* Plan: flesh out PR7 (MCