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use core::cell::{Cell, RefCell};
use alloc::{
boxed::Box,
string::{String, ToString},
vec,
vec::Vec,
};
use crate::{
error::Error,
hir::{self, Config, Flags, Hir, HirKind},
};
// These are all of the errors that can occur while parsing a regex. Unlike
// regex-syntax, our errors are not particularly great. They are just enough
// to get a general sense of what went wrong. But in exchange, the error
// reporting mechanism is *much* simpler than what's in regex-syntax.
//
// By convention, we use each of these messages in exactly one place. That
// way, every branch that leads to an error has a unique message. This in turn
// means that given a message, one can precisely identify which part of the
// parser reported it.
//
// Finally, we give names to each message so that we can reference them in
// tests.
const ERR_TOO_MUCH_NESTING: &str = "pattern has too much nesting";
const ERR_TOO_MANY_CAPTURES: &str = "too many capture groups";
const ERR_DUPLICATE_CAPTURE_NAME: &str = "duplicate capture group name";
const ERR_UNCLOSED_GROUP: &str = "found open group without closing ')'";
const ERR_UNCLOSED_GROUP_QUESTION: &str =
"expected closing ')', but got end of pattern";
const ERR_UNOPENED_GROUP: &str = "found closing ')' without matching '('";
const ERR_LOOK_UNSUPPORTED: &str = "look-around is not supported";
const ERR_EMPTY_FLAGS: &str = "empty flag directive '(?)' is not allowed";
const ERR_MISSING_GROUP_NAME: &str =
"expected capture group name, but got end of pattern";
const ERR_INVALID_GROUP_NAME: &str = "invalid group name";
const ERR_UNCLOSED_GROUP_NAME: &str =
"expected end of capture group name, but got end of pattern";
const ERR_EMPTY_GROUP_NAME: &str = "empty capture group names are not allowed";
const ERR_FLAG_UNRECOGNIZED: &str = "unrecognized inline flag";
const ERR_FLAG_REPEATED_NEGATION: &str =
"inline flag negation cannot be repeated";
const ERR_FLAG_DUPLICATE: &str = "duplicate inline flag is not allowed";
const ERR_FLAG_UNEXPECTED_EOF: &str =
"expected ':' or ')' to end inline flags, but got end of pattern";
const ERR_FLAG_DANGLING_NEGATION: &str =
"inline flags cannot end with negation directive";
const ERR_DECIMAL_NO_DIGITS: &str =
"expected decimal number, but found no digits";
const ERR_DECIMAL_INVALID: &str = "got invalid decimal number";
const ERR_HEX_BRACE_INVALID_DIGIT: &str =
"expected hexadecimal number in braces, but got non-hex digit";
const ERR_HEX_BRACE_UNEXPECTED_EOF: &str =
"expected hexadecimal number, but saw end of pattern before closing brace";
const ERR_HEX_BRACE_EMPTY: &str =
"expected hexadecimal number in braces, but got no digits";
const ERR_HEX_BRACE_INVALID: &str = "got invalid hexadecimal number in braces";
const ERR_HEX_FIXED_UNEXPECTED_EOF: &str =
"expected fixed length hexadecimal number, but saw end of pattern first";
const ERR_HEX_FIXED_INVALID_DIGIT: &str =
"expected fixed length hexadecimal number, but got non-hex digit";
const ERR_HEX_FIXED_INVALID: &str =
"got invalid fixed length hexadecimal number";
const ERR_HEX_UNEXPECTED_EOF: &str =
"expected hexadecimal number, but saw end of pattern first";
const ERR_ESCAPE_UNEXPECTED_EOF: &str =
"saw start of escape sequence, but saw end of pattern before it finished";
const ERR_BACKREF_UNSUPPORTED: &str = "backreferences are not supported";
const ERR_UNICODE_CLASS_UNSUPPORTED: &str =
"Unicode character classes are not supported";
const ERR_ESCAPE_UNRECOGNIZED: &str = "unrecognized escape sequence";
const ERR_POSIX_CLASS_UNRECOGNIZED: &str =
"unrecognized POSIX character class";
const ERR_UNCOUNTED_REP_SUB_MISSING: &str =
"uncounted repetition operator must be applied to a sub-expression";
const ERR_COUNTED_REP_SUB_MISSING: &str =
"counted repetition operator must be applied to a sub-expression";
const ERR_COUNTED_REP_UNCLOSED: &str =
"found unclosed counted repetition operator";
const ERR_COUNTED_REP_MIN_UNCLOSED: &str =
"found incomplete and unclosed counted repetition operator";
const ERR_COUNTED_REP_COMMA_UNCLOSED: &str =
"found counted repetition operator with a comma that is unclosed";
const ERR_COUNTED_REP_MIN_MAX_UNCLOSED: &str =
"found counted repetition with min and max that is unclosed";
const ERR_COUNTED_REP_INVALID: &str =
"expected closing brace for counted repetition, but got something else";
const ERR_COUNTED_REP_INVALID_RANGE: &str =
"found counted repetition with a min bigger than its max";
const ERR_CLASS_UNCLOSED_AFTER_ITEM: &str =
"non-empty character class has no closing bracket";
const ERR_CLASS_INVALID_RANGE_ITEM: &str =
"character class ranges must start and end with a single character";
const ERR_CLASS_INVALID_ITEM: &str =
"invalid escape sequence in character class";
const ERR_CLASS_UNCLOSED_AFTER_DASH: &str =
"non-empty character class has no closing bracket after dash";
const ERR_CLASS_UNCLOSED_AFTER_NEGATION: &str =
"negated character class has no closing bracket";
const ERR_CLASS_UNCLOSED_AFTER_CLOSING: &str =
"character class begins with literal ']' but has no closing bracket";
const ERR_CLASS_INVALID_RANGE: &str = "invalid range in character class";
const ERR_CLASS_UNCLOSED: &str = "found unclosed character class";
const ERR_CLASS_NEST_UNSUPPORTED: &str =
"nested character classes are not supported";
const ERR_CLASS_INTERSECTION_UNSUPPORTED: &str =
"character class intersection is not supported";
const ERR_CLASS_DIFFERENCE_UNSUPPORTED: &str =
"character class difference is not supported";
const ERR_CLASS_SYMDIFFERENCE_UNSUPPORTED: &str =
"character class symmetric difference is not supported";
const ERR_SPECIAL_WORD_BOUNDARY_UNCLOSED: &str =
"special word boundary assertion is unclosed or has an invalid character";
const ERR_SPECIAL_WORD_BOUNDARY_UNRECOGNIZED: &str =
"special word boundary assertion is unrecognized";
const ERR_SPECIAL_WORD_OR_REP_UNEXPECTED_EOF: &str =
"found start of special word boundary or repetition without an end";
/// A regular expression parser.
///
/// This parses a string representation of a regular expression into an
/// abstract syntax tree. The size of the tree is proportional to the length
/// of the regular expression pattern.
///
/// A `Parser` can be configured in more detail via a [`ParserBuilder`].
#[derive(Clone, Debug)]
pub(super) struct Parser<'a> {
/// The configuration of the parser as given by the caller.
config: Config,
/// The pattern we're parsing as given by the caller.
pattern: &'a str,
/// The call depth of the parser. This is incremented for each
/// sub-expression parsed. Its peak value is the maximum nesting of the
/// pattern.
depth: Cell<u32>,
/// The current position of the parser.
pos: Cell<usize>,
/// The current codepoint of the parser. The codepoint corresponds to the
/// codepoint encoded in `pattern` beginning at `pos`.
///
/// This is `None` if and only if `pos == pattern.len()`.
char: Cell<Option<char>>,
/// The current capture index.
capture_index: Cell<u32>,
/// The flags that are currently set.
flags: RefCell<Flags>,
/// A sorted sequence of capture names. This is used to detect duplicate
/// capture names and report an error if one is detected.
capture_names: RefCell<Vec<String>>,
}
/// The constructor and a variety of helper routines.
impl<'a> Parser<'a> {
/// Build a parser from this configuration with the given pattern.
pub(super) fn new(config: Config, pattern: &'a str) -> Parser<'a> {
Parser {
config,
pattern,
depth: Cell::new(0),
pos: Cell::new(0),
char: Cell::new(pattern.chars().next()),
capture_index: Cell::new(0),
flags: RefCell::new(config.flags),
capture_names: RefCell::new(vec![]),
}
}
/// Returns the full pattern string that we're parsing.
fn pattern(&self) -> &str {
self.pattern
}
/// Return the current byte offset of the parser.
///
/// The offset starts at `0` from the beginning of the regular expression
/// pattern string.
fn pos(&self) -> usize {
self.pos.get()
}
/// Increments the call depth of the parser.
///
/// If the call depth would exceed the configured nest limit, then this
/// returns an error.
///
/// This returns the old depth.
fn increment_depth(&self) -> Result<u32, Error> {
let old = self.depth.get();
if old > self.config.nest_limit {
return Err(Error::new(ERR_TOO_MUCH_NESTING));
}
// OK because our depth starts at 0, and we return an error if it
// ever reaches the limit. So the call depth can never exceed u32::MAX.
let new = old.checked_add(1).unwrap();
self.depth.set(new);
Ok(old)
}
/// Decrements the call depth of the parser.
///
/// This panics if the current depth is 0.
fn decrement_depth(&self) {
let old = self.depth.get();
// If this fails then the caller has a bug in how they're incrementing
// and decrementing the depth of the parser's call stack.
let new = old.checked_sub(1).unwrap();
self.depth.set(new);
}
/// Return the codepoint at the current position of the parser.
