tyon

Description:

tyon

TYON #
This is a parser for Tyon documents written in Dart 3. Currently, this package is just a parser, a.k.a. decoder, and not an encoder. For compatibility with JSON, the tyonDecode function returns a Map<String, dynamic>, even if the specification seems to allow multiple identical keys and requires the keys to be ordered. Also, comments are obviously lost when parsing a document. All values are strings, lists or maps.
Usage #
print(tyonDecode('''
; This is a TYON document

title = "TYON Example" ; files are implicitly maps

list = [1 2 3]

map = (
first = John
last = Doe
age = 42
"favorite numbers" = [13 42]
)

; strings can contain any character except ", which is escaped as ""
string = "hello, this is a string
with some ""quoted text"" and
multiple lines"

; a type declaration specifies the keys for the type
/person = (first last age)

; a typed map matches the type keys to values in order
owner = /person (Mary Sue 36) ; first = Mary, last = Sue, age = 36

; a value of _ in a typed map means there is no corresponding value
employee = /person (Other _ 25) ; first = Other, age = 25

; lists can also be typed, with the type applying to the children
typed-list = /person [
(John Doe 42)
(Mary Sue 36)
]

; types can be declared inline
points = /(x y z) [
(1 2 3)
(4 5 6)
(7 8 9)
]

; types can be overridden
people = /person [
(John Doe 42)
/(x y) (1 2) ; type overridden by the inline type
/_ ( ; type overridden to be untyped
a = 1
b = 2
c = 3
)
]
'''));
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Grammar #
I derived this EBNF grammar from the specification:
tyon = { typeDecl | keyValuePair }
typeDecl = '/' Literal '=' keys
keys = '(' { key } ')'
key = Literal | String
keyValuePair = key '=' value
value = Literal | String | list | map | typedValue
list = '[' { value } ']'
map = '(' { keyValuePair } ')'
typedValue = inlineType (listValues | mapValues)
inlineType = "/" (Literal | keys)
listValues = '[' { listValue } ']'
listValue = listValues | typedValue | untypedValue | mapValues
untypedValue = "/" "_" (list | map)
mapValues = "(" { value } ")"
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A Literal is a sequence of non-whitespace characters that doesn't include ()[]=;" and that doesn't start with a /. A String is enclosed in " and may include any unicode character but ". If you want to include a ", use "".
The number of values in mapValues must match the number of keys from its type.

License

For personal and professional use. You cannot resell or redistribute these repositories in their original state.

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