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Re: [json] Strings

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  • Martin Cooper
    ... These statements have me really wondering about what JSON is supposed to be. The reasoning behind removing comments was that it would more closely align
    Message 1 of 12 , Jan 3, 2006
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      On 1/3/06, Douglas Crockford <douglas@...> wrote:
      >
      > JSON has a string notation which is similar to that used in the C
      > family languages. Strings are bounded by double quote characters.
      > Escapement is provided by the backslash. The spec specifically allows
      > the slash to be escaped so that JSON can be delivered in HTML documents.


      These statements have me really wondering about what JSON is supposed to be.
      The reasoning behind removing comments was that it would "more closely align
      JSON with YAML and Python". Now we have double quoted strings only, which is
      "similar to that used in the C family language", and so that it "can be
      delivered in HTML documents".

      And here was me blithely thinking JSON was supposed to be a "JavaScript
      Object Notation". What happened to the JavaScript focus? With all due
      respect, it's beginning to seem like JSON is supposed to be a minimalist
      object notation that's compatible with JavaScript and as many other
      languages as possible. Perhaps it should be renamed "MON" for Minimal Object
      Notation? ;-) The "JSON" moniker is seeming less and less appropriate.

      The single quote convention is not included in JSON because it is not
      > needed.


      It wasn't "needed" in JavaScript / ECMAScript either, but they still
      included it. It's convenient because it frequently allows you to avoid
      backslashes / escapes in string literals.

      All strings can be represented with the double quote notation.
      > C itself does not have single quote strings. Many PHP programmers are
      > confused by JavaScript's single quote strings.


      Add PHP to the list of non-JavaScript languages JSON is trying to cater
      to... (... and add PHP programmers to my list of not-so-smart-folks if they
      can't understand string quoting... ;)

      JSON requires that keys be quoted because of an error in the
      > ECMAScript spec that disallows the use of unquoted reserved words as
      > keys. The list of reserved words is surprisingly long and difficult to
      > remember. The best practice is to always quote keys.


      That is a good reason to document a "best practice". It is in no way a
      reason to ban people from using unquoted key names.

      As an historical note, the very first JSON message contained as one of
      > its keys the word "do". It was not quoted, and it caused a syntax error.


      Not a good start, huh? ;-)

      --
      Martin Cooper


      Yahoo! Groups Links
      >
      >
      >
      >
      >
      >
      >


      [Non-text portions of this message have been removed]
    • Douglas Crockford
      ... That is correct. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of
      Message 2 of 12 , Jan 4, 2006
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        > And here was me blithely thinking JSON was supposed to be a "JavaScript
        > Object Notation". What happened to the JavaScript focus? With all due
        > respect, it's beginning to seem like JSON is supposed to be a minimalist
        > object notation that's compatible with JavaScript and as many other
        > languages as possible.

        That is correct.

        JSON is a text format that is completely language independent but uses
        conventions that are familiar to programmers of the C-family of
        languages, including C, C++, C#, Java, JavaScript, Perl, Python, and
        many others. These properties make JSON an ideal data-interchange
        language.

        JSON is built on two structures:

        * A collection of name/value pairs. In various languages, this is
        realized as an object, record, struct, dictionary, hash table, keyed
        list, or associative array.
        * An ordered list of values. In most languages, this is realized
        as an array, vector, list, table, or sequence.

        These are universal data structures. Virtually all modern programming
        languages support them in one form or another. It makes sense that a
        data format that is interchangable with programming languages also be
        based on these structures.

        See http://www.JSON.org
      • George
        I agree 100% with you. Do as I do and use Javascript Object Literals as they are specified in the Javascript or ECMAScript Reference. Anything the JS parser
        Message 3 of 12 , Jan 4, 2006
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          I agree 100% with you.
          Do as I do and use Javascript Object Literals as they are specified in
          the Javascript or ECMAScript Reference.

          Anything the JS parser allows is considered valid:
          - Comments
          - Quoted/Unquoted keys
          - Numbered Keys
          - Single/Double Quotes
          - Scientific Notation
          - Unicode

          It is up to the coder to define 'best practices' not the format to
          impose or restrict them.

