{⟦
  org() ↦ ⟦
    eolang() ↦ ⟦
      txt() ↦ ⟦
        regex(expression) ↦ ⟦
          φ ↦ ξ.compiled,
          compiled() ↦ ⟦
            λ ⤍ Lorg_eolang_txt_regex_compiled
          ⟧,
          pattern(serialized) ↦ ⟦
            matches(txt) ↦ ⟦
              φ ↦ ξ.ρ.match(ξ.txt).next.exists
            ⟧,
            match(txt) ↦ ⟦
              next ↦ ξ.matched-from-index(1, 0).matched,
              matched-from-index(position, start) ↦ ⟦
                λ ⤍ Lorg_eolang_txt_regex_pattern_match_matched_from_index
              ⟧,
              matched(position, start, from, to, groups) ↦ ⟦
                matched ↦ ξ,
                groups-count ↦ ξ.groups.length,
                exists ↦ ξ.start.gte(0),
                next ↦ ξ.exists.if(
                  ξ.ρ.matched-from-index(ξ.position.plus(1), ξ.to).matched,
                  Φ̇.error("Matched block does not exist, can't get next")
                ),
                text ↦ ξ.exists.if(
                  ξ.group(0), Φ̇.error("Matched block does not exist, can't get text")
                ),
                group(index) ↦ ⟦
                  φ ↦ ξ.ρ.groups.at(ξ.index)
                ⟧
              ⟧,
              not-matched(position) ↦ ⟦
                φ ↦ ξ.ρ.matched(
                  ξ.position,
                  -1,
                  Φ̇.error(
                    "Matched block does not exist, can't get 'from' position"
                  ),
                  Φ̇.error(
                    "Matched block does not exist, can't get 'to' position"
                  ),
                  Φ̇.error("Matched block does not exist, can't get groups")
                )
              ⟧
            ⟧
          ⟧
        ⟧,
        λ ⤍ Package
      ⟧,
      λ ⤍ Package
    ⟧,
    λ ⤍ Package
  ⟧
⟧}