rust/src/libsyntax/parse/token.rs

731 lines
21 KiB
Rust

// Copyright 2012-2013 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 ast;
use ast::{P, Ident, Name, Mrk};
use ast_util;
use parse::token;
use util::interner::{RcStr, StrInterner};
use util::interner;
use serialize::{Decodable, Decoder, Encodable, Encoder};
use std::cast;
use std::char;
use std::fmt;
use std::local_data;
use std::path::BytesContainer;
#[allow(non_camel_case_types)]
#[deriving(Clone, Encodable, Decodable, Eq, IterBytes)]
pub enum BinOp {
PLUS,
MINUS,
STAR,
SLASH,
PERCENT,
CARET,
AND,
OR,
SHL,
SHR,
}
#[allow(non_camel_case_types)]
#[deriving(Clone, Encodable, Decodable, Eq, IterBytes)]
pub enum Token {
/* Expression-operator symbols. */
EQ,
LT,
LE,
EQEQ,
NE,
GE,
GT,
ANDAND,
OROR,
NOT,
TILDE,
BINOP(BinOp),
BINOPEQ(BinOp),
/* Structural symbols */
AT,
DOT,
DOTDOT,
DOTDOTDOT,
COMMA,
SEMI,
COLON,
MOD_SEP,
RARROW,
LARROW,
DARROW,
FAT_ARROW,
LPAREN,
RPAREN,
LBRACKET,
RBRACKET,
LBRACE,
RBRACE,
POUND,
DOLLAR,
/* Literals */
LIT_CHAR(u32),
LIT_INT(i64, ast::IntTy),
LIT_UINT(u64, ast::UintTy),
LIT_INT_UNSUFFIXED(i64),
LIT_FLOAT(ast::Ident, ast::FloatTy),
LIT_FLOAT_UNSUFFIXED(ast::Ident),
LIT_STR(ast::Ident),
LIT_STR_RAW(ast::Ident, uint), /* raw str delimited by n hash symbols */
/* Name components */
// an identifier contains an "is_mod_name" boolean,
// indicating whether :: follows this token with no
// whitespace in between.
IDENT(ast::Ident, bool),
UNDERSCORE,
LIFETIME(ast::Ident),
/* For interpolation */
INTERPOLATED(Nonterminal),
DOC_COMMENT(ast::Ident),
EOF,
}
#[deriving(Clone, Encodable, Decodable, Eq, IterBytes)]
/// For interpolation during macro expansion.
pub enum Nonterminal {
NtItem(@ast::Item),
NtBlock(P<ast::Block>),
NtStmt(@ast::Stmt),
NtPat( @ast::Pat),
NtExpr(@ast::Expr),
NtTy( P<ast::Ty>),
NtIdent(~ast::Ident, bool),
NtAttr(@ast::Attribute), // #[foo]
NtPath(~ast::Path),
NtTT( @ast::TokenTree), // needs @ed to break a circularity
NtMatchers(~[ast::Matcher])
}
pub fn binop_to_str(o: BinOp) -> ~str {
match o {
PLUS => ~"+",
MINUS => ~"-",
STAR => ~"*",
SLASH => ~"/",
PERCENT => ~"%",
CARET => ~"^",
AND => ~"&",
OR => ~"|",
SHL => ~"<<",
SHR => ~">>"
}
}
pub fn to_str(t: &Token) -> ~str {
match *t {
EQ => ~"=",
LT => ~"<",
LE => ~"<=",
EQEQ => ~"==",
NE => ~"!=",
GE => ~">=",
GT => ~">",
NOT => ~"!",
TILDE => ~"~",
OROR => ~"||",
ANDAND => ~"&&",
BINOP(op) => binop_to_str(op),
BINOPEQ(op) => binop_to_str(op) + "=",
/* Structural symbols */
AT => ~"@",
DOT => ~".",
DOTDOT => ~"..",
DOTDOTDOT => ~"...",
COMMA => ~",",
