Question

I’m not really that good with regex, but I understand the basics. I’m trying to figure out how to do a conditional replace based upon a certain value in the match. For example:

Suppose I have some nested string structure that look like this:

"[id value]"//id and value are space delimited.  id will never have spaces

id is some string id that names the [] item and value is another nested [id value] item. Its possible for value to be empty, but I’m not worried about that for now.

If I have something like this:

A) "[vehicle [toyota camry]]"
or
B) "[animal [dog rufus]]"

I’d like to be able to call a certain function (ToString() for example) based upon id that gets output as the regex.Replace is executed from the inner most [] structure.

Going from example A pseudo code:

string Return = "{0}";
var 1stValueComboID = GetInteriorValue/IDFrom("[vehicle [toyota camry]]");
//1stValueComboID.ToString() = "Company: Toyota, Make: Camry"

Return = Format.String(Return,1stValueIDCombo.ToString());


var 2stValueComboID = GetSecondValue/IDFrom("[vehicle [toyota camry]]");
//2stValueComboID.ToString() = "Type: Vehicle, {0}"

Return = Format.String(Return,2ndValueIDCombo.ToString());

This sample obviously has nothing to do with regex, but it hopefully illustrates kind of what I’m trying to do.

Answer 1

JoshD correctly points out that this grammar you’ve proposed (having matching pairs of brackets) cannot be parsed using a regular expression. You need to construct a custom parser with recursive descent behavior.