Escaping special tokens (e.g. colon) in command name?

[joshuatz]

I searched through all open and closed issues, as well as the docs, and it surprisingly seems as though this has never come up before (if so, apologies).

Is it possible to craft a command name that contains special characters / tokens that otherwise break just since they are parsed as such? It looks like multiple characters will cause errors if included as part of a command name (such as =, &, etc.), but I am personally most interested in learning if it would be possible to use : as part of a command name.

The colon character is frequently used in Node development, and you will often find package.json script entries that look like this:

{
  "scripts": {
    "build:prod": "build.js --prod --minify",
    "build:dev": "build.js --dev --source-map --verbose"
  }
}

Where running npm run build:prod works without issue.

If you try to replicate these names in just, you will immediately run into issues:

build:prod:
  build.js --prod --minify

❌ error: Expected '&&', comment, end of file, end of line, identifier, or '(', but found ':'

Is there a way around this? I realize that switching from build:prod to build-prod, or more dynamic build $target or build TARGET would be an immediate solution and perhaps even better practice with just, but I wanted to put this question out there in case A) there was a solution, and B) in case there are other devs hitting this while trying to replicate package.json scripts.

I do see some docs on escaping, but they seem to only apply to the body of commands, not the command name.

[casey]

Good question!

Currently, recipe names must be valid just identifiers, which are of the form [a-zA-Z_][a-zA-Z0-9_-]*, so it isn't possible to use : in a recipe name.

Since the package.json file is JSON, and script names are Javascript strings, there aren't any restrictions on their contents, whereas just recipe names have to be distinguished from other parts of the just language, i.e. the lexer needs to be able to tell where a recipe name ends and the : after the name begins, so there are more restrictions on recipe name contents.

I would suggest using dashes, i.e., foo-bar. It's a pinky reach, but you don't have to press the shift key, so it's kind of a wash.

[joshuatz]

Gotcha, that makes sense. And to be fair to just, it definitely isn't alone in that rule - seems like a lot of task / command running tools that use config files based on or borrowing from YAML syntax all (understandably, due to the significance of : in that context) have that limitation.

I would suggest using dashes, i.e., foo-bar

Yep, agreed. It's not a huge deal for me, but I'm really glad to get an official answer here!

Thanks for all your hard work on this tool and your quick and detailed response here!