Fix regex expression wasn't allowed in EXTRACT

[git-hulk]

This closes #222.

[coveralls]

Pull Request Test Coverage Report for Build 19960820746

Details

• 52 of 84 (61.9%) changed or added relevant lines in 4 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.03%) to 51.079%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
parser/walk.go	4	8	50.0%
parser/ast_visitor.go	0	5	0.0%
parser/parser_column.go	35	41	85.37%
parser/ast.go	13	30	43.33%

Files with Coverage Reduction	New Missed Lines	%
parser/parser_column.go	2	73.34%

Totals
Change from base Build 19957608817:	0.03%
Covered Lines:	7977
Relevant Lines:	15617

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💛 - Coveralls

[Copilot]

Pull request overview

Copilot reviewed 8 out of 8 changed files in this pull request and generated no new comments.

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