SlotSequence¶

Status: Stable

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

Description¶

or SlotSequence[n] represents arguments from the n-th onward.¶

Examples (3)¶

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

Applications (3)¶

In[1]:= (Plus[##] &)[1, 2, 3]
Out[1]= 6

In[2]:= (f[##2] &)[a, b, c]
Out[2]= f[b, c]

In[3]:= FullForm[##]
Out[3]= SlotSequence[1]

Implementation notes¶

SlotSequence[n] (##, ##n) is an inert marker — builtin_slotsequence always returns NULL. During pure-Function application, substitute_slots replaces SlotSequence[n] with a Sequence[...] of copies of arguments n through the last (arg_count − n + 1 of them), which then splices into the surrounding call when the Sequence is flattened by the evaluator. Like Slot, recursion stops at nested Function nodes. ATTR_PROTECTED.

Attributes: Protected.

References¶

Source: src/purefunc.c
Specification: docs/spec/builtins/functional-programming.md
Tests: tests/test_purefunc.c

Notes & additional examples¶

Notes¶

## (SlotSequence[1]) splices all arguments of the enclosing pure function into the surrounding expression; ##n (Out[2]) splices the arguments from the n-th onward.