func (er *expressionRewriter) betweenToScalarFunc(v *ast.BetweenExpr) {
stkLen := len(er.ctxStack)
var op string
var l, r *expression.ScalarFunction
if v.Not {
l, er.err = expression.NewFunction(ast.LT, v.Type, er.ctxStack[stkLen-3], er.ctxStack[stkLen-2])
if er.err == nil {
r, er.err = expression.NewFunction(ast.GT, v.Type, er.ctxStack[stkLen-3].DeepCopy(), er.ctxStack[stkLen-1])
}
op = ast.OrOr
} else {
l, er.err = expression.NewFunction(ast.GE, v.Type, er.ctxStack[stkLen-3], er.ctxStack[stkLen-2])
if er.err == nil {
r, er.err = expression.NewFunction(ast.LE, v.Type, er.ctxStack[stkLen-3].DeepCopy(), er.ctxStack[stkLen-1])
}
op = ast.AndAnd
}
if er.err != nil {
er.err = errors.Trace(er.err)
return
}
function, err := expression.NewFunction(op, v.Type, l, r)
if err != nil {
er.err = errors.Trace(err)
return
}
er.ctxStack = er.ctxStack[:stkLen-3]
er.ctxStack = append(er.ctxStack, function)
}
func (er *expressionRewriter) betweenToExpression(v *ast.BetweenExpr) {
stkLen := len(er.ctxStack)
er.checkArgsOneColumn(er.ctxStack[stkLen-3:]...)
if er.err != nil {
return
}
var op string
var l, r expression.Expression
l, er.err = expression.NewFunction(ast.GE, &v.Type, er.ctxStack[stkLen-3], er.ctxStack[stkLen-2])
if er.err == nil {
r, er.err = expression.NewFunction(ast.LE, &v.Type, er.ctxStack[stkLen-3].Clone(), er.ctxStack[stkLen-1])
}
op = ast.AndAnd
if er.err != nil {
er.err = errors.Trace(er.err)
return
}
function, err := expression.NewFunction(op, &v.Type, l, r)
if err != nil {
er.err = errors.Trace(err)
return
}
if v.Not {
function, err = expression.NewFunction(ast.UnaryNot, &v.Type, function)
if err != nil {
er.err = errors.Trace(err)
return
}
}
er.ctxStack = er.ctxStack[:stkLen-3]
er.ctxStack = append(er.ctxStack, function)
}
func (er *expressionRewriter) notToScalarFunc(b bool, op string, tp *types.FieldType,
args ...expression.Expression) *expression.ScalarFunction {
opFunc := expression.NewFunction(op, tp, args...)
if !b {
return opFunc
}
return expression.NewFunction(ast.UnaryNot, tp, opFunc)
}
func (er *expressionRewriter) handleScalarSubquery(v *ast.SubqueryExpr) (ast.Node, bool) {
np := er.buildSubquery(v)
if er.err != nil {
return v, true
}
np = er.b.buildMaxOneRow(np)
if np.IsCorrelated() {
er.p = er.b.buildApply(er.p, np, nil)
if len(np.GetSchema()) > 1 {
newCols := make([]expression.Expression, 0, len(np.GetSchema()))
for _, col := range np.GetSchema() {
newCols = append(newCols, col.Clone())
}
expr, err := expression.NewFunction(ast.RowFunc, nil, newCols...)
if err != nil {
er.err = errors.Trace(err)
return v, true
}
er.ctxStack = append(er.ctxStack, expr)
} else {
er.ctxStack = append(er.ctxStack, er.p.GetSchema()[len(er.p.GetSchema())-1])
}
return v, true
}
physicalPlan, err := doOptimize(np, er.b.ctx, er.b.allocator)
if err != nil {
er.err = errors.Trace(err)
return v, true
}
d, err := EvalSubquery(physicalPlan, er.b.is, er.b.ctx)
if err != nil {
er.err = errors.Trace(err)
return v, true
}
if len(np.GetSchema()) > 1 {
newCols := make([]expression.Expression, 0, len(np.GetSchema()))
for i, data := range d {
newCols = append(newCols, &expression.Constant{
Value: data,
RetType: np.GetSchema()[i].GetType()})
}
expr, err1 := expression.NewFunction(ast.RowFunc, nil, newCols...)
if err1 != nil {
er.err = errors.Trace(err1)
return v, true
}
er.ctxStack = append(er.ctxStack, expr)
} else {
er.ctxStack = append(er.ctxStack, &expression.Constant{
Value: d[0],
RetType: np.GetSchema()[0].GetType(),
})
}
return v, true
}
func (er *expressionRewriter) caseToExpression(v *ast.CaseExpr) {
stkLen := len(er.ctxStack)
argsLen := 2 * len(v.WhenClauses)
if v.ElseClause != nil {
argsLen++
}
er.checkArgsOneColumn(er.ctxStack[stkLen-argsLen:]...)
if er.err != nil {
return
}
// value -> ctxStack[stkLen-argsLen-1]
// when clause(condition, result) -> ctxStack[stkLen-argsLen:stkLen-1];
// else clause -> ctxStack[stkLen-1]
var args []expression.Expression
if v.Value != nil {
// args: eq scalar func(args: value, condition1), result1,
// eq scalar func(args: value, condition2), result2,
// ...
// else clause
value := er.ctxStack[stkLen-argsLen-1]
args = make([]expression.Expression, 0, argsLen)
for i := stkLen - argsLen; i < stkLen-1; i += 2 {
arg, err := expression.NewFunction(ast.EQ, types.NewFieldType(mysql.TypeTiny), value.Clone(), er.ctxStack[i])
if err != nil {
er.err = errors.Trace(err)
return
}
args = append(args, arg)
args = append(args, er.ctxStack[i+1])
}
if v.ElseClause != nil {
args = append(args, er.ctxStack[stkLen-1])
}
argsLen++ // for trimming the value element later
} else {
// args: condition1, result1,
// condition2, result2,
// ...
