nxml 1.2.0

A parser for NXML (NXML is not XML!)
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# 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.