Documents

The example parses the people document in your selected format. It then reads Ada's age through the document nodes. Typed reads give you these values without serializing the document.

Example

Read Ada's age

people_text holds this document:

edn

287 B

{:#_ada {:name "Ada"
         :role "engineer"
         :age  36}
 :#_bob {:name   "Bob"
         :role   "engineer"
         :age    41
         :mentor {:#link "#_ada"}}
 :#_cy  {:name "Cy"
         :role "designer"
         :age  29}
 :#_tx  {:author "smoke"
         :reason "seed"}}

odin

279 B

people := stardust.parse(people_text, .EDN) or_return
defer stardust.close(&people)

root := stardust.root(people) or_return
ada := stardust.member(people, root, "#_ada") or_return
age := stardust.member(people, ada, "age") or_return
result := stardust.i64(people, age) or_return

Result / 11 B

{:value 36}

Numbers

A document number is an i64 integer or a finite f64 value. The number type defines both.

An integer read requires an integer node. A floating-point node can cause the read to fail.
Choose the typed read that matches the node that you read.

Operations

Operation	Returns	Summary
parse	document	parse(text, format) returns an owned document.
root	node	document.root() returns the root node ID.
count	count	document.count() returns the number of nodes.
read	node_view	document.read(id) returns a node view: kind, boolean, parent, position, first_child, next_sibling, key and text.
read_many	node_views	document.read_many(start, capacity) reads consecutive node views.
member	node	document.member(id, key) returns the first matching object member ID.
child_iterator	node_views	document.children(id) iterates the node views of a node's children in order.
members	Unavailable	document.members(id) iterates the members of an object node in order, each with its key.
i64	integer	Read an exact signed integer.
f64	real	Read a finite floating-point number.
close	none	Release the document handle.

parse

odin

114 B

parse :: proc(
	text: string,
	format: Source_Format,
	allocator := context.allocator,
) -> (
	Document,
	Error,
)

Parameters

Parameter	Type	Ownership	Default	Meaning
`text`	`string`	Value	Required	Encoded input bytes in the selected format. TRON is binary.
`format`	`Source_Format`	Value	Required	The codec to use for this operation.
`allocator`	`mem.Allocator`	Value	context.allocator	Allocator for copied return values and diagnostics. The caller releases them with the same allocator.

Errors

Status	When
`.Invalid_JSON`	JSON text is malformed
`.Invalid_Argument`	the text is malformed, the format is unknown or a number is outside `i64` or finite `f64`
`.Out_Of_Memory`	native memory is exhausted

Examples

Parse the shared DUST expression fixture

expression_text holds these bytes:

text

278 B

// One expression built once and evaluated against several inputs. The
// evaluate examples load this file, build `expression`, evaluate it with each
// of `inputs` in order and compare each result with `expected`.
expression [+ ?x 1]
inputs     [{x 1} {x 41}]
expected   [2 42]

odin

88 B

result := stardust.parse(expression_text, .DUST) or_return
defer stardust.close(&result)

Result / 330 B

{:value {:$comment   "One expression built once and evaluated against several inputs. The\nevaluate examples load this file, build `expression`, evaluate it with each\nof `inputs` in order and compare each result with `expected`."
         :expression ["+" ?x 1]
         :inputs     [{:x 1} {:x 41}]
         :expected   [2 42]}}

Report a malformed byte at offset zero

malformed holds these bytes:

text

1 B

odin

110 B

failed, result := stardust.parse(malformed, .DUST)
defer stardust.close(&failed)
defer stardust.close(&result)

Result / 204 B

{:value {:code    "invalid_dust"
         :message "Invalid_Syntax at offset 0"
         :path    nil
         :field   nil
         :entity  nil
         :offset  0
         :status  "invalid_argument"}}

Report malformed DUST

malformed holds these bytes:

text

1 B

odin

110 B

failed, result := stardust.parse(malformed, .DUST)
defer stardust.close(&failed)
defer stardust.close(&result)

Result / 204 B

{:value {:code    "invalid_dust"
         :message "Unexpected_End at offset 2"
         :path    nil
         :field   nil
         :entity  nil
         :offset  2
         :status  "invalid_argument"}}

C exports: stardust_parse, stardust_document_error

Status	When
`.Closed`	the document is closed

Status	When
`.Closed`	the document is closed

read

odin

63 B

read :: proc(document: Document, id: u32) -> (Node_View, Error)

Parameters

Parameter	Type	Ownership	Default	Meaning
`document`	`Document`	Borrowed for the call	Required	The document owner for this operation. Keep it alive during the call.
`id`	`u32`	Value	Required	A node ID within the receiver document.

Errors

Status	When
`.Invalid_Argument`	id is not a node of the document
`.Closed`	the document is closed

Notes

Text contains string values. Read numbers with i64 or f64.

