2024-05-24 06:28:48 +02:00
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// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
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// All rights reserved.
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// function.go
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package expr
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import (
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"fmt"
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"strings"
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)
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// ---- Function template
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type FuncTemplate func(ctx ExprContext, name string, args []any) (result any, err error)
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// ---- Common functor definition
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type baseFunctor struct {
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info ExprFunc
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}
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func (functor *baseFunctor) ToString(opt FmtOpt) (s string) {
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if functor.info != nil {
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s = functor.info.ToString(opt)
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} else {
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s = "func() {<body>}"
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}
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return s
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}
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2024-06-01 16:31:50 +02:00
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func (functor *baseFunctor) GetParams() (params []ExprFuncParam) {
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if functor.info != nil {
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return functor.info.Params()
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} else {
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return []ExprFuncParam{}
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}
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}
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2024-05-24 06:28:48 +02:00
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func (functor *baseFunctor) SetFunc(info ExprFunc) {
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functor.info = info
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}
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func (functor *baseFunctor) GetFunc() ExprFunc {
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return functor.info
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}
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// ---- Function Parameters
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type paramFlags uint16
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const (
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2024-06-07 09:45:02 +02:00
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PfDefault paramFlags = 1 << iota
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PfOptional
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PfRepeat
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2024-05-24 06:28:48 +02:00
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)
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type funcParamInfo struct {
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name string
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flags paramFlags
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defaultValue any
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}
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2024-06-06 05:31:35 +02:00
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func NewFuncParam(name string) ExprFuncParam {
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2024-05-24 06:28:48 +02:00
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return &funcParamInfo{name: name}
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}
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2024-06-06 05:31:35 +02:00
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func NewFuncParamFlag(name string, flags paramFlags) ExprFuncParam {
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2024-05-24 06:28:48 +02:00
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return &funcParamInfo{name: name, flags: flags}
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}
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2024-06-06 05:31:35 +02:00
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func NewFuncParamFlagDef(name string, flags paramFlags, defValue any) *funcParamInfo {
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2024-05-24 06:28:48 +02:00
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return &funcParamInfo{name: name, flags: flags, defaultValue: defValue}
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}
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func (param *funcParamInfo) Name() string {
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return param.name
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}
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func (param *funcParamInfo) Type() string {
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2024-06-07 09:45:02 +02:00
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return TypeAny
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}
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func (param *funcParamInfo) IsDefault() bool {
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return (param.flags & PfDefault) != 0
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2024-05-24 06:28:48 +02:00
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}
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func (param *funcParamInfo) IsOptional() bool {
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2024-06-06 05:31:35 +02:00
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return (param.flags & PfOptional) != 0
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2024-05-24 06:28:48 +02:00
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}
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func (param *funcParamInfo) IsRepeat() bool {
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return (param.flags & PfRepeat) != 0
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2024-05-24 06:28:48 +02:00
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}
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func (param *funcParamInfo) DefaultValue() any {
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return param.defaultValue
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}
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// --- Functions
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type funcInfo struct {
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name string
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minArgs int
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maxArgs int
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functor Functor
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params []ExprFuncParam
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returnType string
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}
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func newFuncInfo(name string, functor Functor, returnType string, params []ExprFuncParam) (info *funcInfo, err error) {
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var minArgs = 0
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var maxArgs = 0
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if params != nil {
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for _, p := range params {
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if maxArgs == -1 {
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return nil, fmt.Errorf("no more params can be specified after the ellipsis symbol: %q", p.Name())
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}
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if p.IsDefault() || p.IsOptional() {
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maxArgs++
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} else if maxArgs == minArgs {
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minArgs++
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maxArgs++
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} else {
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return nil, fmt.Errorf("can't specify non-optional param after optional ones: %q", p.Name())
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}
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if p.IsRepeat() {
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2024-06-02 11:30:24 +02:00
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minArgs--
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maxArgs = -1
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}
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}
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}
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info = &funcInfo{
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name: name, minArgs: minArgs, maxArgs: maxArgs, functor: functor, returnType: returnType, params: params,
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}
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functor.SetFunc(info)
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return info, nil
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}
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func newUnnamedFuncInfo(functor Functor, returnType string, params []ExprFuncParam) (info *funcInfo, err error) {
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return newFuncInfo("unnamed", functor, returnType, params)
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}
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func (info *funcInfo) Params() []ExprFuncParam {
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return info.params
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}
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func (info *funcInfo) ReturnType() string {
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return info.returnType
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}
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func (info *funcInfo) ToString(opt FmtOpt) string {
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var sb strings.Builder
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if len(info.Name()) == 0 {
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sb.WriteString("func")
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} else {
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sb.WriteString(info.Name())
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}
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sb.WriteByte('(')
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if info.params != nil {
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for i, p := range info.params {
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if i > 0 {
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sb.WriteString(", ")
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}
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sb.WriteString(p.Name())
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if p.IsDefault() {
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sb.WriteByte('=')
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if s, ok := p.DefaultValue().(string); ok {
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sb.WriteByte('"')
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sb.WriteString(s)
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sb.WriteByte('"')
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} else {
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sb.WriteString(fmt.Sprintf("%v", p.DefaultValue()))
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}
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}
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}
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}
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if info.maxArgs < 0 {
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sb.WriteString(" ...")
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}
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sb.WriteString("):")
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if len(info.returnType) > 0 {
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sb.WriteString(info.returnType)
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} else {
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sb.WriteString(TypeAny)
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2024-05-24 06:28:48 +02:00
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}
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sb.WriteString(" {<body>}")
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return sb.String()
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}
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func (info *funcInfo) Name() string {
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return info.name
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}
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func (info *funcInfo) MinArgs() int {
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return info.minArgs
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}
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func (info *funcInfo) MaxArgs() int {
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return info.maxArgs
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}
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func (info *funcInfo) Functor() Functor {
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return info.functor
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}
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