(&context, field.node.ident).to_owned()