How do you implement an exact match token

[dryan-cais]

Imagine a dynamic list of allowable fields: somefield, somefield2, somefield3

I can create a regex token for the allowable fields dynamically resulting in something like:

private val fieldToken: Token by regexToken("somefield|somefield2|somefield3")

The problem is that the first match for "somefield2" is "somefield" resultings in parser error due to unexpected "2" (not withstanding it matches the wrong field anyway).

This can be fixed using an exact match:

private val fieldToken: Token by regexToken("^somefield$|^somefield2$|^somefield3$")

Unfortunately, when I look to extend the grammar to support stuff like "somefield2=blue", when there is no whitespace, the exact match falls over.

Apologies for what is probably a newbie question but I can't get my head around this. Any help would be appreciated.

[dryan-cais]

Never mind; just my lack of skill using regular expressions. This is what I needed: https://www.regular-expressions.info/wordboundaries.html