SEMI => ~";",
COLON => ~":",
MOD_SEP => ~"::",
RARROW => ~"->",
LARROW => ~"<-",
DARROW => ~"<->",
FAT_ARROW => ~"=>",
LPAREN => ~"(",
RPAREN => ~")",
LBRACKET => ~"[",
RBRACKET => ~"]",
LBRACE => ~"{",
RBRACE => ~"}",
POUND => ~"#",
DOLLAR => ~"$",
/* Literals */
LIT_CHAR(c) => {
let mut res = ~"'";
char::from_u32(c).unwrap().escape_default(|c| {
res.push_char(c);
});
res.push_char('\'');
res
}
LIT_INT(i, t) => {
i.to_str() + ast_util::int_ty_to_str(t)
}
LIT_UINT(u, t) => {
u.to_str() + ast_util::uint_ty_to_str(t)
}
LIT_INT_UNSUFFIXED(i) => { i.to_str() }
LIT_FLOAT(s, t) => {
let mut body = get_ident(s).get().to_str();
if body.ends_with(".") {
body.push_char('0'); // `10.f` is not a float literal
}
body + ast_util::float_ty_to_str(t)
}
LIT_FLOAT_UNSUFFIXED(s) => {
let mut body = get_ident(s).get().to_str();
if body.ends_with(".") {
body.push_char('0'); // `10.f` is not a float literal
}
body
}
LIT_STR(s) => {
format!("\"{}\"", get_ident(s).get().escape_default())
}
LIT_STR_RAW(s, n) => {
format!("r{delim}\"{string}\"{delim}",
delim="#".repeat(n), string=get_ident(s))
}
/* Name components */
IDENT(s, _) => get_ident(s).get().to_str(),
LIFETIME(s) => {
format!("'{}", get_ident(s))
}
UNDERSCORE => ~"_",
/* Other */
DOC_COMMENT(s) => get_ident(s).get().to_str(),
EOF => ~"<eof>",
INTERPOLATED(ref nt) => {
match nt {
&NtExpr(e) => ::print::pprust::expr_to_str(e),
&NtAttr(e) => ::print::pprust::attribute_to_str(e),
_ => {
~"an interpolated " +
match *nt {
NtItem(..) => ~"item",
NtBlock(..) => ~"block",
NtStmt(..) => ~"statement",
NtPat(..) => ~"pattern",
NtAttr(..) => fail!("should have been handled"),
NtExpr(..) => fail!("should have been handled above"),
NtTy(..) => ~"type",
NtIdent(..) => ~"identifier",
NtPath(..) => ~"path",
NtTT(..) => ~"tt",
NtMatchers(..) => ~"matcher sequence"
}
}
}
}
}
}
pub fn can_begin_expr(t: &Token) -> bool {
match *t {
LPAREN => true,
LBRACE => true,
LBRACKET => true,
IDENT(_, _) => true,
UNDERSCORE => true,
TILDE => true,
LIT_CHAR(_) => true,
LIT_INT(_, _) => true,
LIT_UINT(_, _) => true,
LIT_INT_UNSUFFIXED(_) => true,
LIT_FLOAT(_, _) => true,
LIT_FLOAT_UNSUFFIXED(_) => true,
LIT_STR(_) => true,
LIT_STR_RAW(_, _) => true,
POUND => true,
AT => true,
NOT => true,
BINOP(MINUS) => true,
BINOP(STAR) => true,
BINOP(AND) => true,
BINOP(OR) => true, // in lambda syntax
OROR => true, // in lambda syntax
MOD_SEP => true,
INTERPOLATED(NtExpr(..))
| INTERPOLATED(NtIdent(..))
| INTERPOLATED(NtBlock(..))
| INTERPOLATED(NtPath(..)) => true,
_ => false
}
}
/// what's the opposite delimiter?