          Then again, it is a 'subset' of JavaScript Object Literals, lowest
          common denominator to be compatible with other languages.

          If your target are web apps, HTML and JS, just go and use the whole
          set and more.

          Crockford knows I always opposed his stubbornness ;-)

          George

          --- In json@yahoogroups.com, Martin Cooper <mfncooper@g...> wrote:
          >
          > On 1/3/06, Douglas Crockford <douglas@c...> wrote:
          > >
          > > JSON has a string notation which is similar to that used in the C
          > > family languages. Strings are bounded by double quote characters.
          > > Escapement is provided by the backslash. The spec specifically allows
          > > the slash to be escaped so that JSON can be delivered in HTML
          documents.
          >
          >
          > These statements have me really wondering about what JSON is
          supposed to be.
          > The reasoning behind removing comments was that it would "more
          closely align
          > JSON with YAML and Python". Now we have double quoted strings only,
          which is
          > "similar to that used in the C family language", and so that it "can be
          > delivered in HTML documents".
          >
          > And here was me blithely thinking JSON was supposed to be a "JavaScript
          > Object Notation". What happened to the JavaScript focus? With all due
          > respect, it's beginning to seem like JSON is supposed to be a minimalist
          > object notation that's compatible with JavaScript and as many other
          > languages as possible. Perhaps it should be renamed "MON" for
          Minimal Object
          > Notation? ;-) The "JSON" moniker is seeming less and less appropriate.
          >
          > The single quote convention is not included in JSON because it is not
          > > needed.
          >
          >
          > It wasn't "needed" in JavaScript / ECMAScript either, but they still
          > included it. It's convenient because it frequently allows you to avoid
          > backslashes / escapes in string literals.
          >
          > All strings can be represented with the double quote notation.
          > > C itself does not have single quote strings. Many PHP programmers are
          > > confused by JavaScript's single quote strings.
          >
          >
          > Add PHP to the list of non-JavaScript languages JSON is trying to cater
          > to... (... and add PHP programmers to my list of not-so-smart-folks
          if they
          > can't understand string quoting... ;)
          >
          > JSON requires that keys be quoted because of an error in the
          > > ECMAScript spec that disallows the use of unquoted reserved words as
          > > keys. The list of reserved words is surprisingly long and difficult to
          > > remember. The best practice is to always quote keys.
          >
          >
          > That is a good reason to document a "best practice". It is in no way a
          > reason to ban people from using unquoted key names.
          >
          > As an historical note, the very first JSON message contained as one of
          > > its keys the word "do". It was not quoted, and it caused a syntax
          error.
          >
          >
          > Not a good start, huh? ;-)
          >
          > --
          > Martin Cooper
          >
          >
          > Yahoo! Groups Links
          > >
          > >
          > >
          > >
          > >
          > >
          > >
          >
          >
          > [Non-text portions of this message have been removed]
          >
        • Michal Migurski
          ... Beginning to? I thought this was the idea all along? Syntax that s valid Javascript, Python, and easy to write parsers for other languages. I m already
          Message 4 of 12 , Jan 4, 2006
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            > And here was me blithely thinking JSON was supposed to be a
            > "JavaScript
            > Object Notation". What happened to the JavaScript focus? With all due
            > respect, it's beginning to seem like JSON is supposed to be a
            > minimalist
            > object notation that's compatible with JavaScript and as many other
            > languages as possible.

            Beginning to? I thought this was the idea all along? Syntax that's
            valid Javascript, Python, and easy to write parsers for other
            languages. I'm already using it in a number of situations where
            Javascript plays no role whatsoever (e.g., interprocess communication
            between Python and PHP), and its simplicity makes me quite happy.

            > Add PHP to the list of non-JavaScript languages JSON is trying to
            > cater
            > to... (... and add PHP programmers to my list of not-so-smart-folks
            > if they
            > can't understand string quoting... ;)

            !

            Honestly, I don't understand the desire to gum up the works here.
            Comments, quoting options - use raw Javascript or XOXO for strings,
            lists and dictionaries if you need such extras. JSON as a spec is
            simple, elegant, and complete.

