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HoldAllComplete
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HoldAllComplete

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is an attribute which specifies that all arguments to a function are not to be modified or looked at in any way in the process of evaluation.

Details

  • By setting the attribute HoldAllComplete, you can effectively shield the arguments of a function from all aspects of the standard Wolfram Language evaluation process.
  • HoldAllComplete not only prevents arguments from being evaluated, but also prevents Sequence objects from being flattened, Unevaluated wrappers from being stripped, and upvalues associated with arguments from being used.
  • Evaluate cannot be used to override HoldAllComplete.

Examples

open allclose all

Basic Examples  (1)Summary of the most common use cases

In[1]:=1
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https://wolfram.com/xid/0dc25cqtfg0a-elpafz
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0dc25cqtfg0a-fhfasa
Out[2]=2

Properties & Relations  (4)Properties of the function, and connections to other functions

HoldComplete is a standard container with attribute HoldAllComplete:

In[1]:=1
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https://wolfram.com/xid/0dc25cqtfg0a-j8mwov
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0dc25cqtfg0a-e8t0u
Out[2]=2

No form of evaluation control affects an expression with attribute HoldAllComplete:

In[1]:=1
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https://wolfram.com/xid/0dc25cqtfg0a-mfz595
Out[1]=1
In[2]:=2
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https://wolfram.com/xid/0dc25cqtfg0a-bi2tm9
Out[2]=2
In[3]:=3
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https://wolfram.com/xid/0dc25cqtfg0a-d2omjr
Out[3]=3
In[4]:=4
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https://wolfram.com/xid/0dc25cqtfg0a-fayu9r
In[5]:=5
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https://wolfram.com/xid/0dc25cqtfg0a-fvnlrk
Out[5]=5

Substitution still happens inside an expression with attribute HoldAllComplete:

In[1]:=1
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https://wolfram.com/xid/0dc25cqtfg0a-dkq45e
Out[1]=1

Unevaluated has the attribute HoldAllComplete:

In[1]:=1
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https://wolfram.com/xid/0dc25cqtfg0a-c7ilcb
Out[1]=1

Possible Issues  (2)Common pitfalls and unexpected behavior

HoldAllComplete affects only evaluation; input transformations are still applied:

In[1]:=1
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https://wolfram.com/xid/0dc25cqtfg0a-cvaxms

HoldAllComplete does not prevent formatting:

In[1]:=1
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https://wolfram.com/xid/0dc25cqtfg0a-6o1lu3
Out[1]=1

Add DisableFormatting to prevent formatting:

In[2]:=2
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https://wolfram.com/xid/0dc25cqtfg0a-va5hcj
Out[2]=2

Neat Examples  (1)Surprising or curious use cases

A fast way to compute the Hofstadter–Conway sequence [more info]:

In[1]:=1
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https://wolfram.com/xid/0dc25cqtfg0a-mxr47u
In[2]:=2
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https://wolfram.com/xid/0dc25cqtfg0a-mba45
Out[2]=2
Wolfram Research (1996), HoldAllComplete, Wolfram Language function, https://reference.wolfram.com/language/ref/HoldAllComplete.html.
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Wolfram Research (1996), HoldAllComplete, Wolfram Language function, https://reference.wolfram.com/language/ref/HoldAllComplete.html.

Text

Wolfram Research (1996), HoldAllComplete, Wolfram Language function, https://reference.wolfram.com/language/ref/HoldAllComplete.html.

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Wolfram Research (1996), HoldAllComplete, Wolfram Language function, https://reference.wolfram.com/language/ref/HoldAllComplete.html.

CMS

Wolfram Language. 1996. "HoldAllComplete." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/HoldAllComplete.html.

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Wolfram Language. 1996. "HoldAllComplete." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/HoldAllComplete.html.

APA

Wolfram Language. (1996). HoldAllComplete. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/HoldAllComplete.html

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Wolfram Language. (1996). HoldAllComplete. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/HoldAllComplete.html

BibTeX

@misc{reference.wolfram_2025_holdallcomplete, author="Wolfram Research", title="{HoldAllComplete}", year="1996", howpublished="\url{https://reference.wolfram.com/language/ref/HoldAllComplete.html}", note=[Accessed: 29-April-2025 ]}

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@misc{reference.wolfram_2025_holdallcomplete, author="Wolfram Research", title="{HoldAllComplete}", year="1996", howpublished="\url{https://reference.wolfram.com/language/ref/HoldAllComplete.html}", note=[Accessed: 29-April-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_holdallcomplete, organization={Wolfram Research}, title={HoldAllComplete}, year={1996}, url={https://reference.wolfram.com/language/ref/HoldAllComplete.html}, note=[Accessed: 29-April-2025 ]}

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@online{reference.wolfram_2025_holdallcomplete, organization={Wolfram Research}, title={HoldAllComplete}, year={1996}, url={https://reference.wolfram.com/language/ref/HoldAllComplete.html}, note=[Accessed: 29-April-2025 ]}