pub fn flip_delimiter(t: &token::Token) -> token::Token {
match *t {
LPAREN => RPAREN,
LBRACE => RBRACE,
LBRACKET => RBRACKET,
RPAREN => LPAREN,
RBRACE => LBRACE,
RBRACKET => LBRACKET,
_ => fail!()
}
}
pub fn is_lit(t: &Token) -> bool {
match *t {
LIT_CHAR(_) => true,
LIT_INT(_, _) => true,
LIT_UINT(_, _) => true,
LIT_INT_UNSUFFIXED(_) => true,
LIT_FLOAT(_, _) => true,
LIT_FLOAT_UNSUFFIXED(_) => true,
LIT_STR(_) => true,
LIT_STR_RAW(_, _) => true,
_ => false
}
}
pub fn is_ident(t: &Token) -> bool {
match *t { IDENT(_, _) => true, _ => false }
}
pub fn is_ident_or_path(t: &Token) -> bool {
match *t {
IDENT(_, _) | INTERPOLATED(NtPath(..)) => true,
_ => false
}
}
pub fn is_plain_ident(t: &Token) -> bool {
match *t { IDENT(_, false) => true, _ => false }
}
pub fn is_bar(t: &Token) -> bool {
match *t { BINOP(OR) | OROR => true, _ => false }
}
// Get the first "argument"
macro_rules! first {
( $first:expr, $( $remainder:expr, )* ) => ( $first )
}
// Get the last "argument" (has to be done recursively to avoid phoney local ambiguity error)
macro_rules! last {
( $first:expr, $( $remainder:expr, )+ ) => ( last!( $( $remainder, )+ ) );
( $first:expr, ) => ( $first )
}
// In this macro, there is the requirement that the name (the number) must be monotonically
// increasing by one in the special identifiers, starting at 0; the same holds for the keywords,
// except starting from the next number instead of zero, and with the additional exception that
// special identifiers are *also* allowed (they are deduplicated in the important place, the
// interner), an exception which is demonstrated by "static" and "self".
macro_rules! declare_special_idents_and_keywords {(
// So now, in these rules, why is each definition parenthesised?
// Answer: otherwise we get a spurious local ambiguity bug on the "}"
pub mod special_idents {
$( ($si_name:expr, $si_static:ident, $si_str:expr); )*
}
pub mod keywords {
'strict:
$( ($sk_name:expr, $sk_variant:ident, $sk_str:expr); )*
'reserved:
$( ($rk_name:expr, $rk_variant:ident, $rk_str:expr); )*
}
) => {
static STRICT_KEYWORD_START: Name = first!($( $sk_name, )*);
static STRICT_KEYWORD_FINAL: Name = last!($( $sk_name, )*);
static RESERVED_KEYWORD_START: Name = first!($( $rk_name, )*);
static RESERVED_KEYWORD_FINAL: Name = last!($( $rk_name, )*);
pub mod special_idents {
use ast::Ident;
$( pub static $si_static: Ident = Ident { name: $si_name, ctxt: 0 }; )*
}
/**
* All the valid words that have meaning in the Rust language.
*
* Rust keywords are either 'strict' or 'reserved'. Strict keywords may not
* appear as identifiers at all. Reserved keywords are not used anywhere in
* the language and may not appear as identifiers.
*/
pub mod keywords {
use ast::Ident;
pub enum Keyword {
$( $sk_variant, )*
$( $rk_variant, )*
}
impl Keyword {
pub fn to_ident(&self) -> Ident {
match *self {
$( $sk_variant => Ident { name: $sk_name, ctxt: 0 }, )*
$( $rk_variant => Ident { name: $rk_name, ctxt: 0 }, )*
}
}
}
}
fn mk_fresh_ident_interner() -> IdentInterner {
// The indices here must correspond to the numbers in
// special_idents, in Keyword to_ident(), and in static
// constants below.
let init_vec = ~[
$( $si_str, )*
$( $sk_str, )*
$( $rk_str, )*
];
interner::StrInterner::prefill(init_vec)
}
}}
// If the special idents get renumbered, remember to modify these two as appropriate
static SELF_KEYWORD_NAME: Name = 1;
static STATIC_KEYWORD_NAME: Name = 2;
declare_special_idents_and_keywords! {
pub mod special_idents {
// These ones are statics
(0, invalid, "");
(super::SELF_KEYWORD_NAME, self_, "self");
(super::STATIC_KEYWORD_NAME, statik, "static");
// for matcher NTs
(3, tt, "tt");
(4, matchers, "matchers");
// outside of libsyntax
(5, clownshoe_abi, "__rust_abi");
(6, opaque, "<opaque>");
(7, unnamed_field, "<unnamed_field>");
(8, type_self, "Self");
}
pub mod keywords {
// These ones are variants of the Keyword enum
'strict:
(9, As, "as");
(10, Break, "break");
(11, Const, "const");
(12, Crate, "crate");
(13, Else, "else");
