Rename search package to filter package

pkg/filter/ast.go

@@ -0,0 +1,87 @@
+package filter
+
+import (
+	"encoding/gob"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+type Expression interface {
+	String() string
+}
+
+type PrefixExpression struct {
+	Operator TokenType
+	Right    Expression
+}
+
+func (pe PrefixExpression) String() string {
+	b := strings.Builder{}
+	b.WriteString("(")
+	b.WriteString(pe.Operator.String())
+	b.WriteString(" ")
+	b.WriteString(pe.Right.String())
+	b.WriteString(")")
+
+	return b.String()
+}
+
+type InfixExpression struct {
+	Operator TokenType
+	Left     Expression
+	Right    Expression
+}
+
+func (ie InfixExpression) String() string {
+	b := strings.Builder{}
+	b.WriteString("(")
+	b.WriteString(ie.Left.String())
+	b.WriteString(" ")
+	b.WriteString(ie.Operator.String())
+	b.WriteString(" ")
+	b.WriteString(ie.Right.String())
+	b.WriteString(")")
+
+	return b.String()
+}
+
+type StringLiteral struct {
+	Value string
+}
+
+func (sl StringLiteral) String() string {
+	return strconv.Quote(sl.Value)
+}
+
+type RegexpLiteral struct {
+	*regexp.Regexp
+}
+
+func (rl RegexpLiteral) String() string {
+	return strconv.Quote(rl.Regexp.String())
+}
+
+func (rl RegexpLiteral) MarshalBinary() ([]byte, error) {
+	return []byte(rl.Regexp.String()), nil
+}
+
+func (rl *RegexpLiteral) UnmarshalBinary(data []byte) error {
+	re, err := regexp.Compile(string(data))
+	if err != nil {
+		return err
+	}
+
+	*rl = RegexpLiteral{re}
+
+	return nil
+}
+
+func init() {
+	// The `filter` package was previously named `search`.
+	// We use the legacy names for backwards compatibility with existing database data.
+	gob.RegisterName("github.com/dstotijn/hetty/pkg/search.PrefixExpression", PrefixExpression{})
+	gob.RegisterName("github.com/dstotijn/hetty/pkg/search.InfixExpression", InfixExpression{})
+	gob.RegisterName("github.com/dstotijn/hetty/pkg/search.StringLiteral", StringLiteral{})
+	gob.RegisterName("github.com/dstotijn/hetty/pkg/search.RegexpLiteral", RegexpLiteral{})
+}