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