            ----------------------------------------------------------------
            michal migurski- contact info and pgp key:
            sf/ca http://mike.teczno.com/contact.html





            [Non-text portions of this message have been removed]
          • Martin Cooper
            ... Then can you please explain why it is called JavaScript Object Notation? -- Martin Cooper but uses ... [Non-text portions of this message have been
            Message 5 of 12 , Jan 4, 2006
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              On 1/4/06, Douglas Crockford <douglas@...> wrote:
              >
              > > And here was me blithely thinking JSON was supposed to be a "JavaScript
              > > Object Notation". What happened to the JavaScript focus? With all due
              > > respect, it's beginning to seem like JSON is supposed to be a minimalist
              > > object notation that's compatible with JavaScript and as many other
              > > languages as possible.
              >
              > That is correct.
              >
              > JSON is a text format that is completely language independent


              Then can you please explain why it is called JavaScript Object Notation?

              --
              Martin Cooper


              but uses
              > conventions that are familiar to programmers of the C-family of
              > languages, including C, C++, C#, Java, JavaScript, Perl, Python, and
              > many others. These properties make JSON an ideal data-interchange
              > language.
              >
              > JSON is built on two structures:
              >
              > * A collection of name/value pairs. In various languages, this is
              > realized as an object, record, struct, dictionary, hash table, keyed
              > list, or associative array.
              > * An ordered list of values. In most languages, this is realized
              > as an array, vector, list, table, or sequence.
              >
              > These are universal data structures. Virtually all modern programming
              > languages support them in one form or another. It makes sense that a
              > data format that is interchangable with programming languages also be
              > based on these structures.
              >
              > See http://www.JSON.org
              >
              >
              >
              >
              >
              >
              > Yahoo! Groups Links
              >
              >
              >
              >
              >
              >
              >


              [Non-text portions of this message have been removed]
            • Douglas Crockford
              ... JSON is based on a subset of the JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999. See http://www.JSON.org/
              Message 6 of 12 , Jan 4, 2006
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                > Then can you please explain why it is called JavaScript Object Notation?

                JSON is based on a subset of the JavaScript Programming Language,
                Standard ECMA-262 3rd Edition - December 1999.

                See http://www.JSON.org/
              • Atif Aziz
                ... It is up to the coder to define best practices not the format to impose or restrict them.
                Message 7 of 12 , Jan 5, 2006
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                  >>
                  It is up to the coder to define 'best practices' not the format to
                  impose or restrict them.
                  <<

                  Agreed. The problem lies in some of the inconsistencies surrounding
                  the goals, purpose and application of JSON and which I am interested
                  in seeing disambiguated. As it stands, right now, the contents of
                  the specification are, without a doubt, really good enough for a
                  machine encoder. There is little information in there to guide the
                  decoders. A human encoder is only at the mercy of the decoder's
                  flexibility and there's even more trouble if the implementation
                  swaps from underneath his or her feet. Why are humans such a big
                  issue? Well, it's right there as the second claim in the
                  specification: "It is easy for humans to read and write." The rules
                  about strings and unquotable member names is less of a concern for
                  humans because allowing a smaller subset means remembering fewer
                  rules. However, the resistance to mention comments whatsoever is
                  just incomprehensible and beyond me.

                  >>
                  Then again, it is a 'subset' of JavaScript Object Literals, lowest
                  common denominator to be compatible with other languages.
                  <<

                  Incidentally, what is a data format doing concerning itself with
                  lanugages and bindings? I can understand leveraging familiarity with
                  existing syntax across the C-family of languages, but that can only
                  be used with grain of salt in the design of the data format. The
                  lowest common denominator argument is only good enough while things
                  remain simple.

