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Goes towards implementing #10598, which asks for a spread operator in lists, in records, and when calling commands (continuation of #11006, which only implements it in lists) # Description This PR is for adding a spread operator that can be used when building records. Additional functionality can be added later. Changes: - Previously, the `Expr::Record` variant held `(Expression, Expression)` pairs. It now holds instances of an enum `RecordItem` (the name isn't amazing) that allows either a key-value mapping or a spread operator. - `...` will be treated as the spread operator when it appears before `$`, `{`, or `(` inside records (no whitespace allowed in between) (not implemented yet) - The error message for duplicate columns now includes the column name itself, because if two spread records are involved in such an error, you can't tell which field was duplicated from the spans alone `...` will still be treated as a normal string outside records, and even in records, it is not treated as a spread operator when not followed immediately by a `$`, `{`, or `(`. # User-Facing Changes Users will be able to use `...` when building records. ``` > let rec = { x: 1, ...{ a: 2 } } > $rec ╭───┬───╮ │ x │ 1 │ │ a │ 2 │ ╰───┴───╯ > { foo: bar, ...$rec, baz: blah } ╭─────┬──────╮ │ foo │ bar │ │ x │ 1 │ │ a │ 2 │ │ baz │ blah │ ╰─────┴──────╯ ``` If you want to update a field of a record, you'll have to use `merge` instead: ``` > { ...$rec, x: 5 } Error: nu:🐚:column_defined_twice × Record field or table column used twice: x ╭─[entry #2:1:1] 1 │ { ...$rec, x: 5 } · ──┬─ ┬ · │ ╰── field redefined here · ╰── field first defined here ╰──── > $rec | merge { x: 5 } ╭───┬───╮ │ x │ 5 │ │ a │ 2 │ ╰───┴───╯ ``` # Tests + Formatting # After Submitting |
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