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tidb/expression/builtin.go

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// Copyright 2013 The ql Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSES/QL-LICENSE file.
// Copyright 2015 PingCAP, 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package expression
import (
"strings"
"github.com/juju/errors"
"github.com/pingcap/tidb/ast"
"github.com/pingcap/tidb/context"
"github.com/pingcap/tidb/parser/opcode"
"github.com/pingcap/tidb/util/types"
)
// baseBuiltinFunc will be contained in every struct that implement builtinFunc interface.
type baseBuiltinFunc struct {
args []Expression
argValues []types.Datum
ctx context.Context
deterministic bool
}
func newBaseBuiltinFunc(args []Expression, ctx context.Context) baseBuiltinFunc {
return baseBuiltinFunc{
args: args,
argValues: make([]types.Datum, len(args)),
ctx: ctx,
deterministic: true,
}
}
func (b *baseBuiltinFunc) evalArgs(row []types.Datum) (_ []types.Datum, err error) {
for i, arg := range b.args {
b.argValues[i], err = arg.Eval(row, b.ctx)
if err != nil {
return nil, errors.Trace(err)
}
}
return b.argValues, nil
}
// isDeterministic will be true by default. Non-deterministic function will override this function.
func (b *baseBuiltinFunc) isDeterministic() bool {
return b.deterministic
}
func (b *baseBuiltinFunc) getArgs() []Expression {
return b.args
}
// equal only checks if both functions are non-deterministic and if these arguments are same.
// Function name will be checked outside.
func (b *baseBuiltinFunc) equal(fun builtinFunc) bool {
if !b.isDeterministic() || !fun.isDeterministic() {
return false
}
funArgs := fun.getArgs()
if len(funArgs) != len(b.args) {
return false
}
for i := range b.args {
if !b.args[i].Equal(funArgs[i], b.ctx) {
return false
}
}
return true
}
func (b *baseBuiltinFunc) getCtx() context.Context {
return b.ctx
}
// builtinFunc stands for a particular function signature.
type builtinFunc interface {
// eval does evaluation by the given row.
eval([]types.Datum) (types.Datum, error)
// getArgs returns the arguments expressions.
getArgs() []Expression
// isDeterministic checks if a function is deterministic.
// A function is deterministic if it returns same results for same inputs.
// e.g. random is non-deterministic.
isDeterministic() bool
// equal check if this function equals to another function.
equal(builtinFunc) bool
// getCtx returns this function's context.
getCtx() context.Context
}
// baseFunctionClass will be contained in every struct that implement functionClass interface.
type baseFunctionClass struct {
funcName string
minArgs int
maxArgs int
}
func (b *baseFunctionClass) verifyArgs(args []Expression) error {
l := len(args)
if l < b.minArgs || (b.maxArgs != -1 && l > b.maxArgs) {
return errIncorrectParameterCount.GenByArgs(b.funcName)
}
return nil
}
// builtinFunc stands for a class for a function which may contains multiple functions.
type functionClass interface {
// getFunction gets a function signature by the types and the counts of given arguments.
getFunction(args []Expression, ctx context.Context) (builtinFunc, error)
}
// BuiltinFunc is the function signature for builtin functions
type BuiltinFunc func([]types.Datum, context.Context) (types.Datum, error)
// Func is for a builtin function.
type Func struct {
// F is the specific calling function.
F BuiltinFunc
// MinArgs is the minimal arguments needed,
MinArgs int
// MaxArgs is the maximal arguments needed, -1 for infinity.
MaxArgs int
}
// Funcs holds all registered builtin functions.
