A basic impl of Rewrite for ast::Expr

This commit is contained in:
Gaëtan Cassiers 2015-06-16 17:29:05 +02:00
parent c10bfecdc2
commit c012d311c4
4 changed files with 233 additions and 189 deletions

View File

@ -8,9 +8,9 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use visitor::FmtVisitor;
use utils::*;
use lists::{write_list, ListFormatting, SeparatorTactic, ListTactic};
use rewrite::{Rewrite, RewriteContext};
use syntax::{ast, ptr};
use syntax::codemap::{Pos, Span};
@ -19,194 +19,246 @@ use syntax::print::pprust;
use MIN_STRING;
impl<'a> FmtVisitor<'a> {
fn rewrite_string_lit(&mut self, s: &str, span: Span, width: usize, offset: usize) -> String {
// FIXME I bet this stomps unicode escapes in the source string
// Check if there is anything to fix: we always try to fixup multi-line
// strings, or if the string is too long for the line.
let l_loc = self.codemap.lookup_char_pos(span.lo);
let r_loc = self.codemap.lookup_char_pos(span.hi);
if l_loc.line == r_loc.line && r_loc.col.to_usize() <= config!(max_width) {
return self.snippet(span);
}
// TODO if lo.col > IDEAL - 10, start a new line (need cur indent for that)
let s = s.escape_default();
let offset = offset + 1;
let indent = make_indent(offset);
let indent = &indent;
let mut cur_start = 0;
let mut result = String::with_capacity(round_up_to_power_of_two(s.len()));
result.push('"');
loop {
let max_chars = if cur_start == 0 {
// First line.
width - 2 // 2 = " + \
} else {
config!(max_width) - offset - 1 // 1 = either \ or ;
};
let mut cur_end = cur_start + max_chars;
if cur_end >= s.len() {
result.push_str(&s[cur_start..]);
break;
}
// Make sure we're on a char boundary.
cur_end = next_char(&s, cur_end);
// Push cur_end left until we reach whitespace
while !s.char_at(cur_end-1).is_whitespace() {
cur_end = prev_char(&s, cur_end);
if cur_end - cur_start < MIN_STRING {
// We can't break at whitespace, fall back to splitting
// anywhere that doesn't break an escape sequence
cur_end = next_char(&s, cur_start + max_chars);
while s.char_at(prev_char(&s, cur_end)) == '\\' {
cur_end = prev_char(&s, cur_end);
impl Rewrite for ast::Expr {
fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String> {
match self.node {
ast::Expr_::ExprLit(ref l) => {
match l.node {
ast::Lit_::LitStr(ref is, _) => {
let result = rewrite_string_lit(context, &is, l.span, width, offset);
debug!("string lit: `{:?}`", result);
return result;
}
break;
_ => {}
}
}
// Make sure there is no whitespace to the right of the break.
while cur_end < s.len() && s.char_at(cur_end).is_whitespace() {
cur_end = next_char(&s, cur_end+1);
ast::Expr_::ExprCall(ref callee, ref args) => {
return rewrite_call(context, callee, args, width, offset);
}
result.push_str(&s[cur_start..cur_end]);
result.push_str("\\\n");
result.push_str(indent);
cur_start = cur_end;
ast::Expr_::ExprParen(ref subexpr) => {
return rewrite_paren(context, subexpr, width, offset);
}
ast::Expr_::ExprStruct(ref path, ref fields, ref base) => {
return rewrite_struct_lit(context, path,
fields,
base.as_ref().map(|e| &**e),
width,
offset);
}
ast::Expr_::ExprTup(ref items) => {
return rewrite_tuple_lit(context, items, width, offset);
}
_ => {}
}
result.push('"');
result
context.codemap.span_to_snippet(self.span).ok()
}
}
fn rewrite_string_lit(context: &RewriteContext, s: &str, span: Span, width: usize, offset: usize) -> Option<String> {
// FIXME I bet this stomps unicode escapes in the source string
// Check if there is anything to fix: we always try to fixup multi-line
// strings, or if the string is too long for the line.
