ddn.data.json5¶

JSON5 parsing and serialization support for the D programming language.

Overview¶

This module provides comprehensive support for JSON5, a superset of JSON that aims to be easier for humans to write and maintain. It includes a full-featured parser and writer that maps JSON5 values to and from ddn.var.

JSON5 Features Supported:

Comments: // line and /* */ block comments
Trailing commas in arrays and objects
Unquoted keys when identifier-compatible
Single-quoted strings and escape sequences
Numbers with leading +, hex (0x...), leading/trailing decimal points
Special numbers: NaN, Infinity, -Infinity
UTF-8 BOM accepted at the beginning of input

Enums¶

`Json5Feature`¶

enum Json5Feature : uint

Feature switches for JSON5 support.

Member	Description
`COMMENTS`	Allow `//` and `/* */` comments
`TRAILING_COMMAS`	Allow trailing commas in arrays/objects
`UNQUOTED_KEYS`	Allow unquoted identifier keys
`SINGLE_QUOTED_STRINGS`	Allow `'single quoted'` strings
`HEX_NUMBERS`	Allow `0xDEADBEEF` notation
`LEADING_DECIMAL_POINT`	Allow `.5` as `0.5`
`TRAILING_DECIMAL_POINT`	Allow `5.` as `5.0`
`EXPLICIT_PLUS`	Allow `+1.5` notation
`SPECIAL_NUMBERS`	Allow `NaN`, `Infinity`, `-Infinity`
`LINE_CONTINUATION`	Allow backslash line continuation in strings

`Json5ErrorCode`¶

enum Json5ErrorCode : ushort

Error codes returned by the JSON5 parser.

Member	Description
`NONE`	No error
`UNEXPECTED_EOF`	Unexpected end of input
`UNEXPECTED_TOKEN`	Unexpected token encountered
`INVALID_NUMBER`	Invalid numeric literal
`INVALID_STRING`	Invalid string literal
`INVALID_ESCAPE`	Invalid escape sequence
`UNTERMINATED_STRING`	String not properly terminated
`UNTERMINATED_COMMENT`	Block comment not closed
`DUPLICATE_KEY`	Duplicate key in object
`MAX_DEPTH_EXCEEDED`	Nesting depth limit exceeded
`INVALID_UTF8`	Invalid UTF-8 encoding

`Json5QuoteStyle`¶

enum Json5QuoteStyle : ubyte

Quote style for string output.

Member	Description
`DOUBLE`	Use double quotes (`"`)
`SINGLE`	Use single quotes (`'`)
`AUTO`	Choose based on content (fewer escapes)

`Json5WriteMode`¶

enum Json5WriteMode : ubyte

Output format mode.

Member	Description
`JSON5`	JSON5 format (unquoted keys, single quotes, etc.)
`JSON`	Strict JSON format

`Json5FloatFormat`¶

enum Json5FloatFormat : ubyte

Floating-point number formatting options.

Member	Description
`DEFAULT`	Default formatting
`SCIENTIFIC`	Scientific notation
`FIXED`	Fixed-point notation

`Json5NegativeZeroStyle`¶

enum Json5NegativeZeroStyle : ubyte

How to handle negative zero (-0.0).

Member	Description
`PRESERVE`	Preserve `-0.0`
`POSITIVE`	Convert to `0.0`

`Json5StreamResult`¶

enum Json5StreamResult : ubyte

Result codes for streaming parser operations.

Member	Description
`OK`	Operation succeeded
`NEED_MORE`	More input needed
`ERROR`	Parse error occurred
`DONE`	Parsing complete

`Json5TokenKind`¶

enum Json5TokenKind : ushort

Token types produced by the lexer.

Member	Description
`EOF`	End of input
`LBRACE`	`{`
`RBRACE`	`}`
`LBRACKET`	`[`
`RBRACKET`	`]`
`COLON`	`:`
`COMMA`	`,`
`STRING`	String literal
`NUMBER`	Numeric literal
`TRUE`	`true`
`FALSE`	`false`
`NULL`	`null`
`IDENTIFIER`	Unquoted identifier
`NAN`	`NaN`
`INFINITY`	`Infinity`
`NEG_INFINITY`	`-Infinity`

`Json5PatchOpKind`¶

enum Json5PatchOpKind : ubyte

JSON Patch operation types.

Member	Description
`ADD`	Add a value
`REMOVE`	Remove a value
`REPLACE`	Replace a value
`MOVE`	Move a value
`COPY`	Copy a value
`TEST`	Test a value

Structs¶

`Json5Policy`¶

struct Json5Policy

Configuration for JSON5 parsing behavior.

Fields:

Name	Type	Description
`features`	`uint`	Bitmask of enabled `Json5Feature` flags
`maxDepth`	`uint`	Maximum nesting depth (default: 512)
`maxStringLength`	`size_t`	Maximum string length

`Json5Error`¶

struct Json5Error

Error information from parsing operations.

Fields:

Name	Type	Description
`code`	`Json5ErrorCode`	Error code
`message`	`string`	Human-readable error message
`line`	`size_t`	Line number (1-based)
`column`	`size_t`	Column number (1-based)

`Json5WriteOptions`¶

struct Json5WriteOptions

Configuration for JSON5 serialization.

