Re: Feature request: "u" option to file:read

[Dirk Laurie <dirk.laurie@...>]

2018-02-23 17:54 GMT+02:00 Roberto Ierusalimschy <roberto@inf.puc-rio.br>:
>> If we have to be able to put the read pointer back where it was before
>> the read in case the character is invalid (e.g. so a different
>> function could read out the raw bytes) then that couldn't be done with
>> a single unget.
>
> The reading of numbers already poses a similar problem, and Lua solves
> it the simple way. From the manual:
>
>   "n": reads a numeral and returns it as a float or an integer,
>   following the lexical conventions of Lua. (The numeral may have leading
>   spaces and a sign.)  This format always reads the longest input sequence
>   that is a valid prefix for a numeral; if that prefix does not form a
>   valid numeral (e.g., an empty string, "0x", or "3.4e-"), it is discarded
>   and the function returns nil.

I'll be happy with something similar.