internals

How jq Label and Break Enable Early Exit: Implementation and Usage

April 11, 2026 jqlang/jq ↗

The label and break constructs in jq compile to a bytecode pattern using GENLABEL, try-catch, and BACKTRACK opcodes to provide the only mechanism for aborting a running pipeline before its normal completion.

The jqlang/jq repository implements these specialized control-flow instructions to escape deep computation trees that would otherwise run to completion. Unlike standard filters that transform data, label and break work in tandem to create runtime markers that, when triggered, unwind the execution stack through a controlled backtracking mechanism implemented

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