rust/src/librustsyntax/parse/parser.rs
2012-04-19 21:58:45 -07:00

2440 lines
77 KiB
Rust

import result::result;
import either::{either, left, right};
import std::map::{hashmap, str_hash};
import token::{can_begin_expr, is_ident, is_plain_ident};
import codemap::{span,fss_none};
import util::interner;
import ast::spanned;
import ast_util::{mk_sp, ident_to_path};
import lexer::reader;
import prec::{op_spec, as_prec};
import attr::{parse_outer_attrs_or_ext,
parse_inner_attrs_and_next,
parse_outer_attributes,
parse_optional_meta};
import common::*;
export expect;
export file_type;
export mk_item;
export restriction;
export parser;
export parse_crate_directives;
export parse_crate_mod;
export parse_expr;
export parse_item;
export parse_mod_items;
export parse_pat;
export parse_seq;
export parse_stmt;
export parse_ty;
export parse_lit;
export parse_syntax_ext_naked;
// FIXME: #ast expects to find this here but it's actually defined in `parse`
// Fixing this will be easier when we have export decls on individual items --
// then parse can export this publicly, and everything else crate-visibly.
// (See #1893)
import parse_from_source_str;
export parse_from_source_str;
enum restriction {
UNRESTRICTED,
RESTRICT_STMT_EXPR,
RESTRICT_NO_CALL_EXPRS,
RESTRICT_NO_BAR_OP,
}
enum file_type { CRATE_FILE, SOURCE_FILE, }
type parser = @{
sess: parse_sess,
cfg: ast::crate_cfg,
file_type: file_type,
mut token: token::token,
mut span: span,
mut last_span: span,
mut buffer: [{tok: token::token, span: span}],
mut restriction: restriction,
reader: reader,
binop_precs: @[op_spec],
keywords: hashmap<str, ()>,
bad_expr_words: hashmap<str, ()>
};
impl parser for parser {
fn bump() {
self.last_span = self.span;
if vec::len(self.buffer) == 0u {
let next = lexer::next_token(self.reader);
self.token = next.tok;
self.span = ast_util::mk_sp(next.chpos, self.reader.chpos);
} else {
let next = vec::pop(self.buffer);
self.token = next.tok;
self.span = next.span;
}
}
fn swap(next: token::token, lo: uint, hi: uint) {
self.token = next;
self.span = ast_util::mk_sp(lo, hi);
}
fn look_ahead(distance: uint) -> token::token {
while vec::len(self.buffer) < distance {
let next = lexer::next_token(self.reader);
let sp = ast_util::mk_sp(next.chpos, self.reader.chpos);
self.buffer = [{tok: next.tok, span: sp}] + self.buffer;
}
ret self.buffer[distance - 1u].tok;
}
fn fatal(m: str) -> ! {
self.sess.span_diagnostic.span_fatal(self.span, m)
}
fn span_fatal(sp: span, m: str) -> ! {
self.sess.span_diagnostic.span_fatal(sp, m)
}
fn bug(m: str) -> ! {
self.sess.span_diagnostic.span_bug(self.span, m)
}
fn warn(m: str) {
self.sess.span_diagnostic.span_warn(self.span, m)
}
fn get_str(i: token::str_num) -> str {
interner::get(*self.reader.interner, i)
}
fn get_id() -> node_id { next_node_id(self.sess) }
}
fn parse_ty_fn(p: parser) -> ast::fn_decl {
fn parse_fn_input_ty(p: parser) -> ast::arg {
let mode = parse_arg_mode(p);
let name = if is_plain_ident(p.token)
&& p.look_ahead(1u) == token::COLON {
let name = parse_value_ident(p);
p.bump();
name
} else { "" };
ret {mode: mode, ty: parse_ty(p, false), ident: name, id: p.get_id()};
}
let inputs =
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_fn_input_ty, p);
// FIXME: constrs is empty because right now, higher-order functions
// can't have constrained types.
// Not sure whether that would be desirable anyway. See #34 for the
// story on constrained types.
let constrs: [@ast::constr] = [];
let (ret_style, ret_ty) = parse_ret_ty(p);
ret {inputs: inputs.node, output: ret_ty,
purity: ast::impure_fn, cf: ret_style,
constraints: constrs};
}
fn parse_ty_methods(p: parser) -> [ast::ty_method] {
parse_seq(token::LBRACE, token::RBRACE, seq_sep_none(), {|p|
let attrs = parse_outer_attributes(p);
let flo = p.span.lo;
let pur = parse_fn_purity(p);
let ident = parse_method_name(p);
let tps = parse_ty_params(p);
let d = parse_ty_fn(p), fhi = p.last_span.hi;
expect(p, token::SEMI);
{ident: ident, attrs: attrs, decl: {purity: pur with d}, tps: tps,
span: ast_util::mk_sp(flo, fhi)}
}, p).node
}
fn parse_mt(p: parser) -> ast::mt {
let mutbl = parse_mutability(p);
let t = parse_ty(p, false);
ret {ty: t, mutbl: mutbl};
}
fn parse_ty_field(p: parser) -> ast::ty_field {
let lo = p.span.lo;
let mutbl = parse_mutability(p);
let id = parse_ident(p);
expect(p, token::COLON);
let ty = parse_ty(p, false);
ret spanned(lo, ty.span.hi, {ident: id, mt: {ty: ty, mutbl: mutbl}});
}
// if i is the jth ident in args, return j
// otherwise, fail
fn ident_index(p: parser, args: [ast::arg], i: ast::ident) -> uint {
let mut j = 0u;
for args.each {|a| if a.ident == i { ret j; } j += 1u; }
p.fatal("unbound variable `" + i + "` in constraint arg");
}
fn parse_type_constr_arg(p: parser) -> @ast::ty_constr_arg {
let sp = p.span;
let mut carg = ast::carg_base;
expect(p, token::BINOP(token::STAR));
if p.token == token::DOT {
// "*..." notation for record fields
p.bump();
let pth = parse_path(p);
carg = ast::carg_ident(pth);
}
// No literals yet, I guess?
ret @{node: carg, span: sp};
}
fn parse_constr_arg(args: [ast::arg], p: parser) -> @ast::constr_arg {
let sp = p.span;
let mut carg = ast::carg_base;
if p.token == token::BINOP(token::STAR) {
p.bump();
} else {
let i: ast::ident = parse_value_ident(p);
carg = ast::carg_ident(ident_index(p, args, i));
}
ret @{node: carg, span: sp};
}
fn parse_ty_constr(fn_args: [ast::arg], p: parser) -> @ast::constr {
let lo = p.span.lo;
let path = parse_path(p);
let args: {node: [@ast::constr_arg], span: span} =
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
{|p| parse_constr_arg(fn_args, p)}, p);
ret @spanned(lo, args.span.hi,
{path: path, args: args.node, id: p.get_id()});
}
fn parse_constr_in_type(p: parser) -> @ast::ty_constr {
let lo = p.span.lo;
let path = parse_path(p);
let args: [@ast::ty_constr_arg] =
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_type_constr_arg, p).node;
let hi = p.span.lo;
let tc: ast::ty_constr_ = {path: path, args: args, id: p.get_id()};
ret @spanned(lo, hi, tc);
}
fn parse_constrs<T: copy>(pser: fn(parser) -> @ast::constr_general<T>,
p: parser) ->
[@ast::constr_general<T>] {
let mut constrs: [@ast::constr_general<T>] = [];
loop {
let constr = pser(p);
constrs += [constr];
if p.token == token::COMMA { p.bump(); } else { ret constrs; }
};
}
fn parse_type_constraints(p: parser) -> [@ast::ty_constr] {
ret parse_constrs(parse_constr_in_type, p);
}
fn parse_ty_postfix(orig_t: ast::ty_, p: parser, colons_before_params: bool,
lo: uint) -> @ast::ty {
fn mk_ty(p: parser, t: ast::ty_, lo: uint, hi: uint) -> @ast::ty {
@{id: p.get_id(),
node: t,
span: ast_util::mk_sp(lo, hi)}
}
if p.token == token::BINOP(token::SLASH) {
let orig_hi = p.last_span.hi;
alt maybe_parse_vstore(p) {
none { }
some(v) {
let t = ast::ty_vstore(mk_ty(p, orig_t, lo, orig_hi), v);
ret mk_ty(p, t, lo, p.last_span.hi);
}
}
}
if colons_before_params && p.token == token::MOD_SEP {
p.bump();
expect(p, token::LT);
} else if !colons_before_params && p.token == token::LT {
p.bump();
} else {
ret mk_ty(p, orig_t, lo, p.last_span.hi);
}
// If we're here, we have explicit type parameter instantiation.
