[squeak-dev] Further steps on BlockClosure controlling methods (was: The Trunk: Kernel-ct.1295.mcz)

Thiede, Christoph Christoph.Thiede at student.hpi.uni-potsdam.de
Sat Mar 7 14:01:50 UTC 2020

Take this as a memo for myself -- of course, it would be great to hear your ideas about the following points!

Further steps:

  *   Implement the same return logic for #while(True|False)[:]. This might also require changes in the Compiler.
Inline #whileNil(:) implementation as well.
General question: Is there such a thing as "too much inlining"? Would it be desirable to inline #cull: and others? Where do we draw the line between performance and Smalltalk-essential explorability?
Implement all these controlling methods in a way that could work without inlining (though slow). At the moment, #whileTrue: refers to itself.
An approach that completely foregos inline code would either need to use recursion (linear complexity) or "thisContext restart" (constant time complexity).
  *   Should we maybe find a way to highlight methods that are inlined? For example, by using a pragma <inlined>. Or rather ask Encoder for it than storing this information in the methods.
Should we warn or forbid the user to override (or even overwrite) such methods?
     *   Similar concern: It is dangerous to override #class et al., should we warn here, too?



Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von commits at source.squeak.org <commits at source.squeak.org>
Gesendet: Dienstag, 3. März 2020 22:38 Uhr
An: squeak-dev at lists.squeakfoundation.org; packages at lists.squeakfoundation.org
Betreff: [squeak-dev] The Trunk: Kernel-ct.1295.mcz

Nicolas Cellier uploaded a new version of Kernel to project The Trunk:

==================== Summary ====================

Name: Kernel-ct.1295
Author: ct
Time: 24 January 2020, 5:20:51.814415 pm
UUID: 18ea3b5d-ee42-2944-9d01-aa48e43207a7
Ancestors: Kernel-nice.1292

Extends BlockClosure >> #whileNil: by returning the final non-nil value. Adds #whileNil analogous to #whileTrue and #whileFalse.

        [Project uiManager chooseFrom: #(foo bar) values: #(Foo Bar)] whileNil.

        [Project uiManager chooseFrom: #(foo bar) values: #(Foo Bar)] whileNil: [self inform: 'You have to decide!']

=============== Diff against Kernel-nice.1292 ===============

Item was added:
+ ----- Method: BlockClosure>>whileNil (in category 'controlling') -----
+ whileNil
+        "Unlike #whileTrue/False this is not compiled inline."
+        | result |
+        [(result := self value) isNil] whileTrue.
+        ^ result
+        !

Item was changed:
  ----- Method: BlockClosure>>whileNil: (in category 'controlling') -----
  whileNil: aBlock
         "Unlike #whileTrue/False: this is not compiled inline."
+        | result |
+        [(result := self value) isNil] whileTrue: [aBlock value].
+        ^ result
-        ^ [self value isNil] whileTrue: [aBlock value]

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