Move pair handling to its own module

5 files changed, 125 insertions, 109 deletions

diff --git a/src/expr.rs b/src/expr.rs
index d9fa4717357..8f167650507 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -31,6 +31,7 @@ use lists::{
 use macros::{rewrite_macro, MacroArg, MacroPosition};
 use matches::rewrite_match;
 use overflow;
+use pairs::{rewrite_pair, PairParts};
 use patterns::{can_be_overflowed_pat, is_short_pattern, TuplePatField};
 use rewrite::{Rewrite, RewriteContext};
 use shape::{Indent, Shape};
@@ -435,109 +436,6 @@ fn rewrite_simple_binaries(
     None
 }
 
-/// Sigils that decorate a binop pair.
-#[derive(new, Clone, Copy)]
-pub struct PairParts<'a> {
-    prefix: &'a str,
-    infix: &'a str,
-    suffix: &'a str,
-}
-
-impl<'a> PairParts<'a> {
-    pub fn infix(infix: &'a str) -> PairParts<'a> {
-        PairParts {
-            prefix: "",
-            infix,
-            suffix: "",
-        }
-    }
-}
-
-pub fn rewrite_pair<LHS, RHS>(
-    lhs: &LHS,
-    rhs: &RHS,
-    pp: PairParts,
-    context: &RewriteContext,
-    shape: Shape,
-    separator_place: SeparatorPlace,
-) -> Option<String>
-where
-    LHS: Rewrite,
-    RHS: Rewrite,
-{
-    let lhs_overhead = match separator_place {
-        SeparatorPlace::Back => shape.used_width() + pp.prefix.len() + pp.infix.trim_right().len(),
-        SeparatorPlace::Front => shape.used_width(),
-    };
-    let lhs_shape = Shape {
-        width: context.budget(lhs_overhead),
-        ..shape
-    };
-    let lhs_result = lhs
-        .rewrite(context, lhs_shape)
-        .map(|lhs_str| format!("{}{}", pp.prefix, lhs_str))?;
-
-    // Try to put both lhs and rhs on the same line.
-    let rhs_orig_result = shape
-        .offset_left(last_line_width(&lhs_result) + pp.infix.len())
-        .and_then(|s| s.sub_width(pp.suffix.len()))
-        .and_then(|rhs_shape| rhs.rewrite(context, rhs_shape));
-    if let Some(ref rhs_result) = rhs_orig_result {
-        // If the length of the lhs is equal to or shorter than the tab width or
-        // the rhs looks like block expression, we put the rhs on the same
-        // line with the lhs even if the rhs is multi-lined.
-        let allow_same_line = lhs_result.len() <= context.config.tab_spaces()
-            || rhs_result
-                .lines()
-                .next()
-                .map(|first_line| first_line.ends_with('{'))
-                .unwrap_or(false);
-        if !rhs_result.contains('\n') || allow_same_line {
-            let one_line_width = last_line_width(&lhs_result)
-                + pp.infix.len()
-                + first_line_width(rhs_result)
-                + pp.suffix.len();
-            if one_line_width <= shape.width {
-                return Some(format!(
-                    "{}{}{}{}",
-                    lhs_result, pp.infix, rhs_result, pp.suffix
-                ));
-            }
-        }
-    }
-
-    // We have to use multiple lines.
-    // Re-evaluate the rhs because we have more space now:
-    let mut rhs_shape = match context.config.indent_style() {
-        IndentStyle::Visual => shape
-            .sub_width(pp.suffix.len() + pp.prefix.len())?
-            .visual_indent(pp.prefix.len()),
-        IndentStyle::Block => {
-            // Try to calculate the initial constraint on the right hand side.
-            let rhs_overhead = shape.rhs_overhead(context.config);
-            Shape::indented(shape.indent.block_indent(context.config), context.config)
-                .sub_width(rhs_overhead)?
-        }
-    };
-    let infix = match separator_place {
-        SeparatorPlace::Back => pp.infix.trim_right(),
-        SeparatorPlace::Front => pp.infix.trim_left(),
-    };
-    if separator_place == SeparatorPlace::Front {
-        rhs_shape = rhs_shape.offset_left(infix.len())?;
-    }
-    let rhs_result = rhs.rewrite(context, rhs_shape)?;
-    let indent_str = rhs_shape.indent.to_string_with_newline(context.config);
-    let infix_with_sep = match separator_place {
-        SeparatorPlace::Back => format!("{}{}", infix, indent_str),
-        SeparatorPlace::Front => format!("{}{}", indent_str, infix),
-    };
-    Some(format!(
-        "{}{}{}{}",
-        lhs_result, infix_with_sep, rhs_result, pp.suffix
-    ))
-}
-
 pub fn rewrite_array<T: Rewrite + Spanned + ToExpr>(
     name: &str,
     exprs: &[&T],
diff --git a/src/lib.rs b/src/lib.rs
index 817ed426e52..2c9a792d92d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -86,6 +86,7 @@ mod matches;
 mod missed_spans;
 pub(crate) mod modules;
 mod overflow;
+mod pairs;
 mod patterns;
 mod reorder;
 mod rewrite;
diff --git a/src/pairs.rs b/src/pairs.rs
new file mode 100644
index 00000000000..55c78b641a0
--- /dev/null
+++ b/src/pairs.rs
@@ -0,0 +1,119 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use config::lists::*;
+
+use config::IndentStyle;
+use rewrite::{Rewrite, RewriteContext};
+use shape::Shape;
+use utils::{first_line_width, last_line_width};
+
+/// Sigils that decorate a binop pair.
+#[derive(new, Clone, Copy)]
+pub struct PairParts<'a> {
+    prefix: &'a str,
+    infix: &'a str,
+    suffix: &'a str,
+}
+
+impl<'a> PairParts<'a> {
+    pub fn infix(infix: &'a str) -> PairParts<'a> {
+        PairParts {
+            prefix: "",
+            infix,
+            suffix: "",
+        }
+    }
+}
+
+pub fn rewrite_pair<LHS, RHS>(
+    lhs: &LHS,
+    rhs: &RHS,
+    pp: PairParts,
+    context: &RewriteContext,
+    shape: Shape,
+    separator_place: SeparatorPlace,
+) -> Option<String>
+where
+    LHS: Rewrite,
+    RHS: Rewrite,
+{
+    let lhs_overhead = match separator_place {
+        SeparatorPlace::Back => shape.used_width() + pp.prefix.len() + pp.infix.trim_right().len(),
+        SeparatorPlace::Front => shape.used_width(),
+    };
+    let lhs_shape = Shape {
+        width: context.budget(lhs_overhead),
+        ..shape
+    };
+    let lhs_result = lhs
+        .rewrite(context, lhs_shape)
+        .map(|lhs_str| format!("{}{}", pp.prefix, lhs_str))?;
+
+    // Try to put both lhs and rhs on the same line.
+    let rhs_orig_result = shape
+        .offset_left(last_line_width(&lhs_result) + pp.infix.len())
+        .and_then(|s| s.sub_width(pp.suffix.len()))
+        .and_then(|rhs_shape| rhs.rewrite(context, rhs_shape));
+    if let Some(ref rhs_result) = rhs_orig_result {
+        // If the length of the lhs is equal to or shorter than the tab width or
+        // the rhs looks like block expression, we put the rhs on the same
+        // line with the lhs even if the rhs is multi-lined.
+        let allow_same_line = lhs_result.len() <= context.config.tab_spaces()
+            || rhs_result
+                .lines()
+                .next()
+                .map(|first_line| first_line.ends_with('{'))
+                .unwrap_or(false);
+        if !rhs_result.contains('\n') || allow_same_line {
+            let one_line_width = last_line_width(&lhs_result)
+                + pp.infix.len()
+                + first_line_width(rhs_result)
+                + pp.suffix.len();
+            if one_line_width <= shape.width {
+                return Some(format!(
+                    "{}{}{}{}",
+                    lhs_result, pp.infix, rhs_result, pp.suffix
+                ));
+            }
+        }
+    }
+
+    // We have to use multiple lines.
+    // Re-evaluate the rhs because we have more space now:
+    let mut rhs_shape = match context.config.indent_style() {
+        IndentStyle::Visual => shape
+            .sub_width(pp.suffix.len() + pp.prefix.len())?
+            .visual_indent(pp.prefix.len()),
+        IndentStyle::Block => {
+            // Try to calculate the initial constraint on the right hand side.
+            let rhs_overhead = shape.rhs_overhead(context.config);
+            Shape::indented(shape.indent.block_indent(context.config), context.config)
+                .sub_width(rhs_overhead)?
+        }
+    };
+    let infix = match separator_place {
+        SeparatorPlace::Back => pp.infix.trim_right(),
+        SeparatorPlace::Front => pp.infix.trim_left(),
+    };
+    if separator_place == SeparatorPlace::Front {
+        rhs_shape = rhs_shape.offset_left(infix.len())?;
+    }
+    let rhs_result = rhs.rewrite(context, rhs_shape)?;
+    let indent_str = rhs_shape.indent.to_string_with_newline(context.config);
+    let infix_with_sep = match separator_place {
+        SeparatorPlace::Back => format!("{}{}", infix, indent_str),
+        SeparatorPlace::Front => format!("{}{}", indent_str, infix),
+    };
+    Some(format!(
+        "{}{}{}{}",
+        lhs_result, infix_with_sep, rhs_result, pp.suffix
+    ))
+}
diff --git a/src/patterns.rs b/src/patterns.rs
index 5e3cbfc31f3..dbe0c8a6f66 100644
--- a/src/patterns.rs
+++ b/src/patterns.rs
@@ -15,15 +15,14 @@ use syntax::ptr;
 