(14, Enum, "enum");
(15, Extern, "extern");
(16, False, "false");
(17, Fn, "fn");
(18, For, "for");
(19, If, "if");
(20, Impl, "impl");
(21, In, "in");
(22, Let, "let");
(23, __LogLevel, "__log_level");
(24, Loop, "loop");
(25, Match, "match");
(26, Mod, "mod");
(27, Mut, "mut");
(28, Once, "once");
(29, Priv, "priv");
(30, Pub, "pub");
(31, Ref, "ref");
(32, Return, "return");
// Static and Self are also special idents (prefill de-dupes)
(super::STATIC_KEYWORD_NAME, Static, "static");
(super::SELF_KEYWORD_NAME, Self, "self");
(33, Struct, "struct");
(34, Super, "super");
(35, True, "true");
(36, Trait, "trait");
(37, Type, "type");
(38, Unsafe, "unsafe");
(39, Use, "use");
(40, While, "while");
(41, Continue, "continue");
(42, Proc, "proc");
(43, Box, "box");
'reserved:
(44, Alignof, "alignof");
(45, Be, "be");
(46, Offsetof, "offsetof");
(47, Pure, "pure");
(48, Sizeof, "sizeof");
(49, Typeof, "typeof");
(50, Unsized, "unsized");
(51, Yield, "yield");
(52, Do, "do");
}
}
/**
* Maps a token to a record specifying the corresponding binary
* operator
*/
pub fn token_to_binop(tok: &Token) -> Option<ast::BinOp> {
match *tok {
BINOP(STAR) => Some(ast::BiMul),
BINOP(SLASH) => Some(ast::BiDiv),
BINOP(PERCENT) => Some(ast::BiRem),
BINOP(PLUS) => Some(ast::BiAdd),
BINOP(MINUS) => Some(ast::BiSub),
BINOP(SHL) => Some(ast::BiShl),
BINOP(SHR) => Some(ast::BiShr),
BINOP(AND) => Some(ast::BiBitAnd),
BINOP(CARET) => Some(ast::BiBitXor),
BINOP(OR) => Some(ast::BiBitOr),
LT => Some(ast::BiLt),
LE => Some(ast::BiLe),
GE => Some(ast::BiGe),
GT => Some(ast::BiGt),
EQEQ => Some(ast::BiEq),
NE => Some(ast::BiNe),
ANDAND => Some(ast::BiAnd),
OROR => Some(ast::BiOr),
_ => None
}
}
// looks like we can get rid of this completely...
pub type IdentInterner = StrInterner;
// if an interner exists in TLS, return it. Otherwise, prepare a
// fresh one.
pub fn get_ident_interner() -> @IdentInterner {
local_data_key!(key: @::parse::token::IdentInterner)
match local_data::get(key, |k| k.map(|k| *k)) {
Some(interner) => interner,
None => {
let interner = @mk_fresh_ident_interner();
local_data::set(key, interner);
interner
}
}
}
/// Represents a string stored in the task-local interner. Because the
/// interner lives for the life of the task, this can be safely treated as an
/// immortal string, as long as it never crosses between tasks.
///
/// FIXME(pcwalton): You must be careful about what you do in the destructors
/// of objects stored in TLS, because they may run after the interner is
/// destroyed. In particular, they must not access string contents. This can
/// be fixed in the future by just leaking all strings until task death
/// somehow.
#[deriving(Clone, Eq, IterBytes, Ord, TotalEq, TotalOrd)]
pub struct InternedString {
priv string: RcStr,
}
impl InternedString {
#[inline]
pub fn new(string: &'static str) -> InternedString {
InternedString {
string: RcStr::new(string),
}
}
#[inline]
fn new_from_rc_str(string: RcStr) -> InternedString {
InternedString {
string: string,
}
}
#[inline]
pub fn get<'a>(&'a self) -> &'a str {
self.string.as_slice()
}
}
impl BytesContainer for InternedString {
fn container_as_bytes<'a>(&'a self) -> &'a [u8] {
// FIXME(pcwalton): This is a workaround for the incorrect signature
// of `BytesContainer`, which is itself a workaround for the lack of
// DST.
unsafe {
let this = self.get();
cast::transmute(this.container_as_bytes())
}
}
}
impl fmt::Show for InternedString {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f.buf, "{}", self.string.as_slice())
}
}
impl<'a> Equiv<&'a str> for InternedString {
fn equiv(&self, other: & &'a str) -> bool {
(*other) == self.string.as_slice()
}
}
impl<D:Decoder> Decodable<D> for InternedString {
fn decode(d: &mut D) -> InternedString {
get_name(get_ident_interner().intern(d.read_str()))
}
}
impl<E:Encoder> Encodable<E> for InternedString {
fn encode(&self, e: &mut E) {
e.emit_str(self.string.as_slice())
}
}
/// Returns the string contents of a name, using the task-local interner.