// else clause
args = er.ctxStack[stkLen-argsLen:]
}
function, err := expression.NewFunction(ast.Case, &v.Type, args...)
if err != nil {
er.err = errors.Trace(err)
return
}
er.ctxStack = er.ctxStack[:stkLen-argsLen]
er.ctxStack = append(er.ctxStack, function)
}
func (er *expressionRewriter) funcCallToScalarFunc(v *ast.FuncCallExpr) {
stackLen := len(er.ctxStack)
var function *expression.ScalarFunction
function, er.err = expression.NewFunction(v.FnName.L, v.Type, er.ctxStack[stackLen-len(v.Args):]...)
er.ctxStack = er.ctxStack[:stackLen-len(v.Args)]
er.ctxStack = append(er.ctxStack, function)
}
func (er *expressionRewriter) binaryOpToExpression(v *ast.BinaryOperationExpr) {
stkLen := len(er.ctxStack)
var function expression.Expression
switch v.Op {
case opcode.EQ, opcode.NE, opcode.NullEQ:
function, er.err = er.constructBinaryOpFunction(er.ctxStack[stkLen-2], er.ctxStack[stkLen-1],
opcode.Ops[v.Op])
default:
lLen := getRowLen(er.ctxStack[stkLen-2])
rLen := getRowLen(er.ctxStack[stkLen-1])
switch v.Op {
case opcode.GT, opcode.GE, opcode.LT, opcode.LE:
if lLen != rLen {
er.err = ErrOperandColumns.GenByArgs(lLen)
}
default:
if lLen != 1 || rLen != 1 {
er.err = ErrOperandColumns.GenByArgs(1)
}
}
if er.err != nil {
return
}
function, er.err = expression.NewFunction(opcode.Ops[v.Op], &v.Type, er.ctxStack[stkLen-2:]...)
}
if er.err != nil {
er.err = errors.Trace(er.err)
return
}
er.ctxStack = er.ctxStack[:stkLen-2]
er.ctxStack = append(er.ctxStack, function)
}
func pushDownNot(expr expression.Expression, not bool) expression.Expression {
if f, ok := expr.(*expression.ScalarFunction); ok {
switch f.FuncName.L {
case ast.UnaryNot:
return pushDownNot(f.Args[0], !not)
case ast.LT, ast.GE, ast.GT, ast.LE, ast.EQ, ast.NE:
if not {
nf, _ := expression.NewFunction(oppositeOp[f.FuncName.L], f.GetType(), f.Args...)
return nf
}
for i, arg := range f.Args {
f.Args[i] = pushDownNot(arg, false)
}
return f
case ast.AndAnd:
if not {
args := f.Args
for i, a := range args {
args[i] = pushDownNot(a, true)
}
nf, _ := expression.NewFunction(ast.OrOr, f.GetType(), args...)
return nf
}
for i, arg := range f.Args {
f.Args[i] = pushDownNot(arg, false)
}
return f
case ast.OrOr:
if not {
args := f.Args
for i, a := range args {
args[i] = pushDownNot(a, true)
}
nf, _ := expression.NewFunction(ast.AndAnd, f.GetType(), args...)
return nf
}
for i, arg := range f.Args {
f.Args[i] = pushDownNot(arg, false)
}
return f
}
}
if not {
expr, _ = expression.NewFunction(ast.UnaryNot, types.NewFieldType(mysql.TypeTiny), expr)
}
return expr
}
func (er *expressionRewriter) betweenToScalarFunc(v *ast.BetweenExpr) {
stkLen := len(er.ctxStack)
var op string
var l, r *expression.ScalarFunction
if v.Not {
l = expression.NewFunction(ast.LT, v.Type, er.ctxStack[stkLen-3], er.ctxStack[stkLen-2])
r = expression.NewFunction(ast.GT, v.Type, er.ctxStack[stkLen-3], er.ctxStack[stkLen-1])
op = ast.OrOr
} else {
l = expression.NewFunction(ast.GE, v.Type, er.ctxStack[stkLen-3], er.ctxStack[stkLen-2])
r = expression.NewFunction(ast.LE, v.Type, er.ctxStack[stkLen-3], er.ctxStack[stkLen-1])
op = ast.AndAnd
}
function := expression.NewFunction(op, v.Type, l, r)
er.ctxStack = er.ctxStack[:stkLen-3]
er.ctxStack = append(er.ctxStack, function)
}
func (er *expressionRewriter) notToScalarFunc(hasNot bool, op string, tp *types.FieldType,
args ...expression.Expression) *expression.ScalarFunction {
opFunc, err := expression.NewFunction(op, tp, args...)
if err != nil {
er.err = errors.Trace(err)
return nil
}
if !hasNot {
return opFunc
}
opFunc, err = expression.NewFunction(ast.UnaryNot, tp, opFunc)
if err != nil {
er.err = errors.Trace(err)
return nil
}
return opFunc
}
func (er *expressionRewriter) funcCallToExpression(v *ast.FuncCallExpr) {
stackLen := len(er.ctxStack)
args := er.ctxStack[stackLen-len(v.Args):]
er.checkArgsOneColumn(args...)
if er.err != nil {
return
}
var function expression.Expression
function, er.err = expression.NewFunction(v.FnName.L, &v.Type, args...)
er.ctxStack = er.ctxStack[:stackLen-len(v.Args)]
er.ctxStack = append(er.ctxStack, function)
}
// compose CNF items into a balance deep CNF tree, which benefits a lot for pb decoder/encoder.
func composeCondition(conditions []expression.Expression) expression.Expression {
length := len(conditions)
if length == 0 {
return nil
}
if length == 1 {
return conditions[0]
}
return expression.NewFunction(model.NewCIStr(ast.AndAnd),
[]expression.Expression{composeCondition(conditions[0 : length/2]),
composeCondition(conditions[length/2:])})
}
func (er *expressionRewriter) handleInSubquery(v *ast.PatternInExpr) (ast.Node, bool) {
v.Expr.Accept(er)
if er.err != nil {
return v, true
}
lexpr := er.ctxStack[len(er.ctxStack)-1]
subq, ok := v.Sel.(*ast.SubqueryExpr)
if !ok {
er.err = errors.Errorf("Unknown compare type %T.", v.Sel)
return v, true
}
np, outerSchema := er.buildSubquery(subq)
if er.err != nil {
return v, true
}
if getRowLen(lexpr) != len(np.GetSchema()) {
er.err = errors.Errorf("Operand should contain %d column(s)", getRowLen(lexpr))
return v, true
}
var rexpr expression.Expression
if len(np.GetSchema()) == 1 {
rexpr = np.GetSchema()[0].DeepCopy()
} else {
args := make([]expression.Expression, 0, len(np.GetSchema()))
for _, col := range np.GetSchema() {
args = append(args, col.DeepCopy())
}
rexpr, er.err = expression.NewFunction(ast.RowFunc, nil, args...)
if er.err != nil {
er.err = errors.Trace(er.err)
return v, true
}
}
// a in (subq) will be rewrited as a = any(subq).
