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|
use super::*;
// test expr_literals
// fn foo() {
// let _ = true;
// let _ = false;
// let _ = 1;
// let _ = 2.0;
// let _ = b'a';
// let _ = 'b';
// let _ = "c";
// let _ = r"d";
// let _ = b"e";
// let _ = br"f";
// }
pub(super) fn literal(p: &mut Parser) -> Option<CompletedMarker> {
match p.current() {
TRUE_KW | FALSE_KW | INT_NUMBER | FLOAT_NUMBER | BYTE | CHAR | STRING | RAW_STRING
| BYTE_STRING | RAW_BYTE_STRING => {
let m = p.start();
p.bump();
Some(m.complete(p, LITERAL))
}
_ => None,
}
}
pub(super) fn expr(p: &mut Parser) {
let mut lhs = match prefix_expr(p) {
Some(lhs) => lhs,
None => return,
};
loop {
lhs = match p.current() {
L_PAREN => call_expr(p, lhs),
DOT if p.nth(1) == IDENT =>
if p.nth(2) == L_PAREN {
method_call_expr(p, lhs)
} else {
field_expr(p, lhs)
}
_ => break,
}
}
}
fn prefix_expr(p: &mut Parser) -> Option<CompletedMarker> {
match p.current() {
AMPERSAND => Some(ref_expr(p)),
STAR => Some(deref_expr(p)),
_ => atom_expr(p),
}
}
// test ref_expr
// fn foo() {
// let _ = &1;
// let _ = &mut &f();
// }
fn ref_expr(p: &mut Parser) -> CompletedMarker {
assert!(p.at(AMPERSAND));
let m = p.start();
p.bump();
p.eat(MUT_KW);
expr(p);
m.complete(p, REF_EXPR)
}
// test deref_expr
// fn foo() {
// **&1;
// }
fn deref_expr(p: &mut Parser) -> CompletedMarker {
assert!(p.at(STAR));
let m = p.start();
p.bump();
expr(p);
m.complete(p, DEREF_EXPR)
}
fn atom_expr(p: &mut Parser) -> Option<CompletedMarker> {
match literal(p) {
Some(m) => return Some(m),
None => (),
}
if paths::is_path_start(p) {
return Some(path_expr(p));
}
match p.current() {
L_PAREN => Some(tuple_expr(p)),
_ => {
p.err_and_bump("expected expression");
None
}
}
}
fn tuple_expr(p: &mut Parser) -> CompletedMarker {
assert!(p.at(L_PAREN));
let m = p.start();
p.expect(L_PAREN);
p.expect(R_PAREN);
m.complete(p, TUPLE_EXPR)
}
// test call_expr
// fn foo() {
// let _ = f();
// let _ = f()(1)(1, 2,);
// }
fn call_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
assert!(p.at(L_PAREN));
let m = lhs.precede(p);
arg_list(p);
m.complete(p, CALL_EXPR)
}
// test method_call_expr
// fn foo() {
// x.foo();
// y.bar(1, 2,);
// }
fn method_call_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
assert!(p.at(DOT) && p.nth(1) == IDENT && p.nth(2) == L_PAREN);
let m = lhs.precede(p);
p.bump();
p.bump();
arg_list(p);
m.complete(p, METHOD_CALL_EXPR)
}
// test field_expr
// fn foo() {
// x.foo.bar;
// }
fn field_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
assert!(p.at(DOT) && p.nth(1) == IDENT);
let m = lhs.precede(p);
p.bump();
p.bump();
m.complete(p, FIELD_EXPR)
}
fn arg_list(p: &mut Parser) {
assert!(p.at(L_PAREN));
let m = p.start();
p.bump();
while !p.at(R_PAREN) && !p.at(EOF) {
expr(p);
if !p.at(R_PAREN) && !p.expect(COMMA) {
break;
}
}
p.eat(R_PAREN);
m.complete(p, ARG_LIST);
}
// test path_expr
// fn foo() {
// let _ = a;
// let _ = a::b;
// let _ = ::a::<b>;
// }
fn path_expr(p: &mut Parser) -> CompletedMarker {
assert!(paths::is_path_start(p));
let m = p.start();
paths::expr_path(p);
if p.at(L_CURLY) {
struct_lit(p);
m.complete(p, STRUCT_LIT)
} else {
m.complete(p, PATH_EXPR)
}
}
// test struct_lit
// fn foo() {
// S {};
// S { x, y: 32, };
// S { x, y: 32, ..Default::default() };
// }
fn struct_lit(p: &mut Parser) {
assert!(p.at(L_CURLY));
p.bump();
while !p.at(EOF) && !p.at(R_CURLY) {
match p.current() {
IDENT => {
let m = p.start();
name_ref(p);
if p.eat(COLON) {
expr(p);
}
m.complete(p, STRUCT_LIT_FIELD);
},
DOTDOT => {
p.bump();
expr(p);
},
_ => p.err_and_bump("expected identifier"),
}
if !p.at(R_CURLY) {
p.expect(COMMA);
}
}
p.expect(R_CURLY);
}
|
