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#[derive(Debug)]
#[doc(hidden)]
pub enum FormatError {
UnmatchedCurlyBracket,
InvalidPositionalArgument,
}
#[doc(hidden)]
pub fn try_format<'a>(
str_pattern: &'a str,
argv: &[::std::boxed::Box<dyn ::std::fmt::Display + 'a>],
) -> ::std::result::Result<::std::string::String, FormatError> {
use ::std::fmt::Write;
use ::std::iter::Iterator;
let mut pattern = vec![];
let mut vars = vec![];
let mut finish_or_fail = false;
for (i, part) in str_pattern.split('}').enumerate() {
if finish_or_fail {
return ::std::result::Result::Err(FormatError::UnmatchedCurlyBracket);
}
if part.contains('{') {
let mut part = part.split('{');
let text = part.next().unwrap();
let arg = part.next().ok_or(FormatError::UnmatchedCurlyBracket)?;
if part.next() != ::std::option::Option::None {
return ::std::result::Result::Err(FormatError::UnmatchedCurlyBracket);
}
pattern.push(text);
vars.push(
argv.get::<usize>(if arg.len() > 0 {
arg.parse()
.map_err(|_| FormatError::InvalidPositionalArgument)?
} else {
i
})
.ok_or(FormatError::InvalidPositionalArgument)?,
);
} else {
finish_or_fail = true;
pattern.push(part);
}
}
let mut res = ::std::string::String::with_capacity(str_pattern.len());
let mut pattern = pattern.iter();
let mut vars = vars.iter();
while let ::std::option::Option::Some(text) = pattern.next() {
res.write_str(text).unwrap();
if let ::std::option::Option::Some(var) = vars.next() {
res.write_str(&format!("{}", var)).unwrap();
}
}
::std::result::Result::Ok(res)
}