// a not in (subq) will be rewrited as a != all(subq).
op, all := ast.EQ, false
if v.Not {
op, all = ast.NE, true
}
checkCondition, err := constructBinaryOpFunction(lexpr, rexpr, op)
if err != nil {
er.err = errors.Trace(err)
return v, true
}
er.p = er.b.buildApply(er.p, np, outerSchema, &ApplyConditionChecker{Condition: checkCondition, All: all})
if er.p.IsCorrelated() {
er.correlated = true
}
// The parent expression only use the last column in schema, which represents whether the condition is matched.
er.ctxStack[len(er.ctxStack)-1] = er.p.GetSchema()[len(er.p.GetSchema())-1]
return v, true
}
func (er *expressionRewriter) rowToScalarFunc(v *ast.RowExpr) {
stkLen := len(er.ctxStack)
length := len(v.Values)
rows := make([]expression.Expression, 0, length)
for i := stkLen - length; i < stkLen; i++ {
rows = append(rows, er.ctxStack[i])
}
er.ctxStack = er.ctxStack[:stkLen-length]
function, err := expression.NewFunction(ast.RowFunc, nil, rows...)
if err != nil {
er.err = errors.Trace(err)
return
}
er.ctxStack = append(er.ctxStack, function)
}
// constructBinaryOpFunctions converts (a0,a1,a2) op (b0,b1,b2) to (a0 op b0) and (a1 op b1) and (a2 op b2).
func constructBinaryOpFunction(l expression.Expression, r expression.Expression, op string) (expression.Expression, error) {
lLen, rLen := getRowLen(l), getRowLen(r)
if lLen == 1 && rLen == 1 {
return expression.NewFunction(op, types.NewFieldType(mysql.TypeTiny), l, r)
} else if rLen != lLen {
return nil, errors.Errorf("Operand should contain %d column(s)", lLen)
}
funcs := make([]expression.Expression, lLen)
for i := 0; i < lLen; i++ {
var err error
funcs[i], err = constructBinaryOpFunction(getRowArg(l, i), getRowArg(r, i), op)
if err != nil {
return nil, err
}
}
return expression.ComposeCNFCondition(funcs), nil
}
// constructBinaryOpFunctions converts (a0,a1,a2) op (b0,b1,b2) to (a0 op b0) and (a1 op b1) and (a2 op b2).
func (er *expressionRewriter) constructBinaryOpFunction(l expression.Expression, r expression.Expression, op string) (expression.Expression, error) {
lLen, rLen := getRowLen(l), getRowLen(r)
if lLen == 1 && rLen == 1 {
return expression.NewFunction(op, types.NewFieldType(mysql.TypeTiny), l, r)
} else if rLen != lLen {
return nil, ErrOperandColumns.GenByArgs(lLen)
}
funcs := make([]expression.Expression, lLen)
for i := 0; i < lLen; i++ {
var err error
funcs[i], err = er.constructBinaryOpFunction(getRowArg(l, i), getRowArg(r, i), op)
if err != nil {
return nil, errors.Trace(err)
}
}
return expression.ComposeCNFCondition(funcs), nil
}
// constantSubstitute substitute column expression in a condition by an equivalent constant.
func constantSubstitute(equalities map[string]*expression.Constant, condition expression.Expression) expression.Expression {
switch expr := condition.(type) {
case *expression.Column:
if v, ok := equalities[string(expr.HashCode())]; ok {
return v
}
case *expression.ScalarFunction:
for i, arg := range expr.Args {
expr.Args[i] = constantSubstitute(equalities, arg)
}
if _, ok := evaluator.Funcs[expr.FuncName.L]; ok {
condition, _ = expression.NewFunction(expr.FuncName.L, expr.RetType, expr.Args...)
}
return condition
}
return condition
}
func (er *expressionRewriter) binaryOpToScalarFunc(v *ast.BinaryOperationExpr) {
stkLen := len(er.ctxStack)
var function expression.Expression
switch v.Op {
case opcode.EQ, opcode.NE, opcode.NullEQ:
function, er.err = constructBinaryOpFunction(er.ctxStack[stkLen-2], er.ctxStack[stkLen-1],
opcode.Ops[v.Op])
default:
function, er.err = expression.NewFunction(opcode.Ops[v.Op], v.Type, er.ctxStack[stkLen-2:]...)
}
if er.err != nil {
er.err = errors.Trace(er.err)
return
}
er.ctxStack = er.ctxStack[:stkLen-2]
er.ctxStack = append(er.ctxStack, function)
}
func (er *expressionRewriter) unaryOpToScalarFunc(v *ast.UnaryOperationExpr) {
stkLen := len(er.ctxStack)
if getRowLen(er.ctxStack[stkLen-1]) != 1 {
er.err = errors.New("Operand should contain 1 column(s)")
}
var op string
switch v.Op {
case opcode.Plus:
op = ast.UnaryPlus
case opcode.Minus:
op = ast.UnaryMinus
case opcode.BitNeg:
op = ast.BitNeg
case opcode.Not:
op = ast.UnaryNot
default:
er.err = errors.Errorf("Unknown Unary Op %T", v.Op)
return
}
er.ctxStack[stkLen-1], er.err = expression.NewFunction(op, v.Type, er.ctxStack[stkLen-1])
}
func extractOnCondition(conditions []expression.Expression, left LogicalPlan, right LogicalPlan) (
eqCond []*expression.ScalarFunction, leftCond []expression.Expression, rightCond []expression.Expression,
otherCond []expression.Expression) {
for _, expr := range conditions {
binop, ok := expr.(*expression.ScalarFunction)
if ok && binop.FuncName.L == ast.EQ {
ln, lOK := binop.Args[0].(*expression.Column)
rn, rOK := binop.Args[1].(*expression.Column)
if lOK && rOK {
if left.GetSchema().GetIndex(ln) != -1 && right.GetSchema().GetIndex(rn) != -1 {
eqCond = append(eqCond, binop)
continue
}
if left.GetSchema().GetIndex(rn) != -1 && right.GetSchema().GetIndex(ln) != -1 {
cond, _ := expression.NewFunction(ast.EQ, types.NewFieldType(mysql.TypeTiny), rn, ln)
eqCond = append(eqCond, cond.(*expression.ScalarFunction))
continue
}
}
}
columns, _ := extractColumn(expr, nil, nil)
allFromLeft, allFromRight := true, true
for _, col := range columns {
if left.GetSchema().GetIndex(col) == -1 {
allFromLeft = false
}
if right.GetSchema().GetIndex(col) == -1 {
allFromRight = false
}
}
if allFromRight {
rightCond = append(rightCond, expr)
} else if allFromLeft {
leftCond = append(leftCond, expr)