let seq = parse_seq_to_gt(some(token::COMMA), {|p| parse_ty(p, false)},
p);
alt orig_t {
ast::ty_path(pth, ann) {
ret mk_ty(p, ast::ty_path(@spanned(lo, p.last_span.hi,
{global: pth.node.global,
idents: pth.node.idents,
types: seq}), ann),
lo, p.last_span.hi);
}
_ { p.fatal("type parameter instantiation only allowed for paths"); }
}
}
fn parse_ret_ty(p: parser) -> (ast::ret_style, @ast::ty) {
ret if eat(p, token::RARROW) {
let lo = p.span.lo;
if eat(p, token::NOT) {
(ast::noreturn, @{id: p.get_id(),
node: ast::ty_bot,
span: ast_util::mk_sp(lo, p.last_span.hi)})
} else {
(ast::return_val, parse_ty(p, false))
}
} else {
let pos = p.span.lo;
(ast::return_val, @{id: p.get_id(),
node: ast::ty_nil,
span: ast_util::mk_sp(pos, pos)})
}
}
fn region_from_name(p: parser, s: option<str>) -> ast::region {
let r = alt s {
some (string) {
// FIXME: To be consistent with our type resolution, the
// static region should probably be resolved during type
// checking, not in the parser. (Issue #2256)
if string == "static" {
ast::re_static
} else {
ast::re_named(string)
}
}
none { ast::re_anon }
};
{id: p.get_id(), node: r}
}
fn parse_region(p: parser) -> ast::region {
let name =
alt p.token {
token::IDENT(sid, _) if p.look_ahead(1u) == token::DOT {
p.bump(); p.bump();
some(p.get_str(sid))
}
_ { none }
};
region_from_name(p, name)
}
fn parse_ty(p: parser, colons_before_params: bool) -> @ast::ty {
let lo = p.span.lo;
alt have_dollar(p) {
some(e) {
ret @{id: p.get_id(),
node: ast::ty_mac(spanned(lo, p.span.hi, e)),
span: ast_util::mk_sp(lo, p.span.hi)};
}
none {}
}
let t = if p.token == token::LPAREN {
p.bump();
if p.token == token::RPAREN {
p.bump();
ast::ty_nil
} else {
let mut ts = [parse_ty(p, false)];
while p.token == token::COMMA {
p.bump();
ts += [parse_ty(p, false)];
}
let t = if vec::len(ts) == 1u { ts[0].node }
else { ast::ty_tup(ts) };
expect(p, token::RPAREN);
t
}
} else if p.token == token::AT {
p.bump();
ast::ty_box(parse_mt(p))
} else if p.token == token::TILDE {
p.bump();
ast::ty_uniq(parse_mt(p))
} else if p.token == token::BINOP(token::STAR) {
p.bump();
ast::ty_ptr(parse_mt(p))
} else if p.token == token::LBRACE {
let elems =
parse_seq(token::LBRACE, token::RBRACE, seq_sep_opt(token::COMMA),
parse_ty_field, p);
if vec::len(elems.node) == 0u { unexpected_last(p, token::RBRACE); }
let hi = elems.span.hi;
let t = ast::ty_rec(elems.node);
if p.token == token::COLON {
p.bump();
ast::ty_constr(@{id: p.get_id(),
node: t,
span: ast_util::mk_sp(lo, hi)},
parse_type_constraints(p))
} else { t }
} else if p.token == token::LBRACKET {
expect(p, token::LBRACKET);
let t = ast::ty_vec(parse_mt(p));
expect(p, token::RBRACKET);
t
} else if p.token == token::BINOP(token::AND) {
p.bump();
let region = parse_region(p);
let mt = parse_mt(p);
ast::ty_rptr(region, mt)
} else if eat_word(p, "fn") {
let proto = parse_fn_ty_proto(p);
alt proto {
ast::proto_bare { p.warn("fn is deprecated, use native fn"); }
_ { /* fallthrough */ }
}
ast::ty_fn(proto, parse_ty_fn(p))
} else if eat_word(p, "native") {
expect_word(p, "fn");
ast::ty_fn(ast::proto_bare, parse_ty_fn(p))
} else if p.token == token::MOD_SEP || is_ident(p.token) {
let path = parse_path(p);
ast::ty_path(path, p.get_id())
} else { p.fatal("expecting type"); };
ret parse_ty_postfix(t, p, colons_before_params, lo);
}
fn parse_arg_mode(p: parser) -> ast::mode {
if eat(p, token::BINOP(token::AND)) {
ast::expl(ast::by_mutbl_ref)
} else if eat(p, token::BINOP(token::MINUS)) {
ast::expl(ast::by_move)
} else if eat(p, token::ANDAND) {
ast::expl(ast::by_ref)
} else if eat(p, token::BINOP(token::PLUS)) {
if eat(p, token::BINOP(token::PLUS)) {
ast::expl(ast::by_val)
} else {
ast::expl(ast::by_copy)
}
} else { ast::infer(p.get_id()) }
}
fn parse_arg(p: parser) -> ast::arg {
let m = parse_arg_mode(p);
let i = parse_value_ident(p);
expect(p, token::COLON);
let t = parse_ty(p, false);
ret {mode: m, ty: t, ident: i, id: p.get_id()};
}
fn parse_fn_block_arg(p: parser) -> ast::arg {
let m = parse_arg_mode(p);
let i = parse_value_ident(p);
let t = if eat(p, token::COLON) {
parse_ty(p, false)
} else {
@{id: p.get_id(),
node: ast::ty_infer,
span: ast_util::mk_sp(p.span.lo, p.span.hi)}
};
ret {mode: m, ty: t, ident: i, id: p.get_id()};
}
fn have_dollar(p: parser) -> option<ast::mac_> {
alt p.token {
token::DOLLAR_NUM(num) {
p.bump();
some(ast::mac_var(num))
}
token::DOLLAR_LPAREN {
let lo = p.span.lo;
p.bump();
let e = parse_expr(p);
expect(p, token::RPAREN);
let hi = p.last_span.hi;
some(ast::mac_aq(ast_util::mk_sp(lo,hi), e))
}
_ {none}
}
}
fn maybe_parse_vstore(p: parser) -> option<ast::vstore> {
if p.token == token::BINOP(token::SLASH) {
p.bump();
alt p.token {
token::AT {
p.bump(); some(ast::vstore_box)
}
token::TILDE {
p.bump(); some(ast::vstore_uniq)
}
token::UNDERSCORE {
p.bump(); some(ast::vstore_fixed(none))
}
token::LIT_INT(i, ast::ty_i) if i >= 0i64 {
p.bump(); some(ast::vstore_fixed(some(i as uint)))
}
token::BINOP(token::AND) {
p.bump();
alt p.token {
token::IDENT(sid, _) {
p.bump();
let n = p.get_str(sid);
some(ast::vstore_slice(region_from_name(p, some(n))))
}
_ {
some(ast::vstore_slice(region_from_name(p, none)))
}
}
}
_ {
none
}
}
} else {
none
}
}
fn lit_from_token(p: parser, tok: token::token) -> ast::lit_ {
alt tok {
token::LIT_INT(i, it) { ast::lit_int(i, it) }
token::LIT_UINT(u, ut) { ast::lit_uint(u, ut) }
token::LIT_FLOAT(s, ft) { ast::lit_float(p.get_str(s), ft) }
token::LIT_STR(s) { ast::lit_str(p.get_str(s)) }
token::LPAREN { expect(p, token::RPAREN); ast::lit_nil }
_ { unexpected_last(p, tok); }
}
}
fn parse_lit(p: parser) -> ast::lit {
let lo = p.span.lo;
let lit = if eat_word(p, "true") {
ast::lit_bool(true)
} else if eat_word(p, "false") {
ast::lit_bool(false)
} else {
let tok = p.token;
p.bump();
lit_from_token(p, tok)
};
ret {node: lit, span: ast_util::mk_sp(lo, p.last_span.hi)};
}
fn parse_path(p: parser) -> @ast::path {
let lo = p.span.lo;
let global = eat(p, token::MOD_SEP);
let mut ids = [parse_ident(p)];
while p.look_ahead(1u) != token::LT && eat(p, token::MOD_SEP) {
ids += [parse_ident(p)];
}
ret @spanned(lo, p.last_span.hi,
{global: global, idents: ids, types: []});
}
fn parse_value_path(p: parser) -> @ast::path {
let pt = parse_path(p);
let last_word = pt.node.idents[vec::len(pt.node.idents)-1u];
if p.bad_expr_words.contains_key(last_word) {
p.fatal("found " + last_word + " in expression position");
}
pt
}
fn parse_path_and_ty_param_substs(p: parser, colons: bool) -> @ast::path {
let lo = p.span.lo;
let path = parse_path(p);
let b = if colons {
eat(p, token::MOD_SEP)
} else {
p.token == token::LT
};
if b {
let seq = parse_seq_lt_gt(some(token::COMMA),
{|p| parse_ty(p, false)}, p);
@spanned(lo, seq.span.hi, {types: seq.node with path.node})
} else { path }
}
fn parse_mutability(p: parser) -> ast::mutability {
if eat_word(p, "mut") {
ast::m_mutbl
} else if eat_word(p, "mut") {
ast::m_mutbl
} else if eat_word(p, "const") {
ast::m_const
} else {
ast::m_imm
}
}
fn parse_field(p: parser, sep: token::token) -> ast::field {
let lo = p.span.lo;
let m = parse_mutability(p);
let i = parse_ident(p);
expect(p, sep);
let e = parse_expr(p);
ret spanned(lo, e.span.hi, {mutbl: m, ident: i, expr: e});
}
fn mk_expr(p: parser, lo: uint, hi: uint, node: ast::expr_) -> @ast::expr {
ret @{id: p.get_id(), node: node, span: ast_util::mk_sp(lo, hi)};
}
fn mk_mac_expr(p: parser, lo: uint, hi: uint, m: ast::mac_) -> @ast::expr {
ret @{id: p.get_id(),
node: ast::expr_mac({node: m, span: ast_util::mk_sp(lo, hi)}),
span: ast_util::mk_sp(lo, hi)};
}
fn mk_lit_u32(p: parser, i: u32) -> @ast::expr {
let span = p.span;
let lv_lit = @{node: ast::lit_uint(i as u64, ast::ty_u32),
span: span};
ret @{id: p.get_id(), node: ast::expr_lit(lv_lit), span: span};
}
// We don't allow single-entry tuples in the true AST; that indicates a
// parenthesized expression. However, we preserve them temporarily while
// parsing because `(while{...})+3` parses differently from `while{...}+3`.
