Method D

query/syntax.go:127–170

D := | _ _ field := | | $special_field

()

// D := <field> <condition> <arch_condition> | <package>_<version>_<arch>
// field := <package-name> | <field> | $special_field
func (p *parser) D() deb.PackageQuery {
	if p.input.Current().typ != itemString {
		panic(fmt.Sprintf("unexpected token %s: expecting field or package name", p.input.Current()))
	}

	field := p.input.Current().val
	p.input.Consume()

	operator, value := p.Condition()

	r, _ := utf8.DecodeRuneInString(field)
	if strings.HasPrefix(field, "$") || (unicode.IsUpper(r) && !strings.ContainsRune(field, '_')) {
		// special field or regular field
		q := &deb.FieldQuery{Field: field, Relation: operatorToRelation(operator), Value: value}
		if q.Relation == deb.VersionRegexp {
			var err error
			q.Regexp, err = regexp.Compile(q.Value)
			if err != nil {
				panic(fmt.Sprintf("regexp compile failed: %s", err))
			}
		}
		return q
	} else if operator == 0 && value == "" {
		if pkg, version, arch, ok := parsePackageRef(field); ok {
			// query for specific package
			return &deb.PkgQuery{Pkg: pkg, Version: version, Arch: arch}
		}
	}

	// regular dependency-like query
	q := &deb.DependencyQuery{Dep: deb.Dependency{
		Pkg:          field,
		Relation:     operatorToRelation(operator),
		Version:      value,
		Architecture: p.ArchCondition()}}
	if q.Dep.Relation == deb.VersionRegexp {
		var err error
		q.Dep.Regexp, err = regexp.Compile(q.Dep.Version)
		if err != nil {
			panic(fmt.Sprintf("regexp compile failed: %s", err))
		}
	}
	return q
}

// condition := '(' <operator> value ')' |
// operator := | << | < | <= | > | >> | >= | = | % | ~