 use codemap::SpanUtils;
 use comment::FindUncommented;
-use expr::{
-    can_be_overflowed_expr, rewrite_pair, rewrite_unary_prefix, wrap_struct_field, PairParts,
-};
+use expr::{can_be_overflowed_expr, rewrite_unary_prefix, wrap_struct_field};
 use lists::{
     itemize_list, shape_for_tactic, struct_lit_formatting, struct_lit_shape, struct_lit_tactic,
     write_list,
 };
 use macros::{rewrite_macro, MacroPosition};
 use overflow;
+use pairs::{rewrite_pair, PairParts};
 use rewrite::{Rewrite, RewriteContext};
 use shape::Shape;
 use spanned::Spanned;
diff --git a/src/types.rs b/src/types.rs
index 42dfd3596c8..0c978ea28a6 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -18,12 +18,11 @@ use syntax::symbol::keywords;
 
 use codemap::SpanUtils;
 use config::{IndentStyle, TypeDensity};
-use expr::{
-    rewrite_assign_rhs, rewrite_pair, rewrite_tuple, rewrite_unary_prefix, PairParts, ToExpr,
-};
+use expr::{rewrite_assign_rhs, rewrite_tuple, rewrite_unary_prefix, ToExpr};
 use lists::{definitive_tactic, itemize_list, write_list, ListFormatting, Separator};
 use macros::{rewrite_macro, MacroPosition};
 use overflow;
+use pairs::{rewrite_pair, PairParts};
 use rewrite::{Rewrite, RewriteContext};
 use shape::Shape;
 use spanned::Spanned;