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syntax: Join consecutive string literals in format strings together

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Emit a single rt::Piece per consecutive string literals. String literals
are split on {{ or }} escapes.

Saves a small amount of static storage and emitted code size.
This commit is contained in:
root 2014-07-20 16:31:43 +02:00 committed by Alex Crichton
parent 2357c443e0
commit 0e1880d8fe
1 changed files with 33 additions and 10 deletions
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43
src/libsyntax/ext/format.rs
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@ -49,6 +49,9 @@ struct Context<'a, 'b> {
name_types: HashMap<String, ArgumentType>,
name_ordering: Vec<String>,
/// The latest consecutive literal strings
literal: Option<String>,
/// Collection of the compiled `rt::Piece` structures
pieces: Vec<Gc<ast::Expr>>,
name_positions: HashMap<String, uint>,
@ -362,17 +365,29 @@ impl<'a, 'b> Context<'a, 'b> {
}
}
/// Translate the accumulated string literals to a static `rt::Piece`
fn trans_literal_string(&mut self) -> Option<Gc<ast::Expr>> {
let sp = self.fmtsp;
self.literal.take().map(|s| {
let s = token::intern_and_get_ident(s.as_slice());
self.ecx.expr_call_global(sp,
self.rtpath("String"),
vec!(
self.ecx.expr_str(sp, s)
))
})
}
/// Translate a `parse::Piece` to a static `rt::Piece`
fn trans_piece(&mut self, piece: &parse::Piece) -> Gc<ast::Expr> {
fn trans_piece(&mut self, piece: &parse::Piece) -> Option<Gc<ast::Expr>> {
let sp = self.fmtsp;
match *piece {
parse::String(s) => {
let s = token::intern_and_get_ident(s);
self.ecx.expr_call_global(sp,
self.rtpath("String"),
vec!(
self.ecx.expr_str(sp, s)
))
match self.literal {
Some(ref mut sb) => sb.push_str(s),
ref mut empty => *empty = Some(String::from_str(s)),
}
None
}
parse::Argument(ref arg) => {
// Translate the position
@ -430,7 +445,7 @@ impl<'a, 'b> Context<'a, 'b> {
let s = self.ecx.expr_struct(sp, path, vec!(
self.ecx.field_imm(sp, self.ecx.ident_of("position"), pos),
self.ecx.field_imm(sp, self.ecx.ident_of("format"), fmt)));
self.ecx.expr_call_global(sp, self.rtpath("Argument"), vec!(s))
Some(self.ecx.expr_call_global(sp, self.rtpath("Argument"), vec!(s)))
}
}
}
@ -694,6 +709,7 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt, sp: Span,
name_ordering: name_ordering,
nest_level: 0,
next_arg: 0,
literal: None,
pieces: Vec::new(),
method_statics: Vec::new(),
fmtsp: sp,
@ -712,8 +728,14 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt, sp: Span,
Some(piece) => {
if parser.errors.len() > 0 { break }
cx.verify_piece(&piece);
let piece = cx.trans_piece(&piece);
cx.pieces.push(piece);
match cx.trans_piece(&piece) {
Some(piece) => {
cx.trans_literal_string().map(|piece|
cx.pieces.push(piece));
cx.pieces.push(piece);
}
None => {}
}
}
None => break
}
@ -727,6 +749,7 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt, sp: Span,
}
None => {}
}
cx.trans_literal_string().map(|piece| cx.pieces.push(piece));
// Make sure that all arguments were used and all arguments have types.
for (i, ty) in cx.arg_types.iter().enumerate() {