                  --- In json@yahoogroups.com, "George" <georgenava@y...> wrote:
                  >
                  > I agree 100% with you.
                  > Do as I do and use Javascript Object Literals as they are
                  specified in
                  > the Javascript or ECMAScript Reference.
                  >
                  > Anything the JS parser allows is considered valid:
                  > - Comments
                  > - Quoted/Unquoted keys
                  > - Numbered Keys
                  > - Single/Double Quotes
                  > - Scientific Notation
                  > - Unicode
                  >
                  > It is up to the coder to define 'best practices' not the format to
                  > impose or restrict them.
                  >
                  > Then again, it is a 'subset' of JavaScript Object Literals, lowest
                  > common denominator to be compatible with other languages.
                  >
                  > If your target are web apps, HTML and JS, just go and use the whole
                  > set and more.
                  >
                  > Crockford knows I always opposed his stubbornness ;-)
                  >
                  > George
                  >
                  > --- In json@yahoogroups.com, Martin Cooper <mfncooper@g...> wrote:
                  > >
                  > > On 1/3/06, Douglas Crockford <douglas@c...> wrote:
                  > > >
                  > > > JSON has a string notation which is similar to that used in
                  the C
                  > > > family languages. Strings are bounded by double quote
                  characters.
                  > > > Escapement is provided by the backslash. The spec specifically
                  allows
                  > > > the slash to be escaped so that JSON can be delivered in HTML
                  > documents.
                  > >
                  > >
                  > > These statements have me really wondering about what JSON is
                  > supposed to be.
                  > > The reasoning behind removing comments was that it would "more
                  > closely align
                  > > JSON with YAML and Python". Now we have double quoted strings
                  only,
                  > which is
                  > > "similar to that used in the C family language", and so that
                  it "can be
                  > > delivered in HTML documents".
                  > >
                  > > And here was me blithely thinking JSON was supposed to be
                  a "JavaScript
                  > > Object Notation". What happened to the JavaScript focus? With
                  all due
                  > > respect, it's beginning to seem like JSON is supposed to be a
                  minimalist
                  > > object notation that's compatible with JavaScript and as many
                  other
                  > > languages as possible. Perhaps it should be renamed "MON" for
                  > Minimal Object
                  > > Notation? ;-) The "JSON" moniker is seeming less and less
                  appropriate.
                  > >
                  > > The single quote convention is not included in JSON because it
                  is not
                  > > > needed.
                  > >
                  > >
                  > > It wasn't "needed" in JavaScript / ECMAScript either, but they
                  still
                  > > included it. It's convenient because it frequently allows you to
                  avoid
                  > > backslashes / escapes in string literals.
                  > >
                  > > All strings can be represented with the double quote notation.
                  > > > C itself does not have single quote strings. Many PHP
                  programmers are
                  > > > confused by JavaScript's single quote strings.
                  > >
                  > >
                  > > Add PHP to the list of non-JavaScript languages JSON is trying
                  to cater
                  > > to... (... and add PHP programmers to my list of not-so-smart-
                  folks
                  > if they
                  > > can't understand string quoting... ;)
                  > >
                  > > JSON requires that keys be quoted because of an error in the
                  > > > ECMAScript spec that disallows the use of unquoted reserved
                  words as
                  > > > keys. The list of reserved words is surprisingly long and
                  difficult to
                  > > > remember. The best practice is to always quote keys.
                  > >
                  > >
                  > > That is a good reason to document a "best practice". It is in no
                  way a
                  > > reason to ban people from using unquoted key names.
                  > >
                  > > As an historical note, the very first JSON message contained as
                  one of
                  > > > its keys the word "do". It was not quoted, and it caused a
                  syntax
                  > error.
                  > >
                  > >
                  > > Not a good start, huh? ;-)
                  > >
                  > > --
                  > > Martin Cooper
                  > >
                  > >
                  > > Yahoo! Groups Links
                  > > >
                  > > >
                  > > >
                  > > >
                  > > >
                  > > >
                  > > >
                  > >
                  > >
                  > > [Non-text portions of this message have been removed]
                  > >
                  >
                • Atif Aziz
                  ... And who took away single quoted strings and unquoted member names?! Hell yes, I d like to see the reasoning for changes like that, too.
                  Message 8 of 12 , Jan 5, 2006
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                    Dave said [1]:

                    >>
                    And who took away single quoted strings and unquoted member names?!
                    Hell yes, I'd like to see the reasoning for changes like that, too.<<
                    <<

                    I'd like apologize for this misconception and correct where I have
                    been wrong. It appears that the spec never actually endorsed
                    unquoted keys or single-quote strings. I went back and looked at the
                    earliest version of the spec [2] I could find (dated Apr 17, 2003)
                    and there's no mention of it in there. So technically speaking, it
                    was never removed (unlike comments, which were). Whether they should
                    be added is another story altogether. Right now, I'd just like to
                    stick to clarification.

