regexptest

Documentation

Index

• func Compile(t testing.TB, expr string) *regexp.Regexp
• func CompilePOSIX(t testing.TB, expr string) *regexp.Regexp
• func Match(t testing.TB, pattern string, b []byte) (matched bool)
• func MatchReader(t testing.TB, pattern string, r io.RuneReader) (matched bool)
• func MatchString(t testing.TB, pattern string, s string) (matched bool)

Functions

func Compile

func Compile(t testing.TB, expr string) *regexp.Regexp

Compile parses a regular expression and returns, if successful, a [Regexp] object that can be used to match against text.

When matching against text, the regexp returns a match that begins as early as possible in the input (leftmost), and among those it chooses the one that a backtracking search would have found first. This so-called leftmost-first matching is the same semantics that Perl, Python, and other implementations use, although this package implements it without the expense of backtracking. For POSIX leftmost-longest matching, see CompilePOSIX.

func CompilePOSIX

func CompilePOSIX(t testing.TB, expr string) *regexp.Regexp

CompilePOSIX is like Compile but restricts the regular expression to POSIX ERE (egrep) syntax and changes the match semantics to leftmost-longest.

That is, when matching against text, the regexp returns a match that begins as early as possible in the input (leftmost), and among those it chooses a match that is as long as possible. This so-called leftmost-longest matching is the same semantics that early regular expression implementations used and that POSIX specifies.

However, there can be multiple leftmost-longest matches, with different submatch choices, and here this package diverges from POSIX. Among the possible leftmost-longest matches, this package chooses the one that a backtracking search would have found first, while POSIX specifies that the match be chosen to maximize the length of the first subexpression, then the second, and so on from left to right. The POSIX rule is computationally prohibitive and not even well-defined. See https://swtch.com/~rsc/regexp/regexp2.html#posix for details.

func Match

func Match(t testing.TB, pattern string, b []byte) (matched bool)

Match reports whether the byte slice b contains any match of the regular expression pattern. More complicated queries need to use Compile and the full [Regexp] interface.

func MatchReader

func MatchReader(t testing.TB, pattern string, r io.RuneReader) (matched bool)

MatchReader reports whether the text returned by the io.RuneReader contains any match of the regular expression pattern. More complicated queries need to use Compile and the full [Regexp] interface.

func MatchString

func MatchString(t testing.TB, pattern string, s string) (matched bool)

MatchString reports whether the string s contains any match of the regular expression pattern. More complicated queries need to use Compile and the full [Regexp] interface.