---
bc-version: [all]
domain: style
keywords: [variable-naming, semantic-naming, readability, magic-name, self-documenting]
technologies: [al]
countries: [w1]
application-area: [all]
---

# Variable names must describe what the value means, not just its type

## Description

A variable name must let a reader understand what the value represents
without having to trace every place it is assigned or used. A name built
from a generic type abbreviation plus a sequence number or letter —
`Amt1`, `Amt2`, `Var1`, `OptA`, `Int3`, `TempX` — fails this test: it tells
the reader the data type, which AL already shows via the declaration, but
nothing about the business meaning. `AmountInclVAT` is immediately
readable; `Amt1` requires the reader to go find out what Amt1 is actually
used for.

The fix is not "add more letters" — it is to name the variable for the
business concept it holds: `AmountInclVAT`, `CustomerDiscountPct`,
`RemainingQuantity`, `IsOverdue`. If two variables genuinely hold the same
kind of value in a comparison or calculation (e.g. two amounts being
subtracted), name them for their distinct roles in that calculation
(`OriginalAmount` / `AdjustedAmount`), not for their shared type
(`Amt1` / `Amt2`).

**Exception:** short-lived loop counters and array indices (`i`, `idx`,
`x`) are an accepted convention precisely because their entire meaning is
visible in the two or three lines of the loop that declares and uses them.
This exception does not extend to variables that live longer than a tight
loop body or that carry business meaning beyond "the current position."

## Best Practice

```al
var
    AmountInclVAT: Decimal;
    RemainingQuantity: Decimal;
    IsOverdue: Boolean;
...
for idx := 1 to ArrayLen(SalesLine) do
    TotalAmount += SalesLine[idx];
```

## Anti Pattern

```al
var
    Amt1: Decimal;
    Amt2: Decimal;
    OptA: Option;
    TempX: Integer;
...
if OptA = 1 then
    Amt1 := Amt2 - TempX;
```

A reviewer reading `Amt1 := Amt2 - TempX;` cannot tell what this line is
computing without opening the variable declarations and searching for every
other assignment to `Amt2` and `TempX` first. The same line as
`AmountInclVAT := AmountExclVAT - DiscountAmount;` needs no further lookup.