Regex for variable declaration and initialization in c#
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06-09-2019 - |
Question
I want to write a RegEx to pull out all the variable values and their names from the variable declaration statement. Say i have
int i,k = 10,l=0
i want to write a regex something like int\s^,?|(^,?)* but this will also accept k = 10 i.e. (without int preceding it) Basically idea is If string starts with int then get the variable list seperated by ,
i know to extract csv values, but here my string has some initial value as well. How can i resolve it?
Solution
Start thinking about the structure of a definition, say,
(a line can start with some spaces) followed by,
(Type) followed by
(at least one space)
(variable_1)
(optionally
(comma // next var
|
'='number // initialization
) ...`
then try to convert each group:
^ \s* \w+ \s+ \w+ ? (',' | '=' \d+ ) ...
line some type at least var optionally more or init some
start spaces (some chars) one space (some chars) vars val digits
Left as homework to remove spaces and fix up the final regex.
OTHER TIPS
Here is some useful information which you can use
You could build up your regular expression from the [C# Grammar](http://msdn.microsoft.com/en-us/library/aa664812(VS.71).aspx). But building a parser would certainly be better.
Try this:
^(int|[sS]tring)\s+\w+\s*(=\s*[^,]+)?(,\s*\w+\s*(=\s*[^,]+)?)*$
It'll match your example code
int i,k = 10,l=0
And making a few assumptions about the language you may or may not be using, it'll also match:
int i, j, k=10, l=0
string i=23, j, k=10, l=0