//
// To reflect the fact that the @ast::expr is not a true expr that should be
// part of the AST, we wrap such expressions in the pexpr enum. They
// can then be converted to true expressions by a call to `to_expr()`.
enum pexpr {
pexpr(@ast::expr),
}
fn mk_pexpr(p: parser, lo: uint, hi: uint, node: ast::expr_) -> pexpr {
ret pexpr(mk_expr(p, lo, hi, node));
}
fn to_expr(e: pexpr) -> @ast::expr {
alt e.node {
ast::expr_tup(es) if vec::len(es) == 1u { es[0u] }
_ { *e }
}
}
fn parse_bottom_expr(p: parser) -> pexpr {
let lo = p.span.lo;
let mut hi = p.span.hi;
let mut ex: ast::expr_;
alt have_dollar(p) {
some(x) {ret pexpr(mk_mac_expr(p, lo, p.span.hi, x));}
_ {}
}
if p.token == token::LPAREN {
p.bump();
if p.token == token::RPAREN {
hi = p.span.hi;
p.bump();
let lit = @spanned(lo, hi, ast::lit_nil);
ret mk_pexpr(p, lo, hi, ast::expr_lit(lit));
}
let mut es = [parse_expr(p)];
while p.token == token::COMMA { p.bump(); es += [parse_expr(p)]; }
hi = p.span.hi;
expect(p, token::RPAREN);
// Note: we retain the expr_tup() even for simple
// parenthesized expressions, but only for a "little while".
// This is so that wrappers around parse_bottom_expr()
// can tell whether the expression was parenthesized or not,
// which affects expr_is_complete().
ret mk_pexpr(p, lo, hi, ast::expr_tup(es));
} else if p.token == token::LBRACE {
p.bump();
if is_word(p, "mut") ||
is_plain_ident(p.token) && p.look_ahead(1u) == token::COLON {
let mut fields = [parse_field(p, token::COLON)];
let mut base = none;
while p.token != token::RBRACE {
if eat_word(p, "with") { base = some(parse_expr(p)); break; }
expect(p, token::COMMA);
if p.token == token::RBRACE {
// record ends by an optional trailing comma
break;
}
fields += [parse_field(p, token::COLON)];
}
hi = p.span.hi;
expect(p, token::RBRACE);
ex = ast::expr_rec(fields, base);
} else if token::is_bar(p.token) {
ret pexpr(parse_fn_block_expr(p));
} else {
let blk = parse_block_tail(p, lo, ast::default_blk);
ret mk_pexpr(p, blk.span.lo, blk.span.hi, ast::expr_block(blk));
}
} else if eat_word(p, "new") {
expect(p, token::LPAREN);
let r = parse_expr(p);
expect(p, token::RPAREN);
let v = parse_expr(p);
ret mk_pexpr(p, lo, p.span.hi,
ast::expr_new(r, p.get_id(), v));
} else if eat_word(p, "if") {
ret pexpr(parse_if_expr(p));
} else if eat_word(p, "for") {
ret pexpr(parse_for_expr(p));
} else if eat_word(p, "while") {
ret pexpr(parse_while_expr(p));
} else if eat_word(p, "do") {
ret pexpr(parse_do_while_expr(p));
} else if eat_word(p, "loop") {
ret pexpr(parse_loop_expr(p));
} else if eat_word(p, "alt") {
ret pexpr(parse_alt_expr(p));
} else if eat_word(p, "fn") {
let proto = parse_fn_ty_proto(p);
alt proto {
ast::proto_bare { p.fatal("fn expr are deprecated, use fn@"); }
ast::proto_any { p.fatal("fn* cannot be used in an expression"); }
_ { /* fallthrough */ }
}
ret pexpr(parse_fn_expr(p, proto));
} else if eat_word(p, "unchecked") {
ret pexpr(parse_block_expr(p, lo, ast::unchecked_blk));
} else if eat_word(p, "unsafe") {
ret pexpr(parse_block_expr(p, lo, ast::unsafe_blk));
} else if p.token == token::LBRACKET {
p.bump();
let mutbl = parse_mutability(p);
let es =
parse_seq_to_end(token::RBRACKET, seq_sep(token::COMMA),
parse_expr, p);
hi = p.span.hi;
ex = ast::expr_vec(es, mutbl);
} else if p.token == token::POUND_LT {
p.bump();
let ty = parse_ty(p, false);
expect(p, token::GT);
/* hack: early return to take advantage of specialized function */
ret pexpr(mk_mac_expr(p, lo, p.span.hi,
ast::mac_embed_type(ty)));
} else if p.token == token::POUND_LBRACE {
p.bump();
let blk = ast::mac_embed_block(
parse_block_tail(p, lo, ast::default_blk));
ret pexpr(mk_mac_expr(p, lo, p.span.hi, blk));
} else if p.token == token::ELLIPSIS {
p.bump();
ret pexpr(mk_mac_expr(p, lo, p.span.hi, ast::mac_ellipsis));
} else if eat_word(p, "bind") {
let e = parse_expr_res(p, RESTRICT_NO_CALL_EXPRS);
let es =
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_expr_or_hole, p);
hi = es.span.hi;
ex = ast::expr_bind(e, es.node);
} else if p.token == token::POUND {
let ex_ext = parse_syntax_ext(p);
hi = ex_ext.span.hi;
ex = ex_ext.node;
} else if eat_word(p, "fail") {
if can_begin_expr(p.token) {
let e = parse_expr(p);
hi = e.span.hi;
ex = ast::expr_fail(some(e));
} else { ex = ast::expr_fail(none); }
} else if eat_word(p, "log") {
expect(p, token::LPAREN);
let lvl = parse_expr(p);
expect(p, token::COMMA);
let e = parse_expr(p);
ex = ast::expr_log(2, lvl, e);
hi = p.span.hi;
expect(p, token::RPAREN);
} else if eat_word(p, "assert") {
let e = parse_expr(p);
ex = ast::expr_assert(e);
hi = e.span.hi;
} else if eat_word(p, "check") {
/* Should be a predicate (pure boolean function) applied to
arguments that are all either slot variables or literals.
but the typechecker enforces that. */
let e = parse_expr(p);
hi = e.span.hi;
ex = ast::expr_check(ast::checked_expr, e);
} else if eat_word(p, "claim") {
/* Same rules as check, except that if check-claims
is enabled (a command-line flag), then the parser turns
claims into check */
let e = parse_expr(p);
hi = e.span.hi;
ex = ast::expr_check(ast::claimed_expr, e);
} else if eat_word(p, "ret") {
if can_begin_expr(p.token) {
let e = parse_expr(p);
hi = e.span.hi;
ex = ast::expr_ret(some(e));
} else { ex = ast::expr_ret(none); }
} else if eat_word(p, "break") {
ex = ast::expr_break;
hi = p.span.hi;
} else if eat_word(p, "cont") {
ex = ast::expr_cont;
hi = p.span.hi;
} else if eat_word(p, "be") {
let e = parse_expr(p);
hi = e.span.hi;
ex = ast::expr_be(e);
} else if eat_word(p, "copy") {
let e = parse_expr(p);
ex = ast::expr_copy(e);
hi = e.span.hi;
} else if p.token == token::MOD_SEP ||
is_ident(p.token) && !is_word(p, "true") &&
!is_word(p, "false") {
check_bad_word(p);
let pth = parse_path_and_ty_param_substs(p, true);
hi = pth.span.hi;
ex = ast::expr_path(pth);
} else {
let lit = parse_lit(p);
hi = lit.span.hi;
ex = ast::expr_lit(@lit);
}
// Vstore is legal following expr_lit(lit_str(...)) and expr_vec(...)
// only.
alt ex {
ast::expr_lit(@{node: ast::lit_str(_), span: _}) |
ast::expr_vec(_, _) {
alt maybe_parse_vstore(p) {
none { }
some(v) {
hi = p.span.hi;
ex = ast::expr_vstore(mk_expr(p, lo, hi, ex), v);
}
}
}
_ { }
}
ret mk_pexpr(p, lo, hi, ex);
}
fn parse_block_expr(p: parser,
lo: uint,
blk_mode: ast::blk_check_mode) -> @ast::expr {
expect(p, token::LBRACE);
let blk = parse_block_tail(p, lo, blk_mode);
ret mk_expr(p, blk.span.lo, blk.span.hi, ast::expr_block(blk));
}
fn parse_syntax_ext(p: parser) -> @ast::expr {
let lo = p.span.lo;
expect(p, token::POUND);
ret parse_syntax_ext_naked(p, lo);
}
fn parse_syntax_ext_naked(p: parser, lo: uint) -> @ast::expr {
alt p.token {
token::IDENT(_, _) {}
_ { p.fatal("expected a syntax expander name"); }
}
let pth = parse_path(p);
//temporary for a backwards-compatible cycle:
let sep = seq_sep(token::COMMA);
let mut e = none;
if (p.token == token::LPAREN || p.token == token::LBRACKET) {
let es =
if p.token == token::LPAREN {
parse_seq(token::LPAREN, token::RPAREN,
sep, parse_expr, p)
} else {
parse_seq(token::LBRACKET, token::RBRACKET,
sep, parse_expr, p)
};
let hi = es.span.hi;
e = some(mk_expr(p, es.span.lo, hi,
ast::expr_vec(es.node, ast::m_imm)));
}
let mut b = none;
if p.token == token::LBRACE {
p.bump();
let lo = p.span.lo;
let mut depth = 1u;
while (depth > 0u) {
alt (p.token) {
token::LBRACE {depth += 1u;}
token::RBRACE {depth -= 1u;}
token::EOF {p.fatal("unexpected EOF in macro body");}
_ {}
}
p.bump();
}
let hi = p.last_span.lo;
b = some({span: mk_sp(lo,hi)});
}
ret mk_mac_expr(p, lo, p.span.hi, ast::mac_invoc(pth, e, b));
}
fn parse_dot_or_call_expr(p: parser) -> pexpr {
let b = parse_bottom_expr(p);
parse_dot_or_call_expr_with(p, b)
}
fn permits_call(p: parser) -> bool {
ret p.restriction != RESTRICT_NO_CALL_EXPRS;
}
fn parse_dot_or_call_expr_with(p: parser, e0: pexpr) -> pexpr {
let mut e = e0;
let lo = e.span.lo;
let mut hi = e.span.hi;
loop {
// expr.f
if eat(p, token::DOT) {
alt p.token {
token::IDENT(i, _) {
hi = p.span.hi;
p.bump();
let tys = if eat(p, token::MOD_SEP) {
expect(p, token::LT);
parse_seq_to_gt(some(token::COMMA),
{|p| parse_ty(p, false)}, p)
} else { [] };
e = mk_pexpr(p, lo, hi,
ast::expr_field(to_expr(e),
p.get_str(i),
tys));
}
_ { unexpected(p); }
}
cont;
}
if expr_is_complete(p, e) { break; }
alt p.token {
// expr(...)
