SML Specification

Simple Object

Hierarchical data structure
Two types of nodes: Elements and attributes
One root element
Elements: Can contain child nodes
Attributes: Contain the actual data

Element = Named group of child elements and attributes
Attribute = Named array of string values
Attribute must contain at least one value

String values can be empty or null

Child nodes: are ordered and can have identical names

Elements can be empty

Naming Conventions

Any Unicode character allowed
No restrictions, except for null value

Names are case-insensitive

Example

Simple message example:

The Simple Markup Language

SML is a textual representation of a simple object.

Empty root element:

MyRootElement
End

Case-insensitive:

MyRootElement
End

myrootelement
end

MYROOTELEMENT
END

Root element with one attribute:

MyRootElement
  MyFirstAttribute 123
End

Attribute with multiple values → whitespace-separated:

MyRootElement
  MyFirstAttribute 123
  MySecondAttribute 10 20 30 40 50
End

Attribute values are always strings:

MyRootElement
  MyFirstAttribute "123"
  MySecondAttribute "10" "20" "30" "40" "50"
End

Value with whitespace or special characters → in double quotes:

MyRootElement
  MyFirstAttribute 123
  MySecondAttribute 10 20 30 40 50
  MyThirdAttribute "Hello world"
End

Group with elements:

MyRootElement
  Group1  
    MyFirstAttribute 123
    MySecondAttribute 10 20 30 40 50
  End
  MyThirdAttribute "Hello world"
End

Indentation-insensitive:

MyRootElement
Group1  
MyFirstAttribute 123
MySecondAttribute 10 20 30 40 50
End
MyThirdAttribute "Hello world"
End

Comments:

# My first SML document
MyRootElement
  #Group1
  #  MyFirstAttribute 123
  #  MySecondAttribute 10 20 30 40 50
  #End
  MyThirdAttribute "Hello world"   # Comment
End

Double-quote in value:

MyRootElement
  MyFirstAttribute "Hello ""world""!"
  MySecondAttribute c:\Temp\Readme.txt
End

Hash character in value:

MyRootElement
  MyFirstAttribute "# This is not a comment"
End

Null value and empty string:

MyRootElement
  MyFirstAttribute "-"
  MySecondAttribute -
  MyThirdAttribute ""
  MyFourthAttribute My-Value-123
End

Multi-line string:

MyRootElement
  MyFirstAttribute "Line1"/"Line2"/"Line3"
End

Attributes and elements with identical names:

MyRootElement
  MyFirstAttribute 123
  MyFirstAttribute 3456
  MyFirstAttribute 67
  Element1
  End
  Element1
  End
End

Recent files example:

RecentFiles
  File c:\Temp\Readme.txt
  File "c:\My Files\Todo.txt"
  File c:\Games\Racer\Config.sml
  File d:\Untitled.txt
End

Localized end keyword:

契約
　　個人情報
　　　　名字　田中
　　　　名前　蓮
　　エンド
　　日付　２０２１－０１－０２
エンド

Vertragsdaten
  Personendaten
    Nachname Meier
    Vorname Hans
  Ende
  Datum 2021-01-02
Ende

Special characters in element and attribute names:

"My Root Element"
  "My First Attribute" 123
End

Whitespace-Separated Values

An SML document is actually a WSV document.

It plays nicely together especially if you need tabular data embedded inside of an SML document.

Table-like notation (embedded table with at least 2 columns and the first column not allowing null values):

Actors
  Name          Age  PlaceOfBirth  FavoriteColor  JobTitle
  "John Smith"  33   Vancouver     -
  "Mary Smith"  27   Toronto       Green          Lawyer
End

End Keyword

An attribute can have the same name as the end keyword. An element on the other hand cannot have the same name as the end keyword.

Root
  End 12 13
End

The null value is allowed for end keywords. For elements and attributes it is not. So there will never be a naming collision with the null end keyword.

Root
-

Minification

For minification the end keyword is replaced with the null end keyword and unnecessary whitespace and comments are removed:

# My SML document
MyRootElement
  Group1  
    MyFirstAttribute  123
    MySecondAttribute 10 20  30 40  50 60
  End
  
  MyThirdAttribute "Hello world"
  #MyForthAttribute Test
End
# End of document

Is minified to:

MyRootElement
Group1  
MyFirstAttribute 123
MySecondAttribute 10 20 30 40 50 60
-
MyThirdAttribute "Hello world"
-

Text Encoding

An SML file is a ReliableTXT file. Therefore one of the following encodings must be used:

UTF-8
UTF-16 (Big Endian)
UTF-16 Reversed (Little Endian)
UTF-32 (Big Endian)

All 4 encodings must write a preamble (BOM) indicating the used encoding.

Lines are separated using the line-feed character (LF / 0x0A / U+000A).

Because SML files are ReliableTXT files, there is no need to define the encoding on content level as formats like XML or HTML do:

Errors

WSV Parser Errors

String not closed (2, 30):

Root
  FirstAttribute "hello world
End

Invalid double quote after value (2, 20):

Root
  FirstAttribute ab"c
End

Invalid character after string (2, 31):

Root
  FirstAttribute "hello world"a b c
End

Invalid string line break (2, 26):

Root
  FirstAttribute "Line1"/ "Line2"
End

SML Parser Errors

End keyword could not be detected (2):

# Only
# Comments

Invalid root element start (1):

Root abc
End

Null value as element name is not allowed (1):

-
End

Null value as element name is not allowed (2):

Root
  -
  End
End

Null value as attribute name is not allowed (2):

Root
  - 123
End

Element "Root" not closed (3):

Root
  Element
  End

Only one root element allowed (3):

Root
End
Root2
End

Serialization Errors

When you serialize a simple object using the Simple Markup Language, the implementation must check, that an element's name does not match the end keyword. Otherwise an invalid SML document would be generated.

End
End

Touch Typing Friendliness

SML was designed so that you can type it easily and fast. It only uses four special characters:

Because of the case insensitivity you can type element and attribute names all in lower-case which speeds up typing as you don't have to press the shift key.

< Prev

Next >