HoldForm¶

Status: Stable

documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

Description¶

HoldForm[expr]

prints as the expression expr, with expr maintained in an unevaluated form.

Examples (4)¶

Every input below was run against the current Mathilda build and its output recorded.

Basic examples (1)¶

In[1]:= HoldForm[1 + 1]
Out[1]= 1 + 1

Applications (3)¶

Held, but the wrapper prints invisibly

In[2]:= HoldForm[1 + 1]
Out[2]= 1 + 1

The wrapper is really there

In[3]:= FullForm[HoldForm[1 + 1]]
Out[3]= HoldForm[Plus[1, 1]]

ReleaseHold strips it and evaluates

In[4]:= ReleaseHold[HoldForm[1 + 1]]
Out[4]= 2

Implementation notes¶

HoldForm has no C handler; it is purely an evaluation/display marker. It is given ATTR_HOLDALL | ATTR_PROTECTED in core_init (src/core.c) so its argument stays unevaluated, and the printer renders HoldForm[expr] as just expr (the wrapper is invisible). ReleaseHold strips it.

Attributes: HoldAll, Protected.

References¶

See also: HoldAll

Source: src/core.c
Specification: docs/spec/builtins/expression-information.md
Tests: tests/test_evaluate.c
Tests: tests/test_numeric.c
Tests: tests/test_print.c
Tests: tests/test_releasehold.c

Notes & additional examples¶

Notes¶

HoldForm[expr] holds expr unevaluated exactly like Hold, but the printer renders it as just expr — the wrapper is invisible in output. It is the tool for displaying an expression in unevaluated form while keeping it a genuine held expression, as FullForm reveals.

HoldForm carries HoldAll and is Protected; ReleaseHold removes it.