///
/// This panics if the parser is positioned at the end of the pattern.
fn char(&self) -> char {
self.char.get().expect("codepoint, but parser is done")
}
/// Returns true if the next call to `bump` would return false.
fn is_done(&self) -> bool {
self.pos() == self.pattern.len()
}
/// Returns the flags that are current set for this regex.
fn flags(&self) -> Flags {
*self.flags.borrow()
}
/// Bump the parser to the next Unicode scalar value.
///
/// If the end of the input has been reached, then `false` is returned.
fn bump(&self) -> bool {
if self.is_done() {
return false;
}
self.pos.set(self.pos() + self.char().len_utf8());
self.char.set(self.pattern()[self.pos()..].chars().next());
self.char.get().is_some()
}
/// If the substring starting at the current position of the parser has
/// the given prefix, then bump the parser to the character immediately
/// following the prefix and return true. Otherwise, don't bump the parser
/// and return false.
fn bump_if(&self, prefix: &str) -> bool {
if self.pattern()[self.pos()..].starts_with(prefix) {
for _ in 0..prefix.chars().count() {
self.bump();
}
true
} else {
false
}
}
/// Bump the parser, and if the `x` flag is enabled, bump through any
/// subsequent spaces. Return true if and only if the parser is not done.
fn bump_and_bump_space(&self) -> bool {
if !self.bump() {
return false;
}
self.bump_space();
!self.is_done()
}
/// If the `x` flag is enabled (i.e., whitespace insensitivity with
/// comments), then this will advance the parser through all whitespace
/// and comments to the next non-whitespace non-comment byte.
///
/// If the `x` flag is disabled, then this is a no-op.
///
/// This should be used selectively throughout the parser where
/// arbitrary whitespace is permitted when the `x` flag is enabled. For
/// example, `{ 5 , 6}` is equivalent to `{5,6}`.
fn bump_space(&self) {
if !self.flags().ignore_whitespace {
return;
}
while !self.is_done() {
if self.char().is_whitespace() {
self.bump();
} else if self.char() == '#' {
self.bump();
while !self.is_done() {
let c = self.char();
self.bump();
if c == '\n' {
break;
}
}
} else {
break;
}
}
}
/// Peek at the next character in the input without advancing the parser.
///
/// If the input has been exhausted, then this returns `None`.
fn peek(&self) -> Option<char> {
if self.is_done() {
return None;
}
self.pattern()[self.pos() + self.char().len_utf8()..].chars().next()
}
/// Peeks at the next character in the pattern from the current offset, and
/// will ignore spaces when the parser is in whitespace insensitive mode.
fn peek_space(&self) -> Option<char> {
if !self.flags().ignore_whitespace {
return self.peek();
}
if self.is_done() {
return None;
}
let mut start = self.pos() + self.char().len_utf8();
let mut in_comment = false;
for (i, ch) in self.pattern()[start..].char_indices() {
if ch.is_whitespace() {
continue;
} else if !in_comment && ch == '#' {
in_comment = true;
} else if in_comment && ch == '\n' {
in_comment = false;
} else {
start += i;
break;
}
}
self.pattern()[start..].chars().next()
}
/// Return the next capturing index. Each subsequent call increments the
/// internal index. Since the way capture indices are computed is a public
/// API guarantee, use of this routine depends on the parser being depth
/// first and left-to-right.
///
/// If the capture limit is exceeded, then an error is returned.
fn next_capture_index(&self) -> Result<u32, Error> {
let current = self.capture_index.get();
let next = current
.checked_add(1)
.ok_or_else(|| Error::new(ERR_TOO_MANY_CAPTURES))?;
self.capture_index.set(next);
Ok(next)
}
/// Adds the given capture name to this parser. If this capture name has
/// already been used, then an error is returned.
fn add_capture_name(&self, name: &str) -> Result<(), Error> {
let mut names = self.capture_names.borrow_mut();
match names.binary_search_by(|n| name.cmp(n)) {
Ok(_) => Err(Error::new(ERR_DUPLICATE_CAPTURE_NAME)),
Err(i) => {
names.insert(i, name.to_string());
Ok(())
}
}
}
/// Returns true if and only if the parser is positioned at a look-around
/// prefix. The conditions under which this returns true must always
/// correspond to a regular expression that would otherwise be consider
/// invalid.
///
/// This should only be called immediately after parsing the opening of
/// a group or a set of flags.
fn is_lookaround_prefix(&self) -> bool {
self.bump_if("?=")
|| self.bump_if("?!")
|| self.bump_if("?<=")
|| self.bump_if("?<!")
}
}
/// The actual parser. We try to break out each kind of regex syntax into its
/// own routine.
impl<'a> Parser<'a> {
pub(super) fn parse(&self) -> Result<Hir, Error> {
let hir = self.parse_inner()?;
// While we also check nesting during parsing, that only checks the
// number of recursive parse calls. It does not necessarily cover
// all possible recursive nestings of the Hir itself. For example,
// repetition operators don't require recursive parse calls. So one
// can stack them arbitrarily without overflowing the stack in the
// *parser*. But then if one recurses over the resulting Hir, a stack
// overflow is possible. So here we check the Hir nesting level
// thoroughly to ensure it isn't nested too deeply.
//
// Note that we do still need the nesting limit check in the parser as
// well, since that will avoid overflowing the stack during parse time
// before the complete Hir value is constructed.
check_hir_nesting(&hir, self.config.nest_limit)?;
Ok(hir)
}
fn parse_inner(&self) -> Result<Hir, Error> {
let depth = self.increment_depth()?;
let mut alternates = vec![];
let mut concat = vec![];
loop {
self.bump_space();
if self.is_done() {
break;
}
match self.char() {
'(' => {
// Save the old flags and reset them only when we close
// the group.
let oldflags = *self.flags.borrow();
if let Some(sub) = self.parse_group()? {
concat.push(sub);
// We only reset them here because if 'parse_group'
// returns None, then that means it handled a flag
// directive, e.g., '(?ism)'. And the whole point is
// that those flags remain active until either disabled
// or the end of the pattern or current group.
*self.flags.borrow_mut() = oldflags;
}
if self.char.get() != Some(')') {
return Err(Error::new(ERR_UNCLOSED_GROUP));
}
self.bump();
}
')' => {
if depth == 0 {
return Err(Error::new(ERR_UNOPENED_GROUP));
}
break;
}
'|' => {
alternates.push(Hir::concat(core::mem::take(&mut concat)));
self.bump();
}
'[' => concat.push(self.parse_class()?),
'?' | '*' | '+' => {
concat = self.parse_uncounted_repetition(concat)?;
}
'{' => {
concat = self.parse_counted_repetition(concat)?;
}
_ => concat.push(self.parse_primitive()?),
}
}
self.decrement_depth();
alternates.push(Hir::concat(concat));
// N.B. This strips off the "alternation" if there's only one branch.
Ok(Hir::alternation(alternates))
}
/// Parses a "primitive" pattern. A primitive is any expression that does
/// not contain any sub-expressions.
///
/// This assumes the parser is pointing at the beginning of the primitive.
fn parse_primitive(&self) -> Result<Hir, Error> {
let ch = self.char();
self.bump();
match ch {
'\\' => self.parse_escape(),
'.' => Ok(self.hir_dot()),
'^' => Ok(self.hir_anchor_start()),
'$' => Ok(self.hir_anchor_end()),
ch => Ok(self.hir_char(ch)),
}
}
/// Parse an escape sequence. This always results in a "primitive" HIR,
/// that is, an HIR with no sub-expressions.
///
/// This assumes the parser is positioned at the start of the sequence,
/// immediately *after* the `\`. It advances the parser to the first
/// position immediately following the escape sequence.
fn parse_escape(&self) -> Result<Hir, Error> {
if self.is_done() {
return Err(Error::new(ERR_ESCAPE_UNEXPECTED_EOF));
}
let ch = self.char();
// Put some of the more complicated routines into helpers.
match ch {
'0'..='9' => return Err(Error::new(ERR_BACKREF_UNSUPPORTED)),
'p' | 'P' => {
return Err(Error::new(ERR_UNICODE_CLASS_UNSUPPORTED))
}
'x' | 'u' | 'U' => return self.parse_hex(),
'd' | 's' | 'w' | 'D' | 'S' | 'W' => {
return Ok(self.parse_perl_class());
}
_ => {}
}
// Handle all of the one letter sequences inline.
self.bump();
if hir::is_meta_character(ch) || hir::is_escapeable_character(ch) {
return Ok(self.hir_char(ch));
}
let special = |ch| Ok(self.hir_char(ch));
match ch {
'a' => special('\x07'),
'f' => special('\x0C'),
't' => special('\t'),
'n' => special('\n'),
'r' => special('\r'),
'v' => special('\x0B'),
'A' => Ok(Hir::look(hir::Look::Start)),
'z' => Ok(Hir::look(hir::Look::End)),
'b' => {
let mut hir = Hir::look(hir::Look::Word);
if !self.is_done() && self.char() == '{' {
if let Some(special) =
self.maybe_parse_special_word_boundary()?
{
hir = special;
}
}
Ok(hir)
}
'B' => Ok(Hir::look(hir::Look::WordNegate)),
'<' => Ok(Hir::look(hir::Look::WordStart)),
'>' => Ok(Hir::look(hir::Look::WordEnd)),
_ => Err(Error::new(ERR_ESCAPE_UNRECOGNIZED)),
}
}
/// Attempt to parse a specialty word boundary. That is, `\b{start}`,
/// `\b{end}`, `\b{start-half}` or `\b{end-half}`.
///
/// This is similar to `maybe_parse_ascii_class` in that, in most cases,
/// if it fails it will just return `None` with no error. This is done
/// because `\b{5}` is a valid expression and we want to let that be parsed
/// by the existing counted repetition parsing code. (I thought about just
/// invoking the counted repetition code from here, but it seemed a little
/// ham-fisted.)
///
/// Unlike `maybe_parse_ascii_class` though, this can return an error.
