--- title: Allow lists:member/2 in guard clause when List is a... description: A proposal on the Erlang Forums suggests extending Erlang guard clauses to allow lists:member/2 (or a new erlang:is_list_member/2) when the list argument is a... canonical: https://daily.dev/posts/allow-lists-member-2-in-guard-clause-when-list-is-a-literal-list-gvneyicbx twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Allow lists:member/2 in guard clause when List is a literal list | daily.dev og:description: A proposal on the Erlang Forums suggests extending Erlang guard clauses to allow lists:member/2 (or a new erlang:is_list_member/2) when the list argument is a... og:url: https://daily.dev/posts/allow-lists-member-2-in-guard-clause-when-list-is-a-literal-list-gvneyicbx og:image: https://api.daily.dev/og/posts/gvNEyiCbx.png og:image:alt: Allow lists:member/2 in guard clause when List is a literal list og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Allow lists:member/2 in guard clause when List is a literal list **[Erlang Forums](https://daily.dev/sources/erlangforums)** · 1 min read · 0 upvotes · 0 comments ## Summary A proposal on the Erlang Forums suggests extending Erlang guard clauses to allow lists:member/2 (or a new erlang:is_list_member/2) when the list argument is a compile-time literal, similar to existing guard-safe functions like is_integer/1. The motivation is to simplify pattern matching against a fixed set of known values, replacing verbose chains of orelse Key =:= const comparisons or repetitive function clause overloads. The proposal includes a code example showing how the syntax could be rewritten internally as a chain of =:= orelse comparisons at the AST/forms level, demonstrating that this transformation is technically feasible today via parse_transform, though considered hacky. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Erlang/OTP Proposals / Proposals: Ideas](https://daily.dev/posts/erlang-otp-proposals-proposals-ideas-sfj9ocegf) · Erlang Forums · 0 upvotes · 0 comments - [Guards\! 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