From: "Richard W.M. Jones" <firstname.lastname@example.org> To: email@example.com Subject: [Caml-list] Syntax puzzle / suggestion Date: Fri, 9 Aug 2019 15:27:20 +0100 Message-ID: <firstname.lastname@example.org> (raw) Let's imagine you have a list of named things, but you also want to collect them up into a single list. For example: let item1 = "hello" let item2 = "world" let all_items = [ item1; item2 ] let () = printf "item1 = %s\n" item1; printf "all_items = %s\n" (String.concat ", " all_items) This is fine, but there's a danger that a programmer could add item3 but forget to add it to the "all_items" list. (In the real world problem to which this applies, my items are complex and lengthy structures, and the "all-things-list" is well off the bottom of the page when you're viewing the top item). My idea to fix this was to write: let all_items = [ ("hello" as item1); ("world" as item2); ] Actually I was slightly surprised to find this doesn't compile. I guess because "as" can only be used like this in patterns, not expressions. Also the scoping is wrong because the "as item1" if it worked probably wouldn't apply outside the list. I haven't worked out if it's possible to write this in ordinary OCaml, although I suppose ppx could solve it. Any ideas if this is possible? Rich.
next reply index Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-09 14:27 Richard W.M. Jones [this message] 2019-08-09 14:39 ` Gabriel Scherer 2019-08-09 14:45 ` Richard W.M. Jones 2019-08-09 14:48 ` Martin Riener 2019-08-10 5:19 ` rixed 2019-08-09 14:53 ` Josh Berdine 2019-08-10 15:18 ` Oliver Bandel 2019-08-10 20:34 ` Chet Murthy 2019-08-09 14:56 ` Frédéric Bour
Reply instructions: You may reply publically to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --email@example.com \ --firstname.lastname@example.org \ --email@example.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
caml-list - the Caml user's mailing list Archives are clonable: git clone --mirror https://inbox.ocaml.org/caml-list AGPL code for this site: git clone https://public-inbox.org/ public-inbox