9 Adding a raco Command

▼ |  | raco: Racket Command-Line Tools

1 | raco make: Compiling Source to Bytecode
2 | raco exe: Creating Stand-Alone Executables
3 | raco distribute: Sharing Stand-Alone Executables
4 | raco pack: Packaging Library Collections
5 | raco planet: Automatic Package Distribution
6 | raco setup: Installation Management
7 | raco decompile: Decompiling Bytecode
8 | raco ctool: Working with C Code
9 | Adding a raco Command

► | 9 | Adding a raco Command

9.1 | Command Argument Parsing

On this page:

9.1`` Command Argument Parsing
current-command-name
short-program+ command-name
program+ command-name

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### 9`` Adding a raco Command

The set of commands supported by raco can be extended by installed collections and PLaneT packages. A command is added by defining raco-commands in the "info.rkt" library of a collection or package (see "info.rkt" File Format).

The value bound to raco-commands must be a list of command specifications, where each specification is a list of four values:

( list command-string
implementationmodule-path
description-string
prominence)

The command-string is the command name. Any unambiguous prefix of a command name can be supplied to raco to invoke the command.

The module-path names the implementation though a module path (in the sense of module-path?). The module is loaded and invoked through dynamic-require to run the command. The module can access command-line arguments through the current-command-line-arguments parameter, which is adjusted before loading the command module to include only the arguments to the command. The current-command-name parameter is also set to the command name used to load the command. When raco help is used on a command, the command is launched with an initial --help argument in current-command-line-arguments.

The description string is a short string used to describe the command in response to raco help. The description should not be capitalized or end with a period.

The prominence value should be a read number or #f. A #f value means that the command should not be included in the short list of “frequently used commands.” A number indicates the relative prominence of the command; the help command has a value of 110, and probably no command should be more prominent. The pack tool, which is currently ranked as the least-prominent of the frequently used commands, has a value of 10.

As an example, the "info.rkt" of the "compiler" collection might contain the

( define raco-commands
'(("make" compiler/commands/make "compile source to bytecode" 100)
("decompile" compiler/commands/decompile "decompile bytecode" #f)))

so that make is treated as a frequently used command, while decompile is available as an infrequently used command.

#### 9.1`` Command Argument Parsing

( require raco/command-name)

The raco/command-name library provides functions to help a raco command identify itself to users.

( current-command-name) → (or/c string? #f)
( current-command-name name) → void?
name : (or/c string? #f)

The name of the command currently being loaded via dynamic-require, or #f if raco is not loading any command.

A command implementation can use this parameter to determine whether it was invoked via raco or through some other means.

( short-program+command-name) → string?

Returns a string that identifies the current command. When current-command-name is a string, then the result is the short name of the raco executable followed by a space and the command name. Otherwise, it is the short name of the current executable, as determined by stripping the path from the result of ( find-system-path 'run-file).

The result of this function is suitable for use with command-line. For example, the decompile tool parses command-line arguments with

( define source-files
( command-line
#:program ( short-program+command-name)
#:args source-or-bytecode-file
source-or-bytecode-file))

so that raco decompile --help prints

raco decompile [ <option> ... ] [<source-or-bytecode-file>] ...
where <option> is one of
--help, -h : Show this help
-- : Do not treat any remaining argument as a switch (at this level)
Multiple single-letter switches can be combined after one `-'; for
example: `-h-' is the same as `-h --'

( program+command-name) → string?

Like short-program+command-name, but the path (if any) is not stripped from the current executable’s name.
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