/// Namely, if we definitely know it isn't a counted repetition, then we
/// return an error specific to the specialty word boundaries.
///
/// This assumes the parser is positioned at a `{` immediately following
/// a `\b`. When `None` is returned, the parser is returned to the position
/// at which it started: pointing at a `{`.
///
/// The position given should correspond to the start of the `\b`.
fn maybe_parse_special_word_boundary(&self) -> Result<Option<Hir>, Error> {
assert_eq!(self.char(), '{');
let is_valid_char = |c| match c {
'A'..='Z' | 'a'..='z' | '-' => true,
_ => false,
};
let start = self.pos();
if !self.bump_and_bump_space() {
return Err(Error::new(ERR_SPECIAL_WORD_OR_REP_UNEXPECTED_EOF));
}
// This is one of the critical bits: if the first non-whitespace
// character isn't in [-A-Za-z] (i.e., this can't be a special word
// boundary), then we bail and let the counted repetition parser deal
// with this.
if !is_valid_char(self.char()) {
self.pos.set(start);
self.char.set(Some('{'));
return Ok(None);
}
// Now collect up our chars until we see a '}'.
let mut scratch = String::new();
while !self.is_done() && is_valid_char(self.char()) {
scratch.push(self.char());
self.bump_and_bump_space();
}
if self.is_done() || self.char() != '}' {
return Err(Error::new(ERR_SPECIAL_WORD_BOUNDARY_UNCLOSED));
}
self.bump();
let kind = match scratch.as_str() {
"start" => hir::Look::WordStart,
"end" => hir::Look::WordEnd,
"start-half" => hir::Look::WordStartHalf,
"end-half" => hir::Look::WordEndHalf,
_ => {
return Err(Error::new(ERR_SPECIAL_WORD_BOUNDARY_UNRECOGNIZED))
}
};
Ok(Some(Hir::look(kind)))
}
/// Parse a hex representation of a Unicode codepoint. This handles both
/// hex notations, i.e., `\xFF` and `\x{FFFF}`. This expects the parser to
/// be positioned at the `x`, `u` or `U` prefix. The parser is advanced to
/// the first character immediately following the hexadecimal literal.
fn parse_hex(&self) -> Result<Hir, Error> {
let digit_len = match self.char() {
'x' => 2,
'u' => 4,
'U' => 8,
unk => unreachable!(
"invalid start of fixed length hexadecimal number {}",
unk
),
};
if !self.bump_and_bump_space() {
return Err(Error::new(ERR_HEX_UNEXPECTED_EOF));
}
if self.char() == '{' {
self.parse_hex_brace()
} else {
self.parse_hex_digits(digit_len)
}
}
/// Parse an N-digit hex representation of a Unicode codepoint. This
/// expects the parser to be positioned at the first digit and will advance
/// the parser to the first character immediately following the escape
/// sequence.
///
/// The number of digits given must be 2 (for `\xNN`), 4 (for `\uNNNN`)
/// or 8 (for `\UNNNNNNNN`).
fn parse_hex_digits(&self, digit_len: usize) -> Result<Hir, Error> {
let mut scratch = String::new();
for i in 0..digit_len {
if i > 0 && !self.bump_and_bump_space() {
return Err(Error::new(ERR_HEX_FIXED_UNEXPECTED_EOF));
}
if !is_hex(self.char()) {
return Err(Error::new(ERR_HEX_FIXED_INVALID_DIGIT));
}
scratch.push(self.char());
}
// The final bump just moves the parser past the literal, which may
// be EOF.
self.bump_and_bump_space();
match u32::from_str_radix(&scratch, 16).ok().and_then(char::from_u32) {
None => Err(Error::new(ERR_HEX_FIXED_INVALID)),
Some(ch) => Ok(self.hir_char(ch)),
}
}
/// Parse a hex representation of any Unicode scalar value. This expects
/// the parser to be positioned at the opening brace `{` and will advance
/// the parser to the first character following the closing brace `}`.
fn parse_hex_brace(&self) -> Result<Hir, Error> {
let mut scratch = String::new();
while self.bump_and_bump_space() && self.char() != '}' {
if !is_hex(self.char()) {
return Err(Error::new(ERR_HEX_BRACE_INVALID_DIGIT));
}
scratch.push(self.char());
}
if self.is_done() {
return Err(Error::new(ERR_HEX_BRACE_UNEXPECTED_EOF));
}
assert_eq!(self.char(), '}');
self.bump_and_bump_space();
if scratch.is_empty() {
return Err(Error::new(ERR_HEX_BRACE_EMPTY));
}
match u32::from_str_radix(&scratch, 16).ok().and_then(char::from_u32) {
None => Err(Error::new(ERR_HEX_BRACE_INVALID)),
Some(ch) => Ok(self.hir_char(ch)),
}
}
/// Parse a decimal number into a u32 while trimming leading and trailing
/// whitespace.
///
/// This expects the parser to be positioned at the first position where
/// a decimal digit could occur. This will advance the parser to the byte
/// immediately following the last contiguous decimal digit.
///
/// If no decimal digit could be found or if there was a problem parsing
/// the complete set of digits into a u32, then an error is returned.
fn parse_decimal(&self) -> Result<u32, Error> {
let mut scratch = String::new();
while !self.is_done() && self.char().is_whitespace() {
self.bump();
}
while !self.is_done() && '0' <= self.char() && self.char() <= '9' {
scratch.push(self.char());
self.bump_and_bump_space();
}
while !self.is_done() && self.char().is_whitespace() {
self.bump_and_bump_space();
}
let digits = scratch.as_str();
if digits.is_empty() {
return Err(Error::new(ERR_DECIMAL_NO_DIGITS));
}
match u32::from_str_radix(digits, 10).ok() {
Some(n) => Ok(n),
None => Err(Error::new(ERR_DECIMAL_INVALID)),
}
}
/// Parses an uncounted repetition operator. An uncounted repetition
/// operator includes `?`, `*` and `+`, but does not include the `{m,n}`
/// syntax. The current character should be one of `?`, `*` or `+`. Any
/// other character will result in a panic.
///
/// This assumes that the parser is currently positioned at the repetition
/// operator and advances the parser to the first character after the
/// operator. (Note that the operator may include a single additional `?`,
/// which makes the operator ungreedy.)
///
/// The caller should include the concatenation that is being built. The
/// concatenation returned includes the repetition operator applied to the
/// last expression in the given concatenation.
///
/// If the concatenation is empty, then this returns an error.
fn parse_uncounted_repetition(
&self,
mut concat: Vec<Hir>,
) -> Result<Vec<Hir>, Error> {
let sub = match concat.pop() {
Some(hir) => Box::new(hir),
None => {
return Err(Error::new(ERR_UNCOUNTED_REP_SUB_MISSING));
}
};
let (min, max) = match self.char() {
'?' => (0, Some(1)),
'*' => (0, None),
'+' => (1, None),
unk => unreachable!("unrecognized repetition operator '{}'", unk),
};
let mut greedy = true;
if self.bump() && self.char() == '?' {
greedy = false;
self.bump();
}
if self.flags().swap_greed {
greedy = !greedy;
}
concat.push(Hir::repetition(hir::Repetition {
min,
max,
greedy,
sub,
}));
Ok(concat)
}
/// Parses a counted repetition operation. A counted repetition operator
/// corresponds to the `{m,n}` syntax, and does not include the `?`, `*` or
/// `+` operators.
///
/// This assumes that the parser is currently at the opening `{` and
/// advances the parser to the first character after the operator. (Note
/// that the operator may include a single additional `?`, which makes the
/// operator ungreedy.)
///
/// The caller should include the concatenation that is being built. The
/// concatenation returned includes the repetition operator applied to the
/// last expression in the given concatenation.
///
/// If the concatenation is empty, then this returns an error.
fn parse_counted_repetition(
&self,
mut concat: Vec<Hir>,
) -> Result<Vec<Hir>, Error> {
assert_eq!(self.char(), '{', "expected opening brace");
let sub = match concat.pop() {
Some(hir) => Box::new(hir),
None => {
return Err(Error::new(ERR_COUNTED_REP_SUB_MISSING));
}
};
if !self.bump_and_bump_space() {
return Err(Error::new(ERR_COUNTED_REP_UNCLOSED));
}
let min = self.parse_decimal()?;
let mut max = Some(min);
if self.is_done() {
return Err(Error::new(ERR_COUNTED_REP_MIN_UNCLOSED));
}
if self.char() == ',' {
if !self.bump_and_bump_space() {
return Err(Error::new(ERR_COUNTED_REP_COMMA_UNCLOSED));
}
if self.char() != '}' {
max = Some(self.parse_decimal()?);
} else {
max = None;
}
if self.is_done() {
return Err(Error::new(ERR_COUNTED_REP_MIN_MAX_UNCLOSED));
}
}
if self.char() != '}' {
return Err(Error::new(ERR_COUNTED_REP_INVALID));
}
let mut greedy = true;
if self.bump_and_bump_space() && self.char() == '?' {
greedy = false;
self.bump();
}
if self.flags().swap_greed {
greedy = !greedy;
}
if max.map_or(false, |max| min > max) {
return Err(Error::new(ERR_COUNTED_REP_INVALID_RANGE));
}
concat.push(Hir::repetition(hir::Repetition {
min,
max,
greedy,
sub,
}));
Ok(concat)
}
/// Parses the part of a pattern that starts with a `(`. This is usually
/// a group sub-expression, but might just be a directive that enables
/// (or disables) certain flags.
