bjoernager/rust
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Use Try syntax for Option in place of macros or match

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This commit is contained in:
Matt Brubeck 2017-12-08 17:32:04 -08:00
parent c7b6d8263b
commit 3024c1434a
28 changed files with 92 additions and 230 deletions
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75
src/libsyntax_ext/format_foreign.rs
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@ -8,15 +8,6 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
macro_rules! try_opt {
($e:expr) => {
match $e {
Some(v) => v,
None => return None,
}
};
}
pub mod printf {
use super::strcursor::StrCursor as Cur;
@ -173,7 +164,7 @@ pub mod printf {
s.push_str("{");
if let Some(arg) = self.parameter {
try_opt!(write!(s, "{}", try_opt!(arg.checked_sub(1))).ok());
write!(s, "{}", arg.checked_sub(1)?).ok()?;
}
if has_options {
@ -203,12 +194,12 @@ pub mod printf {
}
if let Some(width) = width {
try_opt!(width.translate(&mut s).ok());
width.translate(&mut s).ok()?;
}
if let Some(precision) = precision {
s.push_str(".");
try_opt!(precision.translate(&mut s).ok());
precision.translate(&mut s).ok()?;
}
if let Some(type_) = type_ {
@ -277,13 +268,9 @@ pub mod printf {
impl<'a> Iterator for Substitutions<'a> {
type Item = Substitution<'a>;
fn next(&mut self) -> Option<Self::Item> {
match parse_next_substitution(self.s) {
Some((sub, tail)) => {
self.s = tail;
Some(sub)
},
None => None,
}
let (sub, tail) = parse_next_substitution(self.s)?;
self.s = tail;
Some(sub)
}
}
@ -303,11 +290,10 @@ pub mod printf {
use self::State::*;
let at = {
let start = try_opt!(s.find('%'));
match s[start+1..].chars().next() {
Some('%') => return Some((Substitution::Escape, &s[start+2..])),
Some(_) => {/* fall-through */},
None => return None,
let start = s.find('%')?;
match s[start+1..].chars().next()? {
'%' => return Some((Substitution::Escape, &s[start+2..])),
_ => {/* fall-through */},
}
Cur::new_at_start(&s[start..])
@ -335,16 +321,16 @@ pub mod printf {
// Used to establish the full span at the end.
let start = at;
// The current position within the string.
let mut at = try_opt!(at.at_next_cp());
let mut at = at.at_next_cp()?;
// `c` is the next codepoint, `next` is a cursor after it.
let (mut c, mut next) = try_opt!(at.next_cp());
let (mut c, mut next) = at.next_cp()?;
// Update `at`, `c`, and `next`, exiting if we're out of input.
macro_rules! move_to {
($cur:expr) => {
{
at = $cur;
let (c_, next_) = try_opt!(at.next_cp());
let (c_, next_) = at.next_cp()?;
c = c_;
next = next_;
}
@ -801,31 +787,27 @@ pub mod shell {
/// Parse the next substitution from the input string.
pub fn parse_next_substitution(s: &str) -> Option<(Substitution, &str)> {
let at = {
let start = try_opt!(s.find('$'));
match s[start+1..].chars().next() {
Some('$') => return Some((Substitution::Escape, &s[start+2..])),
Some(c @ '0' ... '9') => {
let start = s.find('$')?;
match s[start+1..].chars().next()? {
'$' => return Some((Substitution::Escape, &s[start+2..])),
c @ '0' ... '9' => {
let n = (c as u8) - b'0';
return Some((Substitution::Ordinal(n), &s[start+2..]));
},
Some(_) => {/* fall-through */},
None => return None,
_ => {/* fall-through */},
}
Cur::new_at_start(&s[start..])
};
let at = try_opt!(at.at_next_cp());
match at.next_cp() {
Some((c, inner)) => {
if !is_ident_head(c) {
None
} else {
let end = at_next_cp_while(inner, is_ident_tail);
Some((Substitution::Name(at.slice_between(end).unwrap()), end.slice_after()))
}
},
_ => None
let at = at.at_next_cp()?;
let (c, inner) = at.next_cp()?;
if !is_ident_head(c) {
None
} else {
let end = at_next_cp_while(inner, is_ident_tail);
Some((Substitution::Name(at.slice_between(end).unwrap()), end.slice_after()))
}
}
@ -946,10 +928,7 @@ mod strcursor {
}
pub fn next_cp(mut self) -> Option<(char, StrCursor<'a>)> {
let cp = match self.cp_after() {
Some(cp) => cp,
None => return None,
};
let cp = self.cp_after()?;
self.seek_right(cp.len_utf8());
Some((cp, self))
}