token::LPAREN if permits_call(p) {
let es_opt =
parse_seq(token::LPAREN, token::RPAREN,
seq_sep(token::COMMA), parse_expr_or_hole, p);
hi = es_opt.span.hi;
let nd =
if vec::any(es_opt.node, {|e| option::is_none(e) }) {
ast::expr_bind(to_expr(e), es_opt.node)
} else {
let es = vec::map(es_opt.node) {|e| option::get(e) };
ast::expr_call(to_expr(e), es, false)
};
e = mk_pexpr(p, lo, hi, nd);
}
// expr {|| ... }
token::LBRACE if (token::is_bar(p.look_ahead(1u))
&& permits_call(p)) {
p.bump();
let blk = parse_fn_block_expr(p);
alt e.node {
ast::expr_call(f, args, false) {
e = pexpr(@{node: ast::expr_call(f, args + [blk], true)
with *to_expr(e)});
}
_ {
e = mk_pexpr(p, lo, p.last_span.hi,
ast::expr_call(to_expr(e), [blk], true));
}
}
}
// expr[...]
token::LBRACKET {
p.bump();
let ix = parse_expr(p);
hi = ix.span.hi;
expect(p, token::RBRACKET);
p.get_id(); // see ast_util::op_expr_callee_id
e = mk_pexpr(p, lo, hi, ast::expr_index(to_expr(e), ix));
}
_ { ret e; }
}
}
ret e;
}
fn parse_prefix_expr(p: parser) -> pexpr {
let lo = p.span.lo;
let mut hi = p.span.hi;
let mut ex;
alt p.token {
token::NOT {
p.bump();
let e = to_expr(parse_prefix_expr(p));
hi = e.span.hi;
p.get_id(); // see ast_util::op_expr_callee_id
ex = ast::expr_unary(ast::not, e);
}
token::BINOP(b) {
alt b {
token::MINUS {
p.bump();
let e = to_expr(parse_prefix_expr(p));
hi = e.span.hi;
p.get_id(); // see ast_util::op_expr_callee_id
ex = ast::expr_unary(ast::neg, e);
}
token::STAR {
p.bump();
let e = to_expr(parse_prefix_expr(p));
hi = e.span.hi;
ex = ast::expr_unary(ast::deref, e);
}
token::AND {
p.bump();
let m = parse_mutability(p);
let e = to_expr(parse_prefix_expr(p));
hi = e.span.hi;
ex = ast::expr_addr_of(m, e);
}
_ { ret parse_dot_or_call_expr(p); }
}
}
token::AT {
p.bump();
let m = parse_mutability(p);
let e = to_expr(parse_prefix_expr(p));
hi = e.span.hi;
ex = ast::expr_unary(ast::box(m), e);
}
token::TILDE {
p.bump();
let m = parse_mutability(p);
let e = to_expr(parse_prefix_expr(p));
hi = e.span.hi;
ex = ast::expr_unary(ast::uniq(m), e);
}
_ { ret parse_dot_or_call_expr(p); }
}
ret mk_pexpr(p, lo, hi, ex);
}
fn parse_binops(p: parser) -> @ast::expr {
ret parse_more_binops(p, parse_prefix_expr(p), 0);
}
fn parse_more_binops(p: parser, plhs: pexpr, min_prec: int) ->
@ast::expr {
let lhs = to_expr(plhs);
if expr_is_complete(p, plhs) { ret lhs; }
let peeked = p.token;
if peeked == token::BINOP(token::OR) &&
p.restriction == RESTRICT_NO_BAR_OP { ret lhs; }
for vec::each(*p.binop_precs) {|cur|
if cur.prec > min_prec && cur.tok == peeked {
p.bump();
let expr = parse_prefix_expr(p);
let rhs = parse_more_binops(p, expr, cur.prec);
p.get_id(); // see ast_util::op_expr_callee_id
let bin = mk_pexpr(p, lhs.span.lo, rhs.span.hi,
ast::expr_binary(cur.op, lhs, rhs));
ret parse_more_binops(p, bin, min_prec);
}
}
if as_prec > min_prec && eat_word(p, "as") {
let rhs = parse_ty(p, true);
let _as =
mk_pexpr(p, lhs.span.lo, rhs.span.hi, ast::expr_cast(lhs, rhs));
ret parse_more_binops(p, _as, min_prec);
}
ret lhs;
}
fn parse_assign_expr(p: parser) -> @ast::expr {
let lo = p.span.lo;
let lhs = parse_binops(p);
alt p.token {
token::EQ {
p.bump();
let rhs = parse_expr(p);
ret mk_expr(p, lo, rhs.span.hi, ast::expr_assign(lhs, rhs));
}
token::BINOPEQ(op) {
p.bump();
let rhs = parse_expr(p);
let mut aop;
alt op {
token::PLUS { aop = ast::add; }
token::MINUS { aop = ast::subtract; }
token::STAR { aop = ast::mul; }
token::SLASH { aop = ast::div; }
token::PERCENT { aop = ast::rem; }
token::CARET { aop = ast::bitxor; }
token::AND { aop = ast::bitand; }
token::OR { aop = ast::bitor; }
token::LSL { aop = ast::lsl; }
token::LSR { aop = ast::lsr; }
token::ASR { aop = ast::asr; }
}
p.get_id(); // see ast_util::op_expr_callee_id
ret mk_expr(p, lo, rhs.span.hi, ast::expr_assign_op(aop, lhs, rhs));
}
token::LARROW {
p.bump();
let rhs = parse_expr(p);
ret mk_expr(p, lo, rhs.span.hi, ast::expr_move(lhs, rhs));
}
token::DARROW {
p.bump();
let rhs = parse_expr(p);
ret mk_expr(p, lo, rhs.span.hi, ast::expr_swap(lhs, rhs));
}
_ {/* fall through */ }
}
ret lhs;
}
fn parse_if_expr_1(p: parser) ->
{cond: @ast::expr,
then: ast::blk,
els: option<@ast::expr>,
lo: uint,
hi: uint} {
let lo = p.last_span.lo;
let cond = parse_expr(p);
let thn = parse_block(p);
let mut els: option<@ast::expr> = none;
let mut hi = thn.span.hi;
if eat_word(p, "else") {
let elexpr = parse_else_expr(p);
els = some(elexpr);
hi = elexpr.span.hi;
}
ret {cond: cond, then: thn, els: els, lo: lo, hi: hi};
}
fn parse_if_expr(p: parser) -> @ast::expr {
if eat_word(p, "check") {
let q = parse_if_expr_1(p);
ret mk_expr(p, q.lo, q.hi, ast::expr_if_check(q.cond, q.then, q.els));
} else {
let q = parse_if_expr_1(p);
ret mk_expr(p, q.lo, q.hi, ast::expr_if(q.cond, q.then, q.els));
}
}
// Parses:
//
// CC := [copy ID*; move ID*]
//
// where any part is optional and trailing ; is permitted.
fn parse_capture_clause(p: parser) -> @ast::capture_clause {
fn expect_opt_trailing_semi(p: parser) {
if !eat(p, token::SEMI) {
if p.token != token::RBRACKET {
p.fatal("expecting ; or ]");
}
}
}
fn eat_ident_list(p: parser) -> [@ast::capture_item] {
let mut res = [];
loop {
alt p.token {
token::IDENT(_, _) {
let id = p.get_id();
let sp = ast_util::mk_sp(p.span.lo, p.span.hi);
let ident = parse_ident(p);
res += [@{id:id, name:ident, span:sp}];
if !eat(p, token::COMMA) {
ret res;
}
}
_ { ret res; }
}
};
}
let mut copies = [];
let mut moves = [];
if eat(p, token::LBRACKET) {
while !eat(p, token::RBRACKET) {
if eat_word(p, "copy") {
copies += eat_ident_list(p);
expect_opt_trailing_semi(p);
} else if eat_word(p, "move") {
moves += eat_ident_list(p);
expect_opt_trailing_semi(p);
} else {
let s: str = "expecting send, copy, or move clause";
p.fatal(s);
}
}
}
ret @{copies: copies, moves: moves};
}
fn parse_fn_expr(p: parser, proto: ast::proto) -> @ast::expr {
let lo = p.last_span.lo;
let capture_clause = parse_capture_clause(p);
let decl = parse_fn_decl(p, ast::impure_fn);
let body = parse_block(p);
ret mk_expr(p, lo, body.span.hi,
ast::expr_fn(proto, decl, body, capture_clause));
}
fn parse_fn_block_expr(p: parser) -> @ast::expr {
let lo = p.last_span.lo;
let decl = parse_fn_block_decl(p);
let body = parse_block_tail(p, lo, ast::default_blk);
ret mk_expr(p, lo, body.span.hi, ast::expr_fn_block(decl, body));
}
fn parse_else_expr(p: parser) -> @ast::expr {
if eat_word(p, "if") {
ret parse_if_expr(p);
} else {
let blk = parse_block(p);
ret mk_expr(p, blk.span.lo, blk.span.hi, ast::expr_block(blk));
}
}
fn parse_for_expr(p: parser) -> @ast::expr {
let lo = p.last_span;
let call = parse_expr_res(p, RESTRICT_STMT_EXPR);
alt call.node {
ast::expr_call(f, args, true) {
let b_arg = vec::last(args);
let last = mk_expr(p, b_arg.span.lo, b_arg.span.hi,
ast::expr_loop_body(b_arg));
@{node: ast::expr_call(f, vec::init(args) + [last], true)
with *call}
}
_ {
p.span_fatal(lo, "`for` must be followed by a block call");
}
}
}
fn parse_while_expr(p: parser) -> @ast::expr {
let lo = p.last_span.lo;
let cond = parse_expr(p);
let body = parse_block_no_value(p);
let mut hi = body.span.hi;
ret mk_expr(p, lo, hi, ast::expr_while(cond, body));
}
fn parse_do_while_expr(p: parser) -> @ast::expr {
let lo = p.last_span.lo;
let body = parse_block_no_value(p);
expect_word(p, "while");
let cond = parse_expr(p);
let mut hi = cond.span.hi;
ret mk_expr(p, lo, hi, ast::expr_do_while(body, cond));
}
fn parse_loop_expr(p: parser) -> @ast::expr {
let lo = p.last_span.lo;
let body = parse_block_no_value(p);
let mut hi = body.span.hi;
ret mk_expr(p, lo, hi, ast::expr_loop(body));
}
fn parse_alt_expr(p: parser) -> @ast::expr {
let lo = p.last_span.lo;
let mode = if eat_word(p, "check") { ast::alt_check }
else { ast::alt_exhaustive };
let discriminant = parse_expr(p);
expect(p, token::LBRACE);
let mut arms: [ast::arm] = [];
while p.token != token::RBRACE {
let pats = parse_pats(p);
let mut guard = none;
if eat_word(p, "if") { guard = some(parse_expr(p)); }
let blk = parse_block(p);
arms += [{pats: pats, guard: guard, body: blk}];
}
let mut hi = p.span.hi;
p.bump();
ret mk_expr(p, lo, hi, ast::expr_alt(discriminant, arms, mode));
}
fn parse_expr(p: parser) -> @ast::expr {
ret parse_expr_res(p, UNRESTRICTED);
}
fn parse_expr_or_hole(p: parser) -> option<@ast::expr> {
alt p.token {
token::UNDERSCORE { p.bump(); ret none; }
_ { ret some(parse_expr(p)); }
}
}
fn parse_expr_res(p: parser, r: restriction) -> @ast::expr {
let old = p.restriction;
p.restriction = r;
let e = parse_assign_expr(p);
p.restriction = old;
ret e;
}
fn parse_initializer(p: parser) -> option<ast::initializer> {
alt p.token {
token::EQ {
p.bump();
ret some({op: ast::init_assign, expr: parse_expr(p)});
}
token::LARROW {
p.bump();
ret some({op: ast::init_move, expr: parse_expr(p)});
}
// Now that the the channel is the first argument to receive,
// combining it with an initializer doesn't really make sense.
