caml-spec

CAML attributes are block-level constructs. They are not parsed inside other markdown constructs:

• Inline code: `:attrtype::value` renders as a code span.
• Fenced code blocks: CAML inside triple backticks is treated as literal text.
• Indented code blocks: lines indented 4+ spaces are not parsed as CAML.
• Blockquotes: CAML inside > blockquotes is not parsed as an attribute.
• List items: CAML inside - list items is not parsed as an attribute.

CAML attrs are meant to be compatible with wikiattrs.

Single

All of the following examples should generate the same html:

:attrtype::a-string

Some more text.

Some more text.

:attrtype::a-string

(Optional colon prefixes)

attrtype::a-string

Some more text.

Resulting HTML:

<aside class="attrbox">
  <span class="attrbox-title">Attributes</span>
    <dl>
      <dt>attrtype</dt>
        <dd>a-string</dd>
    </dl>
</aside>
<p>Some more text.</p>

List

Lists are also supported. All of the following examples should generate the same html:

Comma-separated lists.

:attrtype::string-a, string-b, string-c

Markdown-style bullet lists.

Dashes.

:attrtype::
- string-a
- string-b
- string-c

Pluses.

:attrtype::
+ string-a
+ string-b
+ string-c

Asterisks.

:attrtype::
* string-a
* string-b
* string-c

Mixed.

:attrtype::
- string-a
+ string-b
* string-c

Optional colon prefix.

attrtype::
- string-a
- string-b
- string-c

Flexible whitespace (see note below).

: attrtype ::
              - string-a
              - string-b
              - string-c

Resulting HTML:

<aside class="attrbox">
  <span class="attrbox-title">Attributes</span>
    <dl>
      <dt>attrtype</dt>
        <dd>string-a</dd>
        <dd>string-b</dd>
        <dd>string-c</dd>
        <!-- etc. -->
    </dl>
</aside>

Note on Flexible Whitespace:

The purpose of flexible whitespacing is for pretty-printing for better legibility:

: type             :: string-a
: med-type         :: 
                      - string-b
                      - string-c
: longer-type-text :: 
                      - string-d
                      - string-e
                      - string-f

Optional whitespace is defined as follows:

• Attrtype text may be prefixed (between first colon : and attrtype text) or suffixed (between attrtype text and double colon ::) by one space.
• List item prefix whitespace (space before the bullet -*+) can have any number of spaces.

Types

CAML supports different value types, similar to YAML:

: null-type    :: 
                 - null
                 - NULL
: boolean-type :: 
                 - true
                 - True
: int-type     :: 
                 - -12                          // negative
                 - 0                            // zero
                 - 12                           // positive
                 - 0x4                          // hexadecimal
                 - 0o4                          // octal
: float-type   :: 
                 - -4.20                        // negative
                 - 0                            // zero
                 - +4.20                        // positive
                 - 2.3e4                        // expo
                 - .inf                         // infinity
                 - .nan                         // not a number
: string-type  :: 
                 - string-no-whitespace
                 - string with whitespace
                 - 'string with single quotes'
                 - "string with double quotes"
: time-type    :: 
                 - 2001-12-15T02:59:43.1Z       // canonical
                 - 2001-12-14t21:59:43.10-05:00 // iso8601
                 - 2001-12-14 21:59:43.10 -5    // spaced
                 - 2002-12-14                   // date

Types can be mixed, also similarly to YAML:

: attrtype :: null, False, 0, nothing, 2002-12-14, [[wikilink]]

Multi-Line Strings

Multi-line strings follow the YAML block scalar spec (see also yaml-multiline.info). They start with a style indicator and terminate when a line with indentation of 0 is detected.

Style indicators determine how newlines within the block are handled:

• > folded: replaces newlines with spaces
• | literal: preserves newlines

An optional chomping indicator controls trailing newlines:

• (default) clip: adds a single trailing newline
• - strip: removes all trailing newlines
• + keep: preserves all trailing newlines

This gives six combinations: >, >-, >+, |, |-, |+.

Folded (>). Newlines become spaces, one trailing newline added (clip).

: attrtype :: >
              This is a long string
              that spans multiple
              lines.

Resulting JSON:

{
  "attrtype": "This is a long string that spans multiple lines.\n"
}

Literal (|). Newlines preserved, one trailing newline added (clip).

: attrtype :: |
              This is a long string
              that spans multiple
              lines.

Resulting JSON:

{
  "attrtype": "This is a long string\nthat spans multiple\nlines.\n"
}

Folded strip (>-). Newlines become spaces, no trailing newline.

: attrtype :: >-
              This is a long string
              that spans multiple
              lines.

Resulting JSON:

{
  "attrtype": "This is a long string that spans multiple lines."
}

Literal strip (|-). Newlines preserved, no trailing newline.

: attrtype :: |-
              line one
              line two

Resulting JSON:

{
  "attrtype": "line one\nline two"
}

Literal keep (|+). Newlines preserved, all trailing newlines preserved.

: attrtype :: |+
              line one
              line two

Resulting JSON:

{
  "attrtype": "line one\nline two\n\n"
}

Folded keep (>+). Newlines become spaces, all trailing newlines preserved.

: attrtype :: >+
              line one
              line two

Resulting JSON:

{
  "attrtype": "line one line two\n\n"
}

Note on Edge Cases:

Multi-paragraph (blank line within block). Folded mode produces a double space; literal mode preserves the blank line.

: attrtype :: >
              line one

              line two

Resulting JSON:

{
  "attrtype": "line one  line two\n"
}

Nested indentation. Literal mode preserves relative indentation.

: attrtype :: |
              line one
                indented
              line two

Resulting JSON:

{
  "attrtype": "line one\n  indented\nline two\n"
}

Empty block. Clip mode produces a single newline.

: attrtype :: >

Resulting JSON:

{
  "attrtype": "\n"
}

Note on HTML Rendering:

Newlines in multi-line values are rendered as <br> elements in the attrbox HTML:

Resulting HTML:

<aside class="attrbox">
  <span class="attrbox-title">Attributes</span>
    <dl>
      <dt>attrtype</dt>
        <dd><span class="attr string attrtype">line one<br>line two<br></span></dd>
    </dl>
</aside>

Multi-line strings can also appear in lists:

:attrtype::first, |
  line one
  line two

:attrtype::
- first
- |
  line one
  line two