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Merged
merged 6 commits into from
Sep 17, 2021
Merged

internal: parser cleanups #10265

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f632b5e
internal: parser cleanups
matklad Sep 17, 2021
715cd8d
internal: more local parsing tests
matklad Sep 17, 2021
55078c8
internal: more local test for mod item
matklad Sep 17, 2021
073d5f7
internal: more focused parsing tests
matklad Sep 17, 2021
77e8421
internal: more local parsing tests for macros
matklad Sep 17, 2021
329b01c
minor: simplify
matklad Sep 17, 2021
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40 changes: 20 additions & 20 deletions crates/parser/src/grammar/attributes.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,31 +12,13 @@ pub(super) fn outer_attrs(p: &mut Parser) {
}
}

pub(super) fn meta(p: &mut Parser) {
let meta = p.start();
paths::use_path(p);

match p.current() {
T![=] => {
p.bump(T![=]);
if expressions::expr(p).0.is_none() {
p.error("expected expression");
}
}
T!['('] | T!['['] | T!['{'] => items::token_tree(p),
_ => {}
}

meta.complete(p, META);
}

fn attr(p: &mut Parser, inner: bool) {
let attr = p.start();
assert!(p.at(T![#]));

let attr = p.start();
p.bump(T![#]);

if inner {
assert!(p.at(T![!]));
p.bump(T![!]);
}

Expand All @@ -51,3 +33,21 @@ fn attr(p: &mut Parser, inner: bool) {
}
attr.complete(p, ATTR);
}

pub(super) fn meta(p: &mut Parser) {
let meta = p.start();
paths::use_path(p);

match p.current() {
T![=] => {
p.bump(T![=]);
if expressions::expr(p).0.is_none() {
p.error("expected expression");
}
}
T!['('] | T!['['] | T!['{'] => items::token_tree(p),
_ => {}
}

meta.complete(p, META);
}
2 changes: 1 addition & 1 deletion crates/parser/src/grammar/expressions.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,7 @@ pub(super) fn stmt(p: &mut Parser, with_semi: StmtWithSemi, prefer_expr: bool) {

// test block_items
// fn a() { fn b() {} }
let m = match items::maybe_item(p, m) {
let m = match items::opt_item(p, m) {
Ok(()) => return,
Err(m) => m,
};
Expand Down
179 changes: 79 additions & 100 deletions crates/parser/src/grammar/items.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,8 @@ pub(super) const ITEM_RECOVERY_SET: TokenSet = TokenSet::new(&[
pub(super) fn item_or_macro(p: &mut Parser, stop_on_r_curly: bool) {
let m = p.start();
attributes::outer_attrs(p);
let m = match maybe_item(p, m) {

let m = match opt_item(p, m) {
Ok(()) => {
if p.at(T![;]) {
p.err_and_bump(
Expand All @@ -56,6 +57,7 @@ pub(super) fn item_or_macro(p: &mut Parser, stop_on_r_curly: bool) {
}
Err(m) => m,
};

if paths::is_use_path_start(p) {
match macro_call(p) {
BlockLike::Block => (),
Expand All @@ -64,30 +66,30 @@ pub(super) fn item_or_macro(p: &mut Parser, stop_on_r_curly: bool) {
}
}
m.complete(p, MACRO_CALL);
} else {
m.abandon(p);
if p.at(T!['{']) {
error_block(p, "expected an item");
} else if p.at(T!['}']) && !stop_on_r_curly {
return;
}

m.abandon(p);
match p.current() {
T!['{'] => error_block(p, "expected an item"),
T!['}'] if !stop_on_r_curly => {
let e = p.start();
p.error("unmatched `}`");
p.bump(T!['}']);
e.complete(p, ERROR);
} else if !p.at(EOF) && !p.at(T!['}']) {
p.err_and_bump("expected an item");
} else {
p.error("expected an item");
}
EOF | T!['}'] => p.error("expected an item"),
_ => p.err_and_bump("expected an item"),
}
}

/// Try to parse an item, completing `m` in case of success.
pub(super) fn maybe_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
pub(super) fn opt_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
// test_err pub_expr
// fn foo() { pub 92; }
let has_visibility = opt_visibility(p);

let m = match items_without_modifiers(p, m) {
let m = match opt_item_without_modifiers(p, m) {
Ok(()) => return Ok(()),
Err(m) => m,
};
Expand Down Expand Up @@ -235,48 +237,20 @@ pub(super) fn maybe_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
Ok(())
}

fn items_without_modifiers(p: &mut Parser, m: Marker) -> Result<(), Marker> {
fn opt_item_without_modifiers(p: &mut Parser, m: Marker) -> Result<(), Marker> {
let la = p.nth(1);
match p.current() {
// test extern_crate
// extern crate foo;
T![extern] if la == T![crate] => extern_crate(p, m),
T![use] => use_item::use_(p, m),
T![mod] => mod_item(p, m),

