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// Copyright 2012-2016 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.
//! # Token Streams
//!
//! TokenStreams represent syntactic objects before they are converted into ASTs.
//! A `TokenStream` is, roughly speaking, a sequence (eg stream) of `TokenTree`s,
//! which are themselves either a single Token, a Delimited subsequence of tokens,
//! or a SequenceRepetition specifier (for the purpose of sequence generation during macro
//! expansion).
//!
//! ## Ownership
//! TokenStreams are persistant data structures construced as ropes with reference
//! counted-children. In general, this means that calling an operation on a TokenStream
//! (such as `slice`) produces an entirely new TokenStream from the borrowed reference to
//! the original. This essentially coerces TokenStreams into 'views' of their subparts,
//! and a borrowed TokenStream is sufficient to build an owned TokenStream without taking
//! ownership of the original.
use ast::{self, AttrStyle, LitKind};
use syntax_pos::{Span, DUMMY_SP, NO_EXPANSION};
use codemap::{Spanned, combine_spans};
use ext::base;
use ext::tt::macro_parser;
use parse::lexer::comments::{doc_comment_style, strip_doc_comment_decoration};
use parse::lexer;
use parse;
use parse::token::{self, Token, Lit, Nonterminal};
use std::fmt;
use std::iter::*;
use std::ops::{self, Index};
use std::rc::Rc;
/// A delimited sequence of token trees
#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
pub struct Delimited {
/// The type of delimiter
pub delim: token::DelimToken,
/// The span covering the opening delimiter
pub open_span: Span,
/// The delimited sequence of token trees
pub tts: Vec<TokenTree>,
/// The span covering the closing delimiter
pub close_span: Span,
}
impl Delimited {
/// Returns the opening delimiter as a token.
pub fn open_token(&self) -> token::Token {
token::OpenDelim(self.delim)
}
/// Returns the closing delimiter as a token.
pub fn close_token(&self) -> token::Token {
token::CloseDelim(self.delim)
}
/// Returns the opening delimiter as a token tree.
pub fn open_tt(&self) -> TokenTree {
TokenTree::Token(self.open_span, self.open_token())
}
/// Returns the closing delimiter as a token tree.
pub fn close_tt(&self) -> TokenTree {
TokenTree::Token(self.close_span, self.close_token())
}
/// Returns the token trees inside the delimiters.
pub fn subtrees(&self) -> &[TokenTree] {
&self.tts
}
}
/// A sequence of token trees
#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
pub struct SequenceRepetition {
/// The sequence of token trees
pub tts: Vec<TokenTree>,
/// The optional separator
pub separator: Option<token::Token>,
/// Whether the sequence can be repeated zero (*), or one or more times (+)
pub op: KleeneOp,
/// The number of `MatchNt`s that appear in the sequence (and subsequences)
pub num_captures: usize,
}
/// A Kleene-style [repetition operator](http://en.wikipedia.org/wiki/Kleene_star)
/// for token sequences.
#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
pub enum KleeneOp {
ZeroOrMore,
OneOrMore,
}
/// When the main rust parser encounters a syntax-extension invocation, it
/// parses the arguments to the invocation as a token-tree. This is a very
/// loose structure, such that all sorts of different AST-fragments can
/// be passed to syntax extensions using a uniform type.
///
/// If the syntax extension is an MBE macro, it will attempt to match its
/// LHS token tree against the provided token tree, and if it finds a
/// match, will transcribe the RHS token tree, splicing in any captured
/// macro_parser::matched_nonterminals into the `SubstNt`s it finds.
///
/// The RHS of an MBE macro is the only place `SubstNt`s are substituted.
/// Nothing special happens to misnamed or misplaced `SubstNt`s.
#[derive(Debug, Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
pub enum TokenTree {
/// A single token
Token(Span, token::Token),
/// A delimited sequence of token trees
Delimited(Span, Rc<Delimited>),
// This only makes sense in MBE macros.
