List Run Split At Cursor Tool

Description

Return cursor as left and runLength minus cursor as right.

A list window uses a start and exclusive end or a center and radius. Boundary clamping, padding, and half-integer centers are separate conventions.

Return cursor as left and runLength minus cursor as right.

Use List Run Split At Cursor when you need an explicit window position or edge-padding budget.

Enter runLength, cursor. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read left, right. Use the output convention below.

Require cursor between zero and runLength. Return cursor as left and runLength minus cursor as right.^[1]

Input field	Meaning and units	Accepted input
runLength	Run Length	Required. Safe integer; minimum 0.
cursor	Cursor	Required. Safe integer; minimum 0.

Output field	Interpretation	Returned shape
left	Left	Required. Safe integer.
right	Right	Required. Safe integer.

json

{
  "input": {
    "runLength": 7,
    "cursor": 3
  },
  "output": {
    "left": 3,
    "right": 4
  }
}

The cursor is a boundary rather than an element index; empty sides and an empty run are allowed.
Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.

Inspect actual list bounds and choose whether to shift, truncate, or pad windows before extracting data.

List Run Length One Boundary Update
Compare leftValue and rightValue exactly.
List Run Boundary Two Neighbor Mask
Mark start when previous differs from current and end when current differs from next.