expr/token.go

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

// token.go
package expr

import (
	"fmt"
	"io"
	"slices"
)

type Token struct {
	Sym    Symbol
	source string
	Value  any
}

func (tk *Token) DevString() string {
	if tk.Value != nil {
		return fmt.Sprintf("[%d]%q{%v}", tk.Sym, tk.source, tk.Value)
	}
	return fmt.Sprintf("[%d]%q{}", tk.Sym, tk.source)
}

func (tk *Token) String() string {
	if tk.Value != nil {
		return fmt.Sprintf("%#v", tk.Value)
	}
	return fmt.Sprintf("%s", tk.source)
}

func NewToken(sym Symbol, source string) *Token {
	return &Token{Sym: sym, source: source}
}

func NewValueToken(sym Symbol, source string, value any) *Token {
	return &Token{Sym: sym, source: source, Value: value}
}

func NewErrorToken(row, col int, err error) *Token {
	if err == io.EOF {
		return NewToken(SymEos, "")
	}
	return NewValueToken(SymError, fmt.Sprintf("[%d:%d]", row, col), err)
}

func (tk *Token) IsEos() bool {
	return tk.Sym == SymEos
}

func (tk *Token) IsError() bool {
	return tk.Sym == SymError
}

func (tk *Token) IsTerm(termSymbols []Symbol) bool {
	return tk.IsEos() || tk.IsError() || (termSymbols != nil && slices.Index(termSymbols, tk.Sym) >= 0)
}