NXML

NXML is a markup language that is not XML. It was based on XML, but went in a very different direction and now does not resemble XML at all.

Syntax explanation

• A node is either a text (hello) or a sequence ([I|am|a|sequence])
• Brackets ([ and ]) surround the sequence
• Nodes can go one after another without any explicit delimiters (text[sequence][sequence]text)
• A vertical bar (|) denotes the end of a text node (otherwise text nodes end at the end of input or at a sequence boundary (a bracket)). This can be used to place text nodes one after another or to create an empty text node
• Every special character (|, [, ] or \) can be escaped with a backslash (\)

Syntax grammar (in pseudo-Backus-Naur Form; may be invalid)

special_character ::= "[" | "]" | "|" | "\\"
text_character ::= !special_character | "\\\\" | "\\[" | "\\]" | "\\|"
text ::= text text_character | text_character | text "|" | "|"
sequence_of_nodes ::= sequence_of_nodes node | node
node ::= text | "[" + sequence_of_nodes + "]" | "[]"

Syntax example

[to-do list|
    [buy some groceries|[
        lettuce |
        cucumber |
        ketchup
    ]]
    [finish NXML|[
        add syntax explanation to the README |
        update syntax examples |
        rewrite the parser
    ]]
    [do the homework]
]


[user|
    [id|123]
    [name|Paul]
    [surname|Brown]
    [profession|Architect]
    [friend ids|[234|345|456]]
]


[
    [message|
        [from|Alice]
        [to|Bob]
        [contents|Hello!]
    ]
    [message|
        [from|Bob]
        [to|Alice]
        [contents|Hi!]
    ]
]


[ARTICLE|
    [TITLE|Cookies are good]
    [CONTENTS|
        [PARAGRAPH|
            [OUTER REFERENCE|[URL|https://en.wikipedia.org/wiki/Cookie][TEXT|Cookies]] are good!
        ]
    ]
]


you can use the sequential parser to parse bare sequential nodes |
something |
something


an empty text node! -> || <- here it is!
another one, this time inside a sequence: [|] (it is between the opening bracket and the vertical bar)

Things to consider when using this library

• This library does not trim the whitespaces at the end or the beginning of text nodes for better flexibility. It is the user's responsibility to trim the excessive whitespaces.