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Diffstat (limited to 'doc/regexprs.txt')
| -rw-r--r-- | doc/regexprs.txt | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/doc/regexprs.txt b/doc/regexprs.txt index 83dbd2eeb..fa7f9d24a 100644 --- a/doc/regexprs.txt +++ b/doc/regexprs.txt @@ -47,16 +47,18 @@ full documentation of Perl's regular expressions. Because the backslash ``\`` is a meta character both in the Nim programming language and in regular expressions, it is strongly recommended that one uses the *raw* strings of Nim, so that -backslashes are interpreted by the regular expression engine:: +backslashes are interpreted by the regular expression engine: +```nim r"\S" # matches any character that is not whitespace +``` A regular expression is a pattern that is matched against a subject string from left to right. Most characters stand for themselves in a pattern, and match the corresponding characters in the subject. As a trivial example, -the pattern:: +the pattern: - The quick brown fox + The quick brown fox matches a portion of a subject string that is identical to itself. The power of regular expressions comes from the ability to include @@ -128,7 +130,7 @@ in patterns in a visible manner. There is no restriction on the appearance of non-printing characters, apart from the binary zero that terminates a pattern, but when a pattern is being prepared by text editing, it is usually easier to use one of the following escape sequences than the binary character it -represents:: +represents: ============== ============================================================ character meaning @@ -146,7 +148,7 @@ character meaning After ``\x``, from zero to two hexadecimal digits are read (letters can be in upper or lower case). In UTF-8 mode, any number of hexadecimal digits may appear between ``\x{`` and ``}``, but the value of the character code must be -less than 2**31 (that is, the maximum hexadecimal value is 7FFFFFFF). If +less than 2^31 (that is, the maximum hexadecimal value is 7FFFFFFF). If characters other than hexadecimal digits appear between ``\x{`` and ``}``, or if there is no terminating ``}``, this form of escape is not recognized. Instead, the initial ``\x`` will be interpreted as a basic hexadecimal escape, @@ -224,7 +226,7 @@ current matching point is at the end of the subject string, all of them fail, since there is no character to match. For compatibility with Perl, ``\s`` does not match the VT character (code 11). -This makes it different from the the POSIX "space" class. The ``\s`` characters +This makes it different from the POSIX "space" class. The ``\s`` characters are HT (9), LF (10), FF (12), CR (13), and space (32). A "word" character is an underscore or any character less than 256 that is @@ -244,7 +246,7 @@ The fourth use of backslash is for certain `simple assertions`:idx:. An assertion specifies a condition that has to be met at a particular point in a match, without consuming any characters from the subject string. The use of subpatterns for more complicated assertions is described below. The -backslashed assertions are:: +backslashed assertions are: ============== ============================================================ assertion meaning |