Merge #5722

5722: Replace SepBy with Itertools

 r=matklad a=matklad

bors r+
🤖

Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>

crates/ra_assists/src/handlers/add_custom_impl.rs

@@ -1,10 +1,10 @@
+use itertools::Itertools;
 use ra_syntax::{
     ast::{self, AstNode},
     Direction, SmolStr,
     SyntaxKind::{IDENT, WHITESPACE},
     TextRange, TextSize,
 };
-use stdx::SepBy;
 
 use crate::{
     assist_context::{AssistContext, Assists},
@@ -61,9 +61,9 @@ pub(crate) fn add_custom_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<
             .filter(|t| t != trait_token.text())
             .collect::<Vec<SmolStr>>();
         let has_more_derives = !new_attr_input.is_empty();
-        let new_attr_input = new_attr_input.iter().sep_by(", ").surround_with("(", ")").to_string();
 
         if has_more_derives {
+            let new_attr_input = format!("({})", new_attr_input.iter().format(", "));
             builder.replace(input.syntax().text_range(), new_attr_input);
         } else {
             let attr_range = attr.syntax().text_range();

crates/ra_assists/src/handlers/generate_impl.rs

@@ -1,5 +1,6 @@
+use itertools::Itertools;
 use ra_syntax::ast::{self, AstNode, GenericParamsOwner, NameOwner};
-use stdx::{format_to, SepBy};
+use stdx::format_to;
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};
 
@@ -50,7 +51,7 @@ pub(crate) fn generate_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<()
                     .filter_map(|it| it.name())
                     .map(|it| it.text().clone());
 
-                let generic_params = lifetime_params.chain(type_params).sep_by(", ");
+                let generic_params = lifetime_params.chain(type_params).format(", ");
                 format_to!(buf, "<{}>", generic_params)
             }
             match ctx.config.snippet_cap {

crates/ra_assists/src/handlers/generate_new.rs

@@ -1,9 +1,10 @@
 use hir::Adt;
+use itertools::Itertools;
 use ra_syntax::{
     ast::{self, AstNode, GenericParamsOwner, NameOwner, StructKind, VisibilityOwner},
     T,
 };
-use stdx::{format_to, SepBy};
+use stdx::format_to;
 
 use crate::{AssistContext, AssistId, AssistKind, Assists};
 
@@ -52,8 +53,8 @@ pub(crate) fn generate_new(acc: &mut Assists, ctx: &AssistContext) -> Option<()>
         let params = field_list
             .fields()
             .filter_map(|f| Some(format!("{}: {}", f.name()?.syntax(), f.ty()?.syntax())))
-            .sep_by(", ");
-        let fields = field_list.fields().filter_map(|f| f.name()).sep_by(", ");
+            .format(", ");
+        let fields = field_list.fields().filter_map(|f| f.name()).format(", ");
 
         format_to!(buf, "    {}fn new({}) -> Self {{ Self {{ {} }} }}", vis, params, fields);
 
@@ -102,7 +103,7 @@ fn generate_impl_text(strukt: &ast::Struct, code: &str) -> String {
             .map(|it| it.text().clone());
         let type_params =
             type_params.type_params().filter_map(|it| it.name()).map(|it| it.text().clone());
-        format_to!(buf, "<{}>", lifetime_params.chain(type_params).sep_by(", "))
+        format_to!(buf, "<{}>", lifetime_params.chain(type_params).format(", "))
     }
 
     format_to!(buf, " {{\n{}\n}}\n", code);

crates/ra_ide/src/completion/presentation.rs

@@ -2,8 +2,8 @@
 //! It also handles scoring (sorting) completions.
 
 use hir::{Docs, HasAttrs, HasSource, HirDisplay, ModPath, ScopeDef, StructKind, Type};
+use itertools::Itertools;
 use ra_syntax::ast::NameOwner;
-use stdx::SepBy;
 use test_utils::mark;
 
