eqnarray and \rm highlighted red?

[adrn]

Prerequisites

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Description

See images below: I'm using the language-latex for editing latex documents. Overall works very nicely, but both eqnarray and \rm are highlighted red for reasons I don't understand (no error messages are shown).

Steps to reproduce & Minimum working example

1. Type \begin{eqnarray} or {\rm x}

[Aerijo]

Because you shouldn’t use them. They are deprecated and objectively bad choices. This is part of this package by design.

By the way, most themes use a yellow colour for deprecated syntax, and reserve red for invalid syntax.

[yudai-nkt]

A bit information on why those are discouraged. The two-letter font commands like \rm are not NFSS compliant and therefore have some defects (e.g., you cannot nest these commands and \it has no italic correction). The eqnarray environments produces wrong spaces around the delimiter and incorrect equation numberings.

Here are some references that explain the deprecation in more detail:

• Two-letter font commands
  • “Correct” way to bold/italicize text?
  • What is the origin of the family/series/shape distinction?
• eqnarray environment
  • eqnarray vs align
  • Is eqnarray really obsolete?
  • Avoid eqnarray! (this contains lots of examples where eqnarray gives bad results.)

[adrn]

Thanks for the context @yudai-nkt. Strangely, some of the journals in my field (astrophysics) still recommend using \rm for, e.g., writing numbers with units where the unit abbreviations shouldn't be math text, so I wasn't aware of the deprecation.

[yitzchak]

@adrn Yout might try siunitx if the journal will allow it. It does an excellent job at units in my experience.