Improve existing support for the Ada extension feature of casing on composite values to handle casing on array values; in particular, casing on an array value whose subtype is unconstrained (or dynamically constrained) so that choices in the case statement may have differing lengths. This commit does not include support for pattern-bound identifiers in such cases.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* exp_ch5.adb (Expand_General_Case_Statement.Pattern_Match): Add
new function Indexed_Element to handle array element
comparisons. Handle case choices that are array aggregates,
string literals, or names denoting constants.
* sem_case.adb (Composite_Case_Ops.Array_Case_Ops): New package
providing utilities needed for casing on arrays.
(Composite_Case_Ops.Choice_Analysis): If necessary, include
array length as a "component" (like a discriminant) when
traversing components. We do not (yet) partition choice analysis
to deal with unequal length choices separately. Instead, we
embed everything in the minimum-dimensionality Cartesian product
space needed to handle all choices properly; this is determined
by the length of the longest choice pattern.
(Composite_Case_Ops.Choice_Analysis.Traverse_Discrete_Parts):
Include length as a "component" in the traversal if necessary.
(Composite_Case_Ops.Choice_Analysis.Parse_Choice.Traverse_Choice):
Add support for case choices that are string literals or names
denoting constants.
(Composite_Case_Ops.Choice_Analysis): Include length as a
"component" in the analysis if necessary.
(Check_Choices.Check_Case_Pattern_Choices.Ops.Value_Sets.Value_Index_Count):
Improve error message when capacity exceeded.
* doc/gnat_rm/implementation_defined_pragmas.rst: Update
documentation to reflect current implementation status.
* gnat_rm.texi: Regenerate.
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