var Funcs = map[string]Func{
// common functions
ast.Coalesce: {builtinCoalesce, 1, -1},
ast.IsNull: {builtinIsNull, 1, 1},
ast.Greatest: {builtinGreatest, 2, -1},
ast.Least: {builtinLeast, 2, -1},
ast.Interval: {builtinInterval, 2, -1},
// math functions
ast.Abs: {builtinAbs, 1, 1},
ast.Ceil: {builtinCeil, 1, 1},
ast.Ceiling: {builtinCeil, 1, 1},
ast.Ln: {builtinLog, 1, 1},
ast.Log: {builtinLog, 1, 2},
ast.Log2: {builtinLog2, 1, 1},
ast.Log10: {builtinLog10, 1, 1},
ast.Pow: {builtinPow, 2, 2},
ast.Power: {builtinPow, 2, 2},
ast.Rand: {builtinRand, 0, 1},
ast.Round: {builtinRound, 1, 2},
ast.Sign: {builtinSign, 1, 1},
ast.Conv: {builtinConv, 3, 3},
ast.CRC32: {builtinCRC32, 1, 1},
// time functions
ast.Curdate: {builtinCurrentDate, 0, 0},
ast.CurrentDate: {builtinCurrentDate, 0, 0},
ast.CurrentTime: {builtinCurrentTime, 0, 1},
ast.Date: {builtinDate, 1, 1},
ast.DateDiff: {builtinDateDiff, 2, 2},
ast.DateAdd: {dateArithFuncFactory(ast.DateArithAdd), 3, 3},
ast.AddDate: {dateArithFuncFactory(ast.DateArithAdd), 3, 3},
ast.DateSub: {dateArithFuncFactory(ast.DateArithSub), 3, 3},
ast.SubDate: {dateArithFuncFactory(ast.DateArithSub), 3, 3},
ast.DateFormat: {builtinDateFormat, 2, 2},
ast.CurrentTimestamp: {builtinNow, 0, 1},
ast.Curtime: {builtinCurrentTime, 0, 1},
ast.Day: {builtinDay, 1, 1},
ast.DayName: {builtinDayName, 1, 1},
ast.DayOfMonth: {builtinDayOfMonth, 1, 1},
ast.DayOfWeek: {builtinDayOfWeek, 1, 1},
ast.DayOfYear: {builtinDayOfYear, 1, 1},
ast.FromDays: {builtinFromDays, 1, 1},
ast.Extract: {builtinExtract, 2, 2},
ast.Hour: {builtinHour, 1, 1},
ast.MicroSecond: {builtinMicroSecond, 1, 1},
ast.Minute: {builtinMinute, 1, 1},
ast.Month: {builtinMonth, 1, 1},
ast.MonthName: {builtinMonthName, 1, 1},
ast.Now: {builtinNow, 0, 1},
ast.Second: {builtinSecond, 1, 1},
ast.StrToDate: {builtinStrToDate, 2, 2},
ast.Sysdate: {builtinSysDate, 0, 1},
ast.Time: {builtinTime, 1, 1},
ast.UTCDate: {builtinUTCDate, 0, 0},
ast.Week: {builtinWeek, 1, 2},
ast.Weekday: {builtinWeekDay, 1, 1},
ast.WeekOfYear: {builtinWeekOfYear, 1, 1},
ast.Year: {builtinYear, 1, 1},
ast.YearWeek: {builtinYearWeek, 1, 2},
ast.FromUnixTime: {builtinFromUnixTime, 1, 2},
ast.TimeDiff: {builtinTimeDiff, 2, 2},
ast.TimestampDiff: {builtinTimestampDiff, 3, 3},
ast.UnixTimestamp: {builtinUnixTimestamp, 0, 1},
// string functions
ast.ASCII: {builtinASCII, 1, 1},
ast.Concat: {builtinConcat, 1, -1},
ast.ConcatWS: {builtinConcatWS, 2, -1},
ast.Convert: {builtinConvert, 2, 2},
ast.Field: {builtinField, 2, -1},
ast.Lcase: {builtinLower, 1, 1},
ast.Left: {builtinLeft, 2, 2},
ast.Length: {builtinLength, 1, 1},
ast.Locate: {builtinLocate, 2, 3},
ast.Lower: {builtinLower, 1, 1},
ast.LTrim: {trimFn(strings.TrimLeft, spaceChars), 1, 1},
ast.Repeat: {builtinRepeat, 2, 2},
ast.Replace: {builtinReplace, 3, 3},
ast.Reverse: {builtinReverse, 1, 1},
ast.RTrim: {trimFn(strings.TrimRight, spaceChars), 1, 1},
ast.Space: {builtinSpace, 1, 1},
ast.Strcmp: {builtinStrcmp, 2, 2},
ast.Substring: {builtinSubstring, 2, 3},
ast.Substr: {builtinSubstring, 2, 3},
ast.SubstringIndex: {builtinSubstringIndex, 3, 3},
ast.Trim: {builtinTrim, 1, 3},
ast.Upper: {builtinUpper, 1, 1},
ast.Ucase: {builtinUpper, 1, 1},
ast.Hex: {builtinHex, 1, 1},
ast.Unhex: {builtinUnHex, 1, 1},
ast.Rpad: {builtinRpad, 3, 3},
ast.BitLength: {builtinBitLength, 1, 1},
ast.CharFunc: {builtinChar, 2, -1},
ast.CharLength: {builtinCharLength, 1, 1},
ast.FindInSet: {builtinFindInSet, 2, 2},
// information functions
ast.ConnectionID: {builtinConnectionID, 0, 0},
ast.CurrentUser: {builtinCurrentUser, 0, 0},
ast.Database: {builtinDatabase, 0, 0},
// This function is a synonym for DATABASE().
