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libsyntax: refactor the parser to consider foreign items as items #3704

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libsyntax: refactor the parser to consider foreign items as items #3704

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90 changes: 55 additions & 35 deletions src/libsyntax/parse/parser.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -125,15 +125,10 @@ type item_info = (ident, item_, Option<~[attribute]>);
enum item_or_view_item {
iovi_none,
iovi_item(@item),
iovi_foreign_item(@foreign_item),
iovi_view_item(@view_item)
}

enum view_item_parse_mode {
VIEW_ITEMS_AND_ITEMS_ALLOWED,
VIEW_ITEMS_ALLOWED,
IMPORTS_AND_ITEMS_ALLOWED
}

/* The expr situation is not as complex as I thought it would be.
The important thing is to make sure that lookahead doesn't balk
at INTERPOLATED tokens */
Expand Down Expand Up @@ -2185,7 +2180,7 @@ impl parser {

let item_attrs = vec::append(first_item_attrs, item_attrs);

match self.parse_item_or_view_item(item_attrs, true) {
match self.parse_item_or_view_item(item_attrs, true, false) {
iovi_item(i) => {
let mut hi = i.span.hi;
let decl = @spanned(lo, hi, decl_item(i));
Expand All @@ -2195,6 +2190,9 @@ impl parser {
self.span_fatal(vi.span, ~"view items must be declared at \
the top of the block");
}
iovi_foreign_item(_) => {
self.fatal(~"foreign items are not allowed here");
}
iovi_none() => { /* fallthrough */ }
}

Expand Down Expand Up @@ -2260,9 +2258,11 @@ impl parser {
let mut stmts = ~[];
let mut expr = None;

let {attrs_remaining, view_items, items: items} =
let {attrs_remaining, view_items, items: items, _} =
self.parse_items_and_view_items(first_item_attrs,
IMPORTS_AND_ITEMS_ALLOWED);
true, // items_allowed
false, // foreign_items_allowed
true); // restrict_to_imports

for items.each |item| {
let decl = @spanned(item.span.lo, item.span.hi, decl_item(*item));
Expand Down Expand Up @@ -2884,9 +2884,11 @@ impl parser {
fn parse_mod_items(term: token::token,
+first_item_attrs: ~[attribute]) -> _mod {
// Shouldn't be any view items since we've already parsed an item attr
let {attrs_remaining, view_items, items: starting_items} =
let {attrs_remaining, view_items, items: starting_items, _} =
self.parse_items_and_view_items(first_item_attrs,
VIEW_ITEMS_AND_ITEMS_ALLOWED);
true, // items_allowed
false, // foreign_items_allowed
false); // restrict_to_imports
let mut items: ~[@item] = move starting_items;

let mut first = true;
Expand All @@ -2898,7 +2900,7 @@ impl parser {
}
debug!("parse_mod_items: parse_item_or_view_item(attrs=%?)",
attrs);
match self.parse_item_or_view_item(attrs, true) {
match self.parse_item_or_view_item(attrs, true, false) {
iovi_item(item) => items.push(item),
iovi_view_item(view_item) => {
self.span_fatal(view_item.span, ~"view items must be \
Expand Down Expand Up @@ -2998,11 +3000,13 @@ impl parser {
+first_item_attrs: ~[attribute]) ->
foreign_mod {
// Shouldn't be any view items since we've already parsed an item attr
let {attrs_remaining, view_items, items: _} =
let {attrs_remaining, view_items, items: _, foreign_items} =
self.parse_items_and_view_items(first_item_attrs,
VIEW_ITEMS_ALLOWED);
false, // items_allowed
true, // foreign_items_allowed
false); // restrict_to_imports

let mut items: ~[@foreign_item] = ~[];
let mut items: ~[@foreign_item] = move foreign_items;
let mut initial_attrs = attrs_remaining;
while self.token != token::RBRACE {
let attrs = vec::append(initial_attrs,
Expand All @@ -3011,7 +3015,7 @@ impl parser {
items.push(self.parse_foreign_item(attrs));
}
return {sort: sort, view_items: view_items,
items: items};
items: items};
}

fn parse_item_foreign_mod(lo: uint,
Expand Down Expand Up @@ -3276,8 +3280,11 @@ impl parser {
}
}

fn parse_item_or_view_item(+attrs: ~[attribute], items_allowed: bool)
fn parse_item_or_view_item(+attrs: ~[attribute], items_allowed: bool,
foreign_items_allowed: bool)
-> item_or_view_item {
assert items_allowed != foreign_items_allowed;

maybe_whole!(iovi self,nt_item);
let lo = self.span.lo;

