slon is Simple Lightweight Object Notation. Like json, but with less punctuation and some smart features.
// slon example
{
name Shakespeare
first_name William
about """
William Shakespeare was an English poet, playwright, and actor,
widely regarded as the greatest writer in the English language
and the world's greatest dramatist (Wikipedia)
"""
books [
{ title Hamlet price 12.34 onSale true }
{ title Macbeth price 42.99 onSale false }
/* sold out
{ title "The Comedy of Errors" price 34.11 onSale no }
*/
]
locations {
Africa.Egypt.Alexandria Antony
Europe.Greece.Athens Timon
Europe.Italy.Venice Othello
Europe.Italy.Verona Romeo
}
readers [Alice Bob Carol]
}
{
"name": "Shakespeare",
"first_name": "William",
"about": "William Shakespeare was an English poet, playwright, and actor,\nwidely regarded as the greatest writer in the English language\nand the world's greatest dramatist (Wikipedia)",
"books": [
{
"title": "Hamlet",
"price": 12.34,
"onSale": true
},
{
"title": "Macbeth",
"price": 42.99,
"onSale": false
}
],
"locations": {
"Africa": {
"Egypt": {
"Alexandria": "Antony"
}
},
"Europe": {
"Greece": {
"Athens": "Timon"
},
"Italy": {
"Venice": "Othello",
"Verona": "Romeo"
}
}
},
"readers": [
"Alice",
"Bob",
"Carol"
]
}
slon is a superset of json, that is, every valid json is also valid slon. Indentation is ignored, except within multiline strings. Array and object delimiters (commas/colons) are optional, object keys don't have to be quoted.
slon supports line comments with # or // and C-style comment blocks /* ... */
# sample data
/*
@author: me
@date: today
*/
{
name Shakespeare // author's name
year 1564 // year of birth
books [Hamlet Macbeth Othello]
Alice: true,
Bob: true,
Carol: true,
}
{
"name": "Shakespeare",
"year": 1564,
"books": [
"Hamlet",
"Macbeth",
"Othello"
],
"Alice": true,
"Bob": true,
"Carol": true
}
Out of the box, slon can encode nulls, numbers, booleans, strings, arrays and objects.
A null value is null or none, case-insensitive:
[ null NULL None none ]
[
null,
null,
null,
null
]
slon supports decimal, hexadecimal, octal and binary integers and decimal floats in the standard notation. Unlike json, leading zeroes are allowed. A number can be preceded by a - or +. Underscores can be used to delimit long numbers.
[
123
123_456_789
+045.990
-12.3e4
0xcafe
0o755
0b1110011
]
[
123,
123456789,
45.99,
-123000.0,
51966,
493,
115
]
Boolean literals are true, on, yes for "true", false, off, no for "false", case-insensitive.
{
select true
update YES
insert ON
delete no
create Off
}
{
"select": true,
"update": true,
"insert": true,
"delete": false,
"create": false
}
Plain strings are enclosed in single or double quotes and cannot contain a literal newline.
Single quoted strings are verbatim, that is, every symbol is interpreted exactly as written.
'Hamlet \xa9 William, 1599. \n bravo \U0001F44F \u{1f44f}'
"Hamlet \\xa9 William, 1599. \\n bravo \\U0001F44F \\u{1f44f}"
Double quoted strings interpret these escape sequences:
\n \r \t \b \f \\ \" \' \/ \\ \0
and unicode escapes in these formats:
\x12 \u1234 \u{12345} \U00012345
"Hamlet \xa9 William, 1599. \n bravo \U0001F44F \u{1f44f}"
"Hamlet © William, 1599. \n bravo 👏 👏"
slon decodes valid unicode surrogate pairs into plane 1 characters:
"smile \ud83d\ude03"
"smile 😃"
slon doesn't allow unicode escapes greater than \u{10FFFF}, but otherwise makes no attempt to validate unicode. Particularly, invalid surrogate pairs and non-characters are left as is.
Strings enclosed in triple quotes (''' or """) or backticks can span across multiple lines.
If a character right after opening quotes is a space or a newline, newlines in the string are preserved, and the string is dedented to its minimal indent:
"""
Scene I.
BERNARDO
Who's there?
FRANCISCO
Nay, answer me: stand, and unfold yourself.
"""
" Scene I.\n\nBERNARDO\n Who's there?\nFRANCISCO\n Nay, answer me: stand, and unfold yourself."
Otherwise, the string is "compressed", so that all whitespace sequences are reduced to a single space character:
"""You are welcome, masters;
welcome, all.
I am glad
to see thee well.
"""
"You are welcome, masters; welcome, all. I am glad to see thee well."