Fields:

Name	Type	Description
`writeMode`	`Json5WriteMode`	Output format (`JSON5` or `JSON`)
`quoteStyle`	`Json5QuoteStyle`	String quote style
`pretty`	`bool`	Enable pretty-printing
`indentWidth`	`uint`	Spaces per indent level
`sortKeys`	`bool`	Sort object keys alphabetically
`trailingCommas`	`bool`	Add trailing commas (JSON5 only)
`maxDepth`	`uint`	Maximum serialization depth

`Json5WriteScratch`¶

struct Json5WriteScratch

Reusable scratch buffers for serialization to reduce allocations.

Usage:

Json5WriteScratch scratch;
foreach (item; items) {
    string json = toJSON5(item, Json5WriteOptions.init, scratch);
    // process json...
}

`Json5PatchOp`¶

struct Json5PatchOp

A single JSON Patch operation.

Fields:

Name	Type	Description
`op`	`Json5PatchOpKind`	Operation type
`path`	`string`	JSON Pointer path
`from`	`string`	Source path (for move/copy)
`value`	`var`	Value (for add/replace/test)

`Json5PatchError`¶

struct Json5PatchError

Error information from patch operations.

Fields:

Name	Type	Description
`message`	`string`	Error description
`opIndex`	`size_t`	Index of failed operation

`Json5Token`¶

struct Json5Token

A lexical token from JSON5 input.

Fields:

Name	Type	Description
`kind`	`Json5TokenKind`	Token type
`text`	`const(char)[]`	Token text
`line`	`size_t`	Line number
`column`	`size_t`	Column number

`Json5Lexer`¶

struct Json5Lexer

Low-level lexical analyzer for JSON5 input.

`Json5Parser`¶

struct Json5Parser

Low-level JSON5 parser.

`Json5StreamParser`¶

struct Json5StreamParser

Streaming JSON5 parser for incremental input processing.

`Json5SaxHandler`¶

struct Json5SaxHandler

SAX-style event handler for streaming JSON5 parsing.

Callback Fields:

Name	Type	Description
`onNull`	`bool delegate()`	Called for `null` values
`onBool`	`bool delegate(bool)`	Called for boolean values
`onNumber`	`bool delegate(var)`	Called for numeric values
`onString`	`bool delegate(string)`	Called for string values
`onStartArray`	`bool delegate()`	Called at array start
`onEndArray`	`bool delegate()`	Called at array end
`onStartObject`	`bool delegate()`	Called at object start
`onKey`	`bool delegate(string)`	Called for object keys
`onEndObject`	`bool delegate()`	Called at object end

Functions¶

`parseJSON5`¶

bool parseJSON5(out var value, const(char)[] input, out Json5Error err) @safe

Parses a JSON5 string into a var value.

Parameters:

Name	Type	Description
`value`	`out var`	Receives the parsed value
`input`	`const(char)[]`	JSON5 input string
`err`	`out Json5Error`	Receives error information on failure

Returns: true on success, false on parse error.

Example:

Json5Error err;
var v;
if (parseJSON5(v, "{a: 1, b: 'hello',}", err)) {
    assert(v["a"].as!long == 1);
    assert(v["b"].as!string == "hello");
} else {
    writefln("Error at %d:%d - %s", err.line, err.column, err.message);
}

`parseJSON5` (with reviver)¶

bool parseJSON5(out var value, const(char)[] input, Json5Reviver reviver, out Json5Error err) @safe

Parses JSON5 with a reviver function for value transformation.

Parameters:

Name	Type	Description
`value`	`out var`	Receives the parsed value
`input`	`const(char)[]`	JSON5 input string
`reviver`	`Json5Reviver`	Transformation function
`err`	`out Json5Error`	Receives error information on failure

Returns: true on success, false on parse error.

`parseJSON5` (from File)¶

bool parseJSON5(out var value, ref File file, out Json5Error err, ...) @safe

Parses JSON5 from a file handle.

`parseJSON5` (from Range)¶

bool parseJSON5(R)(out var value, R input, out Json5Error err, ...) @safe

Parses JSON5 from an input range.

`parseJSON5Sax`¶

bool parseJSON5Sax(const(char)[] input, ref Json5SaxHandler handler, out Json5Error err, ...) @safe

Parses JSON5 using SAX-style event callbacks.

Parameters:

Name	Type	Description
`input`	`const(char)[]`	JSON5 input string
`handler`	`ref Json5SaxHandler`	Event handler callbacks
`err`	`out Json5Error`	Receives error information on failure

Returns: true on success, false on error or handler abort.

`parseJSON5NumericLiteral`¶

bool parseJSON5NumericLiteral(out var value, const(char)[] text, const Json5Policy policy = Json5Policy.init) @safe

Parses a single JSON5 numeric literal.

Parameters:

Name	Type	Description
`value`	`out var`	Receives the parsed number
`text`	`const(char)[]`	Numeric literal text
`policy`	`Json5Policy`	Parsing policy

Returns: true on success, false on invalid input.

