wagjo / serialization-formats

Comparison of selected serialization formats

Eclipse Public License 1.0

21 stars 1 forks source link

readme

Data serialization formats

Comparison of selected data serialization formats.

Whitespace

x	JSON	EDN	CLJ
whitespace character	U+0009 (tab) U+000A (newline) U+000D (return) and U+0020 (space)	:warning: specs does not specify whitespace chars, explicitly mentions just `,`	:warning: specs does not specify whitespace chars, explicitly mentions just `,`
delimiters	whitespaces, all structural (`{` `}` `:` `,` `[` `]`) and literal (`true` `false` `null`) tokens	whitespaces and `[` `]` `{` `}` `(` `)` ( :warning: additional delimiters not mentioned in specs `"` `\` `;`)	`[` `]` `{` `}` `(` `)` `"` `\` `;` `@` `^` ` `~` (:warning: no explicit mention in specs)

Null

x	JSON	EDN	CLJ
null literal	`null`	`nil`	`nil`

Booleans

x	JSON	EDN	CLJ
true literal	`true`	`true`	`true`
false literal	`false`	`false`	`false`

Characters

x	JSON	EDN	CLJ
syntax	NONE :x:	`\X`	`\X`
special characters	n/a	`\newline` `\tab` `\return` `\space`	`\newline` `\tab` `\return` `\space` `\backspace` `\formfeed`
unicode escapes	n/a	`\uNNNN`	`\uNNNN`
octal escapes	n/a	NO :x:	`\o0` to `\o377`

Strings

x	JSON	EDN	CLJ
syntax	wrapped in `"`	wrapped in `"`	wrapped in `"`
may span multiple lines	NO :x:	YES	YES
characters which must be escaped	`"` `\` and control characters (U+0000 to U+001F)	`"` `\`	`"` `\`
escape characters	`\"` `\\` `\/` `\b` `\f` `\n` `\r` `\t`	`\"` `\\` `\n` `\r` `\t`	`\"` `\\` `\'` `\b` `\f` `\n` `\r` `\t`
unicode escapes	`\uNNNN`	NO, not mentioned in specs :x:	`\uNNNN`
octal escapes	NO :x:	NO :x:	`\0` to `\377`

Integers

x	JSON	EDN	CLJ
arbitrary precision indicator	NO :x:	`N` suffix	`N` suffix
valid signs	`-`	`-` `+`	`-` `+`
`-0` is valid	YES	YES	YES
decimal integer	YES	YES	YES
custom radix	NO :x:	NO :x:	`NNrNNNNN`
hexa integer	NO :x:	NO :x:	`0xNNNNN`, but undocumented :warning:
octal integer	NO :x:	NO :x:	`0NNN`, but undocumented :warning:

Non-integral numbers

x	JSON	EDN	CLJ
ratios	NO :x:	NO :x:	`NN/NN`
decimals	NO :x:	`M` suffix	`M` suffix
floats	YES	YES	YES
valid signs	`-`	`-` `+`	`-` `+`

Identifiers

x	JSON	EDN	CLJ
symbols	NO :x:	YES	YES
symbol start character	n/a	alphabetic, `+` `-` `.` followed by non-numeric symbol character, `*` `!` `_` `?` `$` `%` `&` `=` `<` `>` (`/` is special, see below)	alphabetic, `+` `-` `*` `!` `_` `?` (`/` and `.` are special, see below), ( :warning: specs does not mention `$` `=` `<` `>` `%` `&`)
symbol character	n/a	alphanumeric, `+` `-` `.` `*` `!` `_` `?` `$` `%` `&` `=` `<` `>` `:` `#`	alphanumeric, `+` `-` `*` `!` `_` `?` (`.` `/` and `:` are special, see below), ( :warning: specs does not mention `$` `=` `<` `>` `%` `&` `#` `'`)
special symbol character	n/a	`/`, used alone or in following combinations `foo/bar` (:warning: In my opinion specs does not allow `foo//` combination, see this ticket). First character after slash must follow rule for symbol start character	`/`, used alone or in following combinations `foo/bar` `foo//` (:warning: latter combination is undocumented). `.`, used as prefix or suffix is reserved to Clojure, used inside symbol divides namespace or package names. `:` can be used inside symbol, used as suffix is reserved to Clojure (currently it produces an error). (:warning: undocumented restrictions: symbol can not contain `::`, namespace part can not end with `:`, first character after slash must follow rule for symbol start character)
keyword	NO :x:	prefixed with `:`	prefixed with `:`
keyword character	n/a	alphanumeric, `+` `-` `.` `*` `!` `_` `?` `$` `%` `&` `=` `<` `>` `:` `#`	alphanumeric, `+` `-` `*` `!` `_` `?` (`.` `/` and `:` are special, see below), ( :warning: specs does not mention `$` `=` `<` `>` `%` `&` `#` `'`)
keyword invalid second character	n/a	`:`	none special
special keyword character	n/a	`/`, used in following combinations `:foo//` `:foo/bar`. First character after slash must follow rule for symbol start character	`/`, used in following combinations `:foo/bar` `:foo//` (:warning: latter combination is undocumented). `:` used as second character resolves keyword in the current namespace, used as suffix is reserved to Clojure (currently it produces an error). (:warning: undocumented restrictions: keyword can not contain `::` other than as a prefix, namespace part can not end with `:`, first character after slash must follow rule for symbol start character) Specs also say that keywords cannot contain '.' ( :warning: restriction meant probably only for the name part of the keyword) or name classes.

Collections

x	JSON	EDN	CLJ
list	NO :x:	`(a b c)`	`(a b c)`
vector	`[a, b, c]`	`[a b c]`	`[a b c]`
set	NO :x:	`#{a b c}` items are unique	`#{a b c}` items are unique
map	`{string1 : val1, string2 : val2]`	`{key1 val1 key2 val2}` keys are unique	`{key1 val1 key2 val2}` keys are unique

Special

x	JSON	EDN	CLJ
comments	NO :x:	`;` till the end of the line	`;` till the end of the line
discard	NO :x:	`#_` discards next read object	`#_` discards next read object
tagged literal	NO :x:	`#` followed immediately by a symbol starting with an alphabetic character	`#` followed immediately by a symbol starting with an alphabetic character
builtin tags	n/a	`#inst` `#uuid`	`#inst` `#uuid`, deftypes, defrecords and java classes constructors
regular expressions	NO :x:	NO :x:	`#"pattern"`
macros	NO :x:	NO :x:	`'` (quote), `@` (deref), `^` (metadata), `#'` (var quote), `#(% %n %&)` (anonymous function), ` (syntax quote), `~` (unquote), `~@` (unquote splicing). (:warning: undocumented macros `#=` `#!` `#<` and deprecated `#^`)