func()

in eval.go [428:504]

• 71 lines of code
• 26 McCabe index (conditional complexity)

func (d *indexData) regexpToMatchTreeRecursive(r *syntax.Regexp, minTextSize int, fileName bool, caseSensitive bool) (mt matchTree, isEqual bool, singleLine bool, err error) {
	// TODO - we could perhaps transform Begin/EndText in '\n'?
	// TODO - we could perhaps transform CharClass in (OrQuery )
	// if there are just a few runes, and part of a OpConcat?
	switch r.Op {
	case syntax.OpLiteral:
		s := string(r.Rune)
		if len(s) >= minTextSize {
			mt, err := d.newSubstringMatchTree(&query.Substring{Pattern: s, FileName: fileName, CaseSensitive: caseSensitive})
			return mt, true, !strings.Contains(s, "\n"), err
		}
	case syntax.OpCapture:
		return d.regexpToMatchTreeRecursive(r.Sub[0], minTextSize, fileName, caseSensitive)

	case syntax.OpPlus:
		return d.regexpToMatchTreeRecursive(r.Sub[0], minTextSize, fileName, caseSensitive)

	case syntax.OpRepeat:
		if r.Min == 1 {
			return d.regexpToMatchTreeRecursive(r.Sub[0], minTextSize, fileName, caseSensitive)
		} else if r.Min > 1 {
			// (x){2,} can't be expressed precisely by the matchTree
			mt, _, singleLine, err := d.regexpToMatchTreeRecursive(r.Sub[0], minTextSize, fileName, caseSensitive)
			return mt, false, singleLine, err
		}
	case syntax.OpConcat, syntax.OpAlternate:
		var qs []matchTree
		isEq := true
		singleLine = true
		for _, sr := range r.Sub {
			if sq, subIsEq, subSingleLine, err := d.regexpToMatchTreeRecursive(sr, minTextSize, fileName, caseSensitive); sq != nil {
				if err != nil {
					return nil, false, false, err
				}
				isEq = isEq && subIsEq
				singleLine = singleLine && subSingleLine
				qs = append(qs, sq)
			}
		}
		if r.Op == syntax.OpConcat {
			if len(qs) > 1 {
				isEq = false
			}
			newQs := make([]matchTree, 0, len(qs))
			for _, q := range qs {
				if _, ok := q.(*bruteForceMatchTree); ok {
					continue
				}
				newQs = append(newQs, q)
			}
			if len(newQs) == 1 {
				return newQs[0], isEq, singleLine, nil
			}
			if len(newQs) == 0 {
				return &bruteForceMatchTree{}, isEq, singleLine, nil
			}
			if singleLine {
				return &andLineMatchTree{andMatchTree{children: newQs}}, isEq, singleLine, nil
			}
			return &andMatchTree{newQs}, isEq, singleLine, nil
		}
		for _, q := range qs {
			if _, ok := q.(*bruteForceMatchTree); ok {
				return q, isEq, false, nil
			}
		}
		if len(qs) == 0 {
			return &noMatchTree{"const"}, isEq, false, nil
		}
		return &orMatchTree{qs}, isEq, false, nil
	case syntax.OpStar:
		if r.Sub[0].Op == syntax.OpAnyCharNotNL {
			return &bruteForceMatchTree{}, false, true, nil
		}
	}
	return &bruteForceMatchTree{}, false, false, nil
}