} else {
otherCond = append(otherCond, expr)
}
}
return
}
func extractOnCondition(conditions []expression.Expression, left Plan, right Plan) (
eqCond []*expression.ScalarFunction, leftCond []expression.Expression, rightCond []expression.Expression,
otherCond []expression.Expression) {
for _, expr := range conditions {
binop, ok := expr.(*expression.ScalarFunction)
if ok && binop.FuncName.L == ast.EQ {
ln, lOK := binop.Args[0].(*expression.Column)
rn, rOK := binop.Args[1].(*expression.Column)
if lOK && rOK {
if left.GetSchema().GetIndex(ln) != -1 && right.GetSchema().GetIndex(rn) != -1 {
eqCond = append(eqCond, binop)
continue
}
if left.GetSchema().GetIndex(rn) != -1 && right.GetSchema().GetIndex(ln) != -1 {
newEq := expression.NewFunction(model.NewCIStr(ast.EQ), []expression.Expression{rn, ln})
eqCond = append(eqCond, newEq)
continue
}
}
}
columns, _ := extractColumn(expr, nil, nil)
allFromLeft, allFromRight := true, true
for _, col := range columns {
if left.GetSchema().GetIndex(col) != -1 {
allFromRight = false
} else {
allFromLeft = false
}
}
if allFromRight {
rightCond = append(rightCond, expr)
} else if allFromLeft {
leftCond = append(leftCond, expr)
} else {
otherCond = append(otherCond, expr)
}
}
return
}
// calculateResultOfExpression set inner table columns in a expression as null and calculate the finally result of the scalar function.
func calculateResultOfExpression(schema expression.Schema, expr expression.Expression) (expression.Expression, error) {
switch x := expr.(type) {
case *expression.ScalarFunction:
var err error
args := make([]expression.Expression, len(x.Args))
for i, arg := range x.Args {
args[i], err = calculateResultOfExpression(schema, arg)
}
if err != nil {
return nil, errors.Trace(err)
}
return expression.NewFunction(x.FuncName.L, types.NewFieldType(mysql.TypeTiny), args...)
case *expression.Column:
if schema.GetIndex(x) == -1 {
return x, nil
}
constant := &expression.Constant{Value: types.Datum{}}
constant.Value.SetNull()
return constant, nil
default:
return x.DeepCopy(), nil
}
}
func (er *expressionRewriter) unaryOpToExpression(v *ast.UnaryOperationExpr) {
stkLen := len(er.ctxStack)
var op string
switch v.Op {
case opcode.Plus:
// expression (+ a) is equal to a
return
case opcode.Minus:
op = ast.UnaryMinus
case opcode.BitNeg:
op = ast.BitNeg
case opcode.Not:
op = ast.UnaryNot
default:
er.err = errors.Errorf("Unknown Unary Op %T", v.Op)
return
}
if getRowLen(er.ctxStack[stkLen-1]) != 1 {
er.err = ErrOperandColumns.GenByArgs(1)
return
}
er.ctxStack[stkLen-1], er.err = expression.NewFunction(op, &v.Type, er.ctxStack[stkLen-1])
}
// propagateConstant propagate constant values of equality predicates and inequality predicates in a condition.
func propagateConstant(conditions []expression.Expression) []expression.Expression {
if len(conditions) == 0 {
return conditions
}
// Propagate constants in equality predicates.
// e.g. for condition: "a = b and b = c and c = a and a = 1";
// we propagate constant as the following step:
// first: "1 = b and b = c and c = 1 and a = 1";
// next: "1 = b and 1 = c and c = 1 and a = 1";
// next: "1 = b and 1 = c and 1 = 1 and a = 1";
// next: "1 = b and 1 = c and a = 1";
// e.g for condition: "a = b and b = c and b = 2 and a = 1";
// we propagate constant as the following step:
// first: "a = 2 and 2 = c and b = 2 and a = 1";
// next: "a = 2 and 2 = c and b = 2 and 2 = 1";
// next: "0"
isSource := make([]bool, len(conditions))
type transitiveEqualityPredicate map[string]*expression.Constant // transitive equality predicates between one column and one constant
for {
equalities := make(transitiveEqualityPredicate, 0)
for i, getOneEquality := 0, false; i < len(conditions) && !getOneEquality; i++ {
if isSource[i] {
continue
}
expr, ok := conditions[i].(*expression.ScalarFunction)
if !ok {
continue
}
// process the included OR conditions recursively to do the same for CNF item.
switch expr.FuncName.L {
case ast.OrOr:
expressions := expression.SplitDNFItems(conditions[i])
newExpression := make([]expression.Expression, 0)
for _, v := range expressions {
newExpression = append(newExpression, propagateConstant([]expression.Expression{v})...)
}
conditions[i] = expression.ComposeDNFCondition(newExpression)
isSource[i] = true
case ast.AndAnd:
newExpression := propagateConstant(expression.SplitCNFItems(conditions[i]))
conditions[i] = expression.ComposeCNFCondition(newExpression)
isSource[i] = true
case ast.EQ:
var (
col *expression.Column
val *expression.Constant
)
leftConst, leftIsConst := expr.Args[0].(*expression.Constant)
rightConst, rightIsConst := expr.Args[1].(*expression.Constant)
leftCol, leftIsCol := expr.Args[0].(*expression.Column)
rightCol, rightIsCol := expr.Args[1].(*expression.Column)
if rightIsConst && leftIsCol {
col = leftCol
val = rightConst
} else if leftIsConst && rightIsCol {
col = rightCol
val = leftConst
} else {
continue
}
equalities[string(col.HashCode())] = val
isSource[i] = true
getOneEquality = true
}
}
if len(equalities) == 0 {
break
}
for i := 0; i < len(conditions); i++ {
if isSource[i] {
continue
}
if len(equalities) != 0 {
conditions[i] = constantSubstitute(equalities, conditions[i])
}
}
}
// Propagate transitive inequality predicates.
// e.g for conditions "a = b and c = d and a = c and g = h and b > 0 and e != 0 and g like 'abc'",
// we propagate constant as the following step:
// 1. build multiple equality predicates(mep):
// =(a, b, c, d), =(g, h).
