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// Copyright 2012 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::Parser;
use parse::token;
use std::to_bytes;
/// The specific types of unsupported syntax
#[deriving(Eq)]
pub enum ObsoleteSyntax {
ObsoleteSwap,
ObsoleteUnsafeBlock,
ObsoleteBareFnType,
ObsoleteMultipleLocalDecl,
ObsoleteUnsafeExternFn,
ObsoleteTraitFuncVisibility,
ObsoleteConstPointer,
ObsoleteLoopAsContinue,
ObsoleteEnumWildcard,
ObsoleteStructWildcard,
ObsoleteVecDotDotWildcard,
ObsoleteBoxedClosure,
ObsoleteClosureType,
ObsoleteMultipleImport,
ObsoleteManagedPattern,
ObsoleteManagedString,
ObsoleteManagedVec,
}
impl to_bytes::IterBytes for ObsoleteSyntax {
#[inline]
fn iter_bytes(&self, lsb0: bool, f: to_bytes::Cb) -> bool {
(*self as uint).iter_bytes(lsb0, f)
}
}
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) -> @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 ParserObsoleteMethods for Parser {
/// Reports an obsolete syntax non-fatal error.
fn obsolete(&mut self, sp: Span, kind: ObsoleteSyntax) {
let (kind_str, desc) = match kind {
ObsoleteSwap => (
"swap",
"use std::mem::{swap, replace} instead"
),
ObsoleteUnsafeBlock => (
"non-standalone unsafe block",
"use an inner `unsafe { ... }` block instead"
),
ObsoleteBareFnType => (
"bare function type",
"use `|A| -> B` or `extern fn(A) -> B` instead"
),
ObsoleteMultipleLocalDecl => (
"declaration of multiple locals at once",
"instead of e.g. `let a = 1, b = 2`, write \
`let (a, b) = (1, 2)`."
),
ObsoleteUnsafeExternFn => (
"unsafe external function",
"external functions are always unsafe; remove the `unsafe` \
keyword"
),
ObsoleteTraitFuncVisibility => (
"visibility not necessary",
"trait functions inherit the visibility of the trait itself"
),
ObsoleteConstPointer => (
"const pointer",
"instead of `&const Foo` or `@const Foo`, write `&Foo` or \
`@Foo`"
),
ObsoleteLoopAsContinue => (
"`loop` instead of `continue`",
"`loop` is now only used for loops and `continue` is used for \
skipping iterations"
),
ObsoleteEnumWildcard => (
"enum wildcard",
"use `..` instead of `*` for matching all enum fields"
),
ObsoleteStructWildcard => (
"struct wildcard",
"use `..` instead of `_` for matching trailing struct fields"
),
ObsoleteVecDotDotWildcard => (
"vec slice wildcard",
"use `..` instead of `.._` for matching slices"
),
ObsoleteBoxedClosure => (
"managed or owned closure",
"managed closures have been removed and owned closures are \
now written `proc()`"
),
ObsoleteClosureType => (
"closure type",
"closures are now written `|A| -> B` rather than `&fn(A) -> \
B`."
),
ObsoleteMultipleImport => (
"multiple imports",
"only one import is allowed per `use` statement"
),
ObsoleteManagedPattern => (
"managed pointer pattern",
"use a nested `match` expression instead of a managed box \
pattern"
),
ObsoleteManagedString => (
"managed string",
"use `Rc<~str>` instead of a managed string"
),
ObsoleteManagedVec => (
"managed vector",
"use `Rc<~[T]>` instead of a managed vector"
),
};
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) -> @Expr {
self.obsolete(sp, kind);
self.mk_expr(sp.lo, sp.hi, ExprLit(@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));
if !self.obsolete_set.contains(&kind) {
self.sess.span_diagnostic.handler().note(format!("{}", desc));
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
}
}
}
|
