docs/concept: new FAQ: list arithmetic ops removal

This adds an FAQ guide that explains the removal of list arithmetic
operators ("+" and "*") from CUE v0.11 and later.

Closes cue-lang/docs-and-content#178

Preview-Path: /docs/concept/faq/removing-list-arithmetic-operators-v0.11/
Signed-off-by: Jonathan Matthews <[email protected]>
Change-Id: I8d50c273ccedb7cf6ca5295917032d5aa822b413
Dispatch-Trailer: {"type":"trybot","CL":1200357,"patchset":3,"ref":"refs/changes/57/1200357/3","targetBranch":"master"}

content/docs/concept/faq/removing-list-arithmetic-operators-v0.11/en.md

@@ -0,0 +1,39 @@
+---
+title: Removing list arithmetic operators in CUE v0.11
+authors: [jpluscplusm]
+toc_hide: true
+---
+
+In early versions, the CUE language explicitly allowed arithmetic operators
+("`+`" and "`*`") to take list arguments.
+This feature was removed from the language specification
+[several years ago](https://review.gerrithub.io/plugins/gitiles/cue-lang/cue/+/172f0060cd405f30c5873b793e44300e1a3588cb%5E%21/),
+and its removal is now being completed in CUE version `v0.11`.
+This FAQ answers some of your questions about what's changed.
+
+## What's being removed, and from where?
+
+TODO(jcm): The operators `*` and `+` when used with list arguments will stop
+working with the CUE evaluator in the `cue` command, and the CUE Go API.
+
+## Why were list arithmetic operators supported until now?
+
+TODO(jcm): Because folks might have had CUE that used this syntax, but enough
+time has now passed without it being mentioned on cuelang.org or the CUE
+language spec that we can assume it's not being used by anyone.
+
+## What's the replacement for list arithmetic operators?
+
+TODO(jcm): list.Repeat(), list.Concat(), and nested for loops. Show examples.
+
+## Which version of CUE removes list arithmetic operators?
+
+TODO(jcm): any version that starts `v0.11`.
+
+## Am I affected?
+
+TODO(jcm): probably not. FIXME: how to check?
+
+## I *am* affected! How can I fix my CUE?
+
+TODO(jcm): `cue fix` examples. Manual fixup examples.

content/docs/concept/faq/removing-list-arithmetic-operators-v0.11/page.cue

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+package site
+
+content: docs: concept: faq: "removing-list-arithmetic-operators-v0.11": page: _

hugo/content/en/docs/concept/faq/removing-list-arithmetic-operators-v0.11/index.md

@@ -0,0 +1,39 @@
+---
+title: Removing list arithmetic operators in CUE v0.11
+authors: [jpluscplusm]
+toc_hide: true
+---
+
+In early versions, the CUE language explicitly allowed arithmetic operators
+("`+`" and "`*`") to take list arguments.
+This feature was removed from the language specification
+[several years ago](https://review.gerrithub.io/plugins/gitiles/cue-lang/cue/+/172f0060cd405f30c5873b793e44300e1a3588cb%5E%21/),
+and its removal is now being completed in CUE version `v0.11`.
+This FAQ answers some of your questions about what's changed.
+
+## What's being removed, and from where?
+
+TODO(jcm): The operators `*` and `+` when used with list arguments will stop
+working with the CUE evaluator in the `cue` command, and the CUE Go API.
+
+## Why were list arithmetic operators supported until now?
+
+TODO(jcm): Because folks might have had CUE that used this syntax, but enough
+time has now passed without it being mentioned on cuelang.org or the CUE
+language spec that we can assume it's not being used by anyone.
+
+## What's the replacement for list arithmetic operators?
+
+TODO(jcm): list.Repeat(), list.Concat(), and nested for loops. Show examples.
+
+## Which version of CUE removes list arithmetic operators?
+
+TODO(jcm): any version that starts `v0.11`.
+
+## Am I affected?
+
+TODO(jcm): probably not. FIXME: how to check?
+
+## I *am* affected! How can I fix my CUE?
+
+TODO(jcm): `cue fix` examples. Manual fixup examples.