Thank you David for the detailled answer. Le samedi 5 octobre 2019 20:48:11 UTC+2, David Finkel a écrit : > > > > On Thu, Oct 3, 2019 at 11:11 AM Poussier William <william...@gmail.com > <javascript:>> wrote: > >> Hello >> >> The encoding/json package escapes 0xA (line feed), 0xD (carriage return) >> and 0x9 (horizontal tab) using the escape character '\'. However, when it >> comes to 0x8 (backspace) and 0xc (form feed), it uses the Unicode escape >> sequence staring with '\uXXXX'. >> >> Reproducer: https://play.golang.org/p/jihv9sZUjvY >> >> I can't really grasp the reason behind this difference for characters < >> 0x20, even tho it is perfectly valid JSON, I expected to see \f and \b. >> >> Does anyone know the reason, if there is one that lead to this? >> > > It looks like only a few of the RFC 8259 sec 7 special two-byte escapes > are supported: > > https://github.com/golang/go/blob/go1.13.1/src/encoding/json/encode.go#L975-L994 > > > Digging around the CLs linked from blame entries in that code-block, I > found this comment from rsc@ <https://codereview.appspot.com/4678046#msg4> on > the CL that added handling for \r and \n: > >> \r and \n is good. >> let's leave \b and \f out. >> no one cares about \f >> and more people know \b as >> word boundary than as backspace. >> >> > > > Note that using two-letter substitutions are optional according to the RFC > <https://tools.ietf.org/html/rfc8259#section-7>. (the relevant section): > >> Alternatively, there are two-character sequence escape >> representations of some popular characters. So, for example, a >> string containing only a single reverse solidus character *may be* >> represented more compactly as "\\". >> >> To escape an extended character that is not in the Basic Multilingual >> Plane, the character is represented as a 12-character sequence, >> encoding the UTF-16 surrogate pair. So, for example, a string >> containing only the G clef character (U+1D11E) may be represented as >> "\uD834\uDD1E". >> >> string = quotation-mark *char quotation-mark >> >> char = unescaped / >> escape ( >> %x22 / ; " quotation mark U+0022 >> %x5C / ; \ reverse solidus U+005C >> %x2F / ; / solidus U+002F >> %x62 / ; b backspace U+0008 >> %x66 / ; f form feed U+000C >> %x6E / ; n line feed U+000A >> %x72 / ; r carriage return U+000D >> %x74 / ; t tab U+0009 >> %x75 4HEXDIG ) ; uXXXX U+XXXX >> >> escape = %x5C ; \ >> >> quotation-mark = %x22 ; " >> >> unescaped = %x20-21 / %x23-5B / %x5D-10FFFF >> >> > On the other hand, it looks like on the decoding-side, the full complement > are supported: > https://github.com/golang/go/blob/b17fd8e49d24eb298c53de5cd0a8923f1e0270ba/src/encoding/json/decode.go#L1284-L1316 > > > >> >> Thanks >> >> -- >> You received this message because you are subscribed to the Google Groups >> "golang-nuts" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to golan...@googlegroups.com <javascript:>. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/f3c65b8c-c612-4b75-852a-fda7b246a77e%40googlegroups.com >> >> <https://groups.google.com/d/msgid/golang-nuts/f3c65b8c-c612-4b75-852a-fda7b246a77e%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> >
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