Syntax Diagrams - Notation

The command syntax descriptions for the Dump Formatter and Kernel Debugger use a graphical notation, which is now in common use. The diagrams should be read as a road map starting at the sign:

──

and ending at the sign:

─

The command verb and options are shown in upper case type.

Parameter values to be supplied by the user are shown in lower case. The rules governing the use of complex expressions are described under The expression evaluator.

Continuation of the syntax diagram is shown by:

─

at the break, and

─

at the beginning of the continuation line.

Expansion of syntax into detailed subsections is indicated thus:

─┤ section name ├─

Expanded section begins:

section name:
├─

Expanded section ends:

─┤

See below for a more detailed description and example of subsections.

Mutually exclusive options where a non-mandatory selection is required are shown thus:

        ───────┬─────┬────────
               ├─ A ─┤
               ├─ B ─┤
               └─ C ─┘

Here at most one of A, B or C may be selected.

Mutually exclusive options where a mandatory choice is required are shown thus:

        ───────┬─ A ─┬────────
               ├─ B ─┤
               └─ C ─┘

Multiple selections are shown:

               ┌───────┐        ┌───────┐
                      │               │
            ────┬─────┬┴───   ───┬─ D ─┬┴────
                ├─ A ─┤          ├─ E ─┤
                ├─ B ─┤          └─ F ─┘
                └─ C ─┘

One or more of A, B or C is optional, whereas at least one of D, E or F is required.

If a separator is required between parameters then it is shown in the diagram. For example, a comma is required between each selection in the following:

               ┌── , ──┐        ┌── , ──┐
                      │               │
            ────┬─────┬┴───   ───┬─ D ─┬┴────
                ├─ A ─┤          ├─ E ─┤
                ├─ B ─┤          └─ F ─┘
                └─ C ─┘

For the Dump Formatter and Kernel Debugger spaces between parameters options are optional.

Ordered non-exclusive selection lists and parameters are shown in the order they must be specified.

               ┌── , ──┐        ┌── , ──┐
                      │               │
       ── X ────┬─────┬┴─────────┬─ D ─┬┴──────┬─────┬─── = value ───
                ├─ A ─┤          ├─ E ─┤       ├─ H ─┤
                ├─ B ─┤          └─ F ─┘       └─ I ─┘
                └─ C ─┘

Here, X must be specified first, followed optionally by zero or more of A, B or C separated by commas, followed by at least one of D, E or F separated by commas, followed optionally by H or I and finally by the character = and a quantity substituted for value.

The following examples would be correct interpretations of this last syntax diagram:

       X D = 55
       XA,B I=444

Where complex diagrams require splitting into multiple sections, the sections are identified by a lower case italic name. For example:

        ──────────┬───────────────────┬─────────────
                  │                   │
                  ├──┤ section 1 ├────┤
                  │                   │
                  └──┤ section 2 ├────┘



section 1:

        ├─────────────┬─────┬────┬─────┬───────────┤
                      └─ A ─┘    ├─ B ─┤
                                 └──C ─┘

In this example the syntax for section 1 is exclusive with section 2. The options for section 1 are shown at the label section 1 :