/// A kleene-style repetition sequence with a span
Sequence(Span, Rc<SequenceRepetition>),
}
impl TokenTree {
pub fn len(&self) -> usize {
match *self {
TokenTree::Token(_, token::DocComment(name)) => {
match doc_comment_style(&name.as_str()) {
AttrStyle::Outer => 2,
AttrStyle::Inner => 3,
}
}
TokenTree::Token(_, token::SpecialVarNt(..)) => 2,
TokenTree::Token(_, token::MatchNt(..)) => 3,
TokenTree::Token(_, token::Interpolated(Nonterminal::NtTT(..))) => 1,
TokenTree::Delimited(_, ref delimed) => delimed.tts.len() + 2,
TokenTree::Sequence(_, ref seq) => seq.tts.len(),
TokenTree::Token(..) => 0,
}
}
pub fn get_tt(&self, index: usize) -> TokenTree {
match (self, index) {
(&TokenTree::Token(sp, token::DocComment(_)), 0) => TokenTree::Token(sp, token::Pound),
(&TokenTree::Token(sp, token::DocComment(name)), 1)
if doc_comment_style(&name.as_str()) == AttrStyle::Inner => {
TokenTree::Token(sp, token::Not)
}
(&TokenTree::Token(sp, token::DocComment(name)), _) => {
let stripped = strip_doc_comment_decoration(&name.as_str());
// Searches for the occurrences of `"#*` and returns the minimum number of `#`s
// required to wrap the text.
let num_of_hashes = stripped.chars()
.scan(0, |cnt, x| {
*cnt = if x == '"' {
1
} else if *cnt != 0 && x == '#' {
*cnt + 1
} else {
0
};
Some(*cnt)
})
.max()
.unwrap_or(0);
TokenTree::Delimited(sp, Rc::new(Delimited {
delim: token::Bracket,
open_span: sp,
tts: vec![TokenTree::Token(sp, token::Ident(token::str_to_ident("doc"))),
TokenTree::Token(sp, token::Eq),
TokenTree::Token(sp, token::Literal(
token::StrRaw(token::intern(&stripped), num_of_hashes), None))],
close_span: sp,
}))
}
(&TokenTree::Delimited(_, ref delimed), _) => {
if index == 0 {
return delimed.open_tt();
}
if index == delimed.tts.len() + 1 {
return delimed.close_tt();
}
delimed.tts[index - 1].clone()
}
(&TokenTree::Token(sp, token::SpecialVarNt(var)), _) => {
let v = [TokenTree::Token(sp, token::Dollar),
TokenTree::Token(sp, token::Ident(token::str_to_ident(var.as_str())))];
v[index].clone()
}
(&TokenTree::Token(sp, token::MatchNt(name, kind)), _) => {
let v = [TokenTree::Token(sp, token::SubstNt(name)),
TokenTree::Token(sp, token::Colon),
TokenTree::Token(sp, token::Ident(kind))];
v[index].clone()
}
(&TokenTree::Token(_, token::Interpolated(Nonterminal::NtTT(ref tt))), _) => {
tt.clone().unwrap()
}
(&TokenTree::Sequence(_, ref seq), _) => seq.tts[index].clone(),
_ => panic!("Cannot expand a token tree"),
}
}
/// Returns the `Span` corresponding to this token tree.
pub fn get_span(&self) -> Span {
match *self {
TokenTree::Token(span, _) => span,
TokenTree::Delimited(span, _) => span,
TokenTree::Sequence(span, _) => span,
}
}
/// Use this token tree as a matcher to parse given tts.
pub fn parse(cx: &base::ExtCtxt,
mtch: &[TokenTree],
tts: &[TokenTree])
-> macro_parser::NamedParseResult {
// `None` is because we're not interpolating
let arg_rdr = lexer::new_tt_reader_with_doc_flag(&cx.parse_sess().span_diagnostic,
None,
None,
tts.iter().cloned().collect(),
true);
macro_parser::parse(cx.parse_sess(), cx.cfg(), arg_rdr, mtch)
}
/// Check if this TokenTree is equal to the other, regardless of span information.
pub fn eq_unspanned(&self, other: &TokenTree) -> bool {
match (self, other) {
(&TokenTree::Token(_, ref tk), &TokenTree::Token(_, ref tk2)) => tk == tk2,
(&TokenTree::Delimited(_, ref dl), &TokenTree::Delimited(_, ref dl2)) => {
(*dl).delim == (*dl2).delim && dl.tts.len() == dl2.tts.len() &&
{
for (tt1, tt2) in dl.tts.iter().zip(dl2.tts.iter()) {
if !tt1.eq_unspanned(tt2) {
return false;
}
}
true
}
}
(_, _) => false,
}
}
/// Retrieve the TokenTree's span.
pub fn span(&self) -> Span {
match *self {
TokenTree::Token(sp, _) |
TokenTree::Delimited(sp, _) |
TokenTree::Sequence(sp, _) => sp,
}
}
/// Indicates if the stream is a token that is equal to the provided token.
pub fn eq_token(&self, t: Token) -> bool {
match *self {
TokenTree::Token(_, ref tk) => *tk == t,
_ => false,
}
}
/// Indicates if the token is an identifier.
pub fn is_ident(&self) -> bool {
self.maybe_ident().is_some()
}
/// Returns an identifier.