///
/// This assumes the parser is pointing at the opening `(`.
fn parse_group(&self) -> Result<Option<Hir>, Error> {
assert_eq!(self.char(), '(');
self.bump_and_bump_space();
if self.is_lookaround_prefix() {
return Err(Error::new(ERR_LOOK_UNSUPPORTED));
}
if self.bump_if("?P<") || self.bump_if("?<") {
let index = self.next_capture_index()?;
let name = Some(Box::from(self.parse_capture_name()?));
let sub = Box::new(self.parse_inner()?);
let cap = hir::Capture { index, name, sub };
Ok(Some(Hir::capture(cap)))
} else if self.bump_if("?") {
if self.is_done() {
return Err(Error::new(ERR_UNCLOSED_GROUP_QUESTION));
}
let start = self.pos();
// The flags get reset in the top-level 'parse' routine.
*self.flags.borrow_mut() = self.parse_flags()?;
let consumed = self.pos() - start;
if self.char() == ')' {
// We don't allow empty flags, e.g., `(?)`.
if consumed == 0 {
return Err(Error::new(ERR_EMPTY_FLAGS));
}
Ok(None)
} else {
assert_eq!(':', self.char());
self.bump();
self.parse_inner().map(Some)
}
} else {
let index = self.next_capture_index()?;
let sub = Box::new(self.parse_inner()?);
let cap = hir::Capture { index, name: None, sub };
Ok(Some(Hir::capture(cap)))
}
}
/// Parses a capture group name. Assumes that the parser is positioned at
/// the first character in the name following the opening `<` (and may
/// possibly be EOF). This advances the parser to the first character
/// following the closing `>`.
fn parse_capture_name(&self) -> Result<&str, Error> {
if self.is_done() {
return Err(Error::new(ERR_MISSING_GROUP_NAME));
}
let start = self.pos();
loop {
if self.char() == '>' {
break;
}
if !is_capture_char(self.char(), self.pos() == start) {
return Err(Error::new(ERR_INVALID_GROUP_NAME));
}
if !self.bump() {
break;
}
}
let end = self.pos();
if self.is_done() {
return Err(Error::new(ERR_UNCLOSED_GROUP_NAME));
}
assert_eq!(self.char(), '>');
self.bump();
let name = &self.pattern()[start..end];
if name.is_empty() {
return Err(Error::new(ERR_EMPTY_GROUP_NAME));
}
self.add_capture_name(name)?;
Ok(name)
}
/// Parse a sequence of flags starting at the current character.
///
/// This advances the parser to the character immediately following the
/// flags, which is guaranteed to be either `:` or `)`.
///
/// # Errors
///
/// If any flags are duplicated, then an error is returned.
///
/// If the negation operator is used more than once, then an error is
/// returned.
///
/// If no flags could be found or if the negation operation is not followed
/// by any flags, then an error is returned.
fn parse_flags(&self) -> Result<Flags, Error> {
let mut flags = *self.flags.borrow();
let mut negate = false;
// Keeps track of whether the previous flag item was a '-'. We use this
// to detect whether there is a dangling '-', which is invalid.
let mut last_was_negation = false;
// A set to keep track of the flags we've seen. Since all flags are
// ASCII, we only need 128 bytes.
let mut seen = [false; 128];
while self.char() != ':' && self.char() != ')' {
if self.char() == '-' {
last_was_negation = true;
if negate {
return Err(Error::new(ERR_FLAG_REPEATED_NEGATION));
}
negate = true;
} else {
last_was_negation = false;
self.parse_flag(&mut flags, negate)?;
// OK because every valid flag is ASCII, and we're only here if
// the flag is valid.
let flag_byte = u8::try_from(self.char()).unwrap();
if seen[usize::from(flag_byte)] {
return Err(Error::new(ERR_FLAG_DUPLICATE));
}
seen[usize::from(flag_byte)] = true;
}
if !self.bump() {
return Err(Error::new(ERR_FLAG_UNEXPECTED_EOF));
}
}
if last_was_negation {
return Err(Error::new(ERR_FLAG_DANGLING_NEGATION));
}
Ok(flags)
}
/// Parse the current character as a flag. Do not advance the parser.
///
/// This sets the appropriate boolean value in place on the set of flags
/// given. The boolean is inverted when `negate` is true.
///
/// # Errors
///
/// If the flag is not recognized, then an error is returned.
fn parse_flag(
&self,
flags: &mut Flags,
negate: bool,
) -> Result<(), Error> {
let enabled = !negate;
match self.char() {
'i' => flags.case_insensitive = enabled,
'm' => flags.multi_line = enabled,
's' => flags.dot_matches_new_line = enabled,
'U' => flags.swap_greed = enabled,
'R' => flags.crlf = enabled,
'x' => flags.ignore_whitespace = enabled,
// We make a special exception for this flag where we let it
// through as a recognized flag, but treat it as a no-op. This in
// practice retains some compatibility with the regex crate. It is
// a little suspect to do this, but for example, '(?-u:\b).+' in
// the regex crate is equivalent to '\b.+' in regex-lite.
'u' => {}
_ => return Err(Error::new(ERR_FLAG_UNRECOGNIZED)),
}
Ok(())
}
/// Parse a standard character class consisting primarily of characters or
/// character ranges.
///
/// This assumes the parser is positioned at the opening `[`. If parsing
/// is successful, then the parser is advanced to the position immediately
/// following the closing `]`.
fn parse_class(&self) -> Result<Hir, Error> {
assert_eq!(self.char(), '[');
let mut union = vec![];
if !self.bump_and_bump_space() {
return Err(Error::new(ERR_CLASS_UNCLOSED));
}
// Determine whether the class is negated or not.
let negate = if self.char() != '^' {
false
} else {
if !self.bump_and_bump_space() {
return Err(Error::new(ERR_CLASS_UNCLOSED_AFTER_NEGATION));
}
true
};
// Accept any number of `-` as literal `-`.
while self.char() == '-' {
union.push(hir::ClassRange { start: '-', end: '-' });
if !self.bump_and_bump_space() {
return Err(Error::new(ERR_CLASS_UNCLOSED_AFTER_DASH));
}
}
// If `]` is the *first* char in a set, then interpret it as a literal
// `]`. That is, an empty class is impossible to write.
if union.is_empty() && self.char() == ']' {
union.push(hir::ClassRange { start: ']', end: ']' });
if !self.bump_and_bump_space() {
return Err(Error::new(ERR_CLASS_UNCLOSED_AFTER_CLOSING));
}
}
loop {
self.bump_space();
if self.is_done() {
return Err(Error::new(ERR_CLASS_UNCLOSED));
}
match self.char() {
'[' => {
// Attempt to treat this as the beginning of a POSIX class.
// If POSIX class parsing fails, then the parser backs up
// to `[`.
if let Some(class) = self.maybe_parse_posix_class() {
union.extend_from_slice(&class.ranges);
continue;
}
// ... otherwise we don't support nested classes.
return Err(Error::new(ERR_CLASS_NEST_UNSUPPORTED));
}
']' => {
self.bump();
let mut class = hir::Class::new(union);
// Note that we must apply case folding before negation!
// Consider `(?i)[^x]`. If we applied negation first, then
// the result would be the character class that matched any
// Unicode scalar value.
if self.flags().case_insensitive {
class.ascii_case_fold();
}
if negate {
class.negate();
}
return Ok(Hir::class(class));
}
'&' if self.peek() == Some('&') => {
return Err(Error::new(
ERR_CLASS_INTERSECTION_UNSUPPORTED,
));
}
'-' if self.peek() == Some('-') => {
return Err(Error::new(ERR_CLASS_DIFFERENCE_UNSUPPORTED));
}
'~' if self.peek() == Some('~') => {
return Err(Error::new(
ERR_CLASS_SYMDIFFERENCE_UNSUPPORTED,
));
}
_ => self.parse_class_range(&mut union)?,
}
}
}
/// Parse a single primitive item in a character class set. The item to
/// be parsed can either be one of a simple literal character, a range
/// between two simple literal characters or a "primitive" character
/// class like `\w`.
///
/// If an invalid escape is found, or if a character class is found where
/// a simple literal is expected (e.g., in a range), then an error is
/// returned.
///
/// Otherwise, the range (or ranges) are appended to the given union of
/// ranges.
fn parse_class_range(
&self,
union: &mut Vec<hir::ClassRange>,
) -> Result<(), Error> {
let prim1 = self.parse_class_item()?;
self.bump_space();
if self.is_done() {
return Err(Error::new(ERR_CLASS_UNCLOSED_AFTER_ITEM));
}
// If the next char isn't a `-`, then we don't have a range.
// There are two exceptions. If the char after a `-` is a `]`, then
// `-` is interpreted as a literal `-`. Alternatively, if the char
// after a `-` is a `-`, then `--` corresponds to a "difference"
// operation. (Which we don't support in regex-lite, but error about
// specifically in an effort to be loud about differences between the
// main regex crate where possible.)
if self.char() != '-'
|| self.peek_space() == Some(']')
|| self.peek_space() == Some('-')
{
union.extend_from_slice(&into_class_item_ranges(prim1)?);
return Ok(());
}
// OK, now we're parsing a range, so bump past the `-` and parse the
// second half of the range.
if !self.bump_and_bump_space() {
return Err(Error::new(ERR_CLASS_UNCLOSED_AFTER_DASH));
}
let prim2 = self.parse_class_item()?;
let range = hir::ClassRange {
start: into_class_item_range(prim1)?,
end: into_class_item_range(prim2)?,
};
if range.start > range.end {
return Err(Error::new(ERR_CLASS_INVALID_RANGE));
}
union.push(range);
Ok(())
}
/// Parse a single item in a character class as a primitive, where the
/// primitive either consists of a verbatim literal or a single escape
/// sequence.
///
/// This assumes the parser is positioned at the beginning of a primitive,
/// and advances the parser to the first position after the primitive if
/// successful.
