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gda_expr_cli tutorial

This tutorial shows how to run .decTest files with the GDA runner: select files and rows, shard a run, get JSON output and make unsupported rows fail the run. The runner is reached as floating-conformance --backend gda; below, gda abbreviates that command.

Quick start

Build the executable and run the committed smoke file:

just conformance build decimal_gda
_build/conformance/gda/native/release/build/gda-conformance.exe --backend gda
GDA expression execution summary
cases: …
selected cases: …
executable cases: …
passed cases: …
failed cases: 0
skipped cases: …
shard: 0/1

The exit status is 0 when no executable row failed.

Everyday tasks

Run files and directories

gda path/to/add.decTest path/to/multiply.decTest
gda .tmp/decimal/official          # every *.decTest directly in the directory

Files are sorted by path and executed as one run.

Select rows

gda --cases add001 add.decTest
gda --cases add001..add099,addx1001 add.decTest

A range matches ids of the same length that sort between its bounds.

Shard a run

gda --json --shard-count 4 --shard-index 0 .tmp/decimal/official
gda --json --shard-count 4 --shard-index 1 .tmp/decimal/official

Shard i runs the rows whose position (after the --cases filter, across all files) is i modulo the shard count. Adding the JSON counters of all shards gives the counters of the unsharded run.

Fail on unsupported rows

gda --strict-supported add.decTest

With --strict-supported the exit status is 1 if any selected row is unsupported or legacy, even when all executed rows pass.

Going further

  • just conformance run decimal_gda fetches the pinned official corpora, splits them into the phases of testdata/decimal/interpreter_stages.json and runs the shards in parallel with this runner.
  • gda_expr tutorial explains the row semantics and the pass rule.

Common pitfalls

  • --help returns 2. The runner prints its usage as an error; through the dispatcher, --help shows the dispatcher usage instead.
  • First parse error only. A malformed line stops the run with one file:line:1: message; fix it and rerun to see the next.
  • Non-recursive directories. Subdirectories are not searched.

Next steps