value: model the variant_ish concept (index/valueless/visit)#1
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jcelerier wants to merge 1 commit into
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value: model the variant_ish concept (index/valueless/visit)#1jcelerier wants to merge 1 commit into
jcelerier wants to merge 1 commit into
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jk::value wraps the variant in a member, so it satisfied none of the variant concepts used by generic consumers (e.g. Avendish's back-end bindings): value.index()/visit(f, value) didn't resolve. Forward the variant interface (index, valueless_by_exception, and an ADL visit on the wrapped member) so jk::value is usable directly as a variant value without exposing .v at every call site. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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Summary
jk::valuekeeps its variant in a.vmember, so it matches none of the standard variant concepts —value.index()and an unqualifiedvisit(f, value)don't resolve. Generic consumers that program against a variant interface (e.g. Avendish's pd/max/wasm back-end bindings) therefore can't accept ajk::valueoutput directly.This adds, on
jk::value:index()/valueless_by_exception()members,visit(f, value)(lvalue/const/rvalue) forwarding to the configured variant'svisiton.v.No behaviour change for existing code (jk internals already call
config::variant_ns::visitexplicitly); this only makesjk::valuemodel the variant interface for outside concept-based code.Test plan
-std=c++20) with the defaultstd::variantconfig; lvalue/const/rvaluevisitandindex()resolve.🤖 Generated with Claude Code