Changes in src/AST/porting.md [1e97287:54e41b3]

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• src/AST/porting.md (modified) (7 diffs)

src/AST/porting.md

@@ -6 +6 @@
   * specialization: strong pointer `ast::ptr<T>` is used for an ownership relationship
   * specialization: weak pointer `ast::readonly<T>` is used for an observation relationship
-  * added `ast::ptr_base<T,R>::as<S>()` with same semantics as `dynamic_cast<S*>(p)`
+* added `ast::ptr_base<T,R>::as<S>()` with same semantics as `dynamic_cast<S*>(p)`
+* added `N * ast::ptr_base<N,R>::set_and_mutate( const N * n )`
+  * takes ownership of `n`, then returns a mutable version owned by this pointer
+  * Some debate on whether this is a good approach:
+    * makes an easy path to cloning, which we were trying to eliminate
+      * counter-point: these are all mutating clones rather than lifetime-preserving clones, and thus "necessary" (for some definition)
+    * existing uses:
+      * `VariableExpr::VariableExpr`, `UntypedExpr::createDeref`
+        * both involve grabbing a type from elsewhere and making an `lvalue` copy of it
+        * could potentially be replaced by a view class something like this:
+          ```
+          template<unsigned Quals>
+          class AddQualifiersType final : public Type {
+            readonly<Type> base;
+            // ...
+          };
+          ```
+          * requires all `qualifiers` use (and related helpers) to be virtual, non-zero overhead
+          * also subtle semantic change, where mutations to the source decl now change the viewing expression
 
 ## Visitors ##
@@ -36 +54 @@
 * allows compiler to optimize virtual calls to static calls if given static type
 
-Pulled `FuncSpecifiers` and `StorageClasses` out of `Type` into their own headers
+Pulled `FuncSpecifiers`, `StorageClasses`, `CVQualifiers` out of `Type` into their own headers
 * Made `BFCommon` a `MakeBitfield` macro in its own header
   * added default and field-init constructors to macro
@@ -70 +88 @@
         * `Initializer` => `ast::Init`
     * `Statement` => `ast::Stmt`
+        * any field names should follow a similar renaming
   * because they don't really belong to `Type` (and for consistency with `Linkage::Spec`):
     * `Type::StorageClasses` => `ast::Storage::Classes`
           * `Type::Extern` etc. => `ast::Storage::Extern` etc.
+        * `Type::FuncSpecifiers` => `ast::Function::Specs`
+          * `Type::Inline` etc. => `ast::Function::Inline` etc.
+        * `Type::Qualifiers` => `ast::CV::Qualifiers`
+          * `Type::Const` etc. => `ast::CV::Const`
+          * couldn't break name-dependency loop without pulling `Qualifiers` out of `Type`
         * `LinkageSpec::Spec` => `ast::Linkage::Spec`
           * `LinkageSpec::Mangle` etc. => `ast::Linkage::Mangle` etc.
@@ -79 +103 @@
           * `LinkageSpec::isMangled(Spec)` etc. => `Spec.is_mangled` etc.
           * `LinkageSpec::Intrinsic` etc. => `ast::Linkage::Intrinsic` etc.
+* Boolean constructor parameters get replaced with a dedicated flag enum:
+  * e.g. `bool isVarLen;` => `enum LengthFlag { FixedLen, VariableLen };` `LengthFlag isVarLen;`
+  * field can be *read* in the existing boolean contexts, but requires documentation to write
+  * suggest naming all flag enums `FooFlag` to hint at boolean nature
 
 ## Specific Nodes ##
@@ -96 +124 @@
   * allows `newObject` as just default settings
 
+`NamedTypeDecl`
+* `parameters` => `params`
+
 `TypeDecl`
-* stripped `isComplete()` accessor in favour of direct access to `sized`
+* moved `TypeDecl::Kind` to `ast::TypeVar::Kind`
+
+`AggregateDecl`
+* `parameters` => `params`
 