// See http://dev.mysql.com/doc/refman/5.7/en/information-functions.html#function_schema
ast.Schema: {builtinDatabase, 0, 0},
ast.FoundRows: {builtinFoundRows, 0, 0},
ast.LastInsertId: {builtinLastInsertID, 0, 1},
ast.User: {builtinUser, 0, 0},
ast.Version: {builtinVersion, 0, 0},
// control functions
ast.If: {builtinIf, 3, 3},
ast.Ifnull: {builtinIfNull, 2, 2},
ast.Nullif: {builtinNullIf, 2, 2},
// miscellaneous functions
ast.Sleep: {builtinSleep, 1, 1},
// get_lock() and release_lock() is parsed but do nothing.
// It is used for preventing error in Ruby's activerecord migrations.
ast.GetLock: {builtinLock, 2, 2},
ast.ReleaseLock: {builtinReleaseLock, 1, 1},
// only used by new plan
ast.AndAnd: {builtinAndAnd, 2, 2},
ast.OrOr: {builtinOrOr, 2, 2},
ast.GE: {compareFuncFactory(opcode.GE), 2, 2},
ast.LE: {compareFuncFactory(opcode.LE), 2, 2},
ast.EQ: {compareFuncFactory(opcode.EQ), 2, 2},
ast.NE: {compareFuncFactory(opcode.NE), 2, 2},
ast.LT: {compareFuncFactory(opcode.LT), 2, 2},
ast.GT: {compareFuncFactory(opcode.GT), 2, 2},
ast.NullEQ: {compareFuncFactory(opcode.NullEQ), 2, 2},
ast.Plus: {arithmeticFuncFactory(opcode.Plus), 2, 2},
ast.Minus: {arithmeticFuncFactory(opcode.Minus), 2, 2},
ast.Mod: {arithmeticFuncFactory(opcode.Mod), 2, 2},
ast.Div: {arithmeticFuncFactory(opcode.Div), 2, 2},
ast.Mul: {arithmeticFuncFactory(opcode.Mul), 2, 2},
ast.IntDiv: {arithmeticFuncFactory(opcode.IntDiv), 2, 2},
ast.LeftShift: {bitOpFactory(opcode.LeftShift), 2, 2},
ast.RightShift: {bitOpFactory(opcode.RightShift), 2, 2},
ast.And: {bitOpFactory(opcode.And), 2, 2},
ast.Or: {bitOpFactory(opcode.Or), 2, 2},
ast.Xor: {bitOpFactory(opcode.Xor), 2, 2},
ast.LogicXor: {builtinLogicXor, 2, 2},
ast.UnaryNot: {unaryOpFactory(opcode.Not), 1, 1},
ast.BitNeg: {unaryOpFactory(opcode.BitNeg), 1, 1},
ast.UnaryPlus: {unaryOpFactory(opcode.Plus), 1, 1},
ast.UnaryMinus: {unaryOpFactory(opcode.Minus), 1, 1},
ast.In: {builtinIn, 1, -1},
ast.IsTruth: {isTrueOpFactory(opcode.IsTruth), 1, 1},
ast.IsFalsity: {isTrueOpFactory(opcode.IsFalsity), 1, 1},
ast.Like: {builtinLike, 3, 3},
ast.Regexp: {builtinRegexp, 2, 2},
ast.Case: {builtinCaseWhen, 1, -1},
ast.RowFunc: {builtinRow, 2, -1},
ast.SetVar: {builtinSetVar, 2, 2},
ast.GetVar: {builtinGetVar, 1, 1},
}
// funcs holds all registered builtin functions.