pub fn maybe_ident(&self) -> Option<ast::Ident> {
match *self {
TokenTree::Token(_, Token::Ident(t)) => Some(t.clone()),
TokenTree::Delimited(_, ref dl) => {
let tts = dl.subtrees();
if tts.len() != 1 {
return None;
}
tts[0].maybe_ident()
}
_ => None,
}
}
/// Returns a Token literal.
pub fn maybe_lit(&self) -> Option<token::Lit> {
match *self {
TokenTree::Token(_, Token::Literal(l, _)) => Some(l.clone()),
TokenTree::Delimited(_, ref dl) => {
let tts = dl.subtrees();
if tts.len() != 1 {
return None;
}
tts[0].maybe_lit()
}
_ => None,
}
}
/// Returns an AST string literal.
pub fn maybe_str(&self) -> Option<ast::Lit> {
match *self {
TokenTree::Token(sp, Token::Literal(Lit::Str_(s), _)) => {
let l = LitKind::Str(token::intern_and_get_ident(&parse::str_lit(&s.as_str())),
ast::StrStyle::Cooked);
Some(Spanned {
node: l,
span: sp,
})
}
TokenTree::Token(sp, Token::Literal(Lit::StrRaw(s, n), _)) => {
let l = LitKind::Str(token::intern_and_get_ident(&parse::raw_str_lit(&s.as_str())),
ast::StrStyle::Raw(n));
Some(Spanned {
node: l,
span: sp,
})
}
_ => None,
}
}
}
/// #Token Streams
///
/// TokenStreams are a syntactic abstraction over TokenTrees. The goal is for procedural
/// macros to work over TokenStreams instead of arbitrary syntax. For now, however, we
/// are going to cut a few corners (i.e., use some of the AST structure) when we need to
/// for backwards compatibility.
/// TokenStreams are collections of TokenTrees that represent a syntactic structure. The
/// struct itself shouldn't be directly manipulated; the internal structure is not stable,
/// and may be changed at any time in the future. The operators will not, however (except
/// for signatures, later on).
#[derive(Clone, Eq, Hash, RustcEncodable, RustcDecodable)]
pub struct TokenStream {
ts: InternalTS,
}
// NB If Leaf access proves to be slow, inroducing a secondary Leaf without the bounds
// for unsliced Leafs may lead to some performance improvemenet.
#[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
pub enum InternalTS {
Empty(Span),
Leaf {
tts: Rc<Vec<TokenTree>>,
offset: usize,
len: usize,
sp: Span,
},
Node {
left: Rc<InternalTS>,
right: Rc<InternalTS>,
len: usize,
sp: Span,
},
}
impl fmt::Debug for TokenStream {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.ts.fmt(f)
}
}
impl fmt::Debug for InternalTS {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
InternalTS::Empty(..) => Ok(()),
InternalTS::Leaf { ref tts, offset, len, .. } => {
for t in tts.iter().skip(offset).take(len) {
try!(write!(f, "{:?}", t));
}
Ok(())
}
InternalTS::Node { ref left, ref right, .. } => {
try!(left.fmt(f));
right.fmt(f)
}
}
}
}
/// Checks if two TokenStreams are equivalent (including spans). For unspanned
/// equality, see `eq_unspanned`.
impl PartialEq<TokenStream> for TokenStream {
fn eq(&self, other: &TokenStream) -> bool {
self.iter().eq(other.iter())
}
}
// NB this will disregard gaps. if we have [a|{2,5} , b|{11,13}], the resultant span
// will be at {2,13}. Without finer-grained span structures, however, this seems to be
// our only recourse.
// FIXME Do something smarter to compute the expansion id.
