Context¶

Status: Stable

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

Description¶

Context[]

gives the current context ($Context).

Context[sym]

gives the context in which sym resides.

Context["name"]

gives the context of the symbol named "name" if it exists.

Examples (2)¶

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

Applications (2)¶

In[1]:= Context[]
Out[1]= "Global`"

In[2]:= Context[Sin]
Out[2]= "System`"

Implementation notes¶

builtin_context (src/context.c) has three forms. Context[] returns context_current() (the g_current string, default "Global").Context[sym]/Context["name"](the symbol form is held —ATTR_HOLDFIRST) report the symbol's context: if the name already carries a backtick prefix it is peeled off and returned viacontext_prefix_len; otherwise the symbol is looked up withsymtab_lookupand reported as"System" when it is a builtin (def->builtin_func != NULL), else "Global". An unknown string-form name emitsContext::notfoundand leaves the call unevaluated; an unassigned bare symbol defaults to"Global".

Attributes: HoldFirst, Protected.

References¶

Source: src/context.c
Specification: docs/spec/builtins/scoping-constructs.md
Tests: tests/test_context.c

Notes & additional examples¶

Notes¶

Context[] returns the current context (the same value as $Context), while Context[sym] returns the context in which a symbol lives — built-ins such as Sin reside in "System"`.