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add ref-return-scope table
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WalterBright committed May 17, 2023
1 parent a8d38c8 commit 9e98537
Showing 1 changed file with 30 additions and 3 deletions.
33 changes: 30 additions & 3 deletions spec/function.dd
Original file line number Diff line number Diff line change
Expand Up @@ -1905,9 +1905,32 @@ $(H3 $(LNAME2 ref-return-scope-parameters, Ref Return Scope Parameters))
When a parameter is passed by `ref` and has both the `return` and `scope` storage classes,
it gets $(LINK2 #return-scope-parameters, `return scope`) semantics if and only if the `return` and `scope`
keywords appear adjacent to each other, in that order.
Specifying a `return ref` and `scope` parameter enables returning a reference to a scope pointer.
In all other cases, the parameter has $(LINK2 #return-ref-parameters, `return ref`) semantics
and regular $(LINK2 #scope-parameters, `scope`) semantics.)
This behavior is summarized as follows:)

$(TABLE2 Combinations of `ref` $(COMMA) `return` and `scope`,
$(THEAD Order, Interpretation)
$(TROW `ref`, $(REF))
$(TROW `return`, `return`)
$(TROW `scope`, $(SCOPE))
$(TROW `return ref`, $(RETURN_REF))
$(TROW `ref return`, $(RETURN_REF))
$(TROW `return scope`, $(RETURN_SCOPE))
$(TROW `scope return`, $(RETURN_SCOPE))
$(TROW `ref scope`, $(REF) and $(SCOPE))
$(TROW `scope ref`, $(REF) and $(SCOPE))
$(TROW `ref return scope`, $(REF) and $(RETURN_SCOPE))
$(TROW `return scope ref`, $(REF) and $(RETURN_SCOPE))
$(TROW `ref scope return`, $(RETURN_REF) and $(SCOPE))
$(TROW `return ref scope`, $(RETURN_REF) and $(SCOPE))
$(TROW `scope return ref`, $(RETURN_REF) and $(SCOPE))
$(TROW `scope ref return`, $(RETURN_REF) and $(SCOPE))
)

$(BEST_PRACTICE do not use `ref return` and `scope return`.)

$(P Specifying a `return ref` and `scope` parameter enables returning a reference to a scope pointer.
In all other cases, the parameter has $(RETURN_REF) semantics
and regular $(SCOPE) semantics.)

---
U xerxes( ref return scope V v) // (1) ref and return scope
Expand Down Expand Up @@ -4230,3 +4253,7 @@ Macros:
TITLE=Functions
ASSIGNEXPRESSION=$(GLINK2 expression, AssignExpression)
CHECK=✔
REF=$(LINK2 #ref-params, `ref`)
RETURN_REF=$(LINK2 #return-ref-parameters, `return ref`)
SCOPE=$(LINK2 #scope-parameters, `scope`)
RETURN_SCOPE=$(LINK2 #return-scope-parameters, `return scope`)

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