var funcs = map[string]functionClass{
// common functions
ast.Coalesce: &coalesceFunctionClass{baseFunctionClass{ast.Coalesce, 1, -1}},
ast.IsNull: &isNullFunctionClass{baseFunctionClass{ast.IsNull, 1, 1}},
ast.Greatest: &greatestFunctionClass{baseFunctionClass{ast.Greatest, 2, -1}},
ast.Least: &leastFunctionClass{baseFunctionClass{ast.Least, 2, -1}},
ast.Interval: &intervalFunctionClass{baseFunctionClass{ast.Interval, 2, -1}},
// math functions
ast.Abs: &absFunctionClass{baseFunctionClass{ast.Abs, 1, 1}},
ast.Ceil: &ceilFunctionClass{baseFunctionClass{ast.Ceil, 1, 1}},
ast.Ceiling: &ceilFunctionClass{baseFunctionClass{ast.Ceiling, 1, 1}},
ast.Ln: &logFunctionClass{baseFunctionClass{ast.Log, 1, 1}},
ast.Log: &logFunctionClass{baseFunctionClass{ast.Log, 1, 2}},
ast.Log2: &log2FunctionClass{baseFunctionClass{ast.Log2, 1, 1}},
ast.Log10: &log10FunctionClass{baseFunctionClass{ast.Log10, 1, 1}},
ast.Pow: &powFunctionClass{baseFunctionClass{ast.Pow, 2, 2}},
ast.Power: &powFunctionClass{baseFunctionClass{ast.Pow, 2, 2}},
ast.Rand: &randFunctionClass{baseFunctionClass{ast.Rand, 0, 1}},
ast.Round: &roundFunctionClass{baseFunctionClass{ast.Round, 1, 2}},
ast.Sign: &signFunctionClass{baseFunctionClass{ast.Sign, 1, 1}},
ast.Conv: &convFunctionClass{baseFunctionClass{ast.Conv, 3, 3}},
ast.CRC32: &crc32FunctionClass{baseFunctionClass{ast.CRC32, 1, 1}},
// time functions
ast.Curdate: &currentDateFunctionClass{baseFunctionClass{ast.Curdate, 0, 0}},
ast.CurrentDate: &currentDateFunctionClass{baseFunctionClass{ast.CurrentDate, 0, 0}},
ast.CurrentTime: &currentTimeFunctionClass{baseFunctionClass{ast.CurrentTime, 0, 1}},
ast.Date: &dateFunctionClass{baseFunctionClass{ast.Date, 1, 1}},
ast.DateDiff: &dateDiffFunctionClass{baseFunctionClass{ast.DateDiff, 2, 2}},
ast.DateAdd: &dateArithFunctionClass{baseFunctionClass{ast.DateAdd, 3, 3}, ast.DateArithAdd},
ast.AddDate: &dateArithFunctionClass{baseFunctionClass{ast.AddDate, 3, 3}, ast.DateArithAdd},
ast.DateSub: &dateArithFunctionClass{baseFunctionClass{ast.DateSub, 3, 3}, ast.DateArithSub},
ast.SubDate: &dateArithFunctionClass{baseFunctionClass{ast.SubDate, 3, 3}, ast.DateArithSub},
ast.DateFormat: &dateFormatFunctionClass{baseFunctionClass{ast.DateFormat, 2, 2}},
ast.CurrentTimestamp: &nowFunctionClass{baseFunctionClass{ast.CurrentTimestamp, 0, 1}},
ast.Now: &nowFunctionClass{baseFunctionClass{ast.Now, 0, 1}},
ast.Curtime: &currentTimeFunctionClass{baseFunctionClass{ast.Curtime, 0, 1}},
ast.Day: &dayFunctionClass{baseFunctionClass{ast.Day, 1, 1}},
ast.DayName: &dayNameFunctionClass{baseFunctionClass{ast.DayName, 1, 1}},
