Edit a data instance

Query transformations produce a complete data candidate. Preview it before an explicit write: the edit changes instance meaning, and successful parsing checks syntax only. The query reference defines byte preservation, comment handling and candidate validation.

Replace an assignment expression

Create a small data file:

printf 'capacity = 20;\nweights = [1, -2, 3];\nunused = 0;\n' > data.dzn
zincite query --diff 'filter(name("capacity")) | set_value("30")' data.dzn
zincite-query 'filter(name("capacity")) | set_value("10 + 20")' data.dzn

set_value inserts the supplied expression as the selected assignment’s right-hand side. It does not evaluate the expression or create a missing assignment. Default editing prints the candidate; --diff prints a preview. Both leave the original file unchanged. Inspect the candidate, then apply it:

zincite query --write 'filter(name("capacity")) | set_value("30")' data.dzn

Filter literal elements or remove an assignment

zincite query --diff 'filter(name("weights")) | filter_elements(gt(0))' data.dzn
zincite query --diff 'filter(name("unused")) | remove' data.dzn

The reference describes literal inspection and filtering, including supported comparisons and collection shapes. Computed expressions are not arbitrary evaluated values. Removal includes attached comments; separated section comments remain.

Reduce enum membership

An enum with explicit member-keyed data can be reduced without a model:

printf 'Guests = {A, B, C};\n' > guests.dzn
zincite query --diff 'reduce_enum("Guests", keep("A", "C"))' guests.dzn

Supply --model model.mzn when positional array alignment needs declarations. Read the enum reduction contract before reducing dependent arrays, records or nested sets. Incomplete candidates retain located diagnostics and exit 1; --write refuses them. A smaller enum alone does not prove that all dependent data has been reduced.

Write restrictions and failure statuses are in the command reference. The support guide describes the semantic boundaries.