                    The confusion came from two sources. First of all, the JSON spec
                    seemed small enough to keep in the head. In fact, the easiest rule
                    to remember was that, aside from expressions, JSON is really just a
                    formalization of JavaScript's literal notation for dictionaries,
                    arrays and primitives like strings, numbers, booleans and null. It
                    turns out that it's a little less than that, but this detail fades
                    away as you spend time in the various implementations; therein lies
                    the second problem. Most implementations seem to be exercising (and
                    rightly so) a good axiom of the web, "Be liberal in what you require
                    but conservative in what you do." So the spec is clear and thorough
                    from the encoding perspective (conservative) and no one has
                    questioned that (some have been calling it "best practices"). The
                    decoding end, however, varies a lot and leads to confusion
                    (including my own rearding quotes). I originally started my C#
                    implementation as a re-factoring of the Java version 0.1 [3]. At the
                    time, this is what was said about the parser's level of tolerance:

                    ========================================
                    The texts produced by the toString() methods are very strict. The
                    constructors are more forgiving in the texts they will accept.

                    - An extra comma may appear just before the closing brace.
                    - Strings may be quoted with single quotes.
                    - Strings do not need to be quoted at all if they do not contain
                    leading or trailing spaces, and if they do not contain any of these
                    characters: { } [ ] / \ : ,
                    - Numbers may have the 0- (octal) or 0x- (hex) prefix.
                    ========================================

                    The second and third point had somehow ruined my memory of the spec
                    as I started spending more time in unit-testing and bootstrapping
                    the parser with hand-coded JSON samples. The original JavaScript
                    implementation [4] was on par with the above level of acceptance. In
                    fact, both allowed more JavaScript literals to be expressed than
                    JSON permits (which you could argue was reasonable). Today, version
                    2.0 of the Java implementation [4] has gone considerably more
                    liberal:

                    ========================================
                    The constructors are more forgiving in the texts they will accept:

                    - An extra , (comma) may appear just before the closing brace.
                    - Strings may be quoted with ' (single quote).
                    - Strings do not need to be quoted at all if they do not begin with
                    a quote or single quote, and if they do not contain leading or
                    trailing spaces, and if they do not contain any of these characters:
                    { } [ ] / \ : , = ; # and if they do not look like numbers and if
                    they are not the reserved words true, false, or null.
                    - Keys can be followed by = or => as well as by :.
                    - Values can be followed by ; (semicolon) as well as by , (comma).
                    - Numbers may have the 0- (octal) or 0x- (hex) prefix.
                    - Comments written in the slashshlash, slashstar, and hash
                    conventions will be ignored.
                    ========================================

                    Fine, so these are the decisions of merely one implementation. What
                    is disturbing, however, is that the JavaScript version has gone
                    completely in the opposite direction in favor of speed; so as to be
                    able to benefit from native parsing provided strict adherence to the
                    JSON token space. Consequently, it's gone intolerant and sticks to
                    the encoding specification, bit-by-bit. So much so, that a JSON
                    sample (incidentally with comments) on the site [6] won't pass it.
                    Again, if this was done in a compatible manner then it would be less
                    of a problem, but I consider these to be *reference* implementations
                    of the standard!

                    My comments on comments (pun intended), however, still stand in face
                    of weak and subjective arguments that they are not needed. It is
                    precisely in the light of such concerns that I was hoping that
                    comments warrant a mention!