// 2. extract inequality predicates between one constant and one column,
// and rewrite them using the root column of a multiple equality predicate:
// b > 0, e != 0, g like 'abc' ==> a > 0, g like 'abc'.
// ATTENTION: here column 'e' doesn't belong to any mep, so we skip "e != 0".
// 3. propagate constants in these inequality predicates, and we finally get:
// "a = b and c = d and a = c and e = f and g = h and e != 0 and a > 0 and b > 0 and c > 0 and d > 0 and g like 'abc' and h like 'abc' ".
multipleEqualities := make(map[*expression.Column]*expression.Column, 0)
for _, cond := range conditions { // build multiple equality predicates.
expr, ok := cond.(*expression.ScalarFunction)
if ok && expr.FuncName.L == ast.EQ {
left, ok1 := expr.Args[0].(*expression.Column)
right, ok2 := expr.Args[1].(*expression.Column)
if ok1 && ok2 {
UnionColumns(left, right, multipleEqualities)
}
}
}
if len(multipleEqualities) == 0 {
return conditions
}
inequalityFuncs := map[string]string{
ast.LT: ast.LT,
ast.GT: ast.GT,
ast.LE: ast.LE,
ast.GE: ast.GE,
ast.NE: ast.NE,
ast.Like: ast.Like,
}
type inequalityFactor struct {
FuncName string
Factor []*expression.Constant
}
type transitiveInEqualityPredicate map[string][]inequalityFactor // transitive inequality predicates between one column and one constant.
inequalities := make(transitiveInEqualityPredicate, 0)
for i := 0; i < len(conditions); i++ { // extract inequality predicates.
var (
column *expression.Column
equalCol *expression.Column // the root column corresponding to a column in a multiple equality predicate.
val *expression.Constant
funcName string
)
expr, ok := conditions[i].(*expression.ScalarFunction)
if !ok {
continue
}
funcName, ok = inequalityFuncs[expr.FuncName.L]
if !ok {
continue
}
leftConst, leftIsConst := expr.Args[0].(*expression.Constant)
rightConst, rightIsConst := expr.Args[1].(*expression.Constant)
leftCol, leftIsCol := expr.Args[0].(*expression.Column)
rightCol, rightIsCol := expr.Args[1].(*expression.Column)
if rightIsConst && leftIsCol {
column = leftCol
val = rightConst
} else if leftIsConst && rightIsCol {
column = rightCol
val = leftConst
} else {
continue
}
equalCol, ok = multipleEqualities[column]
if !ok { // no need to propagate inequality predicates whose column is only equal to itself.
continue
}
colHashCode := string(equalCol.HashCode())
if funcName == ast.Like { // func 'LIKE' need 3 input arguments, so here we handle it alone.
inequalities[colHashCode] = append(inequalities[colHashCode], inequalityFactor{FuncName: ast.Like, Factor: []*expression.Constant{val, expr.Args[2].(*expression.Constant)}})
} else {
inequalities[colHashCode] = append(inequalities[colHashCode], inequalityFactor{FuncName: funcName, Factor: []*expression.Constant{val}})
}
conditions = append(conditions[:i], conditions[i+1:]...)
i--
}
if len(inequalities) == 0 {
return conditions
}
for k, v := range multipleEqualities { // propagate constants in inequality predicates.
for _, x := range inequalities[string(v.HashCode())] {
funcName, factors := x.FuncName, x.Factor
if funcName == ast.Like {
for i := 0; i < len(factors); i += 2 {
newFunc, _ := expression.NewFunction(funcName, types.NewFieldType(mysql.TypeTiny), k, factors[i], factors[i+1])
conditions = append(conditions, newFunc)
}
} else {
for i := 0; i < len(factors); i++ {
newFunc, _ := expression.NewFunction(funcName, types.NewFieldType(mysql.TypeTiny), k, factors[i])
conditions = append(conditions, newFunc)
i++
}
}
}
}
return conditions
}
// Enter implements Visitor interface.
func (er *expressionRewriter) Enter(inNode ast.Node) (ast.Node, bool) {
switch v := inNode.(type) {
case *ast.AggregateFuncExpr:
index, ok := -1, false
if er.aggrMap != nil {
index, ok = er.aggrMap[v]
}
if !ok {
er.err = errors.New("Can't appear aggrFunctions")
return inNode, true
}
er.ctxStack = append(er.ctxStack, er.schema[index])
return inNode, true
case *ast.ColumnNameExpr:
if index, ok := er.b.colMapper[v]; ok {
er.ctxStack = append(er.ctxStack, er.schema[index])
return inNode, true
}
case *ast.CompareSubqueryExpr:
v.L.Accept(er)
if er.err != nil {
return inNode, true
}
lexpr := er.ctxStack[len(er.ctxStack)-1]
subq, ok := v.R.(*ast.SubqueryExpr)
if !ok {
er.err = errors.Errorf("Unknown compare type %T.", v.R)
return inNode, true
}
np, outerSchema := er.buildSubquery(subq)
if er.err != nil {
return inNode, true
}
// Only (a,b,c) = all (...) and (a,b,c) != any () can use row expression.
canMultiCol := (!v.All && v.Op == opcode.EQ) || (v.All && v.Op == opcode.NE)
if !canMultiCol && (getRowLen(lexpr) != 1 || len(np.GetSchema()) != 1) {
er.err = errors.New("Operand should contain 1 column(s)")
return inNode, true
}
if getRowLen(lexpr) != len(np.GetSchema()) {
er.err = errors.Errorf("Operand should contain %d column(s)", getRowLen(lexpr))
return inNode, true
}
var checkCondition expression.Expression
var rexpr expression.Expression
if len(np.GetSchema()) == 1 {
rexpr = np.GetSchema()[0].DeepCopy()
} else {
args := make([]expression.Expression, 0, len(np.GetSchema()))
for _, col := range np.GetSchema() {
args = append(args, col.DeepCopy())
}
rexpr, er.err = expression.NewFunction(ast.RowFunc, types.NewFieldType(types.KindRow), args...)
if er.err != nil {
er.err = errors.Trace(er.err)
return inNode, true
}
}
switch v.Op {
// Only EQ, NE and NullEQ can be composed with and.
