How to use regexp in @filter

And here is All schema

 `<_basic_info>: string @index(term, trigram) .
<attachment>: [uid] .
<chafen>: string .
<comment>: string @index(term, trigram) .
<create_by>: string @index(term, trigram) .
<create_time>: datetime @index(hour) .
<creator>: string .
<data>: uid .
<delivery_report_url>: string @index(term, trigram) .
<description>: string @index(term, trigram) .
<dgraph.drop.op>: string .
<dgraph.graphql.p_query>: string @index(sha256) .
<dgraph.graphql.schema>: string .
<dgraph.graphql.xid>: string @index(exact) @upsert .
<full_key>: string .
<gongnengshuoming>: string .
<id>: string @index(term) .
<is_for_commercial>: bool @index(bool) .
<last_update_by>: string @index(term, trigram) .
<last_update_time>: datetime @index(hour) .
<library_id>: string @index(term) .
<market_requirement_id>: string @index(term, trigram) .
<modifier>: string .
<name>: string @index(term, trigram) .
<op>: string .
<parent_to_child>: [uid] @reverse .
<peizhi>: string .
<qa>: string @index(term, trigram) .
<rdc>: string .
<rdc_areapath>: string .
<rdc_belong_product>: string .
<rdc_released_version>: string .
<rdc_requirement_priority>: string .
<rdc_workitem_type>: string @index(term, trigram) .
<relation>: [uid] @reverse .
<requirement_apply_location>: string @index(term, trigram) .
<requirement_delivery_sm>: string @index(term, trigram) .
<requirement_delivery_status>: string @index(term, trigram) .
<requirement_delivery_type>: string @index(term, trigram) .
<requirement_id>: string @index(term, trigram) .
<requirement_purpose>: string @index(term, trigram) .
<requirement_specification_url>: string @index(term, trigram) .
<requirement_time>: string @index(term, trigram) .
<requirement_title>: string @index(term, trigram) .
<requirement_version>: string @index(term, trigram) .
<resource_key>: string .
<rich_text>: string @index(term, trigram) .
<scene_factor_keyword>: string @index(term, trigram) .
<scene_mml>: string @index(term, trigram) .
<scene_test_check_point>: string @index(term, trigram) .
<scene_test_step>: string @index(term, trigram) .
<secondType>: string .
<shangyong>: string .
<shengxiaojiancha>: string .
<signaling_stream>: string @index(term, trigram) .
<solution_specification_url>: string @index(term, trigram) .
<target_market>: string @index(term, trigram) .
<test_design_url>: string @index(term, trigram) .
<testcase_url>: string @index(term, trigram) .
<third_party_id>: string .
<third_party_key>: string .
<third_party_url>: string @index(term, trigram) .
<title>: string @index(term, trigram) .
<total_autocase_number>: int @index(int) .
<total_testcase_number>: int @index(int) .
<tse>: string @index(term, trigram) .
<type>: string .
<version>: string .
<workspace_key>: string @index(exact) .
type <dgraph.graphql> {
	dgraph.graphql.schema
	dgraph.graphql.xid
}
type <dgraph.graphql.persisted_query> {
	dgraph.graphql.p_query
}`