A readable and intuitive way to generate Regular Expressions
Project description
EZRegex
A readable and intuitive way to generate Regular Expressions
Try my new frontend for this library at ezregex.org!
TLDR: This is to regular expressions what CMake is to makefiles
Table of Contents
Usage
Quickstart
from ezregex import *
'foo' + number + optional(whitespace) + word
# Matches `foo123abc` and `foo123 abc`
# but not `abc123foo` or `foo bar`
Importing as a named package is recommended
import ezregex as er
# ow is part of er already as optional whitespace
params = er.group(er.atLeastNone(er.ow + er.word + er.ow + er.optional(',') + er.ow))
function = er.word + er.ow + '(' + params + ')'
re.search('some string containing func( param1 , param2)', str(function))
# or the test() method is helpful for debugging, and color codes groups for you
function.test('this should match func(param1,\tparam2 ), foo(), and bar( foo,)')
╭───────────────────────────── Testing Regex ──────────────────────────────╮
│ Testing expression: │
│ \w+(?:\s+)?\(((?:(?:\s+)?\w+(?:\s+)?,?(?:\s+)?)*)\) │
│ for matches in: │
│ this should match func(param1, param2 ), foo(), and bar( foo,) │
│ │
│ Match = "func(param1, param2 )" (18:39) │
│ Unnamed Groups: │
│ 1: "param1, param2 " (23:38) │
│ │
│ Match = "foo()" (41:46) │
│ Unnamed Groups: │
│ 1: "" (45:45) │
│ │
│ Match = "bar( foo,)" (52:62) │
│ Unnamed Groups: │
│ 1: " foo," (56:61) │
│ │
│ │
╰───────────────────────────────── Found ─────────────────────────────────╯
Installation
ezregex is distributed on PyPI as a universal wheel and is available on Linux/macOS and Windows and supports Python 3.10+ and PyPy.
$ pip install ezregex
Inverting
There's also an invert
function (available either as er.invert, or ~(<expression>)) that is useful
for debugging. You pass it an expression, and it returns an example of a string that is guaranteed to
match the provided expression.
Documentation
Notes and Gotchas
- When using the re library, functions like search() and sub() don't accept EZRegexMembers as valid regex patterns. Be sure to call either .str() or .compile() when passing to those. Also, be careful to call the function on the entire pattern: chunk + whitespace.str() is not the same as (chunk isEx+ whitespace).str().
- The
input
parameter can accept strings, other EZRegexMembers, or entire sequences of EZRegex patterns. - A few of these have
greedy
andpossessive
optional parameters. They can be useful, but can get complicated. Refer to the Python re docs for details. - In future versions, conditionals may change to taking in 2 parameters (the current pattern, and their associated condition) instead
- In regular Regex, a lot of random things capture groups for no reason. I find this annoying. All regexes in EZRegex intentionally capture passively, so to capture any groups, use group() or namedGroup().
- All EZRegexMembers (except for raw) auto-sanitize strings given to them, so there's no need to escape braces or question marks and the like. This does mean, however, that you cannot pass actual regex strings to any of them, as they'll think you're talking about it literally. To include already written regex strings, use raw
- Note that I have camelCase and snake_case versions of each of the functions, because I waver back and forth between which I like better. Both versions function identically.
Positionals
These differentiate the string starting with a sequence, and a line starting with a sequence. Do note that the start of the string is also the start of a line. These can also be called without parameters to denote the start/end of a string/line without something specific having to be next to it.
- stringStartsWith
- stringEndsWith
- lineStartsWith
- lineEndsWith
Literals
- tab
- space
- spaceOrTab
- newline
- carriageReturn
- quote
- verticalTab
- formFeed
- comma
- period
Not Literals
- notWhitespace
- notDigit
- notWord
Catagories
- whitespace
- whitechunk
- A "chunk" of whitespace. Just any amount of whitespace together
- digit
- letter
- Matches just a letter -- not numbers or _ like wordChar.
- number
- Matches multiple digits next to each other. Does not match negatives or decimals
- word
- wordChar
- Matches just a single "word character", defined as any letter, number, or _
- anything
- Matches any single character, except a newline. To also match a newline, use literallyAnything
- chunk
- A "chunk": Any clump of characters up until the next newline
- uppercase
- lowercase
- hexDigit
- octDigit
- punctuation
- controller
- Matches a metadata ASCII characters
- printable
- Matches printable ASCII characters
- printableAndSpace
- alphaNum
- unicode
- Matches a unicode character by name
- anyBetween
- Match any char between
char
andand_char
, using the ASCII table for reference
- Match any char between
Amounts
-
matchMax
- Match as many of
input
in the string as you can. This is equivelent to using the unary + operator. Ifinput
is not provided, it works on the previous regex pattern. That's not recommended for clarity's sake though
- Match as many of
-
amt
- Match
num
amount ofinput
in the string
- Match
-
moreThan
- Match more than
min
sequences ofinput
in the string
- Match more than
-
matchRange
- Match between
min
andmax
sequences ofinput
in the string. This also acceptsgreedy
andpossessive
parameters Max can be an empty string to indicate no maximum greedy means it will try to match as many repititions as possible non-greedy will try to match as few repititions as possible possessive means it won't backtrack to try to find any repitions see https://docs.python.org/3/library/re.html for more help
- Match between
-
atLeast
- Match at least
min
sequences ofinput
in the string
- Match at least
-
atMost
- Match at most
max
instances ofinput
in the string
- Match at most
-
atLeastOne
- Match at least one of
input
in the string. This also acceptsgreedy
andpossessive
parameters greedy means it will try to match as many repititions as possible non-greedy will try to match as few repititions as possible possessive means it won't backtrack to try to find any repitions see https://docs.python.org/3/library/re.html for more help
- Match at least one of
-
atLeastNone
- Match 0 or more sequences of
input
. This also acceptsgreedy
andpossessive
parameters greedy means it will try to match as many repititions as possible non-greedy will try to match as few repititions as possible possessive means it won't backtrack to try to find any repitions see https://docs.python.org/3/library/re.html for more help
- Match 0 or more sequences of
Choices
-
optional
- Match
input
if it's there. This also acceptsgreedy
andpossessive
parameters greedy means it will try to match as many repititions as possible non-greedy will try to match as few repititions as possible possessive means it won't backtrack to try to find any repitions see https://docs.python.org/3/library/re.html for more help
- Match
-
either
-
anyOf
- Match any of the given
inputs
. Note thatinputs
can be multiple parameters, or a single string. Can also accept parameters chars and split. If char is set to True, theninputs
must only be a single string, it interpretsinputs
as characters, and splits it up to find any of the chars in the string. If split is set to true, it forces the ?(...) regex syntax instead of the [...] syntax. It should act the same way, but your output regex will look different. By default, it just optimizes it for you.
