Episode 13
013: Make Impossible States Impossible
We discuss two classic talks and how to apply the ideas of Make Impossible States Impossible to your codebase.
September 21, 202056m 43s
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Show Notes
The talks
- Make Impossible States Impossible from Elm Conf 2016
- Make Data Structures from Elm Europe 2018
- Elm Radio Episode 2: Intro to Opaque Types
Dealing with Impossible States
- Building up a "truth table" of possible states (see Evan's guide Types as Sets)
- Which rows are invalid?
- Create a new type with only the valid ones possible
More references
Tereza's
line-chartspackageTereza's elm Europe talk
Snapshot testing (also called Approval Tests)
Jeremy Fairbank's Boolean Blindness talk