''' strings are verbatim, """ and backtick strings interpret the escape sequences. Note that escaped spaces or newlines are preserved when the string is dedented or compressed:
`Enter a King\n
and a Queen very lovingly;\n
the Queen embracing him,\n
and he her.`
"Enter a King\n and a Queen very lovingly;\n the Queen embracing him,\n and he her."
Any sequence of symbols except whitespaces, punctuation and numeric/bool literals is considered a string, so you can write "simple" strings without any quotes at all:
[
Hamlet
claudius@elsinore.castle
$123.45
]
[
"Hamlet",
"claudius@elsinore.castle",
"$123.45"
]
An array (aka list) is a sequence of values separated by commas or whitespaces, enclosed in [...]:
[
Shakespeare
William
"The Tragedy of Hamlet"
[
2017,
2018,
2019,
]
]
[
"Shakespeare",
"William",
"The Tragedy of Hamlet",
[
2017,
2018,
2019
]
]
An object (aka struct, dict) is a sequence of key-value pairs, separated by commas or whitespaces and enclosed in {...}. Keys and values are separated by colons or equal signs or whitespaces. Keys can be strings, integers or booleans:
{
author
Shakespeare
year
1599
"full title": 'The Tragedy of Hamlet'
seasons {
2017 = yes
2018 = no
2019 = yes
}
}
{
"author": "Shakespeare",
"year": 1599,
"full title": "The Tragedy of Hamlet",
"seasons": {
"2017": true,
"2018": false,
"2019": true
}
}
An object key which is a non-quoted ("bare") string can contain dots, in which case slon treats it as a structured ("nested") key and resolves intermediate objects or arrays, creating them on the fly if needed:
{
title.short Hamlet
price { normal 12.34 }
price.sale
5.67
price.special.christmas
8.99
readers.0.name Alice
readers.1.name Bob
readers.2.name Carol
}
{
"title": {
"short": "Hamlet"
},
"price": {
"normal": 12.34,
"sale": 5.67,
"special": {
"christmas": 8.99
}
},
"readers": [
{
"name": "Alice"
},
{
"name": "Bob"
},
{
"name": "Carol"
}
]
}
A + after a key means "append to that array":
{
author Shakespeare
title Hamlet
readers+ { name Alice }
readers+ { name Bob }
readers+ { name Carol }
}
{
"author": "Shakespeare",
"title": "Hamlet",
"readers": [
{
"name": "Alice"
},
{
"name": "Bob"
},
{
"name": "Carol"
}
]
}
If you need a literal dot in a key, quote it:
{
"com.sun.java" installed
}
{
"com.sun.java": "installed"
}
A "bare" string immediately followed by an opening parenthesis ( is treated as a function name ("hook"). A hook function receives one of the basic values and can return whatever you see fit. slon parser accepts the hooks argument, which is an object or a dict containing hook functions (or methods).
You can use hooks to add support for library types like dates or binary strings. For example, this slon file:
// test.slon
{
title
Hamlet
created
date('1599-02-20')
image
bin("\x89PNG\r\n\x1a\n\0\0\0...")
}
can be decoded with this code:
from datetime import date
from functools import partial
hooks = {
'date': date.fromisoformat,
'bin': partial(bytes, encoding='latin1'),
}
with open('test.slon') as fp:
result = slon.loads(fp.read(), hooks=hooks)
print(result) ## {'title': 'Hamlet', 'created': datetime.date(1599, 2, 20), 'image': b'\x89PNG\r\n\x1a\n\x00\x00\x00...'}
pip install slon
The slon module provides a single function:
slon.loads(text: str, as_object=False, as_array=False, hooks=None) -> Any
-
textis a string (str) which contains encodedslon. Note thatbytesinputs are not supported -
as_objectparsestextas an object, that is, puts implicit{...}around it, unlesstextalready starts with a{ -
as_arrayparsestextas an array -
hooksis a hooks dict or object
Examples:
text = """
author Shakespeare
title Hamlet
"""
val = slon.loads(text, as_object=True)
print(val) # {'author': 'Shakespeare', 'title': 'Hamlet'}
text = """
100
200
300
"""
val = slon.loads(text, as_array=True)
print(val) # [100, 200, 300]
npm install slonjs
The slon module provides a single function:
slon.parse(text: string, options: object) -> any
Options are asObject, asArray and hooks, with the same meaning as in python.
let slon = require('slon');
text = `
author Shakespeare
title Hamlet
`
val = slon.parse(text, {asObject: true})
console.log(val) // {author: 'Shakespeare', title: 'Hamlet'}
For browsers, grab index.js and use window.SLON.parse().
(c) 2019 Georg Barikin (https://github.com/gebrkn). MIT license.