OwnValues¶

Status: Stable

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

Description¶

OwnValues[s]

gives a list of own-value rules for s.

Examples (5)¶

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

Basic examples (2)¶

In[1]:= f[x_] := x^2; DownValues[f]
Out[1]= {HoldPattern[f[x_]] :> x^2}

In[2]:= a = 5; OwnValues[a]
Out[2]= {HoldPattern[a] :> 5}

Applications (3)¶

In[3]:= OwnValues[a]
Out[3]= {}

In[4]:= a = 7
Out[4]= 7

In[5]:= OwnValues[a]
Out[5]= {HoldPattern[a] :> 7}

Implementation notes¶

builtin_own_values (1-arg, symbol only) calls symtab_get_own_values(sym) to retrieve the symbol's Rule* list — the immediate x = value assignments — and hands it to the shared rules_to_list helper, which deep-copies each pattern/replacement pair into a Rule[lhs, rhs] node and gathers them into a List. The list is returned unevaluated so the stored values are reported verbatim rather than re-evaluated.

Each rule is returned as HoldPattern[lhs] :> rhs (a RuleDelayed whose left-hand side is wrapped in HoldPattern), matching Mathematica. The HoldPattern keeps the stored pattern from re-matching its own definition, and the RuleDelayed keeps the right-hand side unevaluated, so the returned list is inert: querying DownValues[f] for a recursive f does not re-trigger the recursion, and a right-hand side such as RandomInteger[...] is shown held rather than evaluated afresh on each query.
Returns {} for a symbol that carries no rules of the requested kind.

Attributes: HoldAll, Protected.

References¶

See also: DownValues, RuleDelayed, HoldPattern

Source: src/core.c
Specification: docs/spec/builtins/assignment-and-rules.md
Tests: tests/test_unset.c
Tests: tests/test_upvalues.c

Notes & additional examples¶

Notes¶

OwnValues[s] returns the direct value rules created by s = .... An undefined symbol has an empty list; assigning a = 7 stores a single own-value rule.