ast.DayOfMonth: &dayOfMonthFunctionClass{baseFunctionClass{ast.DayOfMonth, 1, 1}},
ast.DayOfWeek: &dayOfWeekFunctionClass{baseFunctionClass{ast.DayOfWeek, 1, 1}},
ast.DayOfYear: &dayOfYearFunctionClass{baseFunctionClass{ast.DayOfYear, 1, 1}},
ast.Extract: &extractFunctionClass{baseFunctionClass{ast.Extract, 2, 2}},
ast.Hour: &hourFunctionClass{baseFunctionClass{ast.Hour, 1, 1}},
ast.MicroSecond: &microSecondFunctionClass{baseFunctionClass{ast.MicroSecond, 1, 1}},
ast.Minute: &minuteFunctionClass{baseFunctionClass{ast.Minute, 1, 1}},
ast.Month: &monthFunctionClass{baseFunctionClass{ast.Month, 1, 1}},
ast.MonthName: &monthNameFunctionClass{baseFunctionClass{ast.MonthName, 1, 1}},
ast.Second: &secondFunctionClass{baseFunctionClass{ast.Second, 1, 1}},
ast.StrToDate: &strToDateFunctionClass{baseFunctionClass{ast.StrToDate, 2, 2}},
ast.Sysdate: &sysDateFunctionClass{baseFunctionClass{ast.Sysdate, 0, 1}},
ast.Time: &timeFunctionClass{baseFunctionClass{ast.Time, 1, 1}},
ast.UTCDate: &utcDateFunctionClass{baseFunctionClass{ast.UTCDate, 0, 0}},
ast.Week: &weekFunctionClass{baseFunctionClass{ast.Week, 1, 2}},
ast.Weekday: &weekDayFunctionClass{baseFunctionClass{ast.Weekday, 1, 1}},
ast.WeekOfYear: &weekOfYearFunctionClass{baseFunctionClass{ast.WeekOfYear, 1, 1}},
ast.Year: &yearFunctionClass{baseFunctionClass{ast.Year, 1, 1}},
ast.YearWeek: &yearWeekFunctionClass{baseFunctionClass{ast.YearWeek, 1, 2}},
ast.FromUnixTime: &fromUnixTimeFunctionClass{baseFunctionClass{ast.FromUnixTime, 1, 2}},
ast.TimeDiff: &timeDiffFunctionClass{baseFunctionClass{ast.TimeDiff, 2, 2}},
ast.TimestampDiff: &timestampDiffFunctionClass{baseFunctionClass{ast.TimestampDiff, 3, 3}},
ast.UnixTimestamp: &unixTimestampFunctionClass{baseFunctionClass{ast.UnixTimestamp, 0, 1}},
// string functions
ast.ASCII: &asciiFunctionClass{baseFunctionClass{ast.ASCII, 1, 1}},
ast.Concat: &concatFunctionClass{baseFunctionClass{ast.Concat, 1, -1}},
ast.ConcatWS: &concatWSFunctionClass{baseFunctionClass{ast.ConcatWS, 2, -1}},
ast.Convert: &convertFunctionClass{baseFunctionClass{ast.Convert, 2, 2}},
ast.Field: &fieldFunctionClass{baseFunctionClass{ast.Field, 2, -1}},
ast.Lcase: &lowerFunctionClass{baseFunctionClass{ast.Lcase, 1, 1}},
ast.Left: &leftFunctionClass{baseFunctionClass{ast.Left, 2, 2}},
ast.Length: &lengthFunctionClass{baseFunctionClass{ast.Length, 1, 1}},
ast.Locate: &locateFunctionClass{baseFunctionClass{ast.Locate, 2, 3}},
ast.Lower: &lowerFunctionClass{baseFunctionClass{ast.Lower, 1, 1}},
ast.LTrim: &lTrimFunctionClass{baseFunctionClass{ast.LTrim, 1, 1}},