T![type] => type_alias(p, m),

T![struct] => {
// test struct_items
// struct Foo;
// struct Foo {}
// struct Foo();
// struct Foo(String, usize);
// struct Foo {
// a: i32,
// b: f32,
// }
adt::strukt(p, m);
}
T![struct] => adt::strukt(p, m),
T![enum] => adt::enum_(p, m),
IDENT if p.at_contextual_kw("union") && p.nth(1) == IDENT => {
// test union_items
// union Foo {}
// union Foo {
// a: i32,
// b: f32,
// }
adt::union(p, m);
}
IDENT if p.at_contextual_kw("union") && p.nth(1) == IDENT => adt::union(p, m),

// test pub_macro_def
// pub macro m($:ident) {}
T![macro] => {
macro_def(p, m);
}
IDENT if p.at_contextual_kw("macro_rules") && p.nth(1) == BANG => {
macro_rules(p, m);
}
T![macro] => macro_def(p, m),
IDENT if p.at_contextual_kw("macro_rules") && p.nth(1) == BANG => macro_rules(p, m),

T![const] if (la == IDENT || la == T![_] || la == T![mut]) => consts::konst(p, m),
T![static] => consts::static_(p, m),
Expand All @@ -286,26 +260,78 @@ fn items_without_modifiers(p: &mut Parser, m: Marker) -> Result<(), Marker> {
Ok(())
}

// test extern_crate
// extern crate foo;
fn extern_crate(p: &mut Parser, m: Marker) {
assert!(p.at(T![extern]));
p.bump(T![extern]);

assert!(p.at(T![crate]));
p.bump(T![crate]);

if p.at(T![self]) {
// test extern_crate_self
// extern crate self;
let m = p.start();
p.bump(T![self]);
m.complete(p, NAME_REF);
} else {
name_ref(p);
}

// test extern_crate_rename
// extern crate foo as bar;
opt_rename(p);
p.expect(T![;]);
m.complete(p, EXTERN_CRATE);
}

// test mod_item
// mod a;
pub(crate) fn mod_item(p: &mut Parser, m: Marker) {
p.bump(T![mod]);
name(p);
if p.at(T!['{']) {
// test mod_item_curly
// mod b { }
item_list(p);
} else if !p.eat(T![;]) {
p.error("expected `;` or `{`");
}
m.complete(p, MODULE);
}

// test type_alias
// type Foo = Bar;
fn type_alias(p: &mut Parser, m: Marker) {
p.bump(T![type]);

name(p);

// test type_item_type_params
// type Result<T> = ();
type_params::opt_generic_param_list(p);

if p.at(T![:]) {
type_params::bounds(p);
}

// test type_item_where_clause
// type Foo where Foo: Copy = ();
type_params::opt_where_clause(p);
if p.eat(T![=]) {
types::type_(p);
}
p.expect(T![;]);
m.complete(p, TYPE_ALIAS);
}

pub(crate) fn item_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
mod_contents(p, true);
p.expect(T!['}']);
m.complete(p, ITEM_LIST);
}

pub(crate) fn extern_item_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
Expand Down Expand Up @@ -347,54 +373,6 @@ fn fn_(p: &mut Parser) {
}
}

// test type_item
// type Foo = Bar;
fn type_alias(p: &mut Parser, m: Marker) {
assert!(p.at(T![type]));
p.bump(T![type]);

name(p);

// test type_item_type_params
// type Result<T> = ();
type_params::opt_generic_param_list(p);

if p.at(T![:]) {
type_params::bounds(p);
}

// test type_item_where_clause
// type Foo where Foo: Copy = ();
type_params::opt_where_clause(p);
if p.eat(T![=]) {
types::type_(p);
}
p.expect(T![;]);
m.complete(p, TYPE_ALIAS);
}

pub(crate) fn mod_item(p: &mut Parser, m: Marker) {
assert!(p.at(T![mod]));
p.bump(T![mod]);

name(p);
if p.at(T!['{']) {
item_list(p);
} else if !p.eat(T![;]) {
p.error("expected `;` or `{`");
}
m.complete(p, MODULE);
}

pub(crate) fn item_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
mod_contents(p, true);
p.expect(T!['}']);
m.complete(p, ITEM_LIST);
}

fn macro_rules(p: &mut Parser, m: Marker) {
assert!(p.at_contextual_kw("macro_rules"));
p.bump_remap(T![macro_rules]);
Expand Down Expand Up @@ -429,23 +407,24 @@ fn macro_rules(p: &mut Parser, m: Marker) {
}

// test macro_def
// macro m { ($i:ident) => {} }
// macro m($i:ident) {}
fn macro_def(p: &mut Parser, m: Marker) {
p.expect(T![macro]);
name_r(p, ITEM_RECOVERY_SET);
if p.at(T!['{']) {
// test macro_def_curly
// macro m { ($i:ident) => {} }
token_tree(p);
} else if !p.at(T!['(']) {
p.error("unmatched `(`");
} else {
} else if p.at(T!['(']) {
let m = p.start();
token_tree(p);
match p.current() {
T!['{'] | T!['['] | T!['('] => token_tree(p),
_ => p.error("expected `{`, `[`, `(`"),
}
m.complete(p, TOKEN_TREE);
} else {
p.error("unmatched `(`");
}

m.complete(p, MACRO_DEF);
Expand Down
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