func (p *Parser) parseTree(tree *ast.ListCell) (ast.Cell, error) {
for {
switch t := <-p.tokens; t.Type {
// tree is done
case token.RParen:
return tree, nil
// EOF found before tree is done, error
case token.EOF:
return ast.NewEOF(), fmt.Errorf(
"syntax error: hanging parenthese, s-expression %v does not close", tree)
default:
val, err := p.parseAST(t)
if err != nil {
return val, err
}
tree.Add(val)
}
}
}