case opcode.EQ, opcode.NE, opcode.NullEQ:
checkCondition, er.err = constructBinaryOpFunction(lexpr, rexpr, opcode.Ops[v.Op])
if er.err != nil {
er.err = errors.Trace(er.err)
return inNode, true
}
// If op is not EQ, NE, NullEQ, say LT, it will remain as row(a,b) < row(c,d), and be compared as row datum.
default:
checkCondition, er.err = expression.NewFunction(opcode.Ops[v.Op],
types.NewFieldType(mysql.TypeTiny), lexpr, rexpr)
if er.err != nil {
er.err = errors.Trace(er.err)
return inNode, true
}
}
er.p = er.b.buildApply(er.p, np, outerSchema, &ApplyConditionChecker{Condition: checkCondition, All: v.All})
// The parent expression only use the last column in schema, which represents whether the condition is matched.
er.ctxStack[len(er.ctxStack)-1] = er.p.GetSchema()[len(er.p.GetSchema())-1]
return inNode, true
case *ast.ExistsSubqueryExpr:
subq, ok := v.Sel.(*ast.SubqueryExpr)
if !ok {
er.err = errors.Errorf("Unknown exists type %T.", v.Sel)
return inNode, true
}
np, outerSchema := er.buildSubquery(subq)
if er.err != nil {
return inNode, true
}
np = er.b.buildExists(np)
if np.IsCorrelated() {
er.p = er.b.buildApply(er.p, np, outerSchema, nil)
er.ctxStack = append(er.ctxStack, er.p.GetSchema()[len(er.p.GetSchema())-1])
} else {
_, err := np.PruneColumnsAndResolveIndices(np.GetSchema())
if err != nil {
er.err = errors.Trace(err)
return inNode, true
}
d, err := EvalSubquery(np, er.b.is, er.b.ctx)
if err != nil {
er.err = errors.Trace(err)
return inNode, true
}
er.ctxStack = append(er.ctxStack, &expression.Constant{
Value: d[0],
RetType: np.GetSchema()[0].GetType()})
}
return inNode, true
case *ast.PatternInExpr:
if v.Sel != nil {
v.Expr.Accept(er)
if er.err != nil {
return inNode, true
}
lexpr := er.ctxStack[len(er.ctxStack)-1]
subq, ok := v.Sel.(*ast.SubqueryExpr)
if !ok {
er.err = errors.Errorf("Unknown compare type %T.", v.Sel)
return inNode, true
}
np, outerSchema := er.buildSubquery(subq)
if er.err != nil {
return inNode, true
}
if getRowLen(lexpr) != len(np.GetSchema()) {
er.err = errors.Errorf("Operand should contain %d column(s)", getRowLen(lexpr))
return inNode, true
}
var rexpr expression.Expression
if len(np.GetSchema()) == 1 {
rexpr = np.GetSchema()[0].DeepCopy()
} else {
args := make([]expression.Expression, 0, len(np.GetSchema()))
for _, col := range np.GetSchema() {
args = append(args, col.DeepCopy())
}
rexpr, er.err = expression.NewFunction(ast.RowFunc, nil, args...)
if er.err != nil {
er.err = errors.Trace(er.err)
return inNode, true
}
}
// a in (subq) will be rewrited as a = any(subq).
// a not in (subq) will be rewrited as a != all(subq).
op, all := ast.EQ, false
if v.Not {
op, all = ast.NE, true
}
checkCondition, err := constructBinaryOpFunction(lexpr, rexpr, op)
if err != nil {
er.err = errors.Trace(err)
return inNode, true
}
er.p = er.b.buildApply(er.p, np, outerSchema, &ApplyConditionChecker{Condition: checkCondition, All: all})
// The parent expression only use the last column in schema, which represents whether the condition is matched.
er.ctxStack[len(er.ctxStack)-1] = er.p.GetSchema()[len(er.p.GetSchema())-1]
return inNode, true
}
case *ast.SubqueryExpr:
np, outerSchema := er.buildSubquery(v)
if er.err != nil {
return inNode, true
}
np = er.b.buildMaxOneRow(np)
if np.IsCorrelated() {
er.p = er.b.buildApply(er.p, np, outerSchema, nil)
if len(np.GetSchema()) > 1 {
newCols := make([]expression.Expression, 0, len(np.GetSchema()))
for _, col := range np.GetSchema() {
newCols = append(newCols, col.DeepCopy())
}
expr, err := expression.NewFunction(ast.RowFunc, nil, newCols...)
if err != nil {
er.err = errors.Trace(err)
return inNode, true
}
er.ctxStack = append(er.ctxStack, expr)
} else {
er.ctxStack = append(er.ctxStack, er.p.GetSchema()[len(er.p.GetSchema())-1])
}
return inNode, true
}
_, err := np.PruneColumnsAndResolveIndices(np.GetSchema())
if err != nil {
er.err = errors.Trace(err)
return inNode, true
}
d, err := EvalSubquery(np, er.b.is, er.b.ctx)
if err != nil {
er.err = errors.Trace(err)
return inNode, true
}
if len(np.GetSchema()) > 1 {
newCols := make([]expression.Expression, 0, len(np.GetSchema()))
for i, data := range d {
newCols = append(newCols, &expression.Constant{
Value: data,
RetType: np.GetSchema()[i].GetType()})
}
expr, err1 := expression.NewFunction(ast.RowFunc, nil, newCols...)
if err1 != nil {
er.err = errors.Trace(err1)
return inNode, true
}
er.ctxStack = append(er.ctxStack, expr)
} else {
er.ctxStack = append(er.ctxStack, &expression.Constant{
Value: d[0],
RetType: np.GetSchema()[0].GetType(),
})
}
return inNode, true
}
return inNode, false
}
func (er *expressionRewriter) rewriteVariable(v *ast.VariableExpr) {
stkLen := len(er.ctxStack)
name := strings.ToLower(v.Name)
sessionVars := variable.GetSessionVars(er.b.ctx)
globalVars := variable.GetGlobalVarAccessor(er.b.ctx)
if !v.IsSystem {
if v.Value != nil {
er.ctxStack[stkLen-1], er.err = expression.NewFunction(ast.SetVar,
er.ctxStack[stkLen-1].GetType(),
datumToConstant(types.NewDatum(name), mysql.TypeString),
er.ctxStack[stkLen-1])
return
}
if _, ok := sessionVars.Users[name]; ok {
f, err := expression.NewFunction(ast.GetVar,
// TODO: Here is wrong, the sessionVars should store a name -> Datum map. Will fix it later.