fn covering_span(trees: &[TokenTree]) -> Span {
// disregard any dummy spans we have
let trees = trees.iter().filter(|t| t.span() != DUMMY_SP).collect::<Vec<&TokenTree>>();
// if we're out of spans, stop
if trees.len() < 1 {
return DUMMY_SP;
}
// set up the initial values
let fst_span = trees[0].span();
let mut lo_span = fst_span.lo;
let mut hi_span = fst_span.hi;
let mut expn_id = fst_span.expn_id;
// compute the spans iteratively
for t in trees.iter().skip(1) {
let sp = t.span();
if sp.lo < lo_span {
lo_span = sp.lo;
}
if hi_span < sp.hi {
hi_span = sp.hi;
}
if expn_id != sp.expn_id {
expn_id = NO_EXPANSION;
}
}
Span {
lo: lo_span,
hi: hi_span,
expn_id: expn_id,
}
}
impl InternalTS {
fn len(&self) -> usize {
match *self {
InternalTS::Empty(..) => 0,
InternalTS::Leaf { len, .. } => len,
InternalTS::Node { len, .. } => len,
}
}
fn span(&self) -> Span {
match *self {
InternalTS::Empty(sp) |
InternalTS::Leaf { sp, .. } |
InternalTS::Node { sp, .. } => sp,
}
}
fn slice(&self, range: ops::Range<usize>) -> TokenStream {
let from = range.start;
let to = range.end;
if from == to {
return TokenStream::mk_empty();
}
if from > to {
panic!("Invalid range: {} to {}", from, to);
}
if from == 0 && to == self.len() {
return TokenStream { ts: self.clone() }; /* should be cheap */
}
match *self {
InternalTS::Empty(..) => panic!("Invalid index"),
InternalTS::Leaf { ref tts, offset, .. } => {
let offset = offset + from;
let len = to - from;
TokenStream::mk_sub_leaf(tts.clone(),
offset,
len,
covering_span(&tts[offset..offset + len]))
}
InternalTS::Node { ref left, ref right, .. } => {
let left_len = left.len();
if to <= left_len {
left.slice(range)
} else if from >= left_len {
right.slice(from - left_len..to - left_len)
} else {
TokenStream::concat(left.slice(from..left_len), right.slice(0..to - left_len))
}
}
}
}
fn to_vec(&self) -> Vec<&TokenTree> {
fn internal_to_vec(ts: &InternalTS) -> Vec<&TokenTree> {
match *ts {
InternalTS::Empty(..) => Vec::new(),
InternalTS::Leaf { ref tts, offset, len, .. } => {
tts[offset..offset + len].iter().collect()
}
InternalTS::Node { ref left, ref right, .. } => {
let mut v1 = internal_to_vec(left);
let mut v2 = internal_to_vec(right);
v1.append(&mut v2);
v1
}
}
}
internal_to_vec(self)
}
fn to_tts(&self) -> Vec<TokenTree> {
self.to_vec().into_iter().cloned().collect::<Vec<TokenTree>>()
}
// Returns an internal node's children.
fn children(&self) -> Option<(Rc<InternalTS>, Rc<InternalTS>)> {
match *self {
InternalTS::Node { ref left, ref right, .. } => Some((left.clone(), right.clone())),
_ => None,
}
}
}
/// TokenStream operators include basic destructuring, boolean operations, `maybe_...`
/// operations, and `maybe_..._prefix` operations. Boolean operations are straightforward,
/// indicating information about the structure of the stream. The `maybe_...` operations
/// return `Some<...>` if the tokenstream contains the appropriate item.
///
/// Similarly, the `maybe_..._prefix` operations potentially return a
/// partially-destructured stream as a pair where the first element is the expected item
/// and the second is the remainder of the stream. As anb example,
///
/// `maybe_path_prefix("a::b::c(a,b,c).foo()") -> (a::b::c, "(a,b,c).foo()")`
impl TokenStream {
// Construct an empty node with a dummy span.
pub fn mk_empty() -> TokenStream {
TokenStream { ts: InternalTS::Empty(DUMMY_SP) }
}
// Construct an empty node with the provided span.
fn mk_spanned_empty(sp: Span) -> TokenStream {
TokenStream { ts: InternalTS::Empty(sp) }
}
// Construct an leaf node with a 0 offset and length equivalent to the input.
fn mk_leaf(tts: Rc<Vec<TokenTree>>, sp: Span) -> TokenStream {
let len = tts.len();
TokenStream {
ts: InternalTS::Leaf {
tts: tts,
offset: 0,
len: len,
sp: sp,
},
}
}
// Construct an leaft node with the provided values.
fn mk_sub_leaf(tts: Rc<Vec<TokenTree>>, offset: usize, len: usize, sp: Span) -> TokenStream {
TokenStream {
ts: InternalTS::Leaf {
tts: tts,
offset: offset,
len: len,
sp: sp,
},
}
}
// Construct an internal node with the provided values.
fn mk_int_node(left: Rc<InternalTS>,
right: Rc<InternalTS>,
len: usize,
sp: Span)
-> TokenStream {
TokenStream {
ts: InternalTS::Node {
left: left,
right: right,
len: len,
sp: sp,
},
}
}
/// Convert a vector of `TokenTree`s into a `TokenStream`.
pub fn from_tts(trees: Vec<TokenTree>) -> TokenStream {
let span = covering_span(&trees[..]);
TokenStream::mk_leaf(Rc::new(trees), span)
}
/// Manually change a TokenStream's span.
