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@ -1,13 +1,13 @@
= N___ RegEx Library = NRE
== What is NRE? == What is NRE?
A new regular expression library for Nim using PCRE to do the hard work. A regular expression library for Nim using PCRE to do the hard work.
== Why? == Why?
The http://nim-lang.org/re.html[re.nim] module that http://nim-lang.org/[Nim] The http://nim-lang.org/re.html[re.nim] module that http://nim-lang.org/[Nim]
provides in it's standard library is inadequate: provides in its standard library is inadequate:
- It provides only a limited number of captures, while the underling library - It provides only a limited number of captures, while the underling library
(PCRE) allows an unlimited number. (PCRE) allows an unlimited number.
@ -21,50 +21,6 @@ provides in it's standard library is inadequate:
== Documentation == Documentation
Creating a pattern is easy: `re"([0-9]+)"`. By default, the extended flag is
passed in order to encourage readable expressions, so `[0-9]+` is equivalent to
`[0-9] + # foo`. If you'd like to pass your own flags, then `re(r"([0-9]+)",
"<flags>")` will work. Here is a list of the available flags:
- `8` - treat both the pattern and subject as UTF8
- `9` - prevents the pattern from being interpreted as UTF, no matter what
- `A` - as if the pattern had a `^` at the beginning
- `E` - DOLLAR_ENDONLY
- `f` - fails if there is not a match on the first line
- `i` - case insensitive
- `m` - multi-line, `^` and `$` match the beginning and end of lines, not of the
subject string
- `N` - turn off auto-capture, `(?foo)` is necessary to capture.
- `s` - `.` matches newline
- `S` - study the pattern to hopefully improve performance. JIT is unspported at
the moment.
- `U` - expressions are not greedy by default. `?` can be added to a qualifier
to make it greedy.
- `u` - same as `8`
- `W` - Unicode character properties
- `X` - "Extra", character escapes without special meaning (`\w` vs. `\a`) are
errors
- `x` - extended, comments (`#`) and newlines are ignored (extended)
- `Y` - pcre.NO_START_OPTIMIZE,
- `<cr>` - newlines are separated by `\r`
- `<crlf>` - newlines are separated by `\r\n` (Windows default)
- `<lf>` - newlines are separated by `\n` (UNIX default)
- `<anycrlf>` - newlines are separated by any of the above
- `<any>` - newlines are separated by any of the above and Unicode newlines:
[quote, , man pcre]
____
single characters VT (vertical tab, U+000B), FF (form feed, U+000C), NEL
(next line, U+0085), LS (line separator, U+2028), and PS (paragraph
separator, U+2029). For the 8-bit library, the last two are recognized
only in UTF-8 mode.
____
- `<bsr_anycrlf>` - `\R` matches CR, LF, or CRLF
- `<bsr_unicode>` - `\R` matches any unicode newline
- `<js>` - Javascript compatibility
`Sx` is enabled by default in order to encourage use of whitespace for better
readability.
=== Procedures === Procedures
[[proc-match]] [[proc-match]]
@ -144,9 +100,47 @@ fields are as follows:
=== `Pattern` === `Pattern`
Represents the pattern that things are matched against, constructed with Represents the pattern that things are matched against, constructed with
`initRegex(string)` or `re(string)`. `initRegex(string)` or `re(string)`. Examples: `re"foo"`, `re(r"foo # comment",
"Sx<anycrlf>")`.
`pattern: string` :: the string that was used to create the pattern. `pattern: string` :: the string that was used to create the pattern.
`captureCount: int` :: the number of captures that the pattern has. `captureCount: int` :: the number of captures that the pattern has.
`captureNameId: Table[string, int]` :: a table from the capture names to `captureNameId: Table[string, int]` :: a table from the capture names to
their numeric id. their numeric id.
==== Flags
- `8` - treat both the pattern and subject as UTF8
- `9` - prevents the pattern from being interpreted as UTF, no matter what
- `A` - as if the pattern had a `^` at the beginning
- `E` - DOLLAR_ENDONLY
- `f` - fails if there is not a match on the first line
- `i` - case insensitive
- `m` - multi-line, `^` and `$` match the beginning and end of lines, not of the
subject string
- `N` - turn off auto-capture, `(?foo)` is necessary to capture.
- `s` - `.` matches newline
- `S` - study the pattern to hopefully improve performance. JIT is unspported at
the moment.
- `U` - expressions are not greedy by default. `?` can be added to a qualifier
to make it greedy.
- `u` - same as `8`
- `W` - Unicode character properties
- `X` - "Extra", character escapes without special meaning (`\w` vs. `\a`) are
errors
- `x` - extended, comments (`#`) and newlines are ignored (extended)
- `Y` - pcre.NO_START_OPTIMIZE,
- `<cr>` - newlines are separated by `\r`
- `<crlf>` - newlines are separated by `\r\n` (Windows default)
- `<lf>` - newlines are separated by `\n` (UNIX default)
- `<anycrlf>` - newlines are separated by any of the above
- `<any>` - newlines are separated by any of the above and Unicode newlines:
[quote, , man pcre]
____
single characters VT (vertical tab, U+000B), FF (form feed, U+000C), NEL
(next line, U+0085), LS (line separator, U+2028), and PS (paragraph
separator, U+2029). For the 8-bit library, the last two are recognized
only in UTF-8 mode.
____
- `<bsr_anycrlf>` - `\R` matches CR, LF, or CRLF
- `<bsr_unicode>` - `\R` matches any unicode newline
- `<js>` - Javascript compatibility