Command and FISH Reference Notation in the Documents

In this documentation, each command and each FISH function is presented according to a few conventions. Options in a command or a FISH function are denoted by < >. A keyword (command) or argument (FISH) (optional or required) followed by ellipses indicates that an arbitrary number of such parameters may follow. Ellipses notation is common in commands, but somewhat rare in FISH. And note that it is altogether different from use of ellipses as a command or FISH line continuation mechanism (see Continuation in the “Command Shaping” topic).


A command “signature” will show the most rudimentary form of the command first, followed by the available keywords and other options. For example:

wall import keyword ... <range>

Review a handful of commands (try wall import, zone dynamic, model new, and geometry edge delete) to obtain a quick familiarization with command presentation in these documents.

In the command reference documents, indentation is used to indicate levels of keywords. Many commands will follow a basic pattern of command keyword <range>. However, at the first keyword level it is possible to find choices that may themselves take keywords. For instance, at one level indented from the main command might be found:  l1keyword1 keyword ...   and   l1keyword2 <keyword>. Per the notation, the first-level keyword   l1keyword1   takes an arbitrary number of additional keywords, and the first-level keyword   l1keyword2   takes a single optional keyword. Each of the choices for these sub-keywords will be found one indented level out and below their parent keywords.


A FISH function “signature” will show the exact arguments and return values needed for the function. Functions may be read only, write only, or both. An example:

v = domain.max(<i>)
domain.max(<i>) = v

The notation for this function (domain.max) indicates that this function is read/write. The first line is the read version, which shows how to get the upper domain corner vector or component (if <i> is specified) and store it in vector v. The second is the write version, the upper domain corner vector or component is set to value of v. Read (or get) functions are always written with the assignment variable to the left of the equals sign. Write (or set) functions are always shown with the function to the left of the equals sign.

Below the signature, FISH reference pages will show a type and a description for all function arguments and return values.

Visual Reference

In both commands and FISH, values of various types are indicated by the first letter of the type name. In most cases, a single letter is sufficient. In cases where multiple values are supplied, they will tend to be numbered (i1, i2, i3, etc.). Vectors are usually specified with v, where the dimensionality (2D or 3D) will be clear by context. There are cases where this may not be true, in which case the use of v2 and v3 is used to explicitly specify a 2D or 3D vector, respectively. As this usage of numerals is the case with vectors, when multiple vectors are indicated they will be differentiated with letters (v_a, v_b, etc., or v2_a, v2_b, etc.).

Table 1: Typography Conventions for Commands and FISH in Program Documentation

Type style/ character

Used for


command word


keyword word

FISH function name (uses dot notation)


FISH symbol (either a function or variable name)

f, i

a number of float or integer type, respectively


a number of either float or integer type may be supplied


a string value


a boolean value

v, v2, v3

a vector value, a 2d vector, a 3d vector


a 2d vector


any type may be supplied

< >

the item enclosed (e.g., <keyword>) is optional

an indeterminate number of the preceding item may follow