1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
12 Support for parsing unsupported, old syntaxes, for the
13 purpose of reporting errors. Parsing of these syntaxes
14 is tested by compile-test/obsolete-syntax.rs.
16 Obsolete syntax that becomes too hard to parse can be
20 use ast::{Expr, ExprLit, LitNil};
21 use codemap::{Span, respan};
22 use parse::parser::Parser;
27 /// The specific types of unsupported syntax
29 pub enum ObsoleteSyntax {
33 ObsoleteNamedExternModule,
34 ObsoleteMultipleLocalDecl,
35 ObsoleteUnsafeExternFn,
36 ObsoleteTraitFuncVisibility,
38 ObsoleteLoopAsContinue,
40 ObsoleteStructWildcard,
41 ObsoleteVecDotDotWildcard,
44 ObsoleteMultipleImport,
45 ObsoleteExternModAttributesInParens,
46 ObsoleteManagedPattern,
47 ObsoleteManagedString,
50 impl to_bytes::IterBytes for ObsoleteSyntax {
52 fn iter_bytes(&self, lsb0: bool, f: to_bytes::Cb) -> bool {
53 (*self as uint).iter_bytes(lsb0, f)
57 pub trait ParserObsoleteMethods {
58 /// Reports an obsolete syntax non-fatal error.
59 fn obsolete(&mut self, sp: Span, kind: ObsoleteSyntax);
60 // Reports an obsolete syntax non-fatal error, and returns
61 // a placeholder expression
62 fn obsolete_expr(&mut self, sp: Span, kind: ObsoleteSyntax) -> @Expr;
68 fn is_obsolete_ident(&mut self, ident: &str) -> bool;
69 fn eat_obsolete_ident(&mut self, ident: &str) -> bool;
72 impl ParserObsoleteMethods for Parser {
73 /// Reports an obsolete syntax non-fatal error.
74 fn obsolete(&mut self, sp: Span, kind: ObsoleteSyntax) {
75 let (kind_str, desc) = match kind {
78 "Use std::util::{swap, replace} instead"
80 ObsoleteUnsafeBlock => (
81 "non-standalone unsafe block",
82 "use an inner `unsafe { ... }` block instead"
84 ObsoleteBareFnType => (
86 "use `|A| -> B` or `extern fn(A) -> B` instead"
88 ObsoleteNamedExternModule => (
89 "named external module",
90 "instead of `extern mod foo { ... }`, write `mod foo { \
93 ObsoleteMultipleLocalDecl => (
94 "declaration of multiple locals at once",
95 "instead of e.g. `let a = 1, b = 2`, write \
96 `let (a, b) = (1, 2)`."
98 ObsoleteUnsafeExternFn => (
99 "unsafe external function",
100 "external functions are always unsafe; remove the `unsafe` \
103 ObsoleteTraitFuncVisibility => (
104 "visibility not necessary",
105 "trait functions inherit the visibility of the trait itself"
107 ObsoleteConstPointer => (
109 "instead of `&const Foo` or `@const Foo`, write `&Foo` or \
112 ObsoleteLoopAsContinue => (
113 "`loop` instead of `continue`",
114 "`loop` is now only used for loops and `continue` is used for \
117 ObsoleteEnumWildcard => (
119 "use `..` instead of `*` for matching all enum fields"
121 ObsoleteStructWildcard => (
123 "use `..` instead of `_` for matching trailing struct fields"
125 ObsoleteVecDotDotWildcard => (
126 "vec slice wildcard",
127 "use `..` instead of `.._` for matching slices"
129 ObsoleteBoxedClosure => (
130 "managed or owned closure",
131 "managed closures have been removed and owned closures are \
132 now written `proc()`"
134 ObsoleteClosureType => (
136 "closures are now written `|A| -> B` rather than `&fn(A) -> \
139 ObsoleteMultipleImport => (
141 "only one import is allowed per `use` statement"
143 ObsoleteExternModAttributesInParens => (
144 "`extern mod` with linkage attribute list",
145 "use `extern mod foo = \"bar\";` instead of \
146 `extern mod foo (name = \"bar\")`"
148 ObsoleteManagedPattern => (
149 "managed pointer pattern",
150 "use a nested `match` expression instead of a managed box \
153 ObsoleteManagedString => (
155 "use `Rc<~str>` instead of a managed string"
159 self.report(sp, kind, kind_str, desc);
162 // Reports an obsolete syntax non-fatal error, and returns
163 // a placeholder expression
164 fn obsolete_expr(&mut self, sp: Span, kind: ObsoleteSyntax) -> @Expr {
165 self.obsolete(sp, kind);
166 self.mk_expr(sp.lo, sp.hi, ExprLit(@respan(sp, LitNil)))
171 kind: ObsoleteSyntax,
174 self.span_err(sp, format!("obsolete syntax: {}", kind_str));
176 if !self.obsolete_set.contains(&kind) {
177 self.sess.span_diagnostic.handler().note(format!("{}", desc));
178 self.obsolete_set.insert(kind);
182 fn is_obsolete_ident(&mut self, ident: &str) -> bool {
184 token::IDENT(sid, _) => {
185 let interned_string = token::get_ident(sid.name);
186 interned_string.equiv(&ident)
192 fn eat_obsolete_ident(&mut self, ident: &str) -> bool {
193 if self.is_obsolete_ident(ident) {