pub fn respan(self, span: Span) -> TokenStream {
match self.ts {
InternalTS::Empty(..) => TokenStream::mk_spanned_empty(span),
InternalTS::Leaf { tts, offset, len, .. } => {
TokenStream::mk_sub_leaf(tts, offset, len, span)
}
InternalTS::Node { left, right, len, .. } => {
TokenStream::mk_int_node(left, right, len, span)
}
}
}
/// Concatenates two TokenStreams into a new TokenStream.
pub fn concat(left: TokenStream, right: TokenStream) -> TokenStream {
// This internal procedure performs 'aggressive compacting' during concatenation as
// follows:
// - If the nodes' combined total total length is less than 32, we copy both of
// them into a new vector and build a new leaf node.
// - If one node is an internal node and the other is a 'small' leaf (length<32),
// we recur down the internal node on the appropriate side.
// - Otherwise, we construct a new internal node that points to them as left and
// right.
fn concat_internal(left: Rc<InternalTS>, right: Rc<InternalTS>) -> TokenStream {
let llen = left.len();
let rlen = right.len();
let len = llen + rlen;
let span = combine_spans(left.span(), right.span());
if len < 32 {
let mut new_vec = left.to_tts();
let mut rvec = right.to_tts();
new_vec.append(&mut rvec);
return TokenStream::mk_leaf(Rc::new(new_vec), span);
}
match (left.children(), right.children()) {
(Some((lleft, lright)), None) if rlen < 32 => {
let new_right = concat_internal(lright, right);
TokenStream::mk_int_node(lleft, Rc::new(new_right.ts), len, span)
}
(None, Some((rleft, rright))) if llen < 32 => {
let new_left = concat_internal(left, rleft);
TokenStream::mk_int_node(Rc::new(new_left.ts), rright, len, span)
}
(_, _) => TokenStream::mk_int_node(left, right, len, span),
}
}
if left.is_empty() {
right
} else if right.is_empty() {
left
} else {
concat_internal(Rc::new(left.ts), Rc::new(right.ts))
}
}
/// Indicate if the TokenStream is empty.
pub fn is_empty(&self) -> bool {
self.len() == 0
}
/// Return a TokenStream's length.
pub fn len(&self) -> usize {
self.ts.len()
}
/// Convert a TokenStream into a vector of borrowed TokenTrees.
pub fn to_vec(&self) -> Vec<&TokenTree> {
self.ts.to_vec()
}
/// Convert a TokenStream into a vector of TokenTrees (by cloning the TokenTrees).
/// (This operation is an O(n) deep copy of the underlying structure.)
pub fn to_tts(&self) -> Vec<TokenTree> {
self.ts.to_tts()
}
/// Return the TokenStream's span.
pub fn span(&self) -> Span {
self.ts.span()
}
/// Returns an iterator over a TokenStream (as a sequence of TokenTrees).
pub fn iter<'a>(&self) -> Iter {
Iter { vs: self, idx: 0 }
}
/// Splits a TokenStream based on the provided `&TokenTree -> bool` predicate.
pub fn split<P>(&self, pred: P) -> Split<P>
where P: FnMut(&TokenTree) -> bool
{
Split {
vs: self,
pred: pred,
finished: false,
idx: 0,
}
}
/// Produce a slice of the input TokenStream from the `from` index, inclusive, to the
/// `to` index, non-inclusive.
pub fn slice(&self, range: ops::Range<usize>) -> TokenStream {
self.ts.slice(range)
}
/// Slice starting at the provided index, inclusive.
pub fn slice_from(&self, from: ops::RangeFrom<usize>) -> TokenStream {
self.slice(from.start..self.len())
}
/// Slice up to the provided index, non-inclusive.
pub fn slice_to(&self, to: ops::RangeTo<usize>) -> TokenStream {
self.slice(0..to.end)
}
/// Indicates where the stream is a single, delimited expression (e.g., `(a,b,c)` or
/// `{a,b,c}`).
pub fn is_delimited(&self) -> bool {
self.maybe_delimited().is_some()
}
/// Returns the inside of the delimited term as a new TokenStream.
pub fn maybe_delimited(&self) -> Option<TokenStream> {
if !(self.len() == 1) {
return None;
}
// FIXME It would be nice to change Delimited to move the Rc around the TokenTree
// vector directly in order to avoid the clone here.
match self[0] {
TokenTree::Delimited(_, ref rc) => Some(TokenStream::from_tts(rc.tts.clone())),
_ => None,
}
}
/// Indicates if the stream is exactly one identifier.
