sql/types: implement NumberType for system numeric types

sql/types/system_bool.go

@@ -36,6 +36,7 @@ type SystemBoolType struct {
 
 var _ sql.SystemVariableType = SystemBoolType{}
 var _ sql.CollationCoercible = SystemBoolType{}
+var _ sql.NumberType = SystemBoolType{}
 
 // NewSystemBoolType returns a new systemBoolType.
 func NewSystemBoolType(varName string) sql.SystemVariableType {
@@ -184,6 +185,21 @@ func (t SystemBoolType) Zero() interface{} {
 	return int8(0)
 }
 
+// IsNumericType implements the sql.NumberType interface.
+func (t SystemBoolType) IsNumericType() bool {
+	return true
+}
+
+// IsFloat implements the sql.NumberType interface.
+func (t SystemBoolType) IsFloat() bool {
+	return false
+}
+
+// DisplayWidth implements the sql.NumberType interface.
+func (t SystemBoolType) DisplayWidth() int {
+	return t.UnderlyingType().(sql.NumberType).DisplayWidth()
+}
+
 // EncodeValue implements SystemVariableType interface.
 func (t SystemBoolType) EncodeValue(val interface{}) (string, error) {
 	expectedVal, ok := val.(int8)

sql/types/system_double.go

@@ -37,6 +37,7 @@ type systemDoubleType struct {
 
 var _ sql.SystemVariableType = systemDoubleType{}
 var _ sql.CollationCoercible = systemDoubleType{}
+var _ sql.NumberType = systemDoubleType{}
 
 // NewSystemDoubleType returns a new systemDoubleType.
 func NewSystemDoubleType(varName string, lowerbound, upperbound float64) sql.SystemVariableType {
@@ -169,6 +170,21 @@ func (t systemDoubleType) Zero() interface{} {
 	return float64(0)
 }
 
+// IsNumericType implements the sql.NumberType interface.
+func (t systemDoubleType) IsNumericType() bool {
+	return true
+}
+
+// IsFloat implements the sql.NumberType interface.
+func (t systemDoubleType) IsFloat() bool {
+	return true
+}
+
+// DisplayWidth implements the sql.NumberType interface.
+func (t systemDoubleType) DisplayWidth() int {
+	return t.UnderlyingType().(sql.NumberType).DisplayWidth()
+}
+
 // CollationCoercibility implements sql.CollationCoercible interface.
 func (systemDoubleType) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID, coercibility byte) {
 	return sql.Collation_binary, 5

sql/types/system_int.go

@@ -38,6 +38,7 @@ type systemIntType struct {
 
 var _ sql.SystemVariableType = systemIntType{}
 var _ sql.CollationCoercible = systemIntType{}
+var _ sql.NumberType = systemIntType{}
 
 // NewSystemIntType returns a new systemIntType.
 func NewSystemIntType(varName string, lowerbound, upperbound int64, negativeOne bool) sql.SystemVariableType {
@@ -179,6 +180,21 @@ func (t systemIntType) Zero() interface{} {
 	return int64(0)
 }
 
+// IsNumericType implements the sql.NumberType interface.
+func (t systemIntType) IsNumericType() bool {
+	return true
+}
+
+// IsFloat implements the sql.NumberType interface.
+func (t systemIntType) IsFloat() bool {
+	return false
+}
+
+// DisplayWidth implements the sql.NumberType interface.
+func (t systemIntType) DisplayWidth() int {
+	return t.UnderlyingType().(sql.NumberType).DisplayWidth()
+}
+
 // CollationCoercibility implements sql.CollationCoercible interface.
 func (systemIntType) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID, coercibility byte) {
 	return sql.Collation_binary, 5

sql/types/system_types_test.go

@@ -0,0 +1,37 @@
+// Copyright 2024 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package types
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/dolthub/go-mysql-server/sql"
+)
+
+func TestSystemTypesImplementSqlTypeInterfaces(t *testing.T) {
+	assert.True(t, sql.IsNumberType(SystemBoolType{}))
+	assert.True(t, sql.IsNumberType(systemIntType{}))
+	assert.True(t, sql.IsNumberType(systemUintType{}))
+	assert.True(t, sql.IsNumberType(systemDoubleType{}))
+
+	assert.False(t, sql.IsNumberType(systemEnumType{}))
+	assert.False(t, sql.IsNumberType(systemSetType{}))
+	assert.False(t, sql.IsNumberType(systemStringType{}))
+
+	assert.True(t, sql.IsStringType(systemStringType{}))
+	assert.False(t, sql.IsStringType(SystemBoolType{}))
+}

sql/types/system_uint.go

@@ -37,6 +37,7 @@ type systemUintType struct {
 
 var _ sql.SystemVariableType = systemUintType{}
 var _ sql.CollationCoercible = systemUintType{}
+var _ sql.NumberType = systemUintType{}
 
 // NewSystemUintType returns a new systemUintType.
 func NewSystemUintType(varName string, lowerbound, upperbound uint64) sql.SystemVariableType {
@@ -168,6 +169,21 @@ func (t systemUintType) Zero() interface{} {
 	return uint64(0)
 }
 
+// IsNumericType implements the sql.NumberType interface.
+func (t systemUintType) IsNumericType() bool {
+	return true
+}
+
+// IsFloat implements the sql.NumberType interface.
+func (t systemUintType) IsFloat() bool {
+	return false
+}
+
+// DisplayWidth implements the sql.NumberType interface.
+func (t systemUintType) DisplayWidth() int {
+	return t.UnderlyingType().(sql.NumberType).DisplayWidth()
+}
+
 // CollationCoercibility implements sql.CollationCoercible interface.
 func (systemUintType) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID, coercibility byte) {
 	return sql.Collation_binary, 5