Entity Specification

The draw function has an objects argument which is used to define the array of entities (type DrawnEntity) to be rendered on the canvas. This page documents the attributes of the DrawnEntity object type and provides examples for the different kinds of entities supported by MemoryViz.

Core Attributes

All supported entities include the following core attributes, unless explicitly stated otherwise:

Attribute	Type	Description
type	string	Specifies the type of object to be drawn. (e.g., .class, .frame, int, str). See Entity Type for more details.
id	number or null	A unique identifier for the object (duplicate IDs will emit a warning). May be null anywhere to render a blank ID box.
value	Varies	The content of the object to be drawn. Format and type depends on the entity type.
x, y	number	The x and y coordinates for the object on the canvas. Will be automatically calculated if not provided.
width, height	number	The height and width for the object. Will be automatically calculated if not provided. If defined height and/or width is smaller than the minimum required for the object, then they will be overwritten.
style	object or array	Custom visual styling. See Style API for more details.

Entity Type

Type Value	Description
int, float, str, bool, None, complex, bytes, range, datetime.date	Primitives
list, tuple	Sequences
set, frozenset	Sets
dict	Dictionaries
.class	Classes
.frame	Stack Frames
.blank .blank-frame	Blank Objects

Primitives

Attribute	Type	Default	Description
type	string	--	Must be set to one of int, str, bool, float, or None to indicate a primitive object.
value	See below	null	The actual value represented by the primitive object. To render an empty box, set the value as null or don't define it.

type	type of value
int, float	number
str	string
bool	boolean
None, complex, bytes, range, datetime.date	string

Examples

Integer

[
    {
        "type": "int",
        "id": 19,
        "value": 124
    }
]

Blank integer

[
    {
        "type": "int",
        "id": 19,
        "value": ""
    }
]

String

[
    {
        "type": "str",
        "id": 43,
        "value": "David is cool"
    }
]

Boolean

[
    {
        "type": "bool",
        "id": 32,
        "value": true
    }
]

Float

[
    {
        "type": "float",
        "id": 76,
        "value": 3.14
    }
]

Blank float

[
    {
        "type": "float",
        "id": 76,
        "value": ""
    }
]

None

[
    {
        "type": "None",
        "id": 0,
        "value": "None"
    }
]

Complex

[
    {
        "type": "complex",
        "id": 76,
        "value": "(4+2j)"
    }
]

Range

[
    {
        "type": "range",
        "id": 76,
        "value": "range(0, 5)"
    }
]

Bytes

[
    {
        "type": "bytes",
        "id": 76,
        "value": "b'\\x00\\x00'"
    }
]

Date

[
    {
        "type": "date",
        "id": 76,
        "value": "2019-12-04"
    }
]

Empty Box

[
    {
        "type": "bool",
        "id": 0,
        "value": null
    }
]

Sequences

Attribute	Type	Default	Description
type	string	--	Must be set to list to indicate a list object, or tuple to indicate a tuple object.
value	array of number or null	[]	List of object ids (unresolved IDs will emit a warning). Values can be made null to draw blank boxes.
show_indexes	boolean	false	Indicates whether to show indices in the memory box.

Examples

List with blank boxes

[
    {
        "type": "list",
        "id": 82,
        "value": [19, 43, null, 49]
    }
]

List with indices shown

[
    {
        "type": "list",
        "id": 84,
        "value": [32, 10, 90, 57],
        "show_indexes": true
    }
]

Tuple with blank boxes

[
    {
        "type": "tuple",
        "id": 11,
        "value": [82, 76, null]
    }
]

Tuple with indices shown

[
    {
        "type": "tuple",
        "id": 11,
        "value": [82, 76, null],
        "show_indexes": true
    }
]

Sets

Attribute	Type	Default	Description
type	string	--	Must be set to set to indicate a set object.
value	array of number or null	[]	List of object ids (unresolved IDs will emit a warning). Values can be made null to draw blank boxes.

Examples

Set with blank boxes

[
    {
        "type": "set",
        "id": 90,
        "value": [36, 49, null, 64]
    }
]

Set with large width

[
    {
        "type": "set",
        "id": 32,
        "value": [10, 11, 12],
        "width": 500
    }
]

Frozenset

[
    {
        "type": "frozenset",
        "id": 90,
        "value": [36, 49, 72, 64]
    }
]

Frozenset with blank boxes

[
    {
        "type": "frozenset",
        "id": 90,
        "value": [null, 16, null, 84]
    }
]

Dictionaries

Attribute	Type	Default	Description
type	string	--	Must be set to dict to indicate a dictionary object.
value	dict or array of number or null	{}	Dictionary of string object id keys to int object id value pairs or a list of two-element lists, where each inner list is in the form [key id, value id] (unresolved IDs will emit a warning). Keys can be made empty or all-whitespace strings and values can be made null to draw blank boxes.

Examples

Dictionary with blank boxes

[
    {
        "type": "dict",
        "id": 10,
        "value": {
            "": 81,
            "1": null,
            "    ": 12
        }
    }
]

Dictionary with large height

[
    {
        "type": "dict",
        "id": 10,
        "value": { "x": 81, "y": 100, "z": 121 },
        "height": 600
    }
]

Dictionary with value specified using a list

[
    {
        "type": "dict",
        "id": 10,
        "value": [
            ["", 81],
            ["1", null],
            ["", 12]
        ]
    }
]

Classes

Attribute	Type	Default	Description
type	string	--	Must be set to .class to indicate a class object.
name	string	""	The name of the class being drawn.
value	dict of string to number or null	{}	A mapping of attribute names (as keys) to object IDs (as values). Unresolved IDs will emit a warning. Attribute names may be empty or all-whitespace strings and attribute values may be null to render blank boxes, respectively.

Examples

Class with blank boxes

[
    {
        "type": ".class",
        "id": 82,
        "name": "Person",
        "value": {
            "age": 12,
            "name": 17,
            "": null
        }
    }
]

Stack Frames

Attribute	Type	Default	Description
type	string	--	Must be .frame to indicate a stack frame.
name	string	""	The name of the stack frame (e.g., __main__, foo)
value	dict of string to number or null	{}	A mapping of variable names (as keys) to object IDs (as values). Unresolved IDs will emit a warning. These represent the local variables in the scope of the frame. Variable names may be empty or all-whitespace strings and attribute values may be null to render blank boxes, respectively.

Note: Stack frames do not have an id field.

Examples

Main stack frame

[
    {
        "type": ".frame",
        "name": "__main__",
        "value": {
            "lst1": 82,
            "lst2": 84,
            "p": 99,
            "d": 10,
            "t": 11
        }
    },
    {
        "type": ".blank",
        "width": 200,
        "height": 100
    }
]

Function stack frame with blank boxes

[
    {
        "type": ".frame",
        "name": "func",
        "value": {
            "age": 12,
            "name": 17,
            "": null
        }
    },
    {
        "type": ".blank",
        "width": 200,
        "height": 100
    }
]

Blank Objects

Attribute	Type	Default	Description
type	string	--	Must be set to .blank to indicate a blank object, or .blank-frame to indicate a blank frame.
width	number	0	The width of the blank object/frame.
height	number	0	The height of the blank object/frame.

Examples

Blank object

{
    "type": ".blank",
    "width": 200,
    "height": 100
}

Blank frame

{
    "type": ".blank-frame",
    "width": 200,
    "height": 100
}