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// Copyright 2012-2014 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.
/*!
Support for parsing unsupported, old syntaxes, for the
purpose of reporting errors. Parsing of these syntaxes
is tested by compile-test/obsolete-syntax.rs.
Obsolete syntax that becomes too hard to parse can be
removed.
*/
use ast::{Expr, ExprLit, LitNil};
use codemap::{Span, respan};
use parse::parser;
use parse::token;
use std::gc::Gc;
/// The specific types of unsupported syntax
#[deriving(PartialEq, Eq, Hash)]
pub enum ObsoleteSyntax {
ObsoleteOwnedType,
ObsoleteOwnedExpr,
ObsoleteOwnedPattern,
ObsoleteOwnedVector,
}
pub trait ParserObsoleteMethods {
/// Reports an obsolete syntax non-fatal error.
fn obsolete(&mut self, sp: Span, kind: ObsoleteSyntax);
// Reports an obsolete syntax non-fatal error, and returns
// a placeholder expression
fn obsolete_expr(&mut self, sp: Span, kind: ObsoleteSyntax) -> Gc<Expr>;
fn report(&mut self,
sp: Span,
kind: ObsoleteSyntax,
kind_str: &str,
desc: &str);
fn is_obsolete_ident(&mut self, ident: &str) -> bool;
fn eat_obsolete_ident(&mut self, ident: &str) -> bool;
}
impl<'a> ParserObsoleteMethods for parser::Parser<'a> {
/// Reports an obsolete syntax non-fatal error.
fn obsolete(&mut self, sp: Span, kind: ObsoleteSyntax) {
let (kind_str, desc) = match kind {
ObsoleteOwnedType => (
"`~` notation for owned pointers",
"use `Box<T>` in `std::owned` instead"
),
ObsoleteOwnedExpr => (
"`~` notation for owned pointer allocation",
"use the `box` operator instead of `~`"
),
ObsoleteOwnedPattern => (
"`~` notation for owned pointer patterns",
"use the `box` operator instead of `~`"
),
ObsoleteOwnedVector => (
"`~[T]` is no longer a type",
"use the `Vec` type instead"
),
};
self.report(sp, kind, kind_str, desc);
}
// Reports an obsolete syntax non-fatal error, and returns
// a placeholder expression
fn obsolete_expr(&mut self, sp: Span, kind: ObsoleteSyntax) -> Gc<Expr> {
self.obsolete(sp, kind);
self.mk_expr(sp.lo, sp.hi, ExprLit(box(GC) respan(sp, LitNil)))
}
fn report(&mut self,
sp: Span,
kind: ObsoleteSyntax,
kind_str: &str,
desc: &str) {
self.span_err(sp,
format!("obsolete syntax: {}", kind_str).as_slice());
if !self.obsolete_set.contains(&kind) {
self.sess
.span_diagnostic
.handler()
.note(format!("{}", desc).as_slice());
self.obsolete_set.insert(kind);
}
}
fn is_obsolete_ident(&mut self, ident: &str) -> bool {
match self.token {
token::IDENT(sid, _) => {
token::get_ident(sid).equiv(&ident)
}
_ => false
}
}
fn eat_obsolete_ident(&mut self, ident: &str) -> bool {
if self.is_obsolete_ident(ident) {
self.bump();
true
} else {
false
}
}
}
|
