External Subcommand

External subcommands allow the veryl command to be extended by tools which are distributed separately from Veryl. If the given subcommand is not a built-in one, veryl searches PATH for an executable named veryl-<subcommand>, and executes it. As a result, such a tool can be used as if it was a built-in subcommand.

$ veryl import foo.sv

The command above executes veryl-import foo.sv if veryl-import is found on PATH. All arguments following the subcommand name are forwarded as-is, and the exit status of the external command becomes the exit status of veryl.

If a matching executable is not found, an error is reported.

Listing commands

veryl --help shows built-in subcommands only. To show all available commands including external subcommands found on PATH, veryl --list can be used.

$ veryl --list
Available Commands:
  build        Build the target codes corresponding to the current project
  check        Analyze the current project
  ...
  import       Import SystemVerilog files as a Veryl dependency
  ...

Subcommand description

By default, an external subcommand is listed with a fallback description like External Veryl subcommand from PATH (veryl-import). If the executable supports the --info option, its output is used as the description instead. veryl-<subcommand> --info is expected to print a one-line description to stdout, and all of the following conditions must be satisfied:

• The exit status is 0
• The output is a single line without control characters
• The length of the line is 160 characters or less
• The command finishes within 500ms

If any of them is not satisfied, the fallback description is used.

Reserved names

ls is not dispatched as an external subcommand because veryl-ls is the official language server binary. A subcommand name containing a path separator is rejected too.