func checkList(list *ast.ListCell, expect []string) []string {
errors := make([]string, 0)
cell := list.First()
// for each expected value
for i, e := range expect {
// error if value expected but list end
if cell == nil {
unreadStr := fmt.Sprint(expect[i:])
errors = append(errors, "list terminated before cells "+unreadStr)
break
}
// error if wrong cell contents
cellStr := fmt.Sprint(cell)
if cellStr != e {
errors = append(errors,
"expected cell value \""+e+"\", got \""+cellStr+"\"")
}
cell = cell.Next()
}
// error if all expected done but list not done
if cell != nil {
lenDiff := list.Value() - len(expect)
errors = append(errors,
"output too long by "+strconv.Itoa(lenDiff)+" cells")
}
return errors
}
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)
}
}
}