Does ^ work to match beginning of text?

[adisazhar123]

Running a simple example with the code below fails,

lexer.Add([]byte(`^abc`), printSomething)

where printSomething is a function that prints the matched token.

Error message

got err in Scanner Regex parse error in production 'group' : at index 0 line 0 column 1 '^abc' : expected '(' at 0 got '^' of '^abc'
Regex parse error in production 'charClass' : at index 0 line 0 column 1 '^abc' : expected '[' at 0 got '^' of '^abc'
Regex parse error in production 'CHAR' : at index 0 line 0 column 1 '^abc' : unexpected operator, ^
Regex parse error in production 'char' : at index 0 line 0 column 1 '^abc' : Expected a CHAR or charRange at 0, ^abc
Regex parse error in production 'atomic' : at index 0 line 0 column 1 '^abc' : Expected group or char
Regex parse error in production 'Parse' : at index 0 line 0 column 1 '^abc' : unconsumed input

My question is, is the use of ^ to anchor the beginning of a text not supported? Are there any alternatives?

Thank you.