After batch-arena field allocation, profiling cat over 1M-record CSV showed
the remaining ~5M allocations were almost entirely per-record (one each):
the Mlrmap struct, the RecordAndContext wrapper, the CSV writer's []string,
and the go-csv parser's own buffers.
Address the first three:
- mlrval.RecordArena gains NewRecord(), vending the Mlrmap struct itself from
a per-batch slab (respecting --no-hash-records). Rolled out to every
line-based reader (CSV, CSV-lite, TSV, DKVP, NIDX, PPRINT, XTAB, DKVPX) in
place of NewMlrmapAsRecord.
- The CSV reader batch-allocates RecordAndContext wrappers from a per-batch
slab instead of one heap object per record (comment/output-string entries
still allocate individually, but they are rare).
- RecordWriterCSV reuses a single fieldsBuffer []string across records instead
of allocating one per Write; WriteCSVRecordMaybeColorized consumes it
synchronously and the writer is single-goroutine, so this is safe.
Effect (big.*, 1M records, cat, best of 5):
csv 0.26 -> 0.22
dkvp 0.51 -> 0.45 (Mlrmap slab)
For CSV, cat's allocation-object count drops ~5.0M -> ~2.1M. The remaining
~2M are the go-csv parser's per-record backing string and field slice, which
are intrinsic to parsing and would require a zero-copy/batch-slab parser
rework. A CPU profile of cat now shows it is I/O-bound (syscall ~56%, bufio
read+flush), with allocation/GC down to ~10% -- i.e. further allocation
trimming no longer moves cat's wall-clock. GOGC=off confirms (no change).
Verified: go test ./pkg/... and full regression suite pass; output is
byte-identical across all formats including record-retaining verbs (tac),
hashed and --no-hash-records.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* Fix column alignment for wide and combining Unicode chars (#1520, #379)
PPRINT, markdown-aligned, and XTAB writers measured column widths with
utf8.RuneCountInString, which counts codepoints rather than terminal
display columns. East-Asian fullwidth characters (counted as 1 but
displayed as 2) and zero-width combining marks (counted as 1 but
displayed as 0) both caused misalignment.
Add lib.DisplayWidth wrapping uniseg.StringWidth, and use it from the
three writers. The XTAB right-aligned path also drops fmt.Sprintf with
%*s since Go's %*s pads by rune count too.
UTF8Strlen is unchanged so DSL strlen semantics are preserved.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
* Fix PPRINT alignment with multi-character OFS (#1819)
Previously, writePadding repeated the OFS string for each padding slot, so
non-space or multi-character OFS values produced misaligned columns and
leaked the separator into padding (e.g. --ofs=XY yielded aXYXYXYXYb).
Pad with spaces instead, leaving OFS to act only as the column separator.
The default single-space OFS is unchanged.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
* Use non-space multi-char OFS in test 0021 for Windows portability
PowerShell collapses single-quoted ' ' in command lines, which broke
the test on the windows-latest CI runner. Switch to --ofs XY, which
exercises the same multi-character padding code path without shell
quoting hazards.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
PPRINT, markdown-aligned, and XTAB writers measured column widths with
utf8.RuneCountInString, which counts codepoints rather than terminal
display columns. East-Asian fullwidth characters (counted as 1 but
displayed as 2) and zero-width combining marks (counted as 1 but
displayed as 0) both caused misalignment.
Add lib.DisplayWidth wrapping uniseg.StringWidth, and use it from the
three writers. The XTAB right-aligned path also drops fmt.Sprintf with
%*s since Go's %*s pads by rune count too.
UTF8Strlen is unchanged so DSL strlen semantics are preserved.
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Adds a new Markdown-only flag --omd-aligned (alias --omarkdown-aligned)
that left-justifies cells and pads each column to a uniform width.
The rendered table is unaffected; the goal is readability of the raw
markdown source. The flag implies --omd, so users do not need to pass
both.
Implementation batches records by schema (like pprint), computes max
column widths, then emits header / separator / data rows with bars
vertically aligned. Default markdown writer behavior is unchanged.
* fix: preserve key order in YAML output
MlrmapToYAMLNative converted the ordered Mlrmap to map[string]interface{},
which loses insertion order. yaml.v3.Marshal then sorts Go map keys
alphabetically, so YAML output always had sorted keys despite other formats
(JSON, pretty-print) correctly preserving order.
Switch to building yaml.Node trees that preserve the Mlrmap's linked-list
iteration order. Use yaml.Node.Encode for scalar values to correctly handle
edge cases (NaN/Inf, non-UTF-8 strings).
Fixes#2028.
* Update pkg/mlrval/mlrval_yaml_test.go with copilot code-review feedback
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---------
Co-authored-by: lawrence3699 <lawrence3699@users.noreply.github.com>
Co-authored-by: John Kerl <kerl.john.r@gmail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
* Switch to integer ranges in for loops
Signed-off-by: Stephen Kitt <steve@sk2.org>
* Switch to slices functions where appropriate
A number of utility functions can be replaced outright; since Miller
can technically be used as a library, these are deprecated rather than
removed. go:fix directives ensure that they can be replaced
automatically.
Signed-off-by: Stephen Kitt <steve@sk2.org>
* Switch to reflect.TypeFor
This is slightly more efficient than TypeOf when the type is known at
compile time.
Signed-off-by: Stephen Kitt <steve@sk2.org>
* Switch to strings.SplitSeq instead of strings.Split
SplitSeq results in fewer allocations.
Signed-off-by: Stephen Kitt <steve@sk2.org>
* Drop obsolete build directives
Signed-off-by: Stephen Kitt <steve@sk2.org>
* Use min/max instead of explicit comparisons
Signed-off-by: Stephen Kitt <steve@sk2.org>
* Append slices instead of looping
Signed-off-by: Stephen Kitt <steve@sk2.org>
---------
Signed-off-by: Stephen Kitt <steve@sk2.org>
* reader
* record writer
* pkg/output/record_writer_dcf.go
* test/input/test.dcf
* test/cases/io-dcf/
* pkg/cli/option_parse.go
* make fmt
* make dev
* docs and `make dev`
* docs/src/proposal-yaml-io.md
* initial step
* Add `--y2c` etc
* test cases
* docs
* more testing
* more
* more test cases
* git rm docs/src/proposal-yaml-io.md
* make dev
* ylistwrap -> yarray
* Auto-unsparsify CSV
* Update unit-test cases
* More unit-test cases
* Key-change handling for CSV output
* Same for TSV, with unit-test and doc updates
