Regex that will match PHP variable but not object and function invocation
jcubic
I am working on a regex that will match one of
$foo $bar $baz
but not
$foo->bar
So far, I have
/\$([a-zA-Z_][a-zA-Z_0-9]*(?!->))/
Unfortunately, this pattern matches $fo. See this regex demo.
Wiktor Stribiżew
Use a possessive quantifier that will disallow backtracking into the [a-zA-Z_0-9] subpattern:
\$([a-zA-Z_][a-zA-Z_0-9]*+(?!->))
^^
or even (as [a-zA-Z_0-9] = \w if you are not using /u modifier or (*UCP) verb):
\$([a-zA-Z_]\w*(?!->))
See regex demo
The issue is that when the negative lookahead fails backtracking gets into play, and as * allows backtracking into the quantified subpattern, the o that is not followed with -> is found and a match is returned.
See how your regex works, pay special attention at the backtracking steps:
Collected from the Internet
Please contact [email protected] to delete if infringement.
edited at
- Prev: Newton's square root method in Scheme or Common Lisp
- Next: How to Push a New Elixir Release on a Cluster Using exrm?
Related
Related Related
- 1
How to match PHP tags with Regex?
- 2
PHP Regex to match an IP address
- 3
Simple regex to match word in the format variable = [[ word ]] in php
- 4
RegEx - JavaScript .match() with a variable keyword
- 5
PHP: Regex: Match if doesnt contain
- 6
Regex to match a variable in Batch scripting
- 7
SSRS Function with Regex Match
- 8
Get return value of first function invocation match without invoking it twice
- 9
Bash regex string variable match
- 10
PHP - preg_match regex
- 11
Match the body of a function using Regex
- 12
PHP regex - pattern does not match
- 13
get a string php regex match
- 14
PHP Match Multipline Line with Regex
- 15
regex match in PHP
- 16
RegEx - JavaScript .match() with a variable keyword
- 17
PHP regex match multiple pieces
- 18
Regex to match a function
- 19
PHP/Regex - Warning: preg_match_all() [function.preg-match-all]: Unknown modifier
- 20
PHP Regex Match nothing
- 21
SSRS Function with Regex Match
- 22
Get return value of first function invocation match without invoking it twice
- 23
PHP Access a variable inside a function of an object in an object of this object
- 24
Bash regex string variable match
- 25
Regex that will match PHP variable but not object and function invocation
- 26
Java regex to match for variable value
- 27
Regex match for object creation in Java
- 28
filter function using match with regex
- 29
JavaScript - Regex Match Not a Function
Comments