fix and improve parser logic to handle errors better
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3266726f16
commit
c66728ab0e
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@ -13,6 +13,9 @@ pub enum ParseError {
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ExpectedParens,
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ExpectedSym,
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ExpectedTerm,
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BadInt,
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BadStr,
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BadSym(char),
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}
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impl fmt::Display for ParseError {
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@ -22,6 +25,9 @@ impl fmt::Display for ParseError {
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Self::ExpectedParens => write!(f, "expected parenthesis"),
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Self::ExpectedSym => write!(f, "expected symbol"),
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Self::ExpectedTerm => write!(f, "expected semicolon"),
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Self::BadInt => write!(f, "invalid integer"),
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Self::BadStr => write!(f, "unterminated string"),
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Self::BadSym(c) => write!(f, "invalid symbol {c}"),
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}
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}
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}
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@ -75,22 +81,22 @@ impl Symbol {
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fn take<T: Iterator<Item = char>>(
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it: &mut Peekable<T>,
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predicate: fn(c: char) -> bool,
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) -> Vec<char> {
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) -> ParseResult<Vec<char>> {
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let mut v = Vec::new();
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while let Some(c) = it.peek() {
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if !predicate(*c) {
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break;
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return Ok(v);
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}
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v.push(*c);
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it.next();
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}
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v
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Err(ParseError::Eof)
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}
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pub fn parse(s: &str) -> Result<Vec<Self>, String> {
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pub fn parse(s: &str) -> ParseResult<Vec<Self>> {
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let mut syms = Vec::new();
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let mut it = s.chars().peekable();
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@ -109,7 +115,8 @@ impl Symbol {
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it.next();
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}
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let v = Symbol::take(&mut it, |c| c.is_numeric());
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let v = Symbol::take(&mut it, |c| c.is_numeric())
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.map_err(|_| ParseError::BadInt)?;
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if let Ok(n) = v.iter().collect::<String>().parse::<u64>() {
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syms.push(if sign > 0 {
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@ -118,7 +125,7 @@ impl Symbol {
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Self::SInt((n as i64 * sign) as u64)
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});
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} else {
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return Err("invalid integer".to_string());
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return Err(ParseError::BadInt);
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}
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continue;
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@ -129,17 +136,18 @@ impl Symbol {
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'"' => {
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it.next();
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let v = Symbol::take(&mut it, |c| c != '"');
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let v = Symbol::take(&mut it, |c| c != '"').map_err(|_| ParseError::BadStr)?;
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syms.push(Self::Str(v.iter().collect()));
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}
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' ' | '\t' | '\r' => {}
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_ => {
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let err = ParseError::BadSym(c.to_owned());
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if !c.is_alphanumeric() {
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return Err(format!("invalid symbol {}", c));
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return Err(err);
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}
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let v = Symbol::take(&mut it, |c| c.is_alphanumeric());
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let v = Symbol::take(&mut it, |c| c.is_alphanumeric()).map_err(|_| err)?;
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syms.push(Self::Id(Some(v.iter().collect())));
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continue;
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}
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@ -195,12 +203,14 @@ impl<'a> Parser<'a> {
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self.next();
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loop {
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if *self.peek()? == close {
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break;
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}
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let sym = self.peek().map_err(|_| ParseError::ExpectedParens)?;
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if *sym == close {
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break;
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} else {
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node.entries.push(self.parse_expr()?);
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}
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}
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self.expect(close, ParseError::ExpectedParens)?;
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self.next();
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Ok(node)
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@ -8,7 +8,6 @@ pub type Result<T> = std::result::Result<T, Error>;
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pub enum Error {
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ReadError,
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BadFile,
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BadRead(String),
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BadWrite(std::io::Error),
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BadPath(std::io::Error),
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BpError(bp::Error),
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@ -20,7 +19,6 @@ impl fmt::Display for Error {
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match self {
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Self::ReadError => write!(f, "errors found"),
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Self::BadFile => write!(f, "invalid text"),
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Self::BadRead(e) => write!(f, "{e}"),
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Self::BadWrite(e) => write!(f, "{e}"),
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Self::BadPath(e) => write!(f, "{e}"),
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Self::BpError(e) => write!(f, "{e}"),
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@ -35,7 +33,7 @@ fn read_bip<R: BufRead>(buf: R) -> Result<Vec<bip::Node>> {
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.lines()
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.map(|l| {
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l.map_or(Err(Error::BadFile), |l| {
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bip::Symbol::parse(&l).map_err(Error::BadRead)
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bip::Symbol::parse(&l).map_err(Error::ParseError)
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})
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})
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.filter_map(|r| r.map_err(|e| errors.push(e)).ok())
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@ -48,7 +46,7 @@ fn read_bip<R: BufRead>(buf: R) -> Result<Vec<bip::Node>> {
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});
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if err_count > 0 {
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eprintln!("{err_count} errors");
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eprintln!("{err_count} error{}", if err_count == 1 { "" } else { "s" });
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Err(Error::ReadError)
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} else {
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bip::Parser::new(&syms).parse().map_err(Error::ParseError)
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