// case (token::RECV) {
// p.bump();
// ret some(rec(op = ast::init_recv,
// expr = parse_expr(p)));
// }
_ {
ret none;
}
}
}
fn parse_pats(p: parser) -> [@ast::pat] {
let mut pats = [];
loop {
pats += [parse_pat(p)];
if p.token == token::BINOP(token::OR) { p.bump(); } else { ret pats; }
};
}
fn parse_pat(p: parser) -> @ast::pat {
let lo = p.span.lo;
let mut hi = p.span.hi;
let mut pat;
alt p.token {
token::UNDERSCORE { p.bump(); pat = ast::pat_wild; }
token::AT {
p.bump();
let sub = parse_pat(p);
pat = ast::pat_box(sub);
hi = sub.span.hi;
}
token::TILDE {
p.bump();
let sub = parse_pat(p);
pat = ast::pat_uniq(sub);
hi = sub.span.hi;
}
token::LBRACE {
p.bump();
let mut fields = [];
let mut etc = false;
let mut first = true;
while p.token != token::RBRACE {
if first { first = false; } else { expect(p, token::COMMA); }
if p.token == token::UNDERSCORE {
p.bump();
if p.token != token::RBRACE {
p.fatal("expecting }, found " +
token_to_str(p.reader, p.token));
}
etc = true;
break;
}
let lo1 = p.last_span.lo;
let fieldname = parse_ident(p);
let hi1 = p.last_span.lo;
let fieldpath = ast_util::ident_to_path(ast_util::mk_sp(lo1, hi1),
fieldname);
let mut subpat;
if p.token == token::COLON {
p.bump();
subpat = parse_pat(p);
} else {
if p.bad_expr_words.contains_key(fieldname) {
p.fatal("found " + fieldname + " in binding position");
}
subpat = @{id: p.get_id(),
node: ast::pat_ident(fieldpath, none),
span: ast_util::mk_sp(lo, hi)};
}
fields += [{ident: fieldname, pat: subpat}];
}
hi = p.span.hi;
p.bump();
pat = ast::pat_rec(fields, etc);
}
token::LPAREN {
p.bump();
if p.token == token::RPAREN {
hi = p.span.hi;
p.bump();
let lit = @{node: ast::lit_nil, span: ast_util::mk_sp(lo, hi)};
let expr = mk_expr(p, lo, hi, ast::expr_lit(lit));
pat = ast::pat_lit(expr);
} else {
let mut fields = [parse_pat(p)];
while p.token == token::COMMA {
p.bump();
fields += [parse_pat(p)];
}
if vec::len(fields) == 1u { expect(p, token::COMMA); }
hi = p.span.hi;
expect(p, token::RPAREN);
pat = ast::pat_tup(fields);
}
}
tok {
if !is_ident(tok) || is_word(p, "true") || is_word(p, "false") {
let val = parse_expr_res(p, RESTRICT_NO_BAR_OP);
if eat_word(p, "to") {
let end = parse_expr_res(p, RESTRICT_NO_BAR_OP);
hi = end.span.hi;
pat = ast::pat_range(val, end);
} else {
hi = val.span.hi;
pat = ast::pat_lit(val);
}
} else if is_plain_ident(p.token) &&
alt p.look_ahead(1u) {
token::LPAREN | token::LBRACKET | token::LT { false }
_ { true }
} {
let name = parse_value_path(p);
let sub = if eat(p, token::AT) { some(parse_pat(p)) }
else { none };
pat = ast::pat_ident(name, sub);
} else {
let enum_path = parse_path_and_ty_param_substs(p, true);
hi = enum_path.span.hi;
let mut args: [@ast::pat];
alt p.token {
token::LPAREN {
let a =
parse_seq(token::LPAREN, token::RPAREN,
seq_sep(token::COMMA), parse_pat, p);
args = a.node;
hi = a.span.hi;
}
_ { args = []; }
}
// at this point, we're not sure whether it's a enum or a bind
if vec::len(args) == 0u &&
vec::len(enum_path.node.idents) == 1u {
pat = ast::pat_ident(enum_path, none);
}
else {
pat = ast::pat_enum(enum_path, args);
}
}
}
}
ret @{id: p.get_id(), node: pat, span: ast_util::mk_sp(lo, hi)};
}
fn parse_local(p: parser, is_mutbl: bool,
allow_init: bool) -> @ast::local {
let lo = p.span.lo;
let pat = parse_pat(p);
let mut ty = @{id: p.get_id(),
node: ast::ty_infer,
span: ast_util::mk_sp(lo, lo)};
if eat(p, token::COLON) { ty = parse_ty(p, false); }
let init = if allow_init { parse_initializer(p) } else { none };
ret @spanned(lo, p.last_span.hi,
{is_mutbl: is_mutbl, ty: ty, pat: pat,
init: init, id: p.get_id()});
}
fn parse_let(p: parser) -> @ast::decl {
let is_mutbl = eat_word(p, "mut");
let lo = p.span.lo;
let mut locals = [parse_local(p, is_mutbl, true)];
while eat(p, token::COMMA) {
locals += [parse_local(p, is_mutbl, true)];
}
ret @spanned(lo, p.last_span.hi, ast::decl_local(locals));
}
/* assumes "let" token has already been consumed */
fn parse_instance_var(p:parser, pr: ast::privacy) -> @ast::class_member {
let mut is_mutbl = ast::class_immutable;
let lo = p.span.lo;
if eat_word(p, "mut") || eat_word(p, "mutable") {
is_mutbl = ast::class_mutable;
}
if !is_plain_ident(p.token) {
p.fatal("expecting ident");
}
let name = parse_ident(p);
expect(p, token::COLON);
let ty = parse_ty(p, false);
ret @{node: ast::instance_var(name, ty, is_mutbl, p.get_id(), pr),
span: ast_util::mk_sp(lo, p.last_span.hi)};
}
fn parse_stmt(p: parser, first_item_attrs: [ast::attribute]) -> @ast::stmt {
fn check_expected_item(p: parser, current_attrs: [ast::attribute]) {
// If we have attributes then we should have an item
if vec::is_not_empty(current_attrs) {
p.fatal("expected item");
}
}
let lo = p.span.lo;
if is_word(p, "let") {
check_expected_item(p, first_item_attrs);
expect_word(p, "let");
let decl = parse_let(p);
ret @spanned(lo, decl.span.hi, ast::stmt_decl(decl, p.get_id()));
} else {
let mut item_attrs;
alt parse_outer_attrs_or_ext(p, first_item_attrs) {
none { item_attrs = []; }
some(left(attrs)) { item_attrs = attrs; }
some(right(ext)) {
ret @spanned(lo, ext.span.hi, ast::stmt_expr(ext, p.get_id()));
}
}
let item_attrs = first_item_attrs + item_attrs;
alt parse_item(p, item_attrs) {
some(i) {
let mut hi = i.span.hi;
let decl = @spanned(lo, hi, ast::decl_item(i));
ret @spanned(lo, hi, ast::stmt_decl(decl, p.get_id()));
}
none() { /* fallthrough */ }
}
check_expected_item(p, item_attrs);
// Remainder are line-expr stmts.
