Function Repository Resource:

DefinitionData

Source Notebook

Store full definitions for a symbol in a compact object

Contributed by: Richard Hennigan (Wolfram Research)

ResourceFunction["DefinitionData"][symbol]

returns a definition object for symbol and all its dependencies.

ResourceFunction["DefinitionData"][…][property]

returns the definition information specified by property.

Details

In ResourceFunction["DefinitionData"][…][property], possible values for property include:

"Name"

the fully qualified name of the symbol

"Definitions"

an Association containing full definition information

"Symbols"

a list of all the contained symbols, each wrapped in HoldForm

"Names"

a list of fully qualified symbol names

"Size"

the full size of the definition data in bytes

"Contexts"

a list of all contexts for the defined symbols

"DefinitionList"

returns a Language`DefinitionList of the definition data

Get[ResourceFunction["DefinitionData"][…]] will restore all the contained definitions.

Information[ResourceFunction["DefinitionData"][…]] provides a summary of some properties.

Examples

Basic Examples (3)

Get all needed definitions for f, which depends on the function g:

In[1]:=

g[x_] := x^3;
f[x_] := g[x^2];
data = ResourceFunction["DefinitionData"]@f

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View information about the definitions:

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Using Get can restore cleared symbols:

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Applications (4)

Store definitions from a package as an object that can be stored in notebooks:

In[9]:=

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View the definitions:

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This is now equivalent to loading the original package:

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The definition is loaded:

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Properties and Relations (5)

Get a list of available properties:

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See what symbols are contained:

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Use a list of properties to return an Association:

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The InputForm of DefinitionData serializes definitions to protect contexts and initialization states of values:

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Use FullForm to see the actual expression structure:

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When writing DefinitionData to a file as InputForm via Put, CloudPut, Export, etc., original contexts will be preserved in binary form:

In[21]:=

$Context = "MyContext`";
g1[x_] := x^3;
f1[x_] := g1[x^2];
data = ResourceFunction["DefinitionData"]@f1

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In[22]:=

Changing $Context or $ContextPath will not affect which contexts the contained symbols are created in:

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$Context = "Global`";
Remove[MyContext`f1, MyContext`f2];
Get["file.wl"]

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Load the definitions:

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The symbols are redefined in their original contexts:

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Possible Issues (1)

Some contexts (such as System`) are excluded when including definitions:

In[27]:=

a := {b, Table};
b := {MyContext`c, CloudObject};
MyContext`c := 1;
ResourceFunction["DefinitionData"]@a

Out[12]=

In[28]:=

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Related Links

Requirements

Wolfram Language 11.3 (March 2018) or above

Version History

2.0.0 – 13 September 2021
1.0.0 – 15 February 2019

Related Resources

License Information

This work is licensed under a Creative Commons Attribution 4.0 International License