diff options
Diffstat (limited to 'chapter09/README.md')
| -rw-r--r-- | chapter09/README.md | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/chapter09/README.md b/chapter09/README.md index 2ea99ac0..d3b55a19 100644 --- a/chapter09/README.md +++ b/chapter09/README.md @@ -48,6 +48,14 @@ get the same result - and can be shared. constant 17 is not the same as 99, but both are the same `ConstantNode` class and label. The `eq` and `hash` calls check (or hash) these extra bits. +Note the intentional *value* equality here. In many places in Simple we use +*reference* equality - e.g. node/edge maintenance is via reference equality, not +value equality, so e.g. the `Utils.find()` call finds via reference. Through +out the Simple project whenever a Node lookup is happening, beware if its via +*value* or *reference* equality; this is not always explicitly called out but +should be obvious from context. + + Since we edit the graph a lot, Nodes can have their inputs change which changes their hash which means they can't be found in the GVN table. E.g. we swap out the `Add` for a `Con` in: |