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[spec] Tweak array indexing expression docs & mention array bounds checks #4283

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[spec] Tweak array indexing expression docs & mention array bounds checks #4283

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6 changes: 6 additions & 0 deletions spec/arrays.dd
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Original file line number Diff line number Diff line change
Expand Up @@ -237,6 +237,9 @@ assert(b[1] == 2);
---------
)

$(P Dynamic and static array indexing is $(RELATIVE_LINK2 bounds, bounds checked)
by default.)

$(P See also $(GLINK2 expression, IndexOperation).)

$(H3 $(LNAME2 pointer-arithmetic, Pointer Arithmetic))
Expand Down Expand Up @@ -293,6 +296,9 @@ assert(b == [3]);
---------
)

$(P Each index in the slice expression is $(RELATIVE_LINK2 bounds, bounds checked)
by default.)

$(P $(I Expression)`[]` is shorthand for a slice of the entire array.
)

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11 changes: 6 additions & 5 deletions spec/expression.dd
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Expand Up @@ -1858,22 +1858,22 @@ $(GNAME IndexOperation):
$(I ArgumentList) and `$` appears in that scope only.
)

$(P If the $(I PostfixExpression) is an expression of static or
* If the $(I PostfixExpression) is an expression of static or
dynamic array type, the result of the indexing is an lvalue
of the *i*th element in the array, where `i` is an integer
evaluated from $(I ArgumentList).
If $(I PostfixExpression) is a pointer `p`, the result is
See $(DDSUBLINK spec/arrays, indexing, array indexing).

* If $(I PostfixExpression) is a $(DDSUBLINK spec/type, pointers, pointer) `p`, the result is
`*(p + i)` (see $(RELATIVE_LINK2 pointer_arithmetic, Pointer Arithmetic)).
)

$(P If the base $(I PostfixExpression) is a $(DDSUBLINK spec/template, variadic-templates, $(I ValueSeq))
* If the base $(I PostfixExpression) is a $(DDSUBLINK spec/template, variadic-templates, $(I ValueSeq))
then the $(I ArgumentList) must consist of only one argument,
and that must be statically evaluatable to an integral constant.
That integral constant $(I n) then selects the $(I n)th
expression in the $(I ValueSeq), which is the result
of the $(I IndexOperation).
It is an error if $(I n) is out of bounds of the $(I ValueSeq).
)

$(P The index operator can be $(DDSUBLINK spec/operatoroverloading, array, overloaded).
Using multiple indices in *ArgumentList* is only supported for operator
Expand Down Expand Up @@ -1907,6 +1907,7 @@ $(GNAME Slice):
referencing elements `a[i]` to `a[j-1]` inclusive, where `i`
and `j` are integers evaluated from the first and second $(I
AssignExpression) respectively.
See $(DDSUBLINK spec/arrays, slicing, array slicing).

* If the base $(I PostfixExpression) is a $(DDSUBLINK spec/type, pointers, pointer) `p`, the result
will be a dynamic array referencing elements from `p[i]` to `p[j-1]`
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