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--- language:langs:refine [2024/08/11 10:31] – [Multiple refinement options] rajit
+++ language:langs:refine [2025/07/21 19:47] (current) – [Multiple refinement options] rajit
@@ Line 111: / Line 111: @@
 </code>
-In this case, "-ref=2" will //replace// the first refine block with the second. In other words, instance ''i1'' will not
+In this case, the ''refine<2> { ... }'' block behaves as ''refine { refine { ... } }''. In other words, when ''-ref=2'' is specified,
-be created, and ''-ref=2'' will select instance ''j2'' and the ''prs { ... }'' body.
+instance ''i1'' as well as ''j1'' will be created. Furthermore, the refinement option will eliminate the ''chp { ... }'' block from the first level refinement, as this has now been replaced with the second level refinement.
-In general, a refine block has an associated integer refinement level (the default is one). When ACT processes a block with refinement level //r//, it searches for the largest refinement block with level that is at most //r//. (Note: this may be no block, in which case the block is processed as normal.) If a refine block with level //l// is found, then it processes all non-language constructs within the block and then expands the refinement block with level //l// by decrementing the current refinement level by //l//.
+===== Refinement overrides =====
+Sometimes a refinement body needs to [[language:impl#overrides|override]] types. To support this, refinement bodies can be accompanied by refinement overrides. These are overrides that are only applied when the refinement is used.
+The syntax for providing refinement overrides is below:
+<code act>
+refine<2>  +{ e1of2 l; } {
+       inst1 i1;
+       ...
+ }
+</code>
+This will apply the refinement override for ''l'' when this particular refinement body is selected.