Against Query Based Compilers

2 days ago

Query-based compilers apply incremental computation to compiling, allowing selective recomputation when inputs change.
Early cutoff optimization stops change propagation if a function's result remains unchanged despite input changes.
Incremental compilation is crucial for IDEs, requiring updates proportional to the change size, not the codebase size.
The principal limitation is that update work can't be smaller than the change in the result, exemplified by encryption functions with avalanche properties.
Zig's design allows independent file parsing and name resolution, reducing the need for queries, unlike Rust which requires crate-wide operations due to macros.
Language semantics can be leveraged to manually partition compilation tasks into coarse-grained, independent chunks.
In-place updates and diff-based approaches offer more direct methods for maintaining global structures like declaration maps.
Zig plans to use in-place patching for incremental linking, updating binaries without full recomputation.

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