types.NewFieldType(mysql.TypeString),
datumToConstant(types.NewStringDatum(name), mysql.TypeString))
if err != nil {
er.err = errors.Trace(err)
return
}
er.ctxStack = append(er.ctxStack, f)
} else {
// select null user vars is permitted.
er.ctxStack = append(er.ctxStack, &expression.Constant{RetType: types.NewFieldType(mysql.TypeNull)})
}
return
}
sysVar, ok := variable.SysVars[name]
if !ok {
// select null sys vars is not permitted
er.err = variable.UnknownSystemVar.Gen("Unknown system variable '%s'", name)
return
}
if sysVar.Scope == variable.ScopeNone {
er.ctxStack = append(er.ctxStack, datumToConstant(types.NewDatum(sysVar.Value), mysql.TypeString))
return
}
if v.IsGlobal {
value, err := globalVars.GetGlobalSysVar(er.b.ctx, name)
if err != nil {
er.err = errors.Trace(err)
return
}
er.ctxStack = append(er.ctxStack, datumToConstant(types.NewDatum(value), mysql.TypeString))
return
}
d := sessionVars.GetSystemVar(name)
if d.IsNull() {
if sysVar.Scope&variable.ScopeGlobal == 0 {
d.SetString(sysVar.Value)
} else {
// Get global system variable and fill it in session.
globalVal, err := globalVars.GetGlobalSysVar(er.b.ctx, name)
if err != nil {
er.err = errors.Trace(err)
return
}
d.SetString(globalVal)
err = sessionVars.SetSystemVar(name, d)
if err != nil {
er.err = errors.Trace(err)
return
}
}
}
er.ctxStack = append(er.ctxStack, datumToConstant(d, mysql.TypeString))
return
}
func (er *expressionRewriter) handleScalarSubquery(v *ast.SubqueryExpr) (ast.Node, bool) {
np, outerSchema := er.buildSubquery(v)
if er.err != nil {
return v, true
}
np = er.b.buildMaxOneRow(np)
if np.IsCorrelated() {
er.p = er.b.buildApply(er.p, np, outerSchema, nil)
if er.p.IsCorrelated() {
er.correlated = true
}
if len(np.GetSchema()) > 1 {
newCols := make([]expression.Expression, 0, len(np.GetSchema()))
for _, col := range np.GetSchema() {
newCols = append(newCols, col.DeepCopy())
}
expr, err := expression.NewFunction(ast.RowFunc, nil, newCols...)
if err != nil {
er.err = errors.Trace(err)
return v, true
}
er.ctxStack = append(er.ctxStack, expr)
} else {
er.ctxStack = append(er.ctxStack, er.p.GetSchema()[len(er.p.GetSchema())-1])
}
return v, true
}
_, np, er.err = np.PredicatePushDown(nil)
if er.err != nil {
return v, true
}
_, err := np.PruneColumnsAndResolveIndices(np.GetSchema())
if err != nil {
er.err = errors.Trace(err)
return v, true
}
_, res, _, err := np.convert2PhysicalPlan(nil)
if err != nil {
er.err = errors.Trace(err)
return v, true
}
phyPlan := res.p.PushLimit(nil)
d, err := EvalSubquery(phyPlan, er.b.is, er.b.ctx)
if err != nil {
er.err = errors.Trace(err)
return v, true
}
if len(np.GetSchema()) > 1 {
newCols := make([]expression.Expression, 0, len(np.GetSchema()))
for i, data := range d {
newCols = append(newCols, &expression.Constant{
Value: data,
RetType: np.GetSchema()[i].GetType()})
}
expr, err1 := expression.NewFunction(ast.RowFunc, nil, newCols...)
if err1 != nil {
er.err = errors.Trace(err1)
return v, true
}
er.ctxStack = append(er.ctxStack, expr)
} else {
er.ctxStack = append(er.ctxStack, &expression.Constant{
Value: d[0],
RetType: np.GetSchema()[0].GetType(),
})
}
return v, true
}
func (er *expressionRewriter) handleInSubquery(v *ast.PatternInExpr) (ast.Node, bool) {
asScalar := er.asScalar
er.asScalar = true
v.Expr.Accept(er)
if er.err != nil {
return v, true
}
lexpr := er.ctxStack[len(er.ctxStack)-1]
subq, ok := v.Sel.(*ast.SubqueryExpr)
if !ok {
er.err = errors.Errorf("Unknown compare type %T.", v.Sel)
return v, true
}
np := er.buildSubquery(subq)
if er.err != nil {
return v, true
}
lLen := getRowLen(lexpr)
if lLen != len(np.GetSchema()) {
er.err = ErrOperandColumns.GenByArgs(lLen)
return v, true
}
var rexpr expression.Expression
if len(np.GetSchema()) == 1 {
rexpr = np.GetSchema()[0].Clone()
} else {
args := make([]expression.Expression, 0, len(np.GetSchema()))
for _, col := range np.GetSchema() {
args = append(args, col.Clone())
}
rexpr, er.err = expression.NewFunction(ast.RowFunc, nil, args...)
if er.err != nil {
er.err = errors.Trace(er.err)
return v, true
}
}
// a in (subq) will be rewrited as a = any(subq).
// a not in (subq) will be rewrited as a != all(subq).
checkCondition, err := er.constructBinaryOpFunction(lexpr, rexpr, ast.EQ)
if err != nil {
er.err = errors.Trace(err)
return v, true
}
if !np.IsCorrelated() {
er.p = er.b.buildSemiJoin(er.p, np, expression.SplitCNFItems(checkCondition), asScalar, v.Not)
if asScalar {
col := er.p.GetSchema()[len(er.p.GetSchema())-1]
er.ctxStack[len(er.ctxStack)-1] = col
} else {
er.ctxStack = er.ctxStack[:len(er.ctxStack)-1]
}
return v, true
}
if v.Not {
checkCondition, _ = expression.NewFunction(ast.UnaryNot, &v.Type, checkCondition)
}
er.p = er.b.buildApply(er.p, np, &ApplyConditionChecker{Condition: checkCondition, All: v.Not})
// The parent expression only use the last column in schema, which represents whether the condition is matched.
