What is the common preference/recommendation in the community about using parentheses for function calls in Phoenix templates?

Phoenix Forum Questions / Help
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After a long period without doing anything related to Elixir/Phoenix I came back and just upgraded a former project to Phoenix 1.6. Many things have changed but I’m starting to get used to things again at my own pace. :turtle: ^^

Now I’m using heex templates and even added the HEEx HTML Formatter as plugin to mix format.

I see that this formatter plugin will add parentheses to any function call inside heex templates.

For example

<%= render “edit_profile.html”, some_func(assigns) %>

will become

<%= render(“edit_profile.html”, some_func(assigns)) %>

Personnally I find the first synthax prettier and less cumbersome.

And also when I used generators like phx.gen.auth they adopt the first style as well.

So my actual question is:

Is it just a matter of preference or is there a synthax that is encouraged or recommended inside templates?

Thanks. ^^

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I think it’s a matter of preference. But seeing as you asked, the correct preference is to use parentheses for all function calls and optionally, leave them off for macros :wink:

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Why optionally leave them off for macros? That would requiring knowing whether something is a function or a macro, and if you’re not aware of the distinction (as with most beginners), it would look like a random mix (no pun intended), leading to the impression that there is no style.

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Usually the macros, which are setup to not have parenthesis added, are not even perceived as function- or rather macro calls in the first place: defmodule, def, schema, all the phoenix router macros, …

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Agreed. My personal standard (and I think this may be something of an unspoken convention?) is:

  • Macros that modify the environment = no parens. Examples like those you stated.
  • Macros that are “pure” in the sense that they act like functions, but are macros to allow for additional power/expressiveness = parens. Examples include much of the Ecto query api.
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Fair enough for that kind of macro… but what about macros that “look like” functions? Maybe the dividing line could be, rather than function vs. macro, “what looks like a function” vs. everything else.

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Further to what @LostKobrakai and @zachallaun said, sometimes people create DSLs with macros and it is nicer on the eye to leave off the parenthesis.

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