let l_loc = context.codemap.lookup_char_pos(span.lo);
let r_loc = context.codemap.lookup_char_pos(span.hi);
if l_loc.line == r_loc.line && r_loc.col.to_usize() <= config!(max_width) {
return context.codemap.span_to_snippet(span).ok();
}
fn rewrite_call(&mut self,
// TODO if lo.col > IDEAL - 10, start a new line (need cur indent for that)
let s = s.escape_default();
let offset = offset + 1;
let indent = make_indent(offset);
let indent = &indent;
let mut cur_start = 0;
let mut result = String::with_capacity(round_up_to_power_of_two(s.len()));
result.push('"');
loop {
let max_chars = if cur_start == 0 {
// First line.
width - 2 // 2 = " + \
} else {
config!(max_width) - offset - 1 // 1 = either \ or ;
};
let mut cur_end = cur_start + max_chars;
if cur_end >= s.len() {
result.push_str(&s[cur_start..]);
break;
}
// Make sure we're on a char boundary.
cur_end = next_char(&s, cur_end);
// Push cur_end left until we reach whitespace
while !s.char_at(cur_end-1).is_whitespace() {
cur_end = prev_char(&s, cur_end);
if cur_end - cur_start < MIN_STRING {
// We can't break at whitespace, fall back to splitting
// anywhere that doesn't break an escape sequence
cur_end = next_char(&s, cur_start + max_chars);
while s.char_at(prev_char(&s, cur_end)) == '\\' {
cur_end = prev_char(&s, cur_end);
}
break;
}
}
// Make sure there is no whitespace to the right of the break.
while cur_end < s.len() && s.char_at(cur_end).is_whitespace() {
cur_end = next_char(&s, cur_end+1);
}
result.push_str(&s[cur_start..cur_end]);
result.push_str("\\\n");
result.push_str(indent);
cur_start = cur_end;
}
result.push('"');
Some(result)
}
fn rewrite_call(context: &RewriteContext,
callee: &ast::Expr,
args: &[ptr::P<ast::Expr>],
width: usize,
offset: usize)
-> String
{
debug!("rewrite_call, width: {}, offset: {}", width, offset);
-> Option<String>
{
debug!("rewrite_call, width: {}, offset: {}", width, offset);
// TODO using byte lens instead of char lens (and probably all over the place too)
let callee_str = self.rewrite_expr(callee, width, offset);
debug!("rewrite_call, callee_str: `{}`", callee_str);
// 2 is for parens.
let remaining_width = width - callee_str.len() - 2;
let offset = callee_str.len() + 1 + offset;
let arg_count = args.len();
// TODO using byte lens instead of char lens (and probably all over the place too)
let callee_str = match callee.rewrite(context, width, offset) {
Some(s) => s,
None => { return None; }
};
debug!("rewrite_call, callee_str: `{:?}`", callee_str);
// 2 is for parens.
let remaining_width = width - callee_str.len() - 2;
let offset = callee_str.len() + 1 + offset;
let arg_count = args.len();
let args_str = if arg_count > 0 {
let args: Vec<_> = args.iter().map(|e| (self.rewrite_expr(e,
remaining_width,
offset), String::new())).collect();
let fmt = ListFormatting {
tactic: ListTactic::HorizontalVertical,
separator: ",",
trailing_separator: SeparatorTactic::Never,
indent: offset,
h_width: remaining_width,
v_width: remaining_width,
};
write_list(&args, &fmt)
} else {
String::new()
let args_str = if arg_count > 0 {
let mut args_rewritten = Vec::with_capacity(args.len());
for arg in args.iter() {
match arg.rewrite(context, remaining_width, offset) {
Some(s) => { args_rewritten.push((s, String::new())); }
None => { return None; }
}
}
let fmt = ListFormatting {
tactic: ListTactic::HorizontalVertical,
separator: ",",
trailing_separator: SeparatorTactic::Never,
indent: offset,
h_width: remaining_width,
v_width: remaining_width,
};
write_list(&args_rewritten, &fmt)
} else {
String::new()
};
format!("{}({})", callee_str, args_str)
}
Some(format!("{}({})", callee_str, args_str))
}
fn rewrite_paren(&mut self, subexpr: &ast::Expr, width: usize, offset: usize) -> String {
debug!("rewrite_paren, width: {}, offset: {}", width, offset);