er.ctxStack[len(er.ctxStack)-1] = er.p.GetSchema()[len(er.p.GetSchema())-1]
return v, true
}
func (er *expressionRewriter) handleCompareSubquery(v *ast.CompareSubqueryExpr) (ast.Node, bool) {
v.L.Accept(er)
if er.err != nil {
return v, true
}
lexpr := er.ctxStack[len(er.ctxStack)-1]
subq, ok := v.R.(*ast.SubqueryExpr)
if !ok {
er.err = errors.Errorf("Unknown compare type %T.", v.R)
return v, true
}
np, outerSchema := er.buildSubquery(subq)
if er.err != nil {
return v, true
}
// Only (a,b,c) = all (...) and (a,b,c) != any () can use row expression.
canMultiCol := (!v.All && v.Op == opcode.EQ) || (v.All && v.Op == opcode.NE)
if !canMultiCol && (getRowLen(lexpr) != 1 || len(np.GetSchema()) != 1) {
er.err = errors.New("Operand should contain 1 column(s)")
return v, true
}
if getRowLen(lexpr) != len(np.GetSchema()) {
er.err = errors.Errorf("Operand should contain %d column(s)", getRowLen(lexpr))
return v, true
}
var checkCondition expression.Expression
var rexpr expression.Expression
if len(np.GetSchema()) == 1 {
rexpr = np.GetSchema()[0].DeepCopy()
} else {
args := make([]expression.Expression, 0, len(np.GetSchema()))
for _, col := range np.GetSchema() {
args = append(args, col.DeepCopy())
}
rexpr, er.err = expression.NewFunction(ast.RowFunc, types.NewFieldType(types.KindRow), args...)
if er.err != nil {
er.err = errors.Trace(er.err)
return v, true
}
}
switch v.Op {
// Only EQ, NE and NullEQ can be composed with and.
case opcode.EQ, opcode.NE, opcode.NullEQ:
checkCondition, er.err = constructBinaryOpFunction(lexpr, rexpr, opcode.Ops[v.Op])
if er.err != nil {
er.err = errors.Trace(er.err)
return v, true
}
// If op is not EQ, NE, NullEQ, say LT, it will remain as row(a,b) < row(c,d), and be compared as row datum.
default:
checkCondition, er.err = expression.NewFunction(opcode.Ops[v.Op],
types.NewFieldType(mysql.TypeTiny), lexpr, rexpr)
if er.err != nil {
er.err = errors.Trace(er.err)
return v, true
}
}
er.p = er.b.buildApply(er.p, np, outerSchema, &ApplyConditionChecker{Condition: checkCondition, All: v.All})
if er.p.IsCorrelated() {
er.correlated = true
}
// The parent expression only use the last column in schema, which represents whether the condition is matched.
er.ctxStack[len(er.ctxStack)-1] = er.p.GetSchema()[len(er.p.GetSchema())-1]
return v, true
}
// Leave implements Visitor interface.
func (er *expressionRewriter) Leave(inNode ast.Node) (retNode ast.Node, ok bool) {
if er.err != nil {
return retNode, false
}
stkLen := len(er.ctxStack)
switch v := inNode.(type) {
case *ast.AggregateFuncExpr:
case *ast.RowExpr:
length := len(v.Values)
rows := make([]expression.Expression, 0, length)
for i := stkLen - length; i < stkLen; i++ {
rows = append(rows, er.ctxStack[i])
}
er.ctxStack = er.ctxStack[:stkLen-length]
er.ctxStack = append(er.ctxStack, expression.NewFunction(ast.RowFunc, nil, rows...))
case *ast.VariableExpr:
return inNode, er.rewriteVariable(v)
case *ast.FuncCallExpr:
er.funcCallToScalarFunc(v)
case *ast.PositionExpr:
if v.N > 0 && v.N <= len(er.schema) {
er.ctxStack = append(er.ctxStack, er.schema[v.N-1])
} else {
er.err = errors.Errorf("Position %d is out of range", v.N)
}
case *ast.ColumnName:
er.toColumn(v)
case *ast.ColumnNameExpr, *ast.ParenthesesExpr, *ast.WhenClause, *ast.SubqueryExpr, *ast.ExistsSubqueryExpr, *ast.CompareSubqueryExpr:
case *ast.ValueExpr:
value := &expression.Constant{Value: v.Datum, RetType: v.Type}
er.ctxStack = append(er.ctxStack, value)
case *ast.ParamMarkerExpr:
value := &expression.Constant{Value: v.Datum, RetType: v.Type}
er.ctxStack = append(er.ctxStack, value)
case *ast.IsNullExpr:
if getRowLen(er.ctxStack[stkLen-1]) != 1 {
er.err = errors.New("Operand should contain 1 column(s)")
return retNode, false
}
function := er.notToScalarFunc(v.Not, ast.IsNull, v.Type, er.ctxStack[stkLen-1])
er.ctxStack = er.ctxStack[:stkLen-1]
er.ctxStack = append(er.ctxStack, function)
case *ast.IsTruthExpr:
op := ast.IsTruth
if v.True == 0 {
op = ast.IsFalsity
}
function := er.notToScalarFunc(v.Not, op, v.Type, er.ctxStack[stkLen-1])
er.ctxStack = er.ctxStack[:stkLen-1]
er.ctxStack = append(er.ctxStack, function)
case *ast.BinaryOperationExpr:
var function expression.Expression
switch v.Op {
case opcode.EQ, opcode.NE, opcode.NullEQ:
var err error
function, err = constructBinaryOpFunction(er.ctxStack[stkLen-2], er.ctxStack[stkLen-1],
opcode.Ops[v.Op])
if err != nil {
er.err = errors.Trace(err)
return retNode, false
}
default:
function = expression.NewFunction(opcode.Ops[v.Op], v.Type, er.ctxStack[stkLen-2:]...)
}
er.ctxStack = er.ctxStack[:stkLen-2]
er.ctxStack = append(er.ctxStack, function)
case *ast.BetweenExpr:
er.betweenToScalarFunc(v)
case *ast.PatternLikeExpr:
er.likeToScalarFunc(v)
case *ast.PatternInExpr:
if v.Sel == nil {
er.inToScalarFunc(v)
}
case *ast.UnaryOperationExpr:
if getRowLen(er.ctxStack[stkLen-1]) != 1 {
er.err = errors.New("Operand should contain 1 column(s)")
return retNode, false
}
function := expression.NewFunction(opcode.Ops[v.Op], v.Type, er.ctxStack[stkLen-1])
er.ctxStack = er.ctxStack[:stkLen-1]
er.ctxStack = append(er.ctxStack, function)
default:
er.err = errors.Errorf("UnknownType: %T", v)
return retNode, false
}
if er.err != nil {
return retNode, false
}
return inNode, true
}