///
/// Note that it is the caller's responsibility to report an error if an
/// illegal primitive was parsed.
fn parse_class_item(&self) -> Result<Hir, Error> {
let ch = self.char();
self.bump();
if ch == '\\' {
self.parse_escape()
} else {
Ok(Hir::char(ch))
}
}
/// Attempt to parse a POSIX character class, e.g., `[:alnum:]`.
///
/// This assumes the parser is positioned at the opening `[`.
///
/// If no valid POSIX character class could be found, then this does not
/// advance the parser and `None` is returned. Otherwise, the parser is
/// advanced to the first byte following the closing `]` and the
/// corresponding POSIX class is returned.
fn maybe_parse_posix_class(&self) -> Option<hir::Class> {
// POSIX character classes are interesting from a parsing perspective
// because parsing cannot fail with any interesting error. For example,
// in order to use an POSIX character class, it must be enclosed in
// double brackets, e.g., `[[:alnum:]]`. Alternatively, you might think
// of it as "POSIX character classes have the syntax `[:NAME:]` which
// can only appear within character brackets." This means that things
// like `[[:lower:]A]` are legal constructs.
//
// However, if one types an incorrect POSIX character class, e.g.,
// `[[:loower:]]`, then we treat that as if it were normal nested
// character class containing the characters `:elorw`. (Which isn't
// supported and results in an error in regex-lite.) One might argue
// that we should return an error instead since the repeated colons
// give away the intent to write an POSIX class. But what if the user
// typed `[[:lower]]` instead? How can we tell that was intended to be
// a POSXI class and not just a normal nested class?
//
// Reasonable people can probably disagree over this, but for better
// or worse, we implement semantics that never fails at the expense of
// better failure modes.
assert_eq!(self.char(), '[');
// If parsing fails, then we back up the parser to this starting point.
let start_pos = self.pos();
let start_char = self.char.get();
let reset = || {
self.pos.set(start_pos);
self.char.set(start_char);
};
let mut negated = false;
if !self.bump() || self.char() != ':' {
reset();
return None;
}
if !self.bump() {
reset();
return None;
}
if self.char() == '^' {
negated = true;
if !self.bump() {
reset();
return None;
}
}
let name_start = self.pos();
while self.char() != ':' && self.bump() {}
if self.is_done() {
reset();
return None;
}
let name = &self.pattern()[name_start..self.pos()];
if !self.bump_if(":]") {
reset();
return None;
}
if let Ok(ranges) = posix_class(name) {
let mut class = hir::Class::new(ranges);
if negated {
class.negate();
}
return Some(class);
}
reset();
None
}
/// Parse a Perl character class, e.g., `\d` or `\W`. This assumes the
/// parser is currently at a valid character class name and will be
/// advanced to the character immediately following the class.
fn parse_perl_class(&self) -> Hir {
let ch = self.char();
self.bump();
let mut class = hir::Class::new(match ch {
'd' | 'D' => posix_class("digit").unwrap(),
's' | 'S' => posix_class("space").unwrap(),
'w' | 'W' => posix_class("word").unwrap(),
unk => unreachable!("invalid Perl class \\{}", unk),
});
if ch.is_ascii_uppercase() {
class.negate();
}
Hir::class(class)
}
fn hir_dot(&self) -> Hir {
if self.flags().dot_matches_new_line {
Hir::class(hir::Class::new([hir::ClassRange {
start: '\x00',
end: '\u{10FFFF}',
}]))
} else if self.flags().crlf {
Hir::class(hir::Class::new([
hir::ClassRange { start: '\x00', end: '\x09' },
hir::ClassRange { start: '\x0B', end: '\x0C' },
hir::ClassRange { start: '\x0E', end: '\u{10FFFF}' },
]))
} else {
Hir::class(hir::Class::new([
hir::ClassRange { start: '\x00', end: '\x09' },
hir::ClassRange { start: '\x0B', end: '\u{10FFFF}' },
]))
}
}
fn hir_anchor_start(&self) -> Hir {
let look = if self.flags().multi_line {
if self.flags().crlf {
hir::Look::StartCRLF
} else {
hir::Look::StartLF
}
} else {
hir::Look::Start
};
Hir::look(look)
}
fn hir_anchor_end(&self) -> Hir {
let look = if self.flags().multi_line {
if self.flags().crlf {
hir::Look::EndCRLF
} else {
hir::Look::EndLF
}
} else {
hir::Look::End
};
Hir::look(look)
}
fn hir_char(&self, ch: char) -> Hir {
if self.flags().case_insensitive {
let this = hir::ClassRange { start: ch, end: ch };
if let Some(folded) = this.ascii_case_fold() {
return Hir::class(hir::Class::new([this, folded]));
}
}
Hir::char(ch)
}
}
/// This checks the depth of the given `Hir` value, and if it exceeds the given
/// limit, then an error is returned.
fn check_hir_nesting(hir: &Hir, limit: u32) -> Result<(), Error> {
fn recurse(hir: &Hir, limit: u32, depth: u32) -> Result<(), Error> {
if depth > limit {
return Err(Error::new(ERR_TOO_MUCH_NESTING));
}
let Some(next_depth) = depth.checked_add(1) else {
return Err(Error::new(ERR_TOO_MUCH_NESTING));
};
match *hir.kind() {
HirKind::Empty
| HirKind::Char(_)
| HirKind::Class(_)
| HirKind::Look(_) => Ok(()),
HirKind::Repetition(hir::Repetition { ref sub, .. }) => {
recurse(sub, limit, next_depth)
}
HirKind::Capture(hir::Capture { ref sub, .. }) => {
recurse(sub, limit, next_depth)
}
HirKind::Concat(ref subs) | HirKind::Alternation(ref subs) => {
for sub in subs.iter() {
recurse(sub, limit, next_depth)?;
}
Ok(())
}
}
}
recurse(hir, limit, 0)
}
/// Converts the given Hir to a literal char if the Hir is just a single
/// character. Otherwise this returns an error.
///
/// This is useful in contexts where you can only accept a single character,
/// but where it is convenient to parse something more general. For example,
/// parsing a single part of a character class range. It's useful to reuse
/// the literal parsing code, but that code can itself return entire classes
/// which can't be used as the start/end of a class range.
fn into_class_item_range(hir: Hir) -> Result<char, Error> {
match hir.kind {
HirKind::Char(ch) => Ok(ch),
_ => Err(Error::new(ERR_CLASS_INVALID_RANGE_ITEM)),
}
}
fn into_class_item_ranges(
mut hir: Hir,
) -> Result<Vec<hir::ClassRange>, Error> {
match core::mem::replace(&mut hir.kind, HirKind::Empty) {
HirKind::Char(ch) => Ok(vec![hir::ClassRange { start: ch, end: ch }]),
HirKind::Class(hir::Class { ranges }) => Ok(ranges),
_ => Err(Error::new(ERR_CLASS_INVALID_ITEM)),
}
}
/// Returns an iterator of character class ranges for the given named POSIX
/// character class. If no such character class exists for the name given, then
/// an error is returned.
fn posix_class(
kind: &str,
) -> Result<impl Iterator<Item = hir::ClassRange>, Error> {
let slice: &'static [(u8, u8)] = match kind {
"alnum" => &[(b'0', b'9'), (b'A', b'Z'), (b'a', b'z')],
"alpha" => &[(b'A', b'Z'), (b'a', b'z')],
"ascii" => &[(b'\x00', b'\x7F')],
"blank" => &[(b'\t', b'\t'), (b' ', b' ')],
"cntrl" => &[(b'\x00', b'\x1F'), (b'\x7F', b'\x7F')],
"digit" => &[(b'0', b'9')],
"graph" => &[(b'!', b'~')],
"lower" => &[(b'a', b'z')],
"print" => &[(b' ', b'~')],
"punct" => &[(b'!', b'/'), (b':', b'@'), (b'[', b'`'), (b'{', b'~')],
"space" => &[
(b'\t', b'\t'),
(b'\n', b'\n'),
(b'\x0B', b'\x0B'),
(b'\x0C', b'\x0C'),
(b'\r', b'\r'),
(b' ', b' '),
],
"upper" => &[(b'A', b'Z')],
"word" => &[(b'0', b'9'), (b'A', b'Z'), (b'_', b'_'), (b'a', b'z')],
"xdigit" => &[(b'0', b'9'), (b'A', b'F'), (b'a', b'f')],
_ => return Err(Error::new(ERR_POSIX_CLASS_UNRECOGNIZED)),
};
Ok(slice.iter().map(|&(start, end)| hir::ClassRange {
start: char::from(start),
end: char::from(end),
}))
}
/// Returns true if the given character is a hexadecimal digit.
fn is_hex(c: char) -> bool {
('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
}
/// Returns true if the given character is a valid in a capture group name.