// 1 is for opening paren, 2 is for opening+closing, we want to keep the closing
// paren on the same line as the subexpr
let subexpr_str = self.rewrite_expr(subexpr, width-2, offset+1);
debug!("rewrite_paren, subexpr_str: `{}`", subexpr_str);
format!("({})", subexpr_str)
}
fn rewrite_paren(context: &RewriteContext, subexpr: &ast::Expr, width: usize, offset: usize) -> Option<String> {
debug!("rewrite_paren, width: {}, offset: {}", width, offset);
// 1 is for opening paren, 2 is for opening+closing, we want to keep the closing
// paren on the same line as the subexpr
let subexpr_str = subexpr.rewrite(context, width-2, offset+1);
debug!("rewrite_paren, subexpr_str: `{:?}`", subexpr_str);
subexpr_str.map(|s| format!("({})", s))
}
fn rewrite_struct_lit(&mut self,
fn rewrite_struct_lit(context: &RewriteContext,
path: &ast::Path,
fields: &[ast::Field],
base: Option<&ast::Expr>,
width: usize,
offset: usize)
-> String
{
debug!("rewrite_struct_lit: width {}, offset {}", width, offset);
assert!(fields.len() > 0 || base.is_some());
-> Option<String>
{
debug!("rewrite_struct_lit: width {}, offset {}", width, offset);
assert!(fields.len() > 0 || base.is_some());
let path_str = pprust::path_to_string(path);
// Foo { a: Foo } - indent is +3, width is -5.
let indent = offset + path_str.len() + 3;
let budget = width - (path_str.len() + 5);
let path_str = pprust::path_to_string(path);
// Foo { a: Foo } - indent is +3, width is -5.
let indent = offset + path_str.len() + 3;
let budget = width - (path_str.len() + 5);
let mut field_strs: Vec<_> =
fields.iter().map(|f| self.rewrite_field(f, budget, indent)).collect();
if let Some(expr) = base {
// Another 2 on the width/indent for the ..
field_strs.push(format!("..{}", self.rewrite_expr(expr, budget - 2, indent + 2)))
let mut field_strs = Vec::with_capacity(fields.len());
for field in fields.iter() {
match rewrite_field(context, field, budget, indent) {
Some(s) => { field_strs.push(s); }
None => { return None; }
}
}
if let Some(expr) = base {
// Another 2 on the width/indent for the ..
field_strs.push(match expr.rewrite(context, budget - 2, indent + 2) {
Some(s) => format!("..{}", s),
None => { return None; }
});
}
// FIXME comments
let field_strs: Vec<_> = field_strs.into_iter().map(|s| (s, String::new())).collect();
let fmt = ListFormatting {
tactic: ListTactic::HorizontalVertical,
separator: ",",
trailing_separator: if base.is_some() {
SeparatorTactic::Never
} else {
config!(struct_lit_trailing_comma)
},
indent: indent,
h_width: budget,
v_width: budget,
};
let fields_str = write_list(&field_strs, &fmt);
format!("{} {{ {} }}", path_str, fields_str)
// FIXME comments
let field_strs: Vec<_> = field_strs.into_iter().map(|s| (s, String::new())).collect();
let fmt = ListFormatting {
tactic: ListTactic::HorizontalVertical,
separator: ",",
trailing_separator: if base.is_some() {
SeparatorTactic::Never
} else {
config!(struct_lit_trailing_comma)
},
indent: indent,
h_width: budget,
v_width: budget,
};
let fields_str = write_list(&field_strs, &fmt);
Some(format!("{} {{ {} }}", path_str, fields_str))
// FIXME if the usual multi-line layout is too wide, we should fall back to
// Foo {
// a: ...,
// }
}
}
fn rewrite_field(&mut self, field: &ast::Field, width: usize, offset: usize) -> String {
let name = &token::get_ident(field.ident.node);
let overhead = name.len() + 2;
let expr = self.rewrite_expr(&field.expr, width - overhead, offset + overhead);
format!("{}: {}", name, expr)
}
fn rewrite_field(context: &RewriteContext, field: &ast::Field, width: usize, offset: usize) -> Option<String> {
let name = &token::get_ident(field.ident.node);
let overhead = name.len() + 2;
let expr = field.expr.rewrite(context, width - overhead, offset + overhead);
expr.map(|s| format!("{}: {}", name, s))