 use crate::{
@@ -289,16 +289,16 @@ impl Completions {
             .map(|field| (field.name(ctx.db), field.signature_ty(ctx.db)));
         let variant_kind = variant.kind(ctx.db);
         let detail = match variant_kind {
-            StructKind::Tuple | StructKind::Unit => detail_types
-                .map(|(_, t)| t.display(ctx.db).to_string())
-                .sep_by(", ")
-                .surround_with("(", ")")
-                .to_string(),
-            StructKind::Record => detail_types
+            StructKind::Tuple | StructKind::Unit => format!(
+                "({})",
+                detail_types.map(|(_, t)| t.display(ctx.db).to_string()).format(", ")
+            ),
+            StructKind::Record => format!(
+                "{{ {} }}",
+                detail_types
                     .map(|(n, t)| format!("{}: {}", n, t.display(ctx.db).to_string()))
-                .sep_by(", ")
-                .surround_with("{ ", " }")
-                .to_string(),
+                    .format(", ")
+            ),
         };
         let mut res = CompletionItem::new(
             CompletionKind::Reference,
@@ -412,11 +412,10 @@ impl Builder {
             self = self.trigger_call_info();
             let snippet = match (ctx.config.add_call_argument_snippets, params) {
                 (true, Params::Named(params)) => {
-                    let function_params_snippet = params
-                        .iter()
-                        .enumerate()
-                        .map(|(index, param_name)| format!("${{{}:{}}}", index + 1, param_name))
-                        .sep_by(", ");
+                    let function_params_snippet =
+                        params.iter().enumerate().format_with(", ", |(index, param_name), f| {
+                            f(&format_args!("${{{}:{}}}", index + 1, param_name))
+                        });
                     format!("{}({})$0", name, function_params_snippet)
                 }
                 _ => {

crates/ra_ide/src/syntax_highlighting/injection.rs

@@ -4,8 +4,8 @@ use std::{collections::BTreeMap, convert::TryFrom};
 
 use ast::{HasQuotes, HasStringValue};
 use hir::Semantics;
+use itertools::Itertools;
 use ra_syntax::{ast, AstToken, SyntaxNode, SyntaxToken, TextRange, TextSize};
-use stdx::SepBy;
 
 use crate::{
     call_info::ActiveParameter, Analysis, Highlight, HighlightModifier, HighlightTag,
@@ -129,8 +129,7 @@ pub(super) fn extract_doc_comments(
 
             line[pos..].to_owned()
         })
-        .sep_by("\n")
-        .to_string();
+        .join("\n");
 
     if doctest.is_empty() {
         return None;

crates/ra_syntax/src/ast/traits.rs

@@ -1,7 +1,7 @@
 //! Various traits that are implemented by ast nodes.
 //!
 //! The implementations are usually trivial, and live in generated.rs
-use stdx::SepBy;
+use itertools::Itertools;
 
 use crate::{
     ast::{self, support, AstChildren, AstNode, AstToken},
@@ -119,8 +119,7 @@ impl CommentIter {
                 // of a line in markdown.
                 line[pos..end].to_owned()
             })
-            .sep_by("\n")
-            .to_string();
+            .join("\n");
 
         if has_comments {
             Some(docs)

crates/stdx/src/lib.rs

@@ -1,5 +1,5 @@
 //! Missing batteries for standard libraries.
-use std::{cell::Cell, fmt, time::Instant};
+use std::time::Instant;
 
 mod macros;
 
@@ -8,69 +8,6 @@ pub fn is_ci() -> bool {
     option_env!("CI").is_some()
 }
 
-pub trait SepBy: Sized {
-    /// Returns an `impl fmt::Display`, which joins elements via a separator.
-    fn sep_by(self, sep: &str) -> SepByBuilder<'_, Self>;
-}
-
-impl<I> SepBy for I
-where
-    I: Iterator,
-    I::Item: fmt::Display,
-{
-    fn sep_by(self, sep: &str) -> SepByBuilder<'_, Self> {
-        SepByBuilder::new(sep, self)
-    }
-}
-
-pub struct SepByBuilder<'a, I> {
-    sep: &'a str,
-    prefix: &'a str,
-    suffix: &'a str,
-    iter: Cell<Option<I>>,
-}
-
-impl<'a, I> SepByBuilder<'a, I> {
-    fn new(sep: &'a str, iter: I) -> SepByBuilder<'a, I> {
-        SepByBuilder { sep, prefix: "", suffix: "", iter: Cell::new(Some(iter)) }
-    }
-
-    pub fn prefix(mut self, prefix: &'a str) -> Self {
-        self.prefix = prefix;
-        self
-    }
-
-    pub fn suffix(mut self, suffix: &'a str) -> Self {
-        self.suffix = suffix;
-        self
-    }
-
-    /// Set both suffix and prefix.
-    pub fn surround_with(self, prefix: &'a str, suffix: &'a str) -> Self {
-        self.prefix(prefix).suffix(suffix)
-    }
-}
-
-impl<I> fmt::Display for SepByBuilder<'_, I>
-where
-    I: Iterator,
-    I::Item: fmt::Display,
-{
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        f.write_str(self.prefix)?;
-        let mut first = true;
-        for item in self.iter.take().unwrap() {
-            if !first {
-                f.write_str(self.sep)?;
-            }
-            first = false;
-            fmt::Display::fmt(&item, f)?;
-        }
-        f.write_str(self.suffix)?;
-        Ok(())
-    }
-}
-
 #[must_use]
 pub fn timeit(label: &'static str) -> impl Drop {
     struct Guard {