- Match any of the given
-
anyCharExcept
- This matches any char that is NOT in
inputs
.inputs
can be multiple parameters, or a single string of chars to split.
- This matches any char that is NOT in
-
anyExcept
- Matches anything other than
input
, which must be a single string or EZRegex chain, not a list. Also optionally accepts thetype
parameter, which works like this: "Match anytype
other thaninput
". For example, "match any word which is not foo". Do note that this function is new, and I'm still working out the kinks.
- Matches anything other than
Conditionals
- ifProceededBy
- Matches the prior pattern if it has
condition
coming after it
- Matches the prior pattern if it has
- ifNotProceededBy
- Matches the prior pattern if it does not have
condition
coming after it
- Matches the prior pattern if it does not have
- ifPrecededBy
- Matches the prior pattern if it has
condition
coming before it
- Matches the prior pattern if it has
- ifNotPreceededBy
- Matches the prior pattern if it does not have
condition
coming before it
- Matches the prior pattern if it does not have
- ifEnclosedWith
- Matches if the string has
open
, thenstuff
, thenclose
, but only "matches" stuff. Just a convenience combination of ifProceededBy and ifPreceededBy.
- Matches if the string has
Grouping
- group
- Causes
input
to be captured as an unnamed group. Only useful when replacing regexs
- Causes
- passiveGroup
- As all regexs in EZRegex capture passively, this is entirely useless. But if you really want to, here it is
- namedGroup
- Causes
input
to be captured as a named group, with the namename
. Only useful when replacing regexs
- Causes
Replacement
In the intrest of "I don't want to think about any syntax at all", I have included replace members. Do note that they are not interoperable with the other EZRegexMembers, and can only be used with other strings and each other.
- rgroup
- Puts in its place the group specified, either by group number (for unnamed groups) or group name (for named groups). Named groups are also counted by number, I'm pretty sure. Groups are numbered starting from 1.
- replaceEntire
- Puts in its place the entire match
Premade
These are some useful combinations that may be commonly used. They are not as stable, and may be changed and added to in later versions to make them more accurate
- literallyAnything
- Any character, include newline
- signed
- a signed number, including 123, -123, and +123
- unsigned
- Same as number. Will not match +123
- plain_float
- Will match 123.45 and 123.
- full_float
- Will match plain_float as well as things like 1.23e-10 and 1.23e+10
- int_or_float
- ow
- "Optional Whitechunk"
- email
- Matches an email
Misc
These shadow python regex flags, and can just as easily be specified directly to the re library instead. They're provided here for compatibility with other regex dialects. See https://docs.python.org/3/library/re.html#flags for details
- literal
- This is a redundant function. You should always be able to use
... + 'stuff'
just as easily as... + literal('stuff')
- This is a redundant function. You should always be able to use
- isExactly
- This matches the string if and only if the entire string is exactly equal to
input
- This matches the string if and only if the entire string is exactly equal to
- raw
- If you already have some regular regex written, and you want to incorperate it, this will allow you to include it without sanatizing all the backslaches and such, which all the other EZRegexMembers do automatically.
Flags
- ASCII
- DOTALL
- IGNORECASE
- LOCALE
- MULTILINE
- UNICODE
Explanation of How it Works
Everything relies on the EZRegexMember class. In the __init__ file of the package, I have defined a ton of pre-made EZRegexMembers which mimic all (or at least as many as I can) fundamental parts of the regex syntax, plus a few others which are common combinations (like chunk or whitechunk). These have operators overloaded so you can combine them in intuitive ways and call them by intuitive names. All EZRegexMembers take a function parameter (or a string which gets converted to a function for convenience), which gets called with the current regex expression and any parameters passed along when the instance gets called with the () operator. That way you can add things to the front or back of an expression for example, and you can change what exactly gets added to the current expression based on other parameters. You can also chain strings together, and pass them as parameters to other EZRegexMembers, which auto-compiles them and adds them appropriately.
I also have everything which could capture a group capture it passively, except for actual group operators, and always have the (?m) (multiline) flag automatically asserted whenever lineStartsWith/lineEndsWith are used so as to differentiate between capturing at the beginning/end of a string and the beginning/end of a line.
Current limitations
- inverse() is not totally functional yet. It's close, but has a couple bugs I haven't yet figured out. It's very useful, but try not to rely on it too much
- I had previously included seperate dialects of the regex syntax, but ultimately decided it was too much effort and complication to maintain, so I did away with it and it only produces Python-style regex now.
- Not quite all of the regex syntax is implemented yet, though it's close. See the ToDo section
ToDo
See the todo
License
ezregex is distributed under the MIT License
Project details
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