A library for managing regula expressions with templates
Project description
Replus v0.3.0
A wrapper for the regex
library for advanced pattern management.
- Checkout the Full documentation.
Quickstart
Installation
pip install replus
or clone this repo
git clone git@github.com:biagiodistefano/replus.git
and then run
python setup.py install
Template creation
The Engine loads Regular Expression pattern templates written in *.json files from the provided directory, builds and compiles them in the following fashion:
example of template patterns/date.json
:
{
"day": [
"3[01]",
"[12][0-9]",
"0?[1-9]"
],
"month": [
"0?[1-9]",
"1[012]"
],
"year": [
"\\d{4}"
],
"date": [
"{{day}}/{{month}}/{{year}}",
"{{year}}-{{month}}-{{day}}"
],
"$PATTERNS": [
"{{date}}"
]
}
will result in the following regex:
(?P<date_0>(?P<day_0>[12][0-9]|0?[1-9]|3[01])/(?P<month_0>0?[1-9]|1[012])/(?P<year_0>\d{4})|(?P<year_1>\d{4})-(?P<month_1>0?[1-9]|1[012])-(?P<day_1>[12][0-9]|0?[1-9]|3[01]))
Only the patterns under $PATTERNS
will be matched against at runtime.
Querying
It is possible to query as follows:
from replus import Replus
engine = Replus('patterns')
for match in engine.parse("Look at this date: 2012-20-10"):
print(match)
# <[Match date] span(19, 29): 2012-12-10>
date = match.group('date')
print(date)
# <[Group date_0] span(19, 29): 2012-12-10>
day = date.group('day')
print(day)
# <[Group day_1] span(27, 29): 10>
month = date.group('month')
print(month)
# <[Group month_1] span(24, 26): 12>
year = date.group('year')
print(year)
# [Group year_1] span(19, 23): 2012>
Filtering
it is possible to filter regexes by type, being the type given by the json's filename's stem. E.g., in the above example, results matched by the patterns under patterns/date.json
's $PATTERNS
will have type date
filters = ["dates", "cities"]
for match in engine.parse(my_string, *filters):
# do stuff
Extra features
There are two useful secondary features:
- non-capturing groups: these are specified by using the "?:" prefix in the group name or key
- atomic groups: these are specified by using the "?>" prefix in the group name or key
- dynamic backreferences: use
#
to reference a previous group and@<n>
to specify how many groups behind
template:
{
"?:number": [
"\\d"
],
"abg": [
"alpha",
"beta",
"gamma"
],
"spam": [
"spam"
],
"eggs": [
"eggs"
],
"patterns": [
"This is an unnamed number group: {{number}}.",
"I can match {{abg}} and {{abg}}, and then re-match the last {{#abg}} or the second last {{#abg@2}}",
"Here is some {{?:spam}} and some {{?>eggs}}"
]
}
It will generate the following regexs:
This is an unnamed number group: (?:\d).
I can match (?P<abg_0>alpha|beta|gamma) and (?P<abg_1>alpha|beta|gamma), and then re-match the last (?P=abg_1) or the second last (?P=abg_0)
Here is some (?:spam) and some (?>eggs)
N.B.: in order to obtain an escape char, such as \d
, in the pattern's model it must be double escaped: \\d
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