Merge pull request #2221 from topecongiro/rfc/blank-lines

Keep vertical spaces between items or statements within range

Author: nrc

build.rs

@@ -14,7 +14,6 @@ use std::io::Write;
 use std::path::PathBuf;
 use std::process::Command;
 
-
 fn main() {
     let out_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
 

src/bin/git-fmt.rs

@@ -14,7 +14,6 @@ use getopts::{Matches, Options};
 use rustfmt::{run, Input};
 use rustfmt::config;
 
-
 fn prune_files(files: Vec<&str>) -> Vec<&str> {
     let prefixes: Vec<_> = files
         .iter()

src/bin/rustfmt.rs

@@ -10,7 +10,6 @@
 
 #![cfg(not(test))]
 
-
 extern crate env_logger;
 extern crate getopts;
 extern crate rustfmt_nightly as rustfmt;

src/closures.rs

@@ -31,7 +31,6 @@ use utils::{last_line_width, left_most_sub_expr, stmt_expr};
 //     statement without needing a semi-colon), then adding or removing braces
 //     can change whether it is treated as an expression or statement.
 
-
 pub fn rewrite_closure(
     capture: ast::CaptureBy,
     fn_decl: &ast::FnDecl,

src/comment.rs

@@ -18,7 +18,7 @@ use config::Config;
 use rewrite::RewriteContext;
 use shape::{Indent, Shape};
 use string::{rewrite_string, StringFormat};
-use utils::{first_line_width, last_line_width};
+use utils::{count_newlines, first_line_width, last_line_width};
 
 fn is_custom_comment(comment: &str) -> bool {
     if !comment.starts_with("//") {
@@ -292,7 +292,7 @@ fn rewrite_comment_inner(
         config: config,
     };
 
-    let line_breaks = orig.trim_right().chars().filter(|&c| c == '\n').count();
+    let line_breaks = count_newlines(orig.trim_right());
     let lines = orig.lines()
         .enumerate()
         .map(|(i, mut line)| {
@@ -829,9 +829,6 @@ impl<'a> Iterator for UngroupedCommentCodeSlices<'a> {
     }
 }
 
-
-
-
 /// Iterator over an alternating sequence of functional and commented parts of
 /// a string. The first item is always a, possibly zero length, subslice of
 /// functional text. Line style comments contain their ending newlines.
@@ -953,7 +950,6 @@ fn changed_comment_content(orig: &str, new: &str) -> bool {
     res
 }
 
-
 /// Iterator over the 'payload' characters of a comment.
 /// It skips whitespace, comment start/end marks, and '*' at the beginning of lines.
 /// The comment must be one comment, ie not more than one start mark (no multiple line comments,
@@ -999,7 +995,6 @@ impl<'a> Iterator for CommentReducer<'a> {
     }
 }
 
-
 fn remove_comment_header(comment: &str) -> &str {
     if comment.starts_with("///") || comment.starts_with("//!") {
         &comment[3..]

src/config.rs

@@ -21,7 +21,6 @@ use file_lines::FileLines;
 use lists::{ListTactic, SeparatorPlace, SeparatorTactic};
 use Summary;
 
-
 macro_rules! is_nightly_channel {
     () => {
         option_env!("CFG_RELEASE_CHANNEL")
@@ -88,7 +87,6 @@ configuration_option_enum! { TypeDensity:
     Wide,
 }
 
-
 impl Density {
     pub fn to_list_tactic(self) -> ListTactic {
         match self {
@@ -579,8 +577,6 @@ pub fn get_toml_path(dir: &Path) -> Result<Option<PathBuf>, Error> {
     Ok(None)
 }
 
-
-
 create_config! {
     // Fundamental stuff
     max_width: usize, 100, true, "Maximum width of each line";
@@ -651,6 +647,10 @@ create_config! {
         "Add trailing semicolon after break, continue and return";
     match_block_trailing_comma: bool, false, false,
         "Put a trailing comma after a block based match arm (non-block arms are not affected)";
+    blank_lines_upper_bound: usize, 1, false,
+        "Maximum number of blank lines which can be put between items.";
+    blank_lines_lower_bound: usize, 0, false,
+        "Minimum number of blank lines which must be put between items.";
 
     // Options that can change the source code beyond whitespace/blocks (somewhat linty things)
     merge_derives: bool, true, true, "Merge multiple `#[derive(...)]` into a single one";

src/expr.rs

@@ -2807,12 +2807,8 @@ pub fn choose_rhs<R: Rewrite>(
 }
 
 fn prefer_next_line(orig_rhs: &str, next_line_rhs: &str) -> bool {
-    fn count_line_breaks(src: &str) -> usize {
-        src.chars().filter(|&x| x == '\n').count()
-    }
-
-    !next_line_rhs.contains('\n')
-        || count_line_breaks(orig_rhs) > count_line_breaks(next_line_rhs) + 1
+    use utils::count_newlines;
+    !next_line_rhs.contains('\n') || count_newlines(orig_rhs) > count_newlines(next_line_rhs) + 1
 }
 
 fn rewrite_expr_addrof(

src/filemap.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-
 // TODO: add tests
 
 use std::fs::{self, File};

src/imports.rs

@@ -13,7 +13,6 @@ use std::cmp::Ordering;
 use syntax::ast;
 use syntax::codemap::{BytePos, Span};
 
-
 use spanned::Spanned;
 use codemap::SpanUtils;
 use comment::combine_strs_with_missing_comments;

src/items.rs

@@ -283,7 +283,6 @@ impl<'a> FmtVisitor<'a> {
         self.format_item(item);
     }
 
-
     fn format_foreign_item(&mut self, item: &ast::ForeignItem) {
         let rewrite = item.rewrite(&self.get_context(), self.shape());
         self.push_rewrite(item.span(), rewrite);

src/lists.rs

@@ -17,7 +17,7 @@ use comment::{find_comment_end, rewrite_comment, FindUncommented};
 use config::{Config, IndentStyle};
 use rewrite::RewriteContext;
 use shape::{Indent, Shape};
-use utils::{first_line_width, last_line_width, mk_sp, starts_with_newline};
+use utils::{count_newlines, first_line_width, last_line_width, mk_sp, starts_with_newline};
 
 /// Formatting tactic for lists. This will be cast down to a
 /// `DefinitiveListTactic` depending on the number and length of the items and
@@ -677,7 +677,7 @@ where
                 // From the end of the first line of comments to the next non-whitespace char.
                 let test_snippet = &test_snippet[..first];
 
-                if test_snippet.chars().filter(|c| c == &'\n').count() > 1 {
+                if count_newlines(test_snippet) > 1 {
                     // There were multiple line breaks which got trimmed to nothing.
                     new_lines = true;
                 }