Package structure refactor.

internal/jet/cast.go

@@ -0,0 +1,93 @@
+package jet
+
+import "strconv"
+
+type Cast interface {
+	AS(castType string) Expression
+
+	AS_CHAR(lenght ...int) StringExpression
+	// Cast expression AS date type
+	AS_DATE() DateExpression
+	// Cast expression AS numeric type, using precision and optionally scale
+	AS_DECIMAL() FloatExpression
+	// Cast expression AS time type
+	AS_TIME() TimeExpression
+}
+
+type CastImpl struct {
+	expression Expression
+}
+
+func NewCastImpl(expression Expression) CastImpl {
+	castImpl := CastImpl{
+		expression: expression,
+	}
+
+	return castImpl
+}
+
+func (b *CastImpl) AS(castType string) Expression {
+	castExp := &castExpression{
+		expression: b.expression,
+		cast:       string(castType),
+	}
+
+	castExp.expressionInterfaceImpl.parent = castExp
+
+	return castExp
+}
+
+func (b *CastImpl) AS_CHAR(lenght ...int) StringExpression {
+	if len(lenght) > 0 {
+		return StringExp(b.AS("CHAR(" + strconv.Itoa(lenght[0]) + ")"))
+	}
+
+	return StringExp(b.AS("CHAR"))
+}
+
+// Cast expression AS date type
+func (b *CastImpl) AS_DATE() DateExpression {
+	return DateExp(b.AS("DATE"))
+}
+
+// Cast expression AS date type
+func (b *CastImpl) AS_DECIMAL() FloatExpression {
+	return FloatExp(b.AS("DECIMAL"))
+}
+
+// Cast expression AS date type
+func (b *CastImpl) AS_TIME() TimeExpression {
+	return TimeExp(b.AS("TIME"))
+}
+
+type castExpression struct {
+	expressionInterfaceImpl
+
+	expression Expression
+	cast       string
+}
+
+func (b *castExpression) accept(visitor visitor) {
+	b.expression.accept(visitor)
+}
+
+func (b *castExpression) serialize(statement StatementType, out *SqlBuilder, options ...SerializeOption) error {
+
+	expression := b.expression
+	castType := b.cast
+
+	if castOverride := out.Dialect.CastOverride(); castOverride != nil {
+		return castOverride(expression, castType)(statement, out, options...)
+	}
+
+	out.WriteString("CAST(")
+	err := expression.serialize(statement, out, options...)
+	if err != nil {
+		return err
+	}
+
+	out.WriteString("AS")
+	out.WriteString(castType + ")")
+
+	return err
+}