let e = parse_expr_res(p, RESTRICT_STMT_EXPR);
ret @spanned(lo, e.span.hi, ast::stmt_expr(e, p.get_id()));
}
}
fn expr_is_complete(p: parser, e: pexpr) -> bool {
log(debug, ("expr_is_complete", p.restriction,
print::pprust::expr_to_str(*e),
classify::expr_requires_semi_to_be_stmt(*e)));
ret p.restriction == RESTRICT_STMT_EXPR &&
!classify::expr_requires_semi_to_be_stmt(*e);
}
fn parse_block(p: parser) -> ast::blk {
let (attrs, blk) = parse_inner_attrs_and_block(p, false);
assert vec::is_empty(attrs);
ret blk;
}
fn parse_inner_attrs_and_block(
p: parser, parse_attrs: bool) -> ([ast::attribute], ast::blk) {
fn maybe_parse_inner_attrs_and_next(
p: parser, parse_attrs: bool) ->
{inner: [ast::attribute], next: [ast::attribute]} {
if parse_attrs {
parse_inner_attrs_and_next(p)
} else {
{inner: [], next: []}
}
}
let lo = p.span.lo;
if eat_word(p, "unchecked") {
expect(p, token::LBRACE);
let {inner, next} = maybe_parse_inner_attrs_and_next(p, parse_attrs);
ret (inner, parse_block_tail_(p, lo, ast::unchecked_blk, next));
} else if eat_word(p, "unsafe") {
expect(p, token::LBRACE);
let {inner, next} = maybe_parse_inner_attrs_and_next(p, parse_attrs);
ret (inner, parse_block_tail_(p, lo, ast::unsafe_blk, next));
} else {
expect(p, token::LBRACE);
let {inner, next} = maybe_parse_inner_attrs_and_next(p, parse_attrs);
ret (inner, parse_block_tail_(p, lo, ast::default_blk, next));
}
}
fn parse_block_no_value(p: parser) -> ast::blk {
// We parse blocks that cannot have a value the same as any other block;
// the type checker will make sure that the tail expression (if any) has
// unit type.
ret parse_block(p);
}
// Precondition: already parsed the '{' or '#{'
// I guess that also means "already parsed the 'impure'" if
// necessary, and this should take a qualifier.
// some blocks start with "#{"...
fn parse_block_tail(p: parser, lo: uint, s: ast::blk_check_mode) -> ast::blk {
parse_block_tail_(p, lo, s, [])
}
fn parse_block_tail_(p: parser, lo: uint, s: ast::blk_check_mode,
first_item_attrs: [ast::attribute]) -> ast::blk {
let mut stmts = [];
let mut expr = none;
let view_items = maybe_parse_view_import_only(p, first_item_attrs);
let mut initial_attrs = first_item_attrs;
if p.token == token::RBRACE && !vec::is_empty(initial_attrs) {
p.fatal("expected item");
}
while p.token != token::RBRACE {
alt p.token {
token::SEMI {
p.bump(); // empty
}
_ {
let stmt = parse_stmt(p, initial_attrs);
initial_attrs = [];
alt stmt.node {
ast::stmt_expr(e, stmt_id) { // Expression without semicolon:
alt p.token {
token::SEMI {
p.bump();
stmts += [@{node: ast::stmt_semi(e, stmt_id) with *stmt}];
}
token::RBRACE {
expr = some(e);
}
t {
if classify::stmt_ends_with_semi(*stmt) {
p.fatal("expected ';' or '}' after expression but \
found '" + token_to_str(p.reader, t) +
"'");
}
stmts += [stmt];
}
}
}
_ { // All other kinds of statements:
stmts += [stmt];
if classify::stmt_ends_with_semi(*stmt) {
expect(p, token::SEMI);
}
}
}
}
}
}
let mut hi = p.span.hi;
p.bump();
let bloc = {view_items: view_items, stmts: stmts, expr: expr,
id: p.get_id(), rules: s};
ret spanned(lo, hi, bloc);
}
fn parse_ty_param(p: parser) -> ast::ty_param {
let mut bounds = [];
let ident = parse_ident(p);
if eat(p, token::COLON) {
while p.token != token::COMMA && p.token != token::GT {
if eat_word(p, "send") { bounds += [ast::bound_send]; }
else if eat_word(p, "copy") { bounds += [ast::bound_copy]; }
else { bounds += [ast::bound_iface(parse_ty(p, false))]; }
}
}
ret {ident: ident, id: p.get_id(), bounds: @bounds};
}
fn parse_ty_params(p: parser) -> [ast::ty_param] {
if eat(p, token::LT) {
parse_seq_to_gt(some(token::COMMA), parse_ty_param, p)
} else { [] }
}
fn parse_fn_decl(p: parser, purity: ast::purity)
-> ast::fn_decl {
let inputs: ast::spanned<[ast::arg]> =
parse_seq(token::LPAREN, token::RPAREN, seq_sep(token::COMMA),
parse_arg, p);
// Use the args list to translate each bound variable
// mentioned in a constraint to an arg index.
// Seems weird to do this in the parser, but I'm not sure how else to.
let mut constrs = [];
if p.token == token::COLON {
p.bump();
constrs = parse_constrs({|x| parse_ty_constr(inputs.node, x) }, p);
}
let (ret_style, ret_ty) = parse_ret_ty(p);
ret {inputs: inputs.node,
output: ret_ty,
purity: purity,
cf: ret_style,
constraints: constrs};
}
fn parse_fn_block_decl(p: parser) -> ast::fn_decl {
let inputs = if eat(p, token::OROR) {
[]
} else {
parse_seq(token::BINOP(token::OR),
token::BINOP(token::OR),
seq_sep(token::COMMA),
parse_fn_block_arg, p).node
};
let output = if eat(p, token::RARROW) {
parse_ty(p, false)
} else {
@{id: p.get_id(), node: ast::ty_infer, span: p.span}
};
ret {inputs: inputs,
output: output,
purity: ast::impure_fn,
cf: ast::return_val,
constraints: []};
}
fn parse_fn_header(p: parser) -> {ident: ast::ident, tps: [ast::ty_param]} {
let id = parse_value_ident(p);
let ty_params = parse_ty_params(p);
ret {ident: id, tps: ty_params};
}
fn mk_item(p: parser, lo: uint, hi: uint, ident: ast::ident, node: ast::item_,
attrs: [ast::attribute]) -> @ast::item {
ret @{ident: ident,
attrs: attrs,
id: p.get_id(),
node: node,
span: ast_util::mk_sp(lo, hi)};
}
fn parse_item_fn(p: parser, purity: ast::purity,
attrs: [ast::attribute]) -> @ast::item {
let lo = p.last_span.lo;
let t = parse_fn_header(p);
let decl = parse_fn_decl(p, purity);
let (inner_attrs, body) = parse_inner_attrs_and_block(p, true);
let attrs = attrs + inner_attrs;
ret mk_item(p, lo, body.span.hi, t.ident,
ast::item_fn(decl, t.tps, body), attrs);
}
fn parse_method_name(p: parser) -> ast::ident {
alt p.token {
token::BINOP(op) { p.bump(); token::binop_to_str(op) }
token::NOT { p.bump(); "!" }
token::LBRACKET { p.bump(); expect(p, token::RBRACKET); "[]" }
_ {
let id = parse_value_ident(p);
if id == "unary" && eat(p, token::BINOP(token::MINUS)) { "unary-" }
else { id }
}
}
}
fn parse_method(p: parser, pr: ast::privacy) -> @ast::method {
let attrs = parse_outer_attributes(p);
let lo = p.span.lo, pur = parse_fn_purity(p);
let ident = parse_method_name(p);
let tps = parse_ty_params(p);
let decl = parse_fn_decl(p, pur);
let (inner_attrs, body) = parse_inner_attrs_and_block(p, true);
let attrs = attrs + inner_attrs;
@{ident: ident, attrs: attrs, tps: tps, decl: decl, body: body,
id: p.get_id(), span: ast_util::mk_sp(lo, body.span.hi),
self_id: p.get_id(), privacy: pr}
}
fn parse_item_iface(p: parser, attrs: [ast::attribute]) -> @ast::item {
let lo = p.last_span.lo, ident = parse_ident(p),
tps = parse_ty_params(p), meths = parse_ty_methods(p);
ret mk_item(p, lo, p.last_span.hi, ident,
ast::item_iface(tps, meths), attrs);
}
// Parses three variants (with the initial params always optional):
// impl <T: copy> of to_str for [T] { ... }
// impl name<T> of to_str for [T] { ... }
// impl name<T> for [T] { ... }
fn parse_item_impl(p: parser, attrs: [ast::attribute]) -> @ast::item {
let lo = p.last_span.lo;
fn wrap_path(p: parser, pt: @ast::path) -> @ast::ty {
@{id: p.get_id(), node: ast::ty_path(pt, p.get_id()), span: pt.span}
}
let mut (ident, tps) = if !is_word(p, "of") {
if p.token == token::LT { (none, parse_ty_params(p)) }
else { (some(parse_ident(p)), parse_ty_params(p)) }
} else { (none, []) };
let ifce = if eat_word(p, "of") {
let path = parse_path_and_ty_param_substs(p, false);
if option::is_none(ident) {
ident = some(path.node.idents[vec::len(path.node.idents) - 1u]);
}
some(wrap_path(p, path))
} else { none };
let ident = alt ident {
some(name) { name }
none { expect_word(p, "of"); fail; }
};
expect_word(p, "for");
let ty = parse_ty(p, false);
let mut meths = [];
expect(p, token::LBRACE);
while !eat(p, token::RBRACE) { meths += [parse_method(p, ast::pub)]; }
ret mk_item(p, lo, p.last_span.hi, ident,
ast::item_impl(tps, ifce, ty, meths), attrs);
}
fn parse_item_res(p: parser, attrs: [ast::attribute]) -> @ast::item {
let lo = p.last_span.lo;
let ident = parse_value_ident(p);
let rp = parse_region_param(p);
let ty_params = parse_ty_params(p);
expect(p, token::LPAREN);
let arg_ident = parse_value_ident(p);
expect(p, token::COLON);
let t = parse_ty(p, false);
expect(p, token::RPAREN);
let dtor = parse_block_no_value(p);
let decl =
{inputs:
[{mode: ast::expl(ast::by_ref), ty: t,
ident: arg_ident, id: p.get_id()}],
output: @{id: p.get_id(),
node: ast::ty_nil,
span: ast_util::mk_sp(lo, lo)},
purity: ast::impure_fn,
cf: ast::return_val,
constraints: []};
ret mk_item(p, lo, dtor.span.hi, ident,
ast::item_res(decl, ty_params, dtor,
p.get_id(), p.get_id(), rp),
attrs);
}
// Instantiates ident <i> with references to <typarams> as arguments
fn ident_to_path_tys(p: parser, i: ast::ident,
typarams: [ast::ty_param]) -> @ast::path {
let s = p.last_span;
let p_: ast::path_ = {global: false, idents: [i],
types: vec::map(typarams,
{|tp| @{id: p.get_id(),
node: ast::ty_path(ident_to_path(s, tp.ident),
p.get_id()),
span: s}})};
@spanned(s.lo, s.hi, p_)
}
fn parse_iface_ref_list(p:parser) -> [ast::iface_ref] {
parse_seq_to_before_end(token::LBRACE, seq_sep(token::COMMA),
{|p| {path: parse_path(p), id: p.get_id()}}, p)
}
fn parse_item_class(p: parser, attrs: [ast::attribute]) -> @ast::item {
let lo = p.last_span.lo;
let class_name = parse_value_ident(p);
let rp = parse_region_param(p);
let ty_params = parse_ty_params(p);
let class_path = ident_to_path_tys(p, class_name, ty_params);
let ifaces : [ast::iface_ref] = if eat_word(p, "implements")
{ parse_iface_ref_list(p) }
else { [] };
expect(p, token::LBRACE);
let mut ms: [@ast::class_member] = [];
let ctor_id = p.get_id();
let mut the_ctor : option<(ast::fn_decl, ast::blk, codemap::span)> = none;
while p.token != token::RBRACE {
alt parse_class_item(p, class_path) {
ctor_decl(a_fn_decl, blk, s) {
the_ctor = some((a_fn_decl, blk, s));
}
members(mms) { ms += mms; }
}
}
p.bump();
alt the_ctor {
some((ct_d, ct_b, ct_s)) {
ret mk_item(p, lo, p.last_span.hi, class_name,
ast::item_class(ty_params, ifaces, ms,
{node: {id: ctor_id,
self_id: p.get_id(),
dec: ct_d,
body: ct_b},
span: ct_s}, rp), attrs); }
/*
Is it strange for the parser to check this?