pub fn is_ident(&self) -> bool {
self.maybe_ident().is_some()
}
/// Returns an identifier
pub fn maybe_ident(&self) -> Option<ast::Ident> {
if !(self.len() == 1) {
return None;
}
match self[0] {
TokenTree::Token(_, Token::Ident(t)) => Some(t),
_ => None,
}
}
/// Compares two TokenStreams, checking equality without regarding span information.
pub fn eq_unspanned(&self, other: &TokenStream) -> bool {
for (t1, t2) in self.iter().zip(other.iter()) {
if !t1.eq_unspanned(t2) {
return false;
}
}
true
}
/// Convert a vector of TokenTrees into a parentheses-delimited TokenStream.
pub fn as_delimited_stream(tts: Vec<TokenTree>, delim: token::DelimToken) -> TokenStream {
let new_sp = covering_span(&tts);
let new_delim = Rc::new(Delimited {
delim: delim,
open_span: DUMMY_SP,
tts: tts,
close_span: DUMMY_SP,
});
TokenStream::from_tts(vec![TokenTree::Delimited(new_sp, new_delim)])
}
}
// FIXME Reimplement this iterator to hold onto a slice iterator for a leaf, getting the
// next leaf's iterator when the current one is exhausted.
pub struct Iter<'a> {
vs: &'a TokenStream,
idx: usize,
}
impl<'a> Iterator for Iter<'a> {
type Item = &'a TokenTree;
fn next(&mut self) -> Option<&'a TokenTree> {
if self.vs.is_empty() || self.idx >= self.vs.len() {
return None;
}
let ret = Some(&self.vs[self.idx]);
self.idx = self.idx + 1;
ret
}
}
pub struct Split<'a, P>
where P: FnMut(&TokenTree) -> bool
{
vs: &'a TokenStream,
pred: P,
finished: bool,
idx: usize,
}
impl<'a, P> Iterator for Split<'a, P>
where P: FnMut(&TokenTree) -> bool
{
type Item = TokenStream;
fn next(&mut self) -> Option<TokenStream> {
if self.finished {
return None;
}
if self.idx >= self.vs.len() {
self.finished = true;
return None;
}
let mut lookup = self.vs.iter().skip(self.idx);
match lookup.position(|x| (self.pred)(&x)) {
None => {
self.finished = true;
Some(self.vs.slice_from(self.idx..))
}
Some(edx) => {
let ret = Some(self.vs.slice(self.idx..self.idx + edx));
self.idx += edx + 1;
ret
}
}
}
}
impl Index<usize> for TokenStream {
type Output = TokenTree;
fn index(&self, index: usize) -> &TokenTree {
&self.ts[index]
}
}
impl Index<usize> for InternalTS {
type Output = TokenTree;
fn index(&self, index: usize) -> &TokenTree {
if self.len() <= index {
panic!("Index {} too large for {:?}", index, self);
}
match *self {
InternalTS::Empty(..) => panic!("Invalid index"),
InternalTS::Leaf { ref tts, offset, .. } => tts.get(index + offset).unwrap(),
InternalTS::Node { ref left, ref right, .. } => {
let left_len = left.len();
if index < left_len {
Index::index(&**left, index)
} else {
Index::index(&**right, index - left_len)
}
}
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use syntax_pos::{Span, BytePos, NO_EXPANSION, DUMMY_SP};
use parse::token::{self, str_to_ident, Token};
use util::parser_testing::string_to_tts;
use std::rc::Rc;
fn sp(a: u32, b: u32) -> Span {
Span {
lo: BytePos(a),
hi: BytePos(b),
expn_id: NO_EXPANSION,
}
}
fn as_paren_delimited_stream(tts: Vec<TokenTree>) -> TokenStream {
TokenStream::as_delimited_stream(tts, token::DelimToken::Paren)
}
#[test]
fn test_concat() {
let test_res = TokenStream::from_tts(string_to_tts("foo::bar::baz".to_string()));
let test_fst = TokenStream::from_tts(string_to_tts("foo::bar".to_string()));
let test_snd = TokenStream::from_tts(string_to_tts("::baz".to_string()));
let eq_res = TokenStream::concat(test_fst, test_snd);
assert_eq!(test_res.len(), 5);
assert_eq!(eq_res.len(), 5);
assert_eq!(test_res.eq_unspanned(&eq_res), true);
}
#[test]
fn test_from_to_bijection() {
let test_start = string_to_tts("foo::bar(baz)".to_string());
let test_end = TokenStream::from_tts(string_to_tts("foo::bar(baz)".to_string())).to_tts();
