Line References

Refer to the value of any earlier line by its line number. References stay correct as you insert or delete lines — the numbers are renumbered live.

Referencing a line

Use line<N> or the short form l<N>. The keyword is case-insensitive, so line1, LINE1, Line1, l1, and L1 all refer to the same line.

42                                     | 42
line1                                  | 42
L1                                     | 42

Use in expressions

Line references behave like any other value — combine them with operators, units, currencies, and other references.

10                                     | 10
5                                      | 5
line1 + line2                          | 15
line1 * 2                              | 20

A reference adopts the value type of the line it points to. If line 1 is an amount with units or a currency, the reference renders the same way:

5 miles                                | 5 miles
line1 + 1                              | 6 miles

Live renumbering

Inserting a line above a reference or deleting a line shifts the numbers automatically — the text line1 is rewritten to line2 (and vice versa) so that the reference keeps pointing at the same logical line.

Cycle and self-reference

A line that references itself, references a line that doesn’t exist, or references a line that hasn’t been parsed yet resolves to NaN rather than raising an error. Arithmetic with a NaN reference also yields NaN.

line5                                  | (empty — no line 5 yet)
line2                                  | (empty — self-reference on line 2)

Word boundaries

Only the bare line<N> and l<N> forms are recognised. The parser will not match references that are run together with other identifiers or contain underscores:

• line1foo — not a reference (would need a space)
• linear — not a reference (it’s a longer identifier)
• l_3 — not a reference (underscores aren’t allowed)