PL-6
PL-6 is a discontinued system programming language based on PL/I. PL-6 was developed by Honeywell, Inc. in the late 1970s as part of the project to develop the CP-6 operating system.
Description
Data types
| Declaration attribute | Description |
|---|---|
| SBIN(n) | Signed binary integer of n bits. If (n) is not specified, 36 bits is the default. Alternatively "SBIN WORD", "SBIN HALF", or "SBIN BYTE" specifies 36, 18, or 9 bits respectively. |
| UBIN(n) | Unsigned binary integer of n bits. Otherwise the same as SBIN. |
| CHAR(c) | Fixed-length character string of length c characters. |
| BIT(b) | Fixed-length bit string of length b bits. |
| PTR | A memory address. |
PL-6 has no provision for floating point data.
Aggregates
Arrays were one dimensional and zero-based, with the zero specified explicitly. For example, DCL x (0:4) SBIN; declares an array of five signed 36-bit integers. The elements were numbered x(0), x(1),...,x(4).
Structures were also supported. For example:
DCL 1 struct,
2 a,
3 b CHAR(3),
3 * CHAR(1),
2 c CHAR(4);
declares a structure named struct consisting to two elements: a minor structure a consisting of a three-character field b and an unnamed one-character element ("*" indicates the element is unnamed), and a four-character element c.
The top level of the structure had to be 1, and the remaining levels 2–10, if used, had to be specified in order with no levels skipped.