ast.Repeat: &repeatFunctionClass{baseFunctionClass{ast.Repeat, 2, 2}},
ast.Replace: &replaceFunctionClass{baseFunctionClass{ast.Replace, 3, 3}},
ast.Reverse: &reverseFunctionClass{baseFunctionClass{ast.Reverse, 1, 1}},
ast.RTrim: &rTrimFunctionClass{baseFunctionClass{ast.RTrim, 1, 1}},
ast.Space: &spaceFunctionClass{baseFunctionClass{ast.Space, 1, 1}},
ast.Strcmp: &strcmpFunctionClass{baseFunctionClass{ast.Strcmp, 2, 2}},
ast.Substring: &substringFunctionClass{baseFunctionClass{ast.Substring, 2, 3}},
ast.Substr: &substringFunctionClass{baseFunctionClass{ast.Substr, 2, 3}},
ast.SubstringIndex: &substringIndexFunctionClass{baseFunctionClass{ast.SubstringIndex, 3, 3}},
ast.Trim: &trimFunctionClass{baseFunctionClass{ast.Trim, 1, 3}},
ast.Upper: &upperFunctionClass{baseFunctionClass{ast.Upper, 1, 1}},
ast.Ucase: &upperFunctionClass{baseFunctionClass{ast.Ucase, 1, 1}},
ast.Hex: &hexFunctionClass{baseFunctionClass{ast.Hex, 1, 1}},
ast.Unhex: &unhexFunctionClass{baseFunctionClass{ast.Unhex, 1, 1}},
ast.Rpad: &rpadFunctionClass{baseFunctionClass{ast.Rpad, 3, 3}},
ast.BitLength: &bitLengthFunctionClass{baseFunctionClass{ast.BitLength, 1, 1}},
ast.CharFunc: &charFunctionClass{baseFunctionClass{ast.CharFunc, 2, -1}},
ast.CharLength: &charLengthFunctionClass{baseFunctionClass{ast.CharLength, 1, 1}},
ast.FindInSet: &findInSetFunctionClass{baseFunctionClass{ast.FindInSet, 2, 2}},
// information functions
ast.ConnectionID: &connectionIDFunctionClass{baseFunctionClass{ast.ConnectionID, 0, 0}},
ast.CurrentUser: &currentUserFunctionClass{baseFunctionClass{ast.CurrentUser, 0, 0}},
ast.Database: &databaseFunctionClass{baseFunctionClass{ast.Database, 0, 0}},
// This function is a synonym for DATABASE().
// See http://dev.mysql.com/doc/refman/5.7/en/information-functions.html#function_schema
ast.Schema: &databaseFunctionClass{baseFunctionClass{ast.Schema, 0, 0}},
ast.FoundRows: &foundRowsFunctionClass{baseFunctionClass{ast.FoundRows, 0, 0}},
ast.LastInsertId: &lastInsertIDFunctionClass{baseFunctionClass{ast.LastInsertId, 0, 1}},
ast.User: &userFunctionClass{baseFunctionClass{ast.User, 0, 0}},
ast.Version: &versionFunctionClass{baseFunctionClass{ast.Version, 0, 0}},
// control functions
ast.If: &ifFunctionClass{baseFunctionClass{ast.If, 3, 3}},
ast.Ifnull: &ifNullFunctionClass{baseFunctionClass{ast.Ifnull, 2, 2}},
ast.Nullif: &nullIfFunctionClass{baseFunctionClass{ast.Nullif, 2, 2}},
// miscellaneous functions
ast.Sleep: &sleepFunctionClass{baseFunctionClass{ast.Sleep, 1, 1}},
// get_lock() and release_lock() are parsed but do nothing.
// It is used for preventing error in Ruby's activerecord migrations.
ast.GetLock: &lockFunctionClass{baseFunctionClass{ast.GetLock, 2, 2}},
ast.ReleaseLock: &releaseLockFunctionClass{baseFunctionClass{ast.ReleaseLock, 1, 1}},
// only used by new plan
ast.AndAnd: &andandFunctionClass{baseFunctionClass{ast.AndAnd, 2, 2}},
ast.OrOr: &ororFunctionClass{baseFunctionClass{ast.OrOr, 2, 2}},
ast.GE: &compareFunctionClass{baseFunctionClass{ast.GE, 2, 2}, opcode.GE},
ast.LE: &compareFunctionClass{baseFunctionClass{ast.LE, 2, 2}, opcode.LE},
ast.EQ: &compareFunctionClass{baseFunctionClass{ast.EQ, 2, 2}, opcode.EQ},
ast.NE: &compareFunctionClass{baseFunctionClass{ast.NE, 2, 2}, opcode.NE},
ast.LT: &compareFunctionClass{baseFunctionClass{ast.LT, 2, 2}, opcode.LT},
ast.GT: &compareFunctionClass{baseFunctionClass{ast.GT, 2, 2}, opcode.GT},
ast.NullEQ: &compareFunctionClass{baseFunctionClass{ast.NullEQ, 2, 2}, opcode.NullEQ},
ast.Plus: &arithmeticFunctionClass{baseFunctionClass{ast.Plus, 2, 2}, opcode.Plus},
ast.Minus: &arithmeticFunctionClass{baseFunctionClass{ast.Minus, 2, 2}, opcode.Minus},
ast.Mod: &arithmeticFunctionClass{baseFunctionClass{ast.Mod, 2, 2}, opcode.Mod},
ast.Div: &arithmeticFunctionClass{baseFunctionClass{ast.Div, 2, 2}, opcode.Div},
ast.Mul: &arithmeticFunctionClass{baseFunctionClass{ast.Mul, 2, 2}, opcode.Mul},
ast.IntDiv: &arithmeticFunctionClass{baseFunctionClass{ast.IntDiv, 2, 2}, opcode.IntDiv},
ast.LeftShift: &bitOpFunctionClass{baseFunctionClass{ast.LeftShift, 2, 2}, opcode.LeftShift},
ast.RightShift: &bitOpFunctionClass{baseFunctionClass{ast.RightShift, 2, 2}, opcode.RightShift},
ast.And: &bitOpFunctionClass{baseFunctionClass{ast.And, 2, 2}, opcode.And},
ast.Or: &bitOpFunctionClass{baseFunctionClass{ast.Or, 2, 2}, opcode.Or},
ast.Xor: &bitOpFunctionClass{baseFunctionClass{ast.Xor, 2, 2}, opcode.Xor},
ast.LogicXor: &logicXorFunctionClass{baseFunctionClass{ast.LogicXor, 2, 2}},
ast.UnaryNot: &unaryOpFunctionClass{baseFunctionClass{ast.UnaryNot, 1, 1}, opcode.Not},
ast.BitNeg: &unaryOpFunctionClass{baseFunctionClass{ast.BitNeg, 1, 1}, opcode.BitNeg},
ast.UnaryPlus: &unaryOpFunctionClass{baseFunctionClass{ast.UnaryPlus, 1, 1}, opcode.Plus},
ast.UnaryMinus: &unaryOpFunctionClass{baseFunctionClass{ast.UnaryMinus, 1, 1}, opcode.Minus},
ast.In: &inFunctionClass{baseFunctionClass{ast.In, 1, -1}},
ast.IsTruth: &isTrueOpFunctionClass{baseFunctionClass{ast.IsTruth, 1, 1}, opcode.IsTruth},
ast.IsFalsity: &isTrueOpFunctionClass{baseFunctionClass{ast.IsFalsity, 1, 1}, opcode.IsFalsity},
ast.Like: &likeFunctionClass{baseFunctionClass{ast.Like, 3, 3}},
ast.Regexp: &regexpFunctionClass{baseFunctionClass{ast.Regexp, 2, 2}},
ast.Case: &caseWhenFunctionClass{baseFunctionClass{ast.Case, 1, -1}},
ast.RowFunc: &rowFunctionClass{baseFunctionClass{ast.RowFunc, 2, -1}},
ast.SetVar: &setVarFunctionClass{baseFunctionClass{ast.SetVar, 2, 2}},
ast.GetVar: &getVarFunctionClass{baseFunctionClass{ast.GetVar, 1, 1}},
}
// DynamicFuncs are those functions that
// use input parameter ctx or
// return an uncertain result would not be constant folded
// the value 0 means nothing
var DynamicFuncs = map[string]int{
"rand": 0,
"connection_id": 0,
"current_user": 0,
"database": 0,
"found_rows": 0,
"last_insert_id": 0,
"user": 0,
"version": 0,
"sleep": 0,
ast.GetVar: 0,
ast.SetVar: 0,
ast.Values: 0,
}