 `EnumDecl`
@@ -105 +139 @@
 * Merged `inferParams`/`resnSlots` into union, as suggested by comment in old version
   * does imply get_/set_ API, and some care about moving backward
+* added constructor that sets result, for benefit of types that set it directly
+
+`ApplicationExpr`
+* `function` => `func`
+
+`UntypedExpr`
+* `function` => `func`
+* removed `begin_args()` in favour of `args.begin()`
+
+`MemberExpr`
+* **TODO** port setup of `result` in constructor
+
+`ConstantExpr`
+* inlined features of `Constant`, never used elsewhere, so removed `Constant`
+  * `Constant Constant::from_int(int)` etc. => `ConstantExpr * ConstantExpr::from_int(CodeLocation, int)`
+    * allocates new `ConstantExpr`, consistent with all existing uses
+
+`SizeofExpr`, `AlignofExpr`
+* `isType` deprecated in favour of boolean check on `type`
+  * all existing uses assume `type` set if true and don't use `expr`
+
+`AttrExpr`
+* did not port due to feature deprecation (e.g. `expr@attribute`)
+
+`LogicalExpr`
+* un-defaulted constructor parameter determining `&&` or `||`
+
+`Init`
+* `bool maybeConstruct` => `enum ConstructFlag { DoConstruct, MaybeConstruct }`
 
 `Label`
@@ -129 +192 @@
 * **TODO** port copy operator
   * Needs to be an almost-shallow clone, where the declarations are cloned only if needed
-  * **TODO** port DeclReplacer
+  * **TODO** port `DeclReplacer`
 * Still a `std::list` for children, rather than `std::vector`
   * allows more-efficient splicing for purposes of later code generation
 
 `Type`
+* `CV::Qualifiers` moved to end of constructor parameter list, defaulted to `{}`
+  * removed getter, setter in favour of public `qualifiers` field
+  * `ReferenceToType` puts a defaulted list of attributes after qualifiers
 * `forall` field split off into `ParameterizedType` subclass
   * any type that needs it can inherit from `ParameterizedType`
+    * currently `FunctionType`, `ReferenceToType`
 * `get_qualifiers()` replaced with accessor `qualifiers()` and mutator `set_qualifiers()`
-  * `get_CV()` replaced with `is_CV()` variants
+  * `get_const()` etc. replaced with `is_const()` etc. variants
+* `referenceDepth()` now returns `unsigned` rather than `int`
 * A number of features only supported on aggregates pushed down to `ReferenceToType`:
   * `attributes`: per docs [1] GCC only supports type attributes on aggregates and typedefs
     * suggest adding a `TypeWithAttributes` wrapper type if this proves insufficient
-  * `getAggr()`
-  * `genericSubstitution()`
+  * `getAggr()` => `aggr()`
+    * also now returns `const AggregateDecl *`
+* `genericSubstitution()` moved to own visitor in `AST/GenericSubstitution.hpp` **TODO** write
 
 `BasicType`
-* does not inherit from `Type` to allow pointer inlining
-* moved `Kind` before qualifiers in constructor to allow for default
 * **TODO** move `kind`, `typeNames` into code generator
 
+`ReferenceToType`
+* deleted `get_baseParameters()` from children
+  * replace with `aggr() ? aggr()->params : nullptr`
+* `parameters` => `params`
+* hoisted `lookup` implementation into parent, made non-virtual
+  * also changed to return vector rather than filling; change back if any great win for reuse
+* `baseStruct` etc. renamed to `base`
+
+`PointerType`/`ArrayType`
+* `is_array()` => `isArray()`
+* `bool isVarLen;` => `enum LengthFlag { FixedLen, VariableLen }; LengthFlag isVarLen;`
+* `bool isStatic;` => `enum DimensionFlag { DynamicDim, StaticDim }; DimensionFlag isStatic;`
+
+`FunctionType`
+* `returnVals` => `returns`
+* `parameters` => `params`
+* `bool isVarArgs;` => `enum ArgumentFlag { FixedArgs, VariableArgs }; ArgumentFlag isVarArgs;`
+
+`TypeInstType`
+* `bool isFtype` => `TypeVar::Kind kind`
+
+`TypeofType`
+* `bool is_basetypeof` => `enum Kind { Typeof, Basetypeof } kind;`
+
+`TupleType`
+* removed `value_type` typedef due to likely error
+  * if readded, should be `const Type *`
+
+`AttrType`
+* did not port due to deprecation of feature
+  * feature is `type@thing` e.g. `int@MAX`
+
 [1] https://gcc.gnu.org/onlinedocs/gcc-9.1.0/gcc/Type-Attributes.html#Type-Attributes