                    -Atif

                    ----------

                    [1] http://shrinkster.com/ahp ;
                    http://groups.yahoo.com/group/json/message/186
                    [2] http://shrinkster.com/ahq ;
                    http://web.archive.org/web/*/http://www.crockford.com/JSON/
                    [3] http://shrinkster.com/ahr ;
                    http://web.archive.org/web/20050306024809/http://www.crockford.com/JS
                    ON/javadoc/org/json/JSONObject.html
                    [4] http://shrinkster.com/ahs ;
                    http://www.raboof.com/Projects/Jayrock/json.js
                    [5] http://shrinkster.com/aht ;
                    http://www.crockford.com/JSON/javadoc/org/json/JSONObject.html
                    [6] http://shrinkster.com/ahu ;
                    http://www.crockford.com/JSON/example.html

                    --- In json@yahoogroups.com, "Douglas Crockford" <douglas@c...>
                    wrote:
                    >
                    > JSON has a string notation which is similar to that used in the C
                    > family languages. Strings are bounded by double quote characters.
                    > Escapement is provided by the backslash. The spec specifically
                    allows
                    > the slash to be escaped so that JSON can be delivered in HTML
                    documents.
                    >
                    > The single quote convention is not included in JSON because it is
                    not
                    > needed. All strings can be represented with the double quote
                    notation.
                    > C itself does not have single quote strings. Many PHP programmers
                    are
                    > confused by JavaScript's single quote strings.
                    >
                    > JSON requires that keys be quoted because of an error in the
                    > ECMAScript spec that disallows the use of unquoted reserved words
                    as
                    > keys. The list of reserved words is surprisingly long and
                    difficult to
                    > remember. The best practice is to always quote keys.
                    >
                    > As an historical note, the very first JSON message contained as
                    one of
                    > its keys the word "do". It was not quoted, and it caused a syntax
                    error.
                    >
                  • Douglas Crockford
                    ... I used to agree what comments would be useful. But since I started using JSON, I never discovered what that use was. I have seen them used very badly. I
                    Message 9 of 12 , Jan 5, 2006
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                      > My comments on comments (pun intended), however, still stand in face
                      > of weak and subjective arguments that they are not needed. It is
                      > precisely in the light of such concerns that I was hoping that
                      > comments warrant a mention!

                      I used to agree what comments would be useful. But since I started
                      using JSON, I never discovered what that use was. I have seen them
                      used very badly. I have asked several times what the value is that
                      requires that support be added to every implementation. I am still
                      listening.
                    • Martin Cooper
                      ... You re not convinced that saving developers time is valuable? OK, then, how about compatibility? There are lots of JSON implementations out there already,
                      Message 10 of 12 , Jan 5, 2006
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                        On 1/5/06, Douglas Crockford <douglas@...> wrote:
                        >
                        > > My comments on comments (pun intended), however, still stand in face
                        > > of weak and subjective arguments that they are not needed. It is
                        > > precisely in the light of such concerns that I was hoping that
                        > > comments warrant a mention!
                        >
                        > I used to agree what comments would be useful. But since I started
                        > using JSON, I never discovered what that use was. I have seen them
                        > used very badly. I have asked several times what the value is that
                        > requires that support be added to every implementation. I am still
                        > listening.


                        You're not convinced that saving developers' time is valuable?

                        OK, then, how about compatibility? There are lots of JSON implementations
                        out there already, and I'm sure most of them already support comments, my
                        own included. Interoperability between those and new ones would be reduced
                        by eliminating comments from the spec now. The cat is already out of the
                        bag.

                        --
                        Martin Cooper


                        Yahoo! Groups Links
                        >
                        >
                        >
                        >
                        >
                        >
                        >
                        >


                        [Non-text portions of this message have been removed]
                      • jemptymethod
                        ... I don t think this is an error in the ... spec .... I can think of at least one other language that disallows unquoted reserved words as keys (Lua), and
                        Message 11 of 12 , Jan 14, 2006
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                          --- In json@yahoogroups.com, "Douglas Crockford" <douglas@c...> wrote:
                          >
                          > JSON requires that keys be quoted because of an error in the
                          > ECMAScript spec that disallows the use of unquoted reserved words as
                          > keys. The list of reserved words is surprisingly long and difficult to
                          > remember. The best practice is to always quote keys.

                          I don't think this is "an error in the ... spec" .... I can think of
                          at least one other language that disallows unquoted reserved words as
                          keys (Lua), and there are others I'm certain
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