assert_eq!(test_start, test_end)
}
#[test]
fn test_to_from_bijection() {
let test_start = TokenStream::from_tts(string_to_tts("foo::bar(baz)".to_string()));
let test_end = TokenStream::from_tts(test_start.clone().to_tts());
assert_eq!(test_start, test_end)
}
#[test]
fn test_eq_0() {
let test_res = TokenStream::from_tts(string_to_tts("foo".to_string()));
let test_eqs = TokenStream::from_tts(string_to_tts("foo".to_string()));
assert_eq!(test_res, test_eqs)
}
#[test]
fn test_eq_1() {
let test_res = TokenStream::from_tts(string_to_tts("::bar::baz".to_string()));
let test_eqs = TokenStream::from_tts(string_to_tts("::bar::baz".to_string()));
assert_eq!(test_res, test_eqs)
}
#[test]
fn test_eq_2() {
let test_res = TokenStream::from_tts(string_to_tts("foo::bar".to_string()));
let test_eqs = TokenStream::from_tts(string_to_tts("foo::bar::baz".to_string()));
assert_eq!(test_res, test_eqs.slice(0..3))
}
#[test]
fn test_eq_3() {
let test_res = TokenStream::from_tts(string_to_tts("".to_string()));
let test_eqs = TokenStream::from_tts(string_to_tts("".to_string()));
assert_eq!(test_res, test_eqs)
}
#[test]
fn test_diseq_0() {
let test_res = TokenStream::from_tts(string_to_tts("::bar::baz".to_string()));
let test_eqs = TokenStream::from_tts(string_to_tts("bar::baz".to_string()));
assert_eq!(test_res == test_eqs, false)
}
#[test]
fn test_diseq_1() {
let test_res = TokenStream::from_tts(string_to_tts("(bar,baz)".to_string()));
let test_eqs = TokenStream::from_tts(string_to_tts("bar,baz".to_string()));
assert_eq!(test_res == test_eqs, false)
}
#[test]
fn test_slice_0() {
let test_res = TokenStream::from_tts(string_to_tts("foo::bar".to_string()));
let test_eqs = TokenStream::from_tts(string_to_tts("foo::bar::baz".to_string()));
assert_eq!(test_res, test_eqs.slice(0..3))
}
#[test]
fn test_slice_1() {
let test_res = TokenStream::from_tts(string_to_tts("foo::bar::baz".to_string()))
.slice(2..3);
let test_eqs = TokenStream::from_tts(vec![TokenTree::Token(sp(5,8),
token::Ident(str_to_ident("bar")))]);
assert_eq!(test_res, test_eqs)
}
#[test]
fn test_is_empty() {
let test0 = TokenStream::from_tts(Vec::new());
let test1 = TokenStream::from_tts(vec![TokenTree::Token(sp(0, 1),
Token::Ident(str_to_ident("a")))]);
let test2 = TokenStream::from_tts(string_to_tts("foo(bar::baz)".to_string()));
assert_eq!(test0.is_empty(), true);
assert_eq!(test1.is_empty(), false);
assert_eq!(test2.is_empty(), false);
}
#[test]
fn test_is_delimited() {
let test0 = TokenStream::from_tts(string_to_tts("foo(bar::baz)".to_string()));
let test1 = TokenStream::from_tts(string_to_tts("(bar::baz)".to_string()));
let test2 = TokenStream::from_tts(string_to_tts("(foo,bar,baz)".to_string()));
let test3 = TokenStream::from_tts(string_to_tts("(foo,bar,baz)(zab,rab,oof)".to_string()));
let test4 = TokenStream::from_tts(string_to_tts("(foo,bar,baz)foo".to_string()));
let test5 = TokenStream::from_tts(string_to_tts("".to_string()));
assert_eq!(test0.is_delimited(), false);
assert_eq!(test1.is_delimited(), true);
assert_eq!(test2.is_delimited(), true);
assert_eq!(test3.is_delimited(), false);
assert_eq!(test4.is_delimited(), false);
assert_eq!(test5.is_delimited(), false);
}
#[test]
fn test_is_ident() {
let test0 = TokenStream::from_tts(string_to_tts("\"foo\"".to_string()));
let test1 = TokenStream::from_tts(string_to_tts("5".to_string()));
let test2 = TokenStream::from_tts(string_to_tts("foo".to_string()));
let test3 = TokenStream::from_tts(string_to_tts("foo::bar".to_string()));
let test4 = TokenStream::from_tts(string_to_tts("foo(bar)".to_string()));
assert_eq!(test0.is_ident(), false);
assert_eq!(test1.is_ident(), false);
assert_eq!(test2.is_ident(), true);