Expand All @@ -3295,6 +3302,9 @@ impl parser {
return iovi_item(self.mk_item(lo, self.last_span.hi, ident, item_,
visibility,
maybe_append(attrs, extra_attrs)));
} else if foreign_items_allowed && self.is_keyword(~"const") {
let item = self.parse_item_foreign_const(visibility, attrs);
return iovi_foreign_item(item);
} else if items_allowed &&
self.is_keyword(~"fn") &&
!self.fn_expr_lookahead(self.look_ahead(1u)) {
Expand All @@ -3309,6 +3319,10 @@ impl parser {
return iovi_item(self.mk_item(lo, self.last_span.hi, ident, item_,
visibility,
maybe_append(attrs, extra_attrs)));
} else if foreign_items_allowed &&
(self.is_keyword(~"fn") || self.is_keyword(~"pure")) {
let item = self.parse_item_foreign_fn(visibility, attrs);
return iovi_foreign_item(item);
} else if items_allowed && self.is_keyword(~"unsafe")
&& self.look_ahead(1u) != token::LBRACE {
self.bump();
Expand Down Expand Up @@ -3395,16 +3409,24 @@ impl parser {
return iovi_item(self.mk_item(lo, self.last_span.hi, id, item_,
visibility, attrs));
} else {
if visibility != inherited {
let mut s = ~"unmatched visibility `";
s += if visibility == public { ~"pub" } else { ~"priv" };
s += ~"`";
self.span_fatal(copy self.last_span, s);
}
return iovi_none;
};
}

fn parse_item(+attrs: ~[attribute]) -> Option<@ast::item> {
match self.parse_item_or_view_item(attrs, true) {
match self.parse_item_or_view_item(attrs, true, false) {
iovi_none =>
None,
iovi_view_item(_) =>
self.fatal(~"view items are not allowed here"),
iovi_foreign_item(_) =>
self.fatal(~"foreign items are not allowed here"),
iovi_item(item) =>
Some(item)
}
Expand Down Expand Up @@ -3536,31 +3558,24 @@ impl parser {
}

fn parse_items_and_view_items(+first_item_attrs: ~[attribute],
mode: view_item_parse_mode)
items_allowed: bool,
foreign_items_allowed: bool,
restricted_to_imports: bool)
-> {attrs_remaining: ~[attribute],
view_items: ~[@view_item],
items: ~[@item]} {
items: ~[@item],
foreign_items: ~[@foreign_item]} {
let mut attrs = vec::append(first_item_attrs,
self.parse_outer_attributes());

let items_allowed;
match mode {
VIEW_ITEMS_AND_ITEMS_ALLOWED | IMPORTS_AND_ITEMS_ALLOWED =>
items_allowed = true,
VIEW_ITEMS_ALLOWED =>
items_allowed = false
}

let (view_items, items) = (DVec(), DVec());
let (view_items, items, foreign_items) = (DVec(), DVec(), DVec());
loop {
match self.parse_item_or_view_item(attrs, items_allowed) {
match self.parse_item_or_view_item(attrs, items_allowed,
foreign_items_allowed) {
iovi_none =>
break,
iovi_view_item(view_item) => {
match mode {
VIEW_ITEMS_AND_ITEMS_ALLOWED |
VIEW_ITEMS_ALLOWED => {}
IMPORTS_AND_ITEMS_ALLOWED =>
if restricted_to_imports {
match view_item.node {
view_item_import(_) => {}
view_item_export(_) | view_item_use(*) =>
Expand All @@ -3575,13 +3590,18 @@ impl parser {
assert items_allowed;
items.push(item)
}
iovi_foreign_item(foreign_item) => {
assert foreign_items_allowed;
foreign_items.push(foreign_item);
}
}
attrs = self.parse_outer_attributes();
}

{attrs_remaining: attrs,
view_items: dvec::unwrap(move view_items),
items: dvec::unwrap(move items)}
items: dvec::unwrap(move items),
foreign_items: dvec::unwrap(move foreign_items)}
}

// Parses a source module as a crate
Expand Down
4 changes: 4 additions & 0 deletions src/test/compile-fail/duplicate-visibility.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
// error-pattern:unmatched visibility `pub`
extern {
pub pub fn foo();
}