`parseJSON5StringLiteral`¶

bool parseJSON5StringLiteral(out string result, const(char)[] text, out Json5ErrorCode errCode) @safe

Parses a single JSON5 string literal.

Parameters:

Name	Type	Description
`result`	`out string`	Receives the decoded string
`text`	`const(char)[]`	String literal text (including quotes)
`errCode`	`out Json5ErrorCode`	Receives error code on failure

Returns: true on success, false on invalid input.

`toJSON5`¶

string toJSON5(const var value, const Json5WriteOptions opts = Json5WriteOptions.init) @safe

Serializes a var to JSON5 text.

Parameters:

Name	Type	Description
`value`	`const var`	Value to serialize
`opts`	`Json5WriteOptions`	Serialization options

Returns: JSON5-formatted string.

Example:

var data;
data["name"] = "example";
data["values"] = [1, 2, 3];

string json5 = toJSON5(data);
// Output: {name:'example',values:[1,2,3]}

`toJSON5` (with scratch)¶

string toJSON5(const var value, const Json5WriteOptions opts, ref Json5WriteScratch scratch) @safe

Serializes a var to JSON5 text using reusable scratch buffers.

`toJSON`¶

string toJSON(const var value, const Json5WriteOptions opts = Json5WriteOptions.init) @safe

Serializes a var to strict JSON text.

Parameters:

Name	Type	Description
`value`	`const var`	Value to serialize
`opts`	`Json5WriteOptions`	Serialization options

Returns: JSON-formatted string.

Notes:

All keys are quoted with double quotes.
NaN and Infinity are emitted as null.
No trailing commas.

Example:

var data;
data["name"] = "example";
data["values"] = [1, 2, 3];

string json = toJSON(data);
// Output: {"name":"example","values":[1,2,3]}

`toJSON` (with scratch)¶

string toJSON(const var value, const Json5WriteOptions opts, ref Json5WriteScratch scratch) @safe

Serializes a var to strict JSON text using reusable scratch buffers.

`minify`¶

string minify(const(char)[] input) @safe

Removes comments and unnecessary whitespace from JSON5 input.

Parameters:

Name	Type	Description
`input`	`const(char)[]`	JSON5 input string

Returns: Minified JSON5 string.

Example:

string compact = minify("{ a: 1, // comment\n b: 2, }");
assert(compact == "{a:1,b:2,}");

`json5Diff`¶

Json5PatchOp[] json5Diff(var from, var to) @safe

Computes the difference between two var values as JSON Patch operations.

Parameters:

Name	Type	Description
`from`	`var`	Original value
`to`	`var`	Target value

Returns: Array of patch operations to transform from into to.

Constants¶

`JSON5_DEFAULT_FEATURES`¶

enum uint JSON5_DEFAULT_FEATURES

Default feature flags enabling all standard JSON5 extensions.

ddn.data.json5¶

Overview¶

Enums¶

Json5Feature¶

Json5ErrorCode¶

Json5QuoteStyle¶

Json5WriteMode¶

Json5FloatFormat¶

Json5NegativeZeroStyle¶

Json5StreamResult¶

Json5TokenKind¶

Json5PatchOpKind¶

Structs¶

Json5Policy¶

Json5Error¶

Json5WriteOptions¶

Json5WriteScratch¶

Json5PatchOp¶

Json5PatchError¶

Json5Token¶

Json5Lexer¶

Json5Parser¶

Json5StreamParser¶

Json5SaxHandler¶

Functions¶

parseJSON5¶

parseJSON5 (with reviver)¶

parseJSON5 (from File)¶

parseJSON5 (from Range)¶

parseJSON5Sax¶

parseJSON5NumericLiteral¶

parseJSON5StringLiteral¶

toJSON5¶

toJSON5 (with scratch)¶

toJSON¶

toJSON (with scratch)¶

minify¶

json5Diff¶

Constants¶

JSON5_DEFAULT_FEATURES¶

See Also¶

`Json5Feature`¶

`Json5ErrorCode`¶

`Json5QuoteStyle`¶

`Json5WriteMode`¶

`Json5FloatFormat`¶

`Json5NegativeZeroStyle`¶

`Json5StreamResult`¶

`Json5TokenKind`¶

`Json5PatchOpKind`¶

`Json5Policy`¶

`Json5Error`¶

`Json5WriteOptions`¶

`Json5WriteScratch`¶

`Json5PatchOp`¶

`Json5PatchError`¶

`Json5Token`¶

`Json5Lexer`¶

`Json5Parser`¶

`Json5StreamParser`¶

`Json5SaxHandler`¶

`parseJSON5`¶

`parseJSON5` (with reviver)¶

`parseJSON5` (from File)¶

`parseJSON5` (from Range)¶

`parseJSON5Sax`¶

`parseJSON5NumericLiteral`¶

`parseJSON5StringLiteral`¶

`toJSON5`¶

`toJSON5` (with scratch)¶

`toJSON`¶

`toJSON` (with scratch)¶

`minify`¶

`json5Diff`¶

`JSON5_DEFAULT_FEATURES`¶