116 lines
2.7 KiB
Go
116 lines
2.7 KiB
Go
// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
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// All rights reserved.
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// operand-func.go
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package expr
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import (
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"errors"
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"fmt"
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)
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// -------- function call term
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func newFuncCallTerm(tk *Token, args []*term) *term {
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return &term{
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tk: *tk,
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parent: nil,
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children: args,
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position: posLeaf,
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priority: priValue,
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evalFunc: evalFuncCall,
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}
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}
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// -------- eval func call
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func checkFunctionCall(ctx ExprContext, name string, params []any) (err error) {
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if info, exists, owner := GetFuncInfo(ctx, name); exists {
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if info.MinArgs() > len(params) {
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err = errTooFewParams(info.MinArgs(), info.MaxArgs(), len(params))
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}
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if err == nil && info.MaxArgs() >= 0 && info.MaxArgs() < len(params) {
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err = errTooMuchParams(info.MaxArgs(), len(params))
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}
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if err == nil && owner != ctx {
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ctx.RegisterFunc(name, info.Functor(), info.MinArgs(), info.MaxArgs())
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}
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} else {
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err = fmt.Errorf("unknown function %s()", name)
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}
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return
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}
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func evalFuncCall(parentCtx ExprContext, self *term) (v any, err error) {
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ctx := cloneContext(parentCtx)
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name, _ := self.tk.Value.(string)
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// fmt.Printf("Call %s(), context: %p\n", name, ctx)
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params := make([]any, len(self.children))
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for i, tree := range self.children {
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var param any
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if param, err = tree.compute(ctx); err != nil {
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break
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}
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params[i] = param
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}
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if err == nil {
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if err = checkFunctionCall(ctx, name, params); err == nil {
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if v, err = ctx.Call(name, params); err == nil {
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exportObjects(parentCtx, ctx)
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}
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}
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}
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return
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}
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// -------- function definition term
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func newFuncDefTerm(tk *Token, args []*term) *term {
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return &term{
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tk: *tk, // value is the expression body
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parent: nil,
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children: args, // function params
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position: posLeaf,
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priority: priValue,
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evalFunc: evalFuncDef,
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}
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}
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// -------- eval func def
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// TODO
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type funcDefFunctor struct {
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params []string
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expr Expr
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}
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func (functor *funcDefFunctor) Invoke(ctx ExprContext, name string, args []any) (result any, err error) {
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for i, p := range functor.params {
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if i < len(args) {
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arg := args[i]
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if functor, ok := arg.(Functor); ok {
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ctx.RegisterFunc(p, functor, 0, -1)
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} else {
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ctx.setVar(p, arg)
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}
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} else {
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ctx.setVar(p, nil)
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}
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}
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result, err = functor.expr.eval(ctx, false)
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return
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}
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func evalFuncDef(ctx ExprContext, self *term) (v any, err error) {
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bodySpec := self.value()
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if expr, ok := bodySpec.(*ast); ok {
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paramList := make([]string, 0, len(self.children))
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for _, param := range self.children {
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paramList = append(paramList, param.source())
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}
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v = &funcDefFunctor{
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params: paramList,
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expr: expr,
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}
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} else {
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err = errors.New("invalid function definition: the body specification must be an expression")
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}
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return
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}
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