}
fn rewrite_tuple_lit(&mut self, items: &[ptr::P<ast::Expr>], width: usize, offset: usize)
-> String {
fn rewrite_tuple_lit(context: &RewriteContext, items: &[ptr::P<ast::Expr>], width: usize, offset: usize)
-> Option<String> {
// opening paren
let indent = offset + 1;
// In case of length 1, need a trailing comma
if items.len() == 1 {
return format!("({},)", self.rewrite_expr(&*items[0], width - 3, indent));
return items[0].rewrite(context, width - 3, indent).map(|s| format!("({},)", s));
}
// Only last line has width-1 as budget, other may take max_width
let item_strs: Vec<_> =
items.iter()
.enumerate()
.map(|(i, item)| self.rewrite_expr(
item,
// last line : given width (minus "("+")"), other lines : max_width
// (minus "("+","))
if i == items.len() - 1 { width - 2 } else { config!(max_width) - indent - 2 },
indent))
.collect();
let mut item_strs = Vec::with_capacity(items.len());
for (i, item) in items.iter().enumerate() {
let rem_width = if i == items.len() - 1 {
width - 2
} else {
config!(max_width) - indent - 2
};
match item.rewrite(context, rem_width, indent) {
Some(s) => { item_strs.push(s); }
None => {return None; }
}
}
let tactics = if item_strs.iter().any(|s| s.contains('\n')) {
ListTactic::Vertical
} else {
@ -223,41 +275,5 @@ impl<'a> FmtVisitor<'a> {
v_width: width - 2,
};
let item_str = write_list(&item_strs, &fmt);
format!("({})", item_str)
Some(format!("({})", item_str))
}
pub fn rewrite_expr(&mut self, expr: &ast::Expr, width: usize, offset: usize) -> String {
match expr.node {
ast::Expr_::ExprLit(ref l) => {
match l.node {
ast::Lit_::LitStr(ref is, _) => {
let result = self.rewrite_string_lit(&is, l.span, width, offset);
debug!("string lit: `{}`", result);
return result;
}
_ => {}
}
}
ast::Expr_::ExprCall(ref callee, ref args) => {
return self.rewrite_call(callee, args, width, offset);
}
ast::Expr_::ExprParen(ref subexpr) => {
return self.rewrite_paren(subexpr, width, offset);
}
ast::Expr_::ExprStruct(ref path, ref fields, ref base) => {
return self.rewrite_struct_lit(path,
fields,
base.as_ref().map(|e| &**e),
width,
offset);
}
ast::Expr_::ExprTup(ref items) => {
return self.rewrite_tuple_lit(items, width, offset);
}
_ => {}
}
self.snippet(expr.span)
}
}

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@ -59,6 +59,7 @@ mod types;
mod expr;
mod imports;
mod issues;
mod rewrite;
const MIN_STRING: usize = 10;
// When we get scoped annotations, we should have rustfmt::skip.

19
src/rewrite.rs Normal file
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@ -0,0 +1,19 @@
// Copyright 2015 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 syntax::codemap::CodeMap;
pub trait Rewrite {
fn rewrite(&self, context: &RewriteContext, width: usize, offset: usize) -> Option<String>;
}
pub struct RewriteContext<'a> {
pub codemap: &'a CodeMap,
}

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@ -16,6 +16,7 @@ use utils;
use SKIP_ANNOTATION;
use changes::ChangeSet;
use rewrite::{Rewrite, RewriteContext};
pub struct FmtVisitor<'a> {
pub codemap: &'a CodeMap,
@ -32,9 +33,16 @@ impl<'a, 'v> visit::Visitor<'v> for FmtVisitor<'a> {
self.codemap.lookup_char_pos(ex.span.hi));
self.format_missing(ex.span.lo);
let offset = self.changes.cur_offset_span(ex.span);
let new_str = self.rewrite_expr(ex, config!(max_width) - offset, offset);
self.changes.push_str_span(ex.span, &new_str);
self.last_pos = ex.span.hi;
match ex.rewrite(&RewriteContext { codemap: self.codemap },
config!(max_width) - offset,
offset) {
Some(new_str) => {
//let new_str = self.rewrite_expr(ex, config!(max_width) - offset, offset);
self.changes.push_str_span(ex.span, &new_str);
self.last_pos = ex.span.hi;
}
None => { self.last_pos = ex.span.lo; }
}
}
fn visit_stmt(&mut self, stmt: &'v ast::Stmt) {