Examples

document/read

input_text holds this document:

edn

7 B

{:x 41}

odin

171 B

source := stardust.parse(input_text, .EDN) or_return
defer stardust.close(&source)

root := stardust.root(source) or_return
result := stardust.read(source, root) or_return

Result / 218 B

{:value {:kind         "object"
         :boolean      false
         :parent       nil
         :position     0
         :first_child  1
         :next_sibling nil
         :key          ""
         :text         ""}}

C exports: stardust_document_read_many

read_many

odin

86 B

read_many :: proc(document: Document, start: u32, output: []Node_View) -> (int, Error)

Parameters

Parameter	Type	Ownership	Default	Meaning
`document`	`Document`	Borrowed for the call	Required	The document owner for this operation. Keep it alive during the call.
`start`	`u32`	Value	Required	The first node ID of the consecutive read.
`output`	`[]Node_View`	Value	Required	The maximum number of node views to read. For output slices, the call uses the caller's slice length.

Errors

Status	When
`.Invalid_Argument`	start is past the last node or capacity is negative
`.Closed`	the document is closed

Examples

document/read_many

input_text holds this document:

edn

7 B

{:x 41}

odin

228 B

source := stardust.parse(input_text, .EDN) or_return
defer stardust.close(&source)

root := stardust.root(source) or_return
views: [1]stardust.Node_View
_ = stardust.read_many(source, root, views[:]) or_return
result := views[0]

Result / 218 B

{:value {:kind         "object"
         :boolean      false
         :parent       nil
         :position     0
         :first_child  1
         :next_sibling nil
         :key          ""
         :text         ""}}

C exports: stardust_document_read_many

Status	When
`.Not_Found`	the object has no member with the key
`.Invalid_Argument`	id is not an object node of the document
`.Closed`	the document is closed

child_iterator

odin

64 B

child_iterator :: proc(doc: Document, id: u32) -> Child_Iterator

Parameters

Parameter	Type	Ownership	Default	Meaning
`doc`	`Document`	Borrowed for the call	Required	The document owner for this operation. Keep it alive during the call.
`id`	`u32`	Value	Required	A node ID within the receiver document.

Errors

Status	When
`.Invalid_Argument`	id is not a node of the document
`.Closed`	the document is closed

Notes

Keep the document open during iteration. A scalar has no children. A read failure is reported once and ends iteration.

Examples

Iterate the children of a node

seed_text holds this document:

edn

287 B

{:#_ada {:name "Ada"
         :role "engineer"
         :age  36}
 :#_bob {:name   "Bob"
         :role   "engineer"
         :age    41
         :mentor {:#link "#_ada"}}
 :#_cy  {:name "Cy"
         :role "designer"
         :age  29}
 :#_tx  {:author "smoke"
         :reason "seed"}}

odin

290 B

seed := stardust.parse(seed_text, .EDN) or_return
defer stardust.close(&seed)

root := stardust.root(seed) or_return
it := stardust.child_iterator(seed, root)
result: i64 = 0
for view in stardust.iterate_children(&it) {
	if len(view.key) > 0 {result += 1}
}
if it.err != nil {return it.err}

Result / 10 B

{:value 4}

C exports: stardust_document_read_many

members

child_iterator views carry each member key. Odin has no separate members iterator.

C exports: stardust_document_read_many

Status	When
`.Invalid_Argument`	the node is not an integer number
`.Closed`	the document is closed

Status	When
`.Invalid_Argument`	the node is not a number or its value overflows `f64`
`.Closed`	the document is closed

Parameter	Type	Ownership	Default	Meaning
`document`	`^Document`	Consumed owner	Required	The document owner to release. Do not use it after this call.

node_view

This record contains the result of read and read_many. The key and text fields borrow the document until it closes.

Field	Type	Unit	Absent	Meaning
`kind`	`Value_Kind`	None	—	—
`boolean`	`bool`	None	—	True only for true.
`parent`	`u32`	None	NO_NODE	—
`position`	`u32`	Count	—	Index within the parent container.
`first_child`	`u32`	None	NO_NODE	—
`next_sibling`	`u32`	None	NO_NODE	—
`key`	`string`	None	—	Member key of an object member, else empty.
`text`	`string`	None	—	Value of a string, else empty. It can contain NUL.

This record supplies a node for add and add_many. The number field holds a typed i64 or f64 value. Go uses I64/F64, Rust and Odin use Number, Clojure uses long or double, and Python uses int or float. This value sets the ABI number kind and the integer or real field.

Field	Type	Absent	Meaning
`parent`	`u32`	NO_NODE	—
`kind`	`Value_Kind`	—	—
`boolean`	`bool`	—	Value of a boolean node.
`number`	`Number`	nil	Value of a number node.
`key`	`string`	—	Member key when the parent is an object.
`text`	`string`	—	Value of a string node.