*/
none {
p.fatal("class with no ctor");
}
}
}
fn parse_single_class_item(p: parser, privcy: ast::privacy)
-> @ast::class_member {
if eat_word(p, "let") {
let a_var = parse_instance_var(p, privcy);
expect(p, token::SEMI);
ret a_var;
}
else {
let m = parse_method(p, privcy);
ret @{node: ast::class_method(m), span: m.span};
}
}
// lets us identify the constructor declaration at
// parse time
enum class_contents { ctor_decl(ast::fn_decl, ast::blk, codemap::span),
members([@ast::class_member]) }
fn parse_class_item(p:parser, class_name_with_tps:@ast::path)
-> class_contents {
if eat_word(p, "new") {
let lo = p.last_span.lo;
// Can ctors have attrs?
// result type is always the type of the class
let decl_ = parse_fn_decl(p, ast::impure_fn);
let decl = {output: @{id: p.get_id(),
node: ast::ty_path(class_name_with_tps, p.get_id()),
span: decl_.output.span}
with decl_};
let body = parse_block(p);
ret ctor_decl(decl, body, ast_util::mk_sp(lo, p.last_span.hi));
}
else if eat_word(p, "priv") {
expect(p, token::LBRACE);
let mut results = [];
while p.token != token::RBRACE {
results += [parse_single_class_item(p, ast::priv)];
}
p.bump();
ret members(results);
}
else {
// Probably need to parse attrs
ret members([parse_single_class_item(p, ast::pub)]);
}
}
fn parse_mod_items(p: parser, term: token::token,
first_item_attrs: [ast::attribute]) -> ast::_mod {
// Shouldn't be any view items since we've already parsed an item attr
let view_items = maybe_parse_view(p, first_item_attrs);
let mut items: [@ast::item] = [];
let mut initial_attrs = first_item_attrs;
while p.token != term {
let attrs = initial_attrs + parse_outer_attributes(p);
#debug["parse_mod_items: parse_item(attrs=%?)", attrs];
alt parse_item(p, attrs) {
some(i) { items += [i]; }
_ {
p.fatal("expected item but found '" +
token_to_str(p.reader, p.token) + "'");
}
}
#debug["parse_mod_items: attrs=%?", attrs];
initial_attrs = [];
}
if vec::is_not_empty(initial_attrs) {
// We parsed attributes for the first item but didn't find the item
p.fatal("expected item");
}
ret {view_items: view_items, items: items};
}
fn parse_item_const(p: parser, attrs: [ast::attribute]) -> @ast::item {
let lo = p.last_span.lo;
let id = parse_value_ident(p);
expect(p, token::COLON);
let ty = parse_ty(p, false);
expect(p, token::EQ);
let e = parse_expr(p);
let mut hi = p.span.hi;
expect(p, token::SEMI);
ret mk_item(p, lo, hi, id, ast::item_const(ty, e), attrs);
}
fn parse_item_mod(p: parser, attrs: [ast::attribute]) -> @ast::item {
let lo = p.last_span.lo;
let id = parse_ident(p);
expect(p, token::LBRACE);
let inner_attrs = parse_inner_attrs_and_next(p);
let first_item_outer_attrs = inner_attrs.next;
let m = parse_mod_items(p, token::RBRACE, first_item_outer_attrs);
let mut hi = p.span.hi;
expect(p, token::RBRACE);
ret mk_item(p, lo, hi, id, ast::item_mod(m), attrs + inner_attrs.inner);
}
fn parse_item_native_fn(p: parser, attrs: [ast::attribute],
purity: ast::purity) -> @ast::native_item {
let lo = p.last_span.lo;
let t = parse_fn_header(p);
let decl = parse_fn_decl(p, purity);
let mut hi = p.span.hi;
expect(p, token::SEMI);
ret @{ident: t.ident,
attrs: attrs,
node: ast::native_item_fn(decl, t.tps),
id: p.get_id(),
span: ast_util::mk_sp(lo, hi)};
}
fn parse_fn_purity(p: parser) -> ast::purity {
if eat_word(p, "fn") { ast::impure_fn }
else if eat_word(p, "pure") { expect_word(p, "fn"); ast::pure_fn }
else if eat_word(p, "unsafe") { expect_word(p, "fn"); ast::unsafe_fn }
else { unexpected(p); }
}
fn parse_native_item(p: parser, attrs: [ast::attribute]) ->
@ast::native_item {
parse_item_native_fn(p, attrs, parse_fn_purity(p))
}
fn parse_native_mod_items(p: parser, first_item_attrs: [ast::attribute]) ->
ast::native_mod {
// Shouldn't be any view items since we've already parsed an item attr
let view_items =
if vec::len(first_item_attrs) == 0u {
parse_native_view(p)
} else { [] };
let mut items: [@ast::native_item] = [];
let mut initial_attrs = first_item_attrs;
while p.token != token::RBRACE {
let attrs = initial_attrs + parse_outer_attributes(p);
initial_attrs = [];
items += [parse_native_item(p, attrs)];
}
ret {view_items: view_items,
items: items};
}
fn parse_item_native_mod(p: parser, attrs: [ast::attribute]) -> @ast::item {
let lo = p.last_span.lo;
expect_word(p, "mod");
let id = parse_ident(p);
expect(p, token::LBRACE);
let more_attrs = parse_inner_attrs_and_next(p);
let inner_attrs = more_attrs.inner;
let first_item_outer_attrs = more_attrs.next;
let m = parse_native_mod_items(p, first_item_outer_attrs);
let mut hi = p.span.hi;
expect(p, token::RBRACE);
ret mk_item(p, lo, hi, id, ast::item_native_mod(m), attrs + inner_attrs);
}
fn parse_type_decl(p: parser) -> {lo: uint, ident: ast::ident} {
let lo = p.last_span.lo;
let id = parse_ident(p);
ret {lo: lo, ident: id};
}
fn parse_item_type(p: parser, attrs: [ast::attribute]) -> @ast::item {
let t = parse_type_decl(p);
let rp = parse_region_param(p);
let tps = parse_ty_params(p);
expect(p, token::EQ);
let ty = parse_ty(p, false);
let mut hi = p.span.hi;
expect(p, token::SEMI);
ret mk_item(p, t.lo, hi, t.ident, ast::item_ty(ty, tps, rp), attrs);
}
fn parse_region_param(p: parser) -> ast::region_param {
if eat(p, token::BINOP(token::SLASH)) {
expect(p, token::BINOP(token::AND));
ast::rp_self
} else {
ast::rp_none
}
}
fn parse_item_enum(p: parser, attrs: [ast::attribute]) -> @ast::item {
let lo = p.last_span.lo;
let id = parse_ident(p);
let rp = parse_region_param(p);
let ty_params = parse_ty_params(p);
let mut variants: [ast::variant] = [];
// Newtype syntax
if p.token == token::EQ {
if p.bad_expr_words.contains_key(id) {
p.fatal("found " + id + " in enum constructor position");
}
p.bump();
let ty = parse_ty(p, false);
expect(p, token::SEMI);
let variant =
spanned(ty.span.lo, ty.span.hi,
{name: id,
attrs: [],
args: [{ty: ty, id: p.get_id()}],
id: p.get_id(),
disr_expr: none});
ret mk_item(p, lo, ty.span.hi, id,
ast::item_enum([variant], ty_params, rp), attrs);
}
expect(p, token::LBRACE);
let mut all_nullary = true, have_disr = false;
while p.token != token::RBRACE {
let variant_attrs = parse_outer_attributes(p);
let vlo = p.span.lo;
let ident = parse_value_ident(p);
let mut args = [], disr_expr = none;
if p.token == token::LPAREN {
all_nullary = false;
let arg_tys = parse_seq(token::LPAREN, token::RPAREN,
seq_sep(token::COMMA),
{|p| parse_ty(p, false)}, p);
for arg_tys.node.each {|ty|
args += [{ty: ty, id: p.get_id()}];
}
} else if eat(p, token::EQ) {
have_disr = true;
disr_expr = some(parse_expr(p));
}
let vr = {name: ident, attrs: variant_attrs,
args: args, id: p.get_id(),
disr_expr: disr_expr};
variants += [spanned(vlo, p.last_span.hi, vr)];
if !eat(p, token::COMMA) { break; }
}
expect(p, token::RBRACE);
if (have_disr && !all_nullary) {
p.fatal("discriminator values can only be used with a c-like enum");
}
ret mk_item(p, lo, p.last_span.hi, id,
ast::item_enum(variants, ty_params, rp), attrs);
}
fn parse_fn_ty_proto(p: parser) -> ast::proto {
alt p.token {