#[inline]
pub fn get_name(name: Name) -> InternedString {
let interner = get_ident_interner();
InternedString::new_from_rc_str(interner.get(name))
}
/// Returns the string contents of an identifier, using the task-local
/// interner.
#[inline]
pub fn get_ident(ident: Ident) -> InternedString {
get_name(ident.name)
}
/// Interns and returns the string contents of an identifier, using the
/// task-local interner.
#[inline]
pub fn intern_and_get_ident(s: &str) -> InternedString {
get_name(intern(s))
}
/// Maps a string to its interned representation.
#[inline]
pub fn intern(s: &str) -> Name {
get_ident_interner().intern(s)
}
/// gensym's a new uint, using the current interner.
#[inline]
pub fn gensym(s: &str) -> Name {
get_ident_interner().gensym(s)
}
/// Maps a string to an identifier with an empty syntax context.
#[inline]
pub fn str_to_ident(s: &str) -> ast::Ident {
ast::Ident::new(intern(s))
}
/// Maps a string to a gensym'ed identifier.
#[inline]
pub fn gensym_ident(s: &str) -> ast::Ident {
ast::Ident::new(gensym(s))
}
// create a fresh name that maps to the same string as the old one.
// note that this guarantees that str_ptr_eq(ident_to_str(src),interner_get(fresh_name(src)));
// that is, that the new name and the old one are connected to ptr_eq strings.
pub fn fresh_name(src: &ast::Ident) -> Name {
let interner = get_ident_interner();
interner.gensym_copy(src.name)
// following: debug version. Could work in final except that it's incompatible with
// good error messages and uses of struct names in ambiguous could-be-binding
// locations. Also definitely destroys the guarantee given above about ptr_eq.
/*let num = rand::rng().gen_uint_range(0,0xffff);
gensym(format!("{}_{}",ident_to_str(src),num))*/
}
// create a fresh mark.
pub fn fresh_mark() -> Mrk {
gensym("mark")
}
// See the macro above about the types of keywords
pub fn is_keyword(kw: keywords::Keyword, tok: &Token) -> bool {
match *tok {
token::IDENT(sid, false) => { kw.to_ident().name == sid.name }
_ => { false }
}
}
pub fn is_any_keyword(tok: &Token) -> bool {
match *tok {
token::IDENT(sid, false) => match sid.name {
SELF_KEYWORD_NAME | STATIC_KEYWORD_NAME |
STRICT_KEYWORD_START .. RESERVED_KEYWORD_FINAL => true,
_ => false,
},
_ => false
}
}
pub fn is_strict_keyword(tok: &Token) -> bool {
match *tok {
token::IDENT(sid, false) => match sid.name {
SELF_KEYWORD_NAME | STATIC_KEYWORD_NAME |
STRICT_KEYWORD_START .. STRICT_KEYWORD_FINAL => true,
_ => false,
},
_ => false,
}
}
pub fn is_reserved_keyword(tok: &Token) -> bool {
match *tok {
token::IDENT(sid, false) => match sid.name {
RESERVED_KEYWORD_START .. RESERVED_KEYWORD_FINAL => true,
_ => false,
},
_ => false,
}
}
pub fn mtwt_token_eq(t1 : &Token, t2 : &Token) -> bool {
match (t1,t2) {
(&IDENT(id1,_),&IDENT(id2,_)) =>
ast_util::mtwt_resolve(id1) == ast_util::mtwt_resolve(id2),
_ => *t1 == *t2
}
}
#[cfg(test)]
mod test {
use super::*;
use ast;
use ast_util;
fn mark_ident(id : ast::Ident, m : ast::Mrk) -> ast::Ident {
ast::Ident{name:id.name,ctxt:ast_util::new_mark(m,id.ctxt)}
}
#[test] fn mtwt_token_eq_test() {
assert!(mtwt_token_eq(&GT,&GT));
let a = str_to_ident("bac");
let a1 = mark_ident(a,92);
assert!(mtwt_token_eq(&IDENT(a,true),&IDENT(a1,false)));
}
}