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Re: Strings

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  • 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 1 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 2 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 3 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 4 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 5 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 6 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 7 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 8 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 9 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 10 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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