token::AT {
p.bump();
ast::proto_box
}
token::TILDE {
p.bump();
ast::proto_uniq
}
token::BINOP(token::AND) {
p.bump();
ast::proto_block
}
_ {
ast::proto_any
}
}
}
fn fn_expr_lookahead(tok: token::token) -> bool {
alt tok {
token::LPAREN | token::AT | token::TILDE | token::BINOP(_) {
true
}
_ {
false
}
}
}
fn parse_item(p: parser, attrs: [ast::attribute]) -> option<@ast::item> {
if eat_word(p, "const") {
ret some(parse_item_const(p, attrs));
} else if is_word(p, "fn") && !fn_expr_lookahead(p.look_ahead(1u)) {
p.bump();
ret some(parse_item_fn(p, ast::impure_fn, attrs));
} else if eat_word(p, "pure") {
expect_word(p, "fn");
ret some(parse_item_fn(p, ast::pure_fn, attrs));
} else if is_word(p, "unsafe") && p.look_ahead(1u) != token::LBRACE {
p.bump();
expect_word(p, "fn");
ret some(parse_item_fn(p, ast::unsafe_fn, attrs));
} else if eat_word(p, "crust") {
expect_word(p, "fn");
ret some(parse_item_fn(p, ast::crust_fn, attrs));
} else if eat_word(p, "mod") {
ret some(parse_item_mod(p, attrs));
} else if eat_word(p, "native") {
ret some(parse_item_native_mod(p, attrs));
} if eat_word(p, "type") {
ret some(parse_item_type(p, attrs));
} else if eat_word(p, "enum") {
ret some(parse_item_enum(p, attrs));
} else if eat_word(p, "iface") {
ret some(parse_item_iface(p, attrs));
} else if eat_word(p, "impl") {
ret some(parse_item_impl(p, attrs));
} else if eat_word(p, "resource") {
ret some(parse_item_res(p, attrs));
} else if eat_word(p, "class") {
ret some(parse_item_class(p, attrs));
}
else { ret none; }
}
fn parse_use(p: parser) -> ast::view_item_ {
let ident = parse_ident(p);
let metadata = parse_optional_meta(p);
ret ast::view_item_use(ident, metadata, p.get_id());
}
fn parse_view_path(p: parser) -> @ast::view_path {
let lo = p.span.lo;
let first_ident = parse_ident(p);
let mut path = [first_ident];
#debug("parsed view_path: %s", first_ident);
alt p.token {
token::EQ {
// x = foo::bar
p.bump();
path = [parse_ident(p)];
while p.token == token::MOD_SEP {
p.bump();
let id = parse_ident(p);
path += [id];
}
let mut hi = p.span.hi;
ret @spanned(lo, hi,
ast::view_path_simple(first_ident,
@spanned(lo, hi,
{global: false, idents: path,
types: []}),
p.get_id()));
}
token::MOD_SEP {
// foo::bar or foo::{a,b,c} or foo::*
while p.token == token::MOD_SEP {
p.bump();
alt p.token {
token::IDENT(i, _) {
p.bump();
path += [p.get_str(i)];
}
// foo::bar::{a,b,c}
token::LBRACE {
let idents =
parse_seq(token::LBRACE, token::RBRACE,
seq_sep(token::COMMA),
parse_path_list_ident, p).node;
let mut hi = p.span.hi;
ret @spanned(lo, hi,
ast::view_path_list(@spanned(lo, hi,
{global: false,
idents: path,
types: []}), idents,
p.get_id()));
}
// foo::bar::*
token::BINOP(token::STAR) {
p.bump();
let mut hi = p.span.hi;
ret @spanned(lo, hi,
ast::view_path_glob(@spanned(lo, hi,
{global: false,
idents: path,
types: []}),
p.get_id()));
}
_ { break; }
}
}
}
_ { }
}
let mut hi = p.span.hi;
let last = path[vec::len(path) - 1u];
ret @spanned(lo, hi,
ast::view_path_simple(last, @spanned(lo, hi,
{global: false,
idents: path,
types: []}),
p.get_id()));
}
fn parse_view_paths(p: parser) -> [@ast::view_path] {
let mut vp = [parse_view_path(p)];
while p.token == token::COMMA {
p.bump();
vp += [parse_view_path(p)];
}
ret vp;
}
fn parse_view_item(p: parser) -> @ast::view_item {
let lo = p.span.lo;
let the_item =
if eat_word(p, "use") {
parse_use(p)
} else if eat_word(p, "import") {
ast::view_item_import(parse_view_paths(p))
} else if eat_word(p, "export") {
ast::view_item_export(parse_view_paths(p))
} else {
fail
};
let mut hi = p.span.lo;
expect(p, token::SEMI);
ret @spanned(lo, hi, the_item);
}
fn is_view_item(p: parser) -> bool {
is_word(p, "use") || is_word(p, "import") || is_word(p, "export")
}
fn maybe_parse_view(
p: parser,
first_item_attrs: [ast::attribute]) -> [@ast::view_item] {
maybe_parse_view_while(p, first_item_attrs, is_view_item)
}
fn maybe_parse_view_import_only(
p: parser,
first_item_attrs: [ast::attribute]) -> [@ast::view_item] {
maybe_parse_view_while(p, first_item_attrs, bind is_word(_, "import"))
}
fn maybe_parse_view_while(
p: parser,
first_item_attrs: [ast::attribute],
f: fn@(parser) -> bool) -> [@ast::view_item] {
if vec::len(first_item_attrs) == 0u {
let mut items = [];
while f(p) { items += [parse_view_item(p)]; }
ret items;
} else {
// Shouldn't be any view items since we've already parsed an item attr
ret [];
}
}
fn parse_native_view(p: parser) -> [@ast::view_item] {
maybe_parse_view_while(p, [], is_view_item)
}
// Parses a source module as a crate
fn parse_crate_mod(p: parser, _cfg: ast::crate_cfg) -> @ast::crate {
let lo = p.span.lo;
let crate_attrs = parse_inner_attrs_and_next(p);
let first_item_outer_attrs = crate_attrs.next;
let m = parse_mod_items(p, token::EOF, first_item_outer_attrs);
ret @spanned(lo, p.span.lo,
{directives: [],
module: m,
attrs: crate_attrs.inner,
config: p.cfg});
}
fn parse_str(p: parser) -> str {
alt p.token {
token::LIT_STR(s) { p.bump(); p.get_str(s) }
_ {
p.fatal("expected string literal")
}
}
}
// Logic for parsing crate files (.rc)
//
// Each crate file is a sequence of directives.
//
// Each directive imperatively extends its environment with 0 or more items.
fn parse_crate_directive(p: parser, first_outer_attr: [ast::attribute]) ->
ast::crate_directive {
// Collect the next attributes
let outer_attrs = first_outer_attr + parse_outer_attributes(p);
// In a crate file outer attributes are only going to apply to mods
let expect_mod = vec::len(outer_attrs) > 0u;
let lo = p.span.lo;
if expect_mod || is_word(p, "mod") {
expect_word(p, "mod");
let id = parse_ident(p);
alt p.token {
// mod x = "foo.rs";
token::SEMI {
let mut hi = p.span.hi;
p.bump();
ret spanned(lo, hi, ast::cdir_src_mod(id, outer_attrs));
}
// mod x = "foo_dir" { ...directives... }
token::LBRACE {
p.bump();
let inner_attrs = parse_inner_attrs_and_next(p);
let mod_attrs = outer_attrs + inner_attrs.inner;
let next_outer_attr = inner_attrs.next;
let cdirs =
parse_crate_directives(p, token::RBRACE, next_outer_attr);
let mut hi = p.span.hi;
expect(p, token::RBRACE);
ret spanned(lo, hi,
ast::cdir_dir_mod(id, cdirs, mod_attrs));
}
_ { unexpected(p); }
}
} else if is_view_item(p) {
let vi = parse_view_item(p);
ret spanned(lo, vi.span.hi, ast::cdir_view_item(vi));
} else { ret p.fatal("expected crate directive"); }
}
fn parse_crate_directives(p: parser, term: token::token,
first_outer_attr: [ast::attribute]) ->
[@ast::crate_directive] {
// This is pretty ugly. If we have an outer attribute then we can't accept
// seeing the terminator next, so if we do see it then fail the same way
// parse_crate_directive would
if vec::len(first_outer_attr) > 0u && p.token == term {
expect_word(p, "mod");
}
let mut cdirs: [@ast::crate_directive] = [];
let mut first_outer_attr = first_outer_attr;
while p.token != term {
let cdir = @parse_crate_directive(p, first_outer_attr);
cdirs += [cdir];
first_outer_attr = [];
}
ret cdirs;
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//