///
/// If `first` is true, then `c` is treated as the first character in the
/// group name (which must be alphabetic or underscore).
fn is_capture_char(c: char, first: bool) -> bool {
if first {
c == '_' || c.is_alphabetic()
} else {
c == '_' || c == '.' || c == '[' || c == ']' || c.is_alphanumeric()
}
}
#[cfg(test)]
mod tests {
use super::*;
fn p(pattern: &str) -> Hir {
Parser::new(Config::default(), pattern).parse_inner().unwrap()
}
fn perr(pattern: &str) -> String {
Parser::new(Config::default(), pattern)
.parse_inner()
.unwrap_err()
.to_string()
}
fn class<I: IntoIterator<Item = (char, char)>>(it: I) -> Hir {
Hir::class(hir::Class::new(
it.into_iter().map(|(start, end)| hir::ClassRange { start, end }),
))
}
fn singles<I: IntoIterator<Item = char>>(it: I) -> Hir {
Hir::class(hir::Class::new(
it.into_iter().map(|ch| hir::ClassRange { start: ch, end: ch }),
))
}
fn posix(name: &str) -> Hir {
Hir::class(hir::Class::new(posix_class(name).unwrap()))
}
fn cap(index: u32, sub: Hir) -> Hir {
Hir::capture(hir::Capture { index, name: None, sub: Box::new(sub) })
}
fn named_cap(index: u32, name: &str, sub: Hir) -> Hir {
Hir::capture(hir::Capture {
index,
name: Some(Box::from(name)),
sub: Box::new(sub),
})
}
#[test]
fn ok_literal() {
assert_eq!(p("a"), Hir::char('a'));
assert_eq!(p("ab"), Hir::concat(vec![Hir::char('a'), Hir::char('b')]));
assert_eq!(p("💩"), Hir::char('💩'));
}
#[test]
fn ok_meta_escapes() {
assert_eq!(p(r"\*"), Hir::char('*'));
assert_eq!(p(r"\+"), Hir::char('+'));
assert_eq!(p(r"\?"), Hir::char('?'));
assert_eq!(p(r"\|"), Hir::char('|'));
assert_eq!(p(r"\("), Hir::char('('));
assert_eq!(p(r"\)"), Hir::char(')'));
assert_eq!(p(r"\^"), Hir::char('^'));
assert_eq!(p(r"\$"), Hir::char('$'));
assert_eq!(p(r"\["), Hir::char('['));
assert_eq!(p(r"\]"), Hir::char(']'));
}
#[test]
fn ok_special_escapes() {
assert_eq!(p(r"\a"), Hir::char('\x07'));
assert_eq!(p(r"\f"), Hir::char('\x0C'));
assert_eq!(p(r"\t"), Hir::char('\t'));
assert_eq!(p(r"\n"), Hir::char('\n'));
assert_eq!(p(r"\r"), Hir::char('\r'));
assert_eq!(p(r"\v"), Hir::char('\x0B'));
assert_eq!(p(r"\A"), Hir::look(hir::Look::Start));
assert_eq!(p(r"\z"), Hir::look(hir::Look::End));
assert_eq!(p(r"\b"), Hir::look(hir::Look::Word));
assert_eq!(p(r"\B"), Hir::look(hir::Look::WordNegate));
}
#[test]
fn ok_hex() {
// fixed length
assert_eq!(p(r"\x41"), Hir::char('A'));
assert_eq!(p(r"\u2603"), Hir::char('☃'));
assert_eq!(p(r"\U0001F4A9"), Hir::char('💩'));
// braces
assert_eq!(p(r"\x{1F4A9}"), Hir::char('💩'));
assert_eq!(p(r"\u{1F4A9}"), Hir::char('💩'));
assert_eq!(p(r"\U{1F4A9}"), Hir::char('💩'));
}
#[test]
fn ok_perl() {
assert_eq!(p(r"\d"), posix("digit"));
assert_eq!(p(r"\s"), posix("space"));
assert_eq!(p(r"\w"), posix("word"));
let negated = |name| {
let mut class = hir::Class::new(posix_class(name).unwrap());
class.negate();
Hir::class(class)
};
assert_eq!(p(r"\D"), negated("digit"));
assert_eq!(p(r"\S"), negated("space"));
assert_eq!(p(r"\W"), negated("word"));
}
#[test]
fn ok_flags_and_primitives() {
assert_eq!(p(r"a"), Hir::char('a'));
assert_eq!(p(r"(?i:a)"), singles(['A', 'a']));
assert_eq!(p(r"^"), Hir::look(hir::Look::Start));
assert_eq!(p(r"(?m:^)"), Hir::look(hir::Look::StartLF));
assert_eq!(p(r"(?mR:^)"), Hir::look(hir::Look::StartCRLF));
assert_eq!(p(r"$"), Hir::look(hir::Look::End));
assert_eq!(p(r"(?m:$)"), Hir::look(hir::Look::EndLF));
assert_eq!(p(r"(?mR:$)"), Hir::look(hir::Look::EndCRLF));
assert_eq!(p(r"."), class([('\x00', '\x09'), ('\x0B', '\u{10FFFF}')]));
assert_eq!(
p(r"(?R:.)"),
class([
('\x00', '\x09'),
('\x0B', '\x0C'),
('\x0E', '\u{10FFFF}'),
])
);
assert_eq!(p(r"(?s:.)"), class([('\x00', '\u{10FFFF}')]));
assert_eq!(p(r"(?sR:.)"), class([('\x00', '\u{10FFFF}')]));
}
#[test]
fn ok_alternate() {
assert_eq!(
p(r"a|b"),
Hir::alternation(vec![Hir::char('a'), Hir::char('b')])
);
assert_eq!(
p(r"(?:a|b)"),
Hir::alternation(vec![Hir::char('a'), Hir::char('b')])
);
assert_eq!(
p(r"(a|b)"),
cap(1, Hir::alternation(vec![Hir::char('a'), Hir::char('b')]))
);
assert_eq!(
p(r"(?<foo>a|b)"),
named_cap(
1,
"foo",
Hir::alternation(vec![Hir::char('a'), Hir::char('b')])
)
);
assert_eq!(
p(r"a|b|c"),
Hir::alternation(vec![
Hir::char('a'),
Hir::char('b'),
Hir::char('c')
])
);
assert_eq!(
p(r"ax|by|cz"),
Hir::alternation(vec![
Hir::concat(vec![Hir::char('a'), Hir::char('x')]),
Hir::concat(vec![Hir::char('b'), Hir::char('y')]),
Hir::concat(vec![Hir::char('c'), Hir::char('z')]),
])
);
assert_eq!(
p(r"(ax|(by|(cz)))"),
cap(
1,
Hir::alternation(vec![
Hir::concat(vec![Hir::char('a'), Hir::char('x')]),
cap(
2,
Hir::alternation(vec![
Hir::concat(vec![Hir::char('b'), Hir::char('y')]),
cap(
3,
Hir::concat(vec![
Hir::char('c'),
Hir::char('z')
])
),
])
),
])
)
);
assert_eq!(
p(r"|"),
Hir::alternation(vec![Hir::empty(), Hir::empty()])
);
assert_eq!(
p(r"||"),
Hir::alternation(vec![Hir::empty(), Hir::empty(), Hir::empty()])
);
assert_eq!(
p(r"a|"),
Hir::alternation(vec![Hir::char('a'), Hir::empty()])
);
assert_eq!(
p(r"|a"),
Hir::alternation(vec![Hir::empty(), Hir::char('a')])
);
assert_eq!(
p(r"(|)"),
cap(1, Hir::alternation(vec![Hir::empty(), Hir::empty()]))
);
assert_eq!(
p(r"(a|)"),
cap(1, Hir::alternation(vec![Hir::char('a'), Hir::empty()]))
);
assert_eq!(
p(r"(|a)"),
cap(1, Hir::alternation(vec![Hir::empty(), Hir::char('a')]))
);
}
#[test]
fn ok_flag_group() {
assert_eq!(
p("a(?i:b)"),
Hir::concat(vec![Hir::char('a'), singles(['B', 'b'])])
);
}
#[test]
fn ok_flag_directive() {
assert_eq!(p("(?i)a"), singles(['A', 'a']));
assert_eq!(p("a(?i)"), Hir::char('a'));
assert_eq!(
p("a(?i)b"),
Hir::concat(vec![Hir::char('a'), singles(['B', 'b'])])
);
assert_eq!(
p("a(?i)a(?-i)a"),
Hir::concat(vec![
Hir::char('a'),
singles(['A', 'a']),
Hir::char('a'),
])
);
assert_eq!(
p("a(?:(?i)a)a"),
Hir::concat(vec![
Hir::char('a'),
singles(['A', 'a']),
Hir::char('a'),
])
);
assert_eq!(
p("a((?i)a)a"),
Hir::concat(vec![
Hir::char('a'),
cap(1, singles(['A', 'a'])),
Hir::char('a'),
])
);
}
#[test]
fn ok_uncounted_repetition() {
assert_eq!(
p(r"a?"),
Hir::repetition(hir::Repetition {
min: 0,
max: Some(1),
greedy: true,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"a*"),
Hir::repetition(hir::Repetition {
min: 0,
max: None,
greedy: true,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"a+"),
Hir::repetition(hir::Repetition {
min: 1,
max: None,
greedy: true,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"a??"),
Hir::repetition(hir::Repetition {
min: 0,
max: Some(1),
greedy: false,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"a*?"),