assert_eq!(test3.is_ident(), false);
assert_eq!(test4.is_ident(), false);
}
#[test]
fn test_maybe_delimited() {
let test0_input = TokenStream::from_tts(string_to_tts("foo(bar::baz)".to_string()));
let test1_input = TokenStream::from_tts(string_to_tts("(bar::baz)".to_string()));
let test2_input = TokenStream::from_tts(string_to_tts("(foo,bar,baz)".to_string()));
let test3_input = TokenStream::from_tts(string_to_tts("(foo,bar,baz)(zab,rab)"
.to_string()));
let test4_input = TokenStream::from_tts(string_to_tts("(foo,bar,baz)foo".to_string()));
let test5_input = TokenStream::from_tts(string_to_tts("".to_string()));
let test0 = test0_input.maybe_delimited();
let test1 = test1_input.maybe_delimited();
let test2 = test2_input.maybe_delimited();
let test3 = test3_input.maybe_delimited();
let test4 = test4_input.maybe_delimited();
let test5 = test5_input.maybe_delimited();
assert_eq!(test0, None);
let test1_expected = TokenStream::from_tts(vec![TokenTree::Token(sp(1, 4),
token::Ident(str_to_ident("bar"))),
TokenTree::Token(sp(4, 6), token::ModSep),
TokenTree::Token(sp(6, 9),
token::Ident(str_to_ident("baz")))]);
assert_eq!(test1, Some(test1_expected));
let test2_expected = TokenStream::from_tts(vec![TokenTree::Token(sp(1, 4),
token::Ident(str_to_ident("foo"))),
TokenTree::Token(sp(4, 5), token::Comma),
TokenTree::Token(sp(5, 8),
token::Ident(str_to_ident("bar"))),
TokenTree::Token(sp(8, 9), token::Comma),
TokenTree::Token(sp(9, 12),
token::Ident(str_to_ident("baz")))]);
assert_eq!(test2, Some(test2_expected));
assert_eq!(test3, None);
assert_eq!(test4, None);
assert_eq!(test5, None);
}
// pub fn maybe_ident(&self) -> Option<ast::Ident>
#[test]
fn test_maybe_ident() {
let test0 = TokenStream::from_tts(string_to_tts("\"foo\"".to_string())).maybe_ident();
let test1 = TokenStream::from_tts(string_to_tts("5".to_string())).maybe_ident();
let test2 = TokenStream::from_tts(string_to_tts("foo".to_string())).maybe_ident();
let test3 = TokenStream::from_tts(string_to_tts("foo::bar".to_string())).maybe_ident();
let test4 = TokenStream::from_tts(string_to_tts("foo(bar)".to_string())).maybe_ident();
assert_eq!(test0, None);
assert_eq!(test1, None);
assert_eq!(test2, Some(str_to_ident("foo")));
assert_eq!(test3, None);
assert_eq!(test4, None);
}
#[test]
fn test_as_delimited_stream() {
let test0 = as_paren_delimited_stream(string_to_tts("foo,bar,".to_string()));
let test1 = as_paren_delimited_stream(string_to_tts("baz(foo,bar)".to_string()));
let test0_tts = vec![TokenTree::Token(sp(0, 3), token::Ident(str_to_ident("foo"))),
TokenTree::Token(sp(3, 4), token::Comma),
TokenTree::Token(sp(4, 7), token::Ident(str_to_ident("bar"))),
TokenTree::Token(sp(7, 8), token::Comma)];
let test0_stream = TokenStream::from_tts(vec![TokenTree::Delimited(sp(0, 8),
Rc::new(Delimited {
delim: token::DelimToken::Paren,
open_span: DUMMY_SP,
tts: test0_tts,
close_span: DUMMY_SP,
}))]);
assert_eq!(test0, test0_stream);
let test1_tts = vec![TokenTree::Token(sp(4, 7), token::Ident(str_to_ident("foo"))),
TokenTree::Token(sp(7, 8), token::Comma),
TokenTree::Token(sp(8, 11), token::Ident(str_to_ident("bar")))];
let test1_parse = vec![TokenTree::Token(sp(0, 3), token::Ident(str_to_ident("baz"))),
TokenTree::Delimited(sp(3, 12),
Rc::new(Delimited {
delim: token::DelimToken::Paren,
open_span: sp(3, 4),
tts: test1_tts,
close_span: sp(11, 12),
}))];
let test1_stream = TokenStream::from_tts(vec![TokenTree::Delimited(sp(0, 12),
Rc::new(Delimited {
delim: token::DelimToken::Paren,
open_span: DUMMY_SP,
tts: test1_parse,
close_span: DUMMY_SP,
}))]);
assert_eq!(test1, test1_stream);
}
}
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