Changeset 275f4b4

Timestamp:

Aug 10, 2017, 3:39:08 PM (7 years ago)

Author:

Aaron Moss <a3moss@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, resolv-new, with_gc

Children:

cd7ef0b

Parents:

2edd80ae

Message:

Update discussion of cost tuple

File:

• doc/working/resolver_design.md (modified) (1 diff)

doc/working/resolver_design.md

@@ -91 +91 @@
 ## Conversion Costs ##
 Each possible resolution of an expression has a _cost_ tuple consisting of 
-the following components: _unsafe_ conversion cost, _polymorphic_ 
-specialization cost, _safe_ conversion cost, a count of _explicit_ 
-conversions, and _qualifier_ conversion cost. 
+the following components:
+1. _unsafe_ conversion cost: summed degree of unsafe conversions; unlike CFA03, this is not a simple count of conversions (for symmetry with the safe conversions)
+2. _polymorphic unifications_: count of parameters and return values bound to some polymorphic type for boxing
+3. _type variables_: number of polymorphic type variables bound
+4. negated _type specializations_: Each type assertion specializes the polymorphism, thus decreasing the cost; nested polymorphic types (e.g. `T*`) are also counted as specializations
+5. _safe_ conversions: summed degree of safe conversions
+6. _qualifier_ conversions: summed degree of qualifier and reference conversions
 These components are lexically-ordered and can be summed element-wise; 
 summation starts at `(0, 0, 0, 0, 0)`.
+
+**TODO** update below for consistency with this
 
 ### Lvalue and Qualifier Conversions ###