Hir::repetition(hir::Repetition {
min: 0,
max: None,
greedy: false,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"a+?"),
Hir::repetition(hir::Repetition {
min: 1,
max: None,
greedy: false,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"a?b"),
Hir::concat(vec![
Hir::repetition(hir::Repetition {
min: 0,
max: Some(1),
greedy: true,
sub: Box::new(Hir::char('a')),
}),
Hir::char('b'),
]),
);
assert_eq!(
p(r"ab?"),
Hir::concat(vec![
Hir::char('a'),
Hir::repetition(hir::Repetition {
min: 0,
max: Some(1),
greedy: true,
sub: Box::new(Hir::char('b')),
}),
]),
);
assert_eq!(
p(r"(?:ab)?"),
Hir::repetition(hir::Repetition {
min: 0,
max: Some(1),
greedy: true,
sub: Box::new(Hir::concat(vec![
Hir::char('a'),
Hir::char('b')
])),
}),
);
assert_eq!(
p(r"(ab)?"),
Hir::repetition(hir::Repetition {
min: 0,
max: Some(1),
greedy: true,
sub: Box::new(cap(
1,
Hir::concat(vec![Hir::char('a'), Hir::char('b')])
)),
}),
);
assert_eq!(
p(r"|a?"),
Hir::alternation(vec![
Hir::empty(),
Hir::repetition(hir::Repetition {
min: 0,
max: Some(1),
greedy: true,
sub: Box::new(Hir::char('a')),
})
]),
);
}
#[test]
fn ok_counted_repetition() {
assert_eq!(
p(r"a{5}"),
Hir::repetition(hir::Repetition {
min: 5,
max: Some(5),
greedy: true,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"a{5}?"),
Hir::repetition(hir::Repetition {
min: 5,
max: Some(5),
greedy: false,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"a{5,}"),
Hir::repetition(hir::Repetition {
min: 5,
max: None,
greedy: true,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"a{5,9}"),
Hir::repetition(hir::Repetition {
min: 5,
max: Some(9),
greedy: true,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"ab{5}c"),
Hir::concat(vec![
Hir::char('a'),
Hir::repetition(hir::Repetition {
min: 5,
max: Some(5),
greedy: true,
sub: Box::new(Hir::char('b')),
}),
Hir::char('c'),
]),
);
assert_eq!(
p(r"a{ 5 }"),
Hir::repetition(hir::Repetition {
min: 5,
max: Some(5),
greedy: true,
sub: Box::new(Hir::char('a')),
}),
);
assert_eq!(
p(r"a{ 5 , 9 }"),
Hir::repetition(hir::Repetition {
min: 5,
max: Some(9),
greedy: true,
sub: Box::new(Hir::char('a')),
}),
);
}
#[test]
fn ok_group_unnamed() {
assert_eq!(p("(a)"), cap(1, Hir::char('a')));
assert_eq!(
p("(ab)"),
cap(1, Hir::concat(vec![Hir::char('a'), Hir::char('b')]))
);
}
#[test]
fn ok_group_named() {
assert_eq!(p("(?P<foo>a)"), named_cap(1, "foo", Hir::char('a')));
assert_eq!(p("(?<foo>a)"), named_cap(1, "foo", Hir::char('a')));
assert_eq!(
p("(?P<foo>ab)"),
named_cap(
1,
"foo",
Hir::concat(vec![Hir::char('a'), Hir::char('b')])
)
);
assert_eq!(
p("(?<foo>ab)"),
named_cap(
1,
"foo",
Hir::concat(vec![Hir::char('a'), Hir::char('b')])
)
);
assert_eq!(p(r"(?<a>z)"), named_cap(1, "a", Hir::char('z')));
assert_eq!(p(r"(?P<a>z)"), named_cap(1, "a", Hir::char('z')));
assert_eq!(p(r"(?<a_1>z)"), named_cap(1, "a_1", Hir::char('z')));
assert_eq!(p(r"(?P<a_1>z)"), named_cap(1, "a_1", Hir::char('z')));
assert_eq!(p(r"(?<a.1>z)"), named_cap(1, "a.1", Hir::char('z')));
assert_eq!(p(r"(?P<a.1>z)"), named_cap(1, "a.1", Hir::char('z')));
assert_eq!(p(r"(?<a[1]>z)"), named_cap(1, "a[1]", Hir::char('z')));
assert_eq!(p(r"(?P<a[1]>z)"), named_cap(1, "a[1]", Hir::char('z')));
assert_eq!(p(r"(?<a¾>z)"), named_cap(1, "a¾", Hir::char('z')));
assert_eq!(p(r"(?P<a¾>z)"), named_cap(1, "a¾", Hir::char('z')));
assert_eq!(p(r"(?<名字>z)"), named_cap(1, "名字", Hir::char('z')));
assert_eq!(p(r"(?P<名字>z)"), named_cap(1, "名字", Hir::char('z')));
}
#[test]
fn ok_class() {
assert_eq!(p(r"[a]"), singles(['a']));
assert_eq!(p(r"[a\]]"), singles(['a', ']']));
assert_eq!(p(r"[a\-z]"), singles(['a', '-', 'z']));
assert_eq!(p(r"[ab]"), class([('a', 'b')]));
assert_eq!(p(r"[a-]"), singles(['a', '-']));
assert_eq!(p(r"[-a]"), singles(['a', '-']));
assert_eq!(p(r"[--a]"), singles(['a', '-']));
assert_eq!(p(r"[---a]"), singles(['a', '-']));
assert_eq!(p(r"[[:alnum:]]"), posix("alnum"));
assert_eq!(p(r"[\w]"), posix("word"));
assert_eq!(p(r"[a\wz]"), posix("word"));
assert_eq!(p(r"[\s\S]"), class([('\x00', '\u{10FFFF}')]));
assert_eq!(p(r"[^\s\S]"), Hir::fail());
assert_eq!(p(r"[a-cx-z]"), class([('a', 'c'), ('x', 'z')]));
assert_eq!(p(r"[☃-⛄]"), class([('☃', '⛄')]));
assert_eq!(p(r"[]]"), singles([']']));
assert_eq!(p(r"[]a]"), singles([']', 'a']));
assert_eq!(p(r"[]\[]"), singles(['[', ']']));
assert_eq!(p(r"[\[]"), singles(['[']));
assert_eq!(p(r"(?i)[a]"), singles(['A', 'a']));
assert_eq!(p(r"(?i)[A]"), singles(['A', 'a']));
assert_eq!(p(r"(?i)[k]"), singles(['K', 'k']));
assert_eq!(p(r"(?i)[s]"), singles(['S', 's']));
assert_eq!(p(r"(?i)[β]"), singles(['β']));
assert_eq!(p(r"[^^]"), class([('\x00', ']'), ('_', '\u{10FFFF}')]));
assert_eq!(
p(r"[^-a]"),
class([('\x00', ','), ('.', '`'), ('b', '\u{10FFFF}')])
);
assert_eq!(
p(r"[-]a]"),
Hir::concat(vec![singles(['-']), Hir::char('a'), Hir::char(']')])
);
}
#[test]
fn ok_verbatim() {
assert_eq!(
p(r"(?x)a{5,9} ?"),
Hir::repetition(hir::Repetition {
min: 5,
max: Some(9),
greedy: false,
sub: Box::new(Hir::char('a')),
})
);
assert_eq!(p(r"(?x)[ a]"), singles(['a']));
assert_eq!(
p(r"(?x)[ ^ a]"),
class([('\x00', '`'), ('b', '\u{10FFFF}')])
);
assert_eq!(p(r"(?x)[ - a]"), singles(['a', '-']));
assert_eq!(p(r"(?x)[ ] a]"), singles([']', 'a']));
assert_eq!(
p(r"(?x)a b"),
Hir::concat(vec![Hir::char('a'), Hir::char('b')])
);
assert_eq!(
p(r"(?x)a b(?-x)a b"),
Hir::concat(vec![
Hir::char('a'),
Hir::char('b'),
Hir::char('a'),
Hir::char(' '),
Hir::char('b'),
])
);
assert_eq!(
p(r"a (?x:a )a "),
Hir::concat(vec![
Hir::char('a'),
Hir::char(' '),
Hir::char('a'),
Hir::char('a'),
Hir::char(' '),
])
);
assert_eq!(
p(r"(?x)( ?P<foo> a )"),
named_cap(1, "foo", Hir::char('a')),
);
assert_eq!(p(r"(?x)( a )"), cap(1, Hir::char('a')));
assert_eq!(p(r"(?x)( ?: a )"), Hir::char('a'));
assert_eq!(p(r"(?x)\x { 53 }"), Hir::char('\x53'));
assert_eq!(p(r"(?x)\ "), Hir::char(' '));
}
#[test]
fn ok_comments() {
let pat = "(?x)
# This is comment 1.
foo # This is comment 2.
# This is comment 3.
bar
# This is comment 4.";
assert_eq!(
p(pat),
Hir::concat(vec![
Hir::char('f'),
Hir::char('o'),
Hir::char('o'),
Hir::char('b'),
Hir::char('a'),
Hir::char('r'),
])
);
}
#[test]
fn err_standard() {
assert_eq!(
ERR_TOO_MUCH_NESTING,
perr("(((((((((((((((((((((((((((((((((((((((((((((((((((a)))))))))))))))))))))))))))))))))))))))))))))))))))"),
);
// This one is tricky, because the only way it can happen is if the
// number of captures overflows u32. Perhaps we should allow setting a
// lower limit?
// assert_eq!(ERR_TOO_MANY_CAPTURES, perr(""));
assert_eq!(ERR_DUPLICATE_CAPTURE_NAME, perr(r"(?P<a>y)(?P<a>z)"));
assert_eq!(ERR_UNCLOSED_GROUP, perr("("));
assert_eq!(ERR_UNCLOSED_GROUP_QUESTION, perr("(?"));
assert_eq!(ERR_UNOPENED_GROUP, perr(")"));
assert_eq!(ERR_LOOK_UNSUPPORTED, perr(r"(?=a)"));
assert_eq!(ERR_LOOK_UNSUPPORTED, perr(r"(?!a)"));
assert_eq!(ERR_LOOK_UNSUPPORTED, perr(r"(?<=a)"));
assert_eq!(ERR_LOOK_UNSUPPORTED, perr(r"(?<!a)"));
assert_eq!(ERR_EMPTY_FLAGS, perr(r"(?)"));
assert_eq!(ERR_MISSING_GROUP_NAME, perr(r"(?P<"));
assert_eq!(ERR_MISSING_GROUP_NAME, perr(r"(?<"));
assert_eq!(ERR_INVALID_GROUP_NAME, perr(r"(?P<1abc>z)"));
assert_eq!(ERR_INVALID_GROUP_NAME, perr(r"(?<1abc>z)"));
assert_eq!(ERR_INVALID_GROUP_NAME, perr(r"(?<¾>z)"));
assert_eq!(ERR_INVALID_GROUP_NAME, perr(r"(?<¾a>z)"));
assert_eq!(ERR_INVALID_GROUP_NAME, perr(r"(?<☃>z)"));
assert_eq!(ERR_INVALID_GROUP_NAME, perr(r"(?<a☃>z)"));
assert_eq!(ERR_UNCLOSED_GROUP_NAME, perr(r"(?P<foo"));
assert_eq!(ERR_UNCLOSED_GROUP_NAME, perr(r"(?<foo"));
assert_eq!(ERR_EMPTY_GROUP_NAME, perr(r"(?P<>z)"));
assert_eq!(ERR_EMPTY_GROUP_NAME, perr(r"(?<>z)"));
assert_eq!(ERR_FLAG_UNRECOGNIZED, perr(r"(?z:foo)"));
assert_eq!(ERR_FLAG_REPEATED_NEGATION, perr(r"(?s-i-R)"));
assert_eq!(ERR_FLAG_DUPLICATE, perr(r"(?isi)"));
assert_eq!(ERR_FLAG_DUPLICATE, perr(r"(?is-i)"));
assert_eq!(ERR_FLAG_UNEXPECTED_EOF, perr(r"(?is"));
assert_eq!(ERR_FLAG_DANGLING_NEGATION, perr(r"(?is-:foo)"));
assert_eq!(ERR_HEX_BRACE_INVALID_DIGIT, perr(r"\x{Z}"));
assert_eq!(ERR_HEX_BRACE_UNEXPECTED_EOF, perr(r"\x{"));
assert_eq!(ERR_HEX_BRACE_UNEXPECTED_EOF, perr(r"\x{A"));
assert_eq!(ERR_HEX_BRACE_EMPTY, perr(r"\x{}"));
assert_eq!(ERR_HEX_BRACE_INVALID, perr(r"\x{FFFFFFFFFFFFFFFFF}"));
assert_eq!(ERR_HEX_FIXED_UNEXPECTED_EOF, perr(r"\xA"));
assert_eq!(ERR_HEX_FIXED_INVALID_DIGIT, perr(r"\xZ"));
assert_eq!(ERR_HEX_FIXED_INVALID_DIGIT, perr(r"\xZA"));
assert_eq!(ERR_HEX_FIXED_INVALID_DIGIT, perr(r"\xAZ"));
assert_eq!(ERR_HEX_FIXED_INVALID, perr(r"\uD800"));
assert_eq!(ERR_HEX_FIXED_INVALID, perr(r"\UFFFFFFFF"));
assert_eq!(ERR_HEX_UNEXPECTED_EOF, perr(r"\x"));
assert_eq!(ERR_ESCAPE_UNEXPECTED_EOF, perr(r"\"));
assert_eq!(ERR_BACKREF_UNSUPPORTED, perr(r"\0"));
assert_eq!(ERR_BACKREF_UNSUPPORTED, perr(r"\1"));
assert_eq!(ERR_BACKREF_UNSUPPORTED, perr(r"\8"));
assert_eq!(ERR_UNICODE_CLASS_UNSUPPORTED, perr(r"\pL"));
assert_eq!(ERR_UNICODE_CLASS_UNSUPPORTED, perr(r"\p{L}"));
assert_eq!(ERR_ESCAPE_UNRECOGNIZED, perr(r"\i"));
assert_eq!(ERR_UNCOUNTED_REP_SUB_MISSING, perr(r"?"));
assert_eq!(ERR_UNCOUNTED_REP_SUB_MISSING, perr(r"*"));
assert_eq!(ERR_UNCOUNTED_REP_SUB_MISSING, perr(r"+"));
assert_eq!(ERR_UNCOUNTED_REP_SUB_MISSING, perr(r"(+)"));
assert_eq!(ERR_UNCOUNTED_REP_SUB_MISSING, perr(r"|?"));
assert_eq!(ERR_UNCOUNTED_REP_SUB_MISSING, perr(r"(?i)?"));
assert_eq!(ERR_COUNTED_REP_SUB_MISSING, perr(r"{5}"));
assert_eq!(ERR_COUNTED_REP_SUB_MISSING, perr(r"({5})"));
assert_eq!(ERR_COUNTED_REP_SUB_MISSING, perr(r"(?i){5}"));
assert_eq!(ERR_COUNTED_REP_UNCLOSED, perr(r"a{"));
assert_eq!(ERR_COUNTED_REP_MIN_UNCLOSED, perr(r"a{5"));
assert_eq!(ERR_COUNTED_REP_COMMA_UNCLOSED, perr(r"a{5,"));
assert_eq!(ERR_COUNTED_REP_MIN_MAX_UNCLOSED, perr(r"a{5,6"));
assert_eq!(ERR_COUNTED_REP_INVALID, perr(r"a{5,6Z"));
assert_eq!(ERR_COUNTED_REP_INVALID_RANGE, perr(r"a{6,5}"));
assert_eq!(ERR_DECIMAL_NO_DIGITS, perr(r"a{}"));
assert_eq!(ERR_DECIMAL_NO_DIGITS, perr(r"a{]}"));
assert_eq!(ERR_DECIMAL_INVALID, perr(r"a{999999999999999}"));
assert_eq!(ERR_CLASS_UNCLOSED_AFTER_ITEM, perr(r"[a"));
assert_eq!(ERR_CLASS_INVALID_RANGE_ITEM, perr(r"[\w-a]"));
assert_eq!(ERR_CLASS_INVALID_RANGE_ITEM, perr(r"[a-\w]"));
assert_eq!(ERR_CLASS_INVALID_ITEM, perr(r"[\b]"));
assert_eq!(ERR_CLASS_UNCLOSED_AFTER_DASH, perr(r"[a-"));
assert_eq!(ERR_CLASS_UNCLOSED_AFTER_NEGATION, perr(r"[^"));
assert_eq!(ERR_CLASS_UNCLOSED_AFTER_CLOSING, perr(r"[]"));
assert_eq!(ERR_CLASS_INVALID_RANGE, perr(r"[z-a]"));
assert_eq!(ERR_CLASS_UNCLOSED, perr(r"["));
assert_eq!(ERR_CLASS_UNCLOSED, perr(r"[a-z"));
assert_eq!(ERR_CLASS_NEST_UNSUPPORTED, perr(r"[a-z[A-Z]]"));
assert_eq!(ERR_CLASS_NEST_UNSUPPORTED, perr(r"[[:alnum]]"));
assert_eq!(ERR_CLASS_INTERSECTION_UNSUPPORTED, perr(r"[a&&b]"));
assert_eq!(ERR_CLASS_DIFFERENCE_UNSUPPORTED, perr(r"[a--b]"));
assert_eq!(ERR_CLASS_SYMDIFFERENCE_UNSUPPORTED, perr(r"[a~~b]"));
assert_eq!(ERR_SPECIAL_WORD_BOUNDARY_UNCLOSED, perr(r"\b{foo"));
assert_eq!(ERR_SPECIAL_WORD_BOUNDARY_UNCLOSED, perr(r"\b{foo!}"));
assert_eq!(ERR_SPECIAL_WORD_BOUNDARY_UNRECOGNIZED, perr(r"\b{foo}"));
assert_eq!(ERR_SPECIAL_WORD_OR_REP_UNEXPECTED_EOF, perr(r"\b{"));
assert_eq!(ERR_SPECIAL_WORD_OR_REP_UNEXPECTED_EOF, perr(r"(?x)\b{ "));
}
#[test]
fn err_verbatim() {
// See: https://github.com/rust-lang/regex/issues/792
assert_eq!(ERR_CLASS_UNCLOSED_AFTER_DASH, perr(r"(?x)[-#]"));
assert_eq!(ERR_CLASS_UNCLOSED_AFTER_ITEM, perr(r"(?x)[a "));
assert_eq!(ERR_CLASS_UNCLOSED_AFTER_DASH, perr(r"(?x)[a- "));
assert_eq!(ERR_CLASS_UNCLOSED, perr(r"(?x)[ "));
}
// This tests a bug fix where the nest limit checker wasn't decrementing
// its depth during post-traversal, which causes long regexes to trip
// the default limit too aggressively.
#[test]
fn regression_454_nest_too_big() {
let pattern = r#"
2(?:
[45]\d{3}|
7(?:
1[0-267]|
2[0-289]|
3[0-29]|
4[01]|
5[1-3]|
6[013]|
7[0178]|
91
)|
8(?:
0[125]|
[139][1-6]|
2[0157-9]|
41|
6[1-35]|
7[1-5]|
8[1-8]|
90
)|
9(?:
0[0-2]|
1[0-4]|
2[568]|
3[3-6]|
5[5-7]|
6[0167]|
7[15]|
8[0146-9]
)
)\d{4}
"#;
p(pattern);
}
// This tests that we treat a trailing `-` in a character class as a
// literal `-` even when whitespace mode is enabled and there is whitespace
// after the trailing `-`.
#[test]
fn regression_455_trailing_dash_ignore_whitespace() {
p("(?x)[ / - ]");
p("(?x)[ a - ]");
p("(?x)[
a
- ]
");
p("(?x)[
a # wat
- ]
");
perr("(?x)[ / -");
perr("(?x)[ / - ");
perr(
"(?x)[
/ -
",
);
perr(
"(?x)[
/ - # wat
",
);
}
#[test]
fn regression_capture_indices() {
let got = p(r"(a|ab|c|bcd){4,10}(d*)");
assert_eq!(
got,
Hir::concat(vec![
Hir::repetition(hir::Repetition {
min: 4,
max: Some(10),
greedy: true,
sub: Box::new(cap(
1,
Hir::alternation(vec![
Hir::char('a'),
Hir::concat(vec![Hir::char('a'), Hir::char('b')]),
Hir::char('c'),
Hir::concat(vec![
Hir::char('b'),
Hir::char('c'),
Hir::char('d')
]),
])
))
}),
cap(
2,
Hir::repetition(hir::Repetition {
min: 0,
max: None,
greedy: true,
sub: Box::new(Hir::char('d')),
})
),
])
);
}
}