Core syntax

The CX surface syntax — the data / document layer specified in lexicon.ebnf, grammar.ebnf, and code.md §3 / cxdm.md. Elements, attributes, scalars and type annotations, atoms, anchors / merges / ids, comments, raw and block content, entity references, namespaces, and table literals. Each example shows a source snippet and its cx fmt canonical render, pinned verbatim to the data conformance corpora.

element

[name attr=val CHILD…] — An element: a bracketed head name followed by optional attributes and a body of text, scalars, or nested elements.

Kind · structure

            [input type=text name=q]
          
            [input type=text name=q]

nested-elements

[parent [child …] …] — Elements nest as body children; whitespace between children is non-semantic and is normalised on render.

Kind · structure

            [config
  [db host=localhost port=5432]
  [server port=8080]
]
          
            [config
  [db host=localhost port=5432]
  [server port=8080]
]

mixed-content

[name TEXT [child] TEXT] — Mixed content interleaves bare text and child elements in one body; bare text runs render quoted.

Kind · structure

            [p text [b bold] more]
          
            [p 'text ' [b bold] ' more']

attribute

name=value — A scalar attribute on an element; the value auto-types (int, bool, atom, string) unless quoted.

Kind · attribute

            [socket port=8080 protocol=:tcp]
          
            [socket port=8080 protocol=:tcp]

boolean-scalar

[name true] / [name false] — Bare `true`/`false` in body position auto-type to booleans; quote them to keep a string.

Kind · scalar

            [active true]
          
            [active true]

null-scalar

[name null] — Bare `null` in body position auto-types to the null value.

Kind · scalar

            [value null]
          
            [value null]

quoted-string

[name 'value'] — A quoted body value is kept verbatim as a string — auto-typing is suppressed.

Kind · scalar

            [status 'true']
          
            [status 'true']

type-annotation

name::Type — A glued `::T` type annotation pins a scalar to an explicit type, overriding auto-typing.

Kind · annotation

            [age::int 30]
          
            [age::int 30]

atom

:NAME — An atom literal: an interned, type-strict symbolic scalar that never equals a same-spelled string.

Kind · scalar

            [status :active]
          
            [status :active]

atom-collection

[:a, :b] / (:a, :b) / {k: :v} — Atoms are first-class scalars usable inside arrays, sequences, and map values.

Kind · scalar

            [transitions [:idle, :running, :complete]]
          
            [transitions [:idle, :running, :complete]]

anchor

&name — An anchor labels an element so it can be aliased or merged elsewhere in the document.

Kind · identity

            [defaults &def timeout=30 retries=3]
          
            [defaults &def timeout=30 retries=3]

merge

*name — A merge pulls an anchored element's attributes into the current element (later attributes win).

Kind · identity

            [defaults &def timeout=30 retries=3]
[production *def host=prod.example.com retries=5]
          
            [defaults &def timeout=30 retries=3]
[production *def host=prod.example.com retries=5]

id

#id — An ID declaration names an element for reference; `@id` refers back to it.

Kind · identity

            [user #u-1 name=alice]
          
            [user #u-1 name=alice]

id-reference

@id — An IDREF refers to a declared `#id`; forward references resolve.

Kind · identity

            [users
  [user #u-1 name=alice]
  [reviewer assigned-to=@u-1]
]
          
            [users
  [user #u-1 name=alice]
  [reviewer assigned-to=@u-1]
]

block-content

[| … |] — Block content: a verbatim text block delimited by `[|` and `|]`.

Kind · structure

            [p [|hello world|]]
          
            [p [|hello world|]]

comment

[; … ] — A block comment `[; … ]` is preserved by the lossless formatter and dropped by the strict canonical form.

Kind · comment

            [;a comment]
[p text]
          
            [;a comment]
[p text]

raw-text

[# … #] — Raw text / CDATA: content between `[#` and `#]` is taken literally (no parsing) — distinct from a comment.

Kind · structure

entity-reference

&name; / &#nnn; — Entity and character references in text: named XML entities and numeric character references are recognised.

Kind · scalar

            [p & < >]
          
            [p & < >]

namespace

xmlns:prefix=URI / prefix:name — XML namespaces: declare with `xmlns` / `xmlns:prefix` and qualify names as `prefix:local`.

Kind · namespace

            [doc xmlns:dc=http://purl.org/dc/elements/1.1/
  [dc:title Hello]
]
          
            [doc xmlns:dc=http://purl.org/dc/elements/1.1/
  [dc:title Hello]
]

table

[table[col::T …]] ROW… — A typed table literal: a column header (`[table[…]]`) followed by whitespace-separated cell rows.

Kind · table

            [users [table[name::string age::int active::bool]]
  alice 30 true
  bob 25 false
]
          
            [users [table[name::string age::int active::bool]]
  alice 30 true
  bob 25 false
]