package lex

import (
	"text/scanner"

	"cmd/internal/src"
)

// A Slice reads from a slice of Tokens.
type Slice struct {
	tokens []Token
	base   *src.PosBase
	line   int
	pos    int
}

func NewSlice(base *src.PosBase, line int, tokens []Token) *Slice {
	return &Slice{
		tokens: tokens,
		base:   base,
		line:   line,
		pos:    -1, // Next will advance to zero.
	}
}

func (s *Slice) Next() ScanToken {

	if macro.args == nil {
		in.Push(NewSlice(in.Base(), in.Line(), macro.tokens))
		return
	}
	tok := in.Stack.Next()
	if tok != '(' {
		// If the macro has arguments but is invoked without them, all we push is the macro name.
		// First, put back the token.
		in.peekToken = tok
		in.peekText = in.text
		in.peek = true
		in.Push(NewSlice(in.Base(), in.Line(), []Token{Make(macroName, macro.name)}))