From: Bob Duff <d...@adacore.com>
Misc comment corrections and clarifications in sinfo.ads
related to generic formal packages.
gcc/ada/
* sinfo.ads: Misc comment corrections and clarifications.
The syntax for GENERIC_ASSOCIATION and FORMAL_PACKAGE_ACTUAL_PART
was wrong.
Emphasize that "others => <>" is not represented as an
N_Generic_Association (with or without Box_Present set),
and give examples illustrating the various possibilities.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/sinfo.ads | 61 +++++++++++++++++++++++++++++++++++------------
1 file changed, 46 insertions(+), 15 deletions(-)
diff --git a/gcc/ada/sinfo.ads b/gcc/ada/sinfo.ads
index 228082eb823..599f4f63cce 100644
--- a/gcc/ada/sinfo.ads
+++ b/gcc/ada/sinfo.ads
@@ -1574,9 +1574,9 @@ package Sinfo is
-- Instance_Spec
-- This field is present in generic instantiation nodes, and also in
-- formal package declaration nodes (formal package declarations are
- -- treated in a manner very similar to package instantiations). It points
- -- to the node for the spec of the instance, inserted as part of the
- -- semantic processing for instantiations in Sem_Ch12.
+ -- treated similarly to package instantiations). It points to the node
+ -- for the spec of the instance, inserted as part of the semantic
+ -- processing for instantiations in Sem_Ch12.
-- Is_Abort_Block
-- Present in N_Block_Statement nodes. True if the block protects a list
@@ -3639,8 +3639,8 @@ package Sinfo is
-- The only choice that appears explicitly is the OTHERS choice, as
-- defined here. Other cases of discrete choice (expression and
- -- discrete range) appear directly. This production is also used
- -- for the OTHERS possibility of an exception choice.
+ -- discrete range) appear directly. N_Others_Choice is also used
+ -- in exception handlers and generic formal packages.
-- Note: in accordance with the syntax, the parser does not check that
-- OTHERS appears at the end on its own in a choice list context. This
@@ -7139,6 +7139,7 @@ package Sinfo is
-- GENERIC_ASSOCIATION ::=
-- [generic_formal_parameter_SELECTOR_NAME =>]
+ -- EXPLICIT_GENERIC_ACTUAL_PARAMETER
-- Note: unlike the procedure call case, a generic association node
-- is generated for every association, even if no formal parameter
@@ -7149,7 +7150,8 @@ package Sinfo is
-- In Ada 2005, a formal may be associated with a box, if the
-- association is part of the list of actuals for a formal package.
-- If the association is given by OTHERS => <>, the association is
- -- an N_Others_Choice.
+ -- an N_Others_Choice (not an N_Generic_Association whose Selector_Name
+ -- is an N_Others_Choice).
-- N_Generic_Association
-- Sloc points to first token of generic association
@@ -7442,7 +7444,7 @@ package Sinfo is
-- Defining_Identifier
-- Name
-- Generic_Associations (set to No_List if (<>) case or
- -- empty generic actual part)
+ -- empty formal package actual part)
-- Box_Present
-- Instance_Spec
-- Is_Known_Guaranteed_ABE
@@ -7452,21 +7454,50 @@ package Sinfo is
--------------------------------------
-- FORMAL_PACKAGE_ACTUAL_PART ::=
- -- ([OTHERS] => <>)
+ -- ([OTHERS =>] <>)
-- | [GENERIC_ACTUAL_PART]
- -- (FORMAL_PACKAGE_ASSOCIATION {. FORMAL_PACKAGE_ASSOCIATION}
+ -- | (FORMAL_PACKAGE_ASSOCIATION {, FORMAL_PACKAGE_ASSOCIATION}
+ -- [, OTHERS => <>])
-- FORMAL_PACKAGE_ASSOCIATION ::=
-- GENERIC_ASSOCIATION
-- | GENERIC_FORMAL_PARAMETER_SELECTOR_NAME => <>
-- There is no explicit node in the tree for a formal package actual
- -- part. Instead the information appears in the parent node (i.e. the
- -- formal package declaration node itself).
-
- -- There is no explicit node for a formal package association. All of
- -- them are represented either by a generic association, possibly with
- -- Box_Present, or by an N_Others_Choice.
+ -- part, nor for a formal package association. A formal package
+ -- association is represented as a generic association, possibly with
+ -- Box_Present.
+ --
+ -- The "others => <>" syntax (both cases) is represented as an
+ -- N_Others_Choice (not an N_Generic_Association whose Selector_Name
+ -- is an N_Others_Choice). This admittedly odd representation does not
+ -- lose information, because "others" cannot be followed by anything
+ -- other than "=> <>". Thus:
+ --
+ -- "... is new G;"
+ -- The N_Formal_Package_Declaration has empty Generic_Associations,
+ -- and Box_Present = False.
+ --
+ -- "... is new G(<>);"
+ -- The N_Formal_Package_Declaration has empty Generic_Associations,
+ -- and Box_Present = True.
+ --
+ -- "... is new G(others => <>);"
+ -- The N_Formal_Package_Declaration has Generic_Associations with a
+ -- single element, which is an N_Others_Choice.
+ -- The N_Formal_Package_Declaration has Box_Present = False.
+ --
+ -- "... is new G(X, F => Y, others => <>);"
+ -- The N_Formal_Package_Declaration has Generic_Associations with
+ -- three elements, the last of which is an N_Others_Choice.
+ -- The N_Formal_Package_Declaration has Box_Present = False.
+ --
+ -- "... is new G(F1 => X, F2 => <>, others => <>);"
+ -- The N_Formal_Package_Declaration has Generic_Associations with
+ -- three elements. The first is an N_Generic_Association with
+ -- Box_Present = False. The second is an N_Generic_Association with
+ -- Box_Present = True. The last is an N_Others_Choice.
+ -- The N_Formal_Package_Declaration has Box_Present = False.
---------------------------------
-- 13.1 Representation clause --
--
2.43.2
