Column types refactoring.

sqlbuilder/numeric_expression.go

@@ -0,0 +1,94 @@
+package sqlbuilder
+
+import (
+	"github.com/dropbox/godropbox/database/sqltypes"
+	"github.com/pkg/errors"
+)
+
+type NumericExpression interface {
+	Expression
+
+	Eq(expression NumericExpression) BoolExpression
+	NotEq(expression NumericExpression) BoolExpression
+	GtEq(rhs NumericExpression) BoolExpression
+	LtEq(rhs NumericExpression) BoolExpression
+
+	Add(expression NumericExpression) NumericExpression
+	Sub(expression NumericExpression) NumericExpression
+	Mul(expression NumericExpression) NumericExpression
+	Div(expression NumericExpression) NumericExpression
+}
+
+type numericInterfaceImpl struct {
+	parent NumericExpression
+}
+
+func (n *numericInterfaceImpl) Eq(expression NumericExpression) BoolExpression {
+	return Eq(n.parent, expression)
+}
+
+func (n *numericInterfaceImpl) NotEq(expression NumericExpression) BoolExpression {
+	return Neq(n.parent, expression)
+}
+
+func (n *numericInterfaceImpl) GtEq(expression NumericExpression) BoolExpression {
+	return Gte(n.parent, expression)
+}
+
+func (n *numericInterfaceImpl) LtEq(expression NumericExpression) BoolExpression {
+	return Lte(n.parent, expression)
+}
+
+func (n *numericInterfaceImpl) Add(expression NumericExpression) NumericExpression {
+	return newBinaryNumericExpression(n.parent, expression, []byte(" + "))
+}
+
+func (n *numericInterfaceImpl) Sub(expression NumericExpression) NumericExpression {
+	return newBinaryNumericExpression(n.parent, expression, []byte(" - "))
+}
+
+func (n *numericInterfaceImpl) Mul(expression NumericExpression) NumericExpression {
+	return newBinaryNumericExpression(n.parent, expression, []byte(" * "))
+}
+
+func (n *numericInterfaceImpl) Div(expression NumericExpression) NumericExpression {
+	return newBinaryNumericExpression(n.parent, expression, []byte(" / "))
+}
+
+//---------------------------------------------------//
+type numericLiteral struct {
+	numericInterfaceImpl
+	literalExpression
+}
+
+func NewNumericLiteral(value interface{}) NumericExpression {
+	numericLiteral := numericLiteral{}
+
+	sqlValue, err := sqltypes.BuildValue(value)
+	if err != nil {
+		panic(errors.Wrap(err, "Invalid literal value"))
+	}
+	numericLiteral.literalExpression = *NewLiteralExpression(sqlValue)
+	numericLiteral.numericInterfaceImpl.parent = &numericLiteral
+
+	return &numericLiteral
+}
+
+//---------------------------------------------------//
+type binaryNumericExpression struct {
+	expressionInterfaceImpl
+	numericInterfaceImpl
+
+	binaryExpression
+}
+
+func newBinaryNumericExpression(lhs, rhs Expression, operator []byte) NumericExpression {
+	numericExpression := binaryNumericExpression{}
+
+	numericExpression.binaryExpression = newBinaryExpression(lhs, rhs, operator)
+
+	numericExpression.expressionInterfaceImpl.parent = &numericExpression
+	numericExpression.numericInterfaceImpl.parent = &numericExpression
+
+	return &numericExpression
+}