expr/simple-func-store.go

// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
// All rights reserved.

// simple-func-store.go
package expr

import "fmt"

type SimpleFuncStore struct {
	SimpleVarStore
	funcStore map[string]*funcInfo
}

type funcInfo struct {
	name    string
	minArgs int
	maxArgs int
	functor Functor
}

func (info *funcInfo) Name() string {
	return info.name
}

func (info *funcInfo) MinArgs() int {
	return info.minArgs
}

func (info *funcInfo) MaxArgs() int {
	return info.maxArgs
}

func (info *funcInfo) Functor() Functor {
	return info.functor
}

func NewSimpleFuncStore() *SimpleFuncStore {
	ctx := &SimpleFuncStore{
		SimpleVarStore: SimpleVarStore{varStore: make(map[string]any)},
		funcStore:      make(map[string]*funcInfo),
	}
	ImportBuiltinsFuncs(ctx)
	return ctx
}

func (ctx *SimpleFuncStore) Clone() ExprContext {
	return &SimpleFuncStore{
		SimpleVarStore: SimpleVarStore{varStore: CloneMap(ctx.varStore)},
		funcStore:      CloneMap(ctx.funcStore),
	}
}

func (ctx *SimpleFuncStore) GetFuncInfo(name string) (info ExprFunc) {
	info, _ = ctx.funcStore[name]
	return
}

func (ctx *SimpleFuncStore) RegisterFunc(name string, functor Functor, minArgs, maxArgs int) {
	ctx.funcStore[name] = &funcInfo{name: name, minArgs: minArgs, maxArgs: maxArgs, functor: functor}
}

func (ctx *SimpleFuncStore) EnumFuncs(acceptor func(name string) (accept bool)) (funcNames []string) {
	funcNames = make([]string, 0)
	for name := range ctx.funcStore {
		if acceptor != nil {
			if acceptor(name) {
				funcNames = append(funcNames, name)
			}
		} else {
			funcNames = append(funcNames, name)
		}
	}
	return
}

func (ctx *SimpleFuncStore) Call(name string, args []any) (result any, err error) {
	if info, exists := ctx.funcStore[name]; exists {
		functor := info.functor
		result, err = functor.Invoke(ctx, name, args)
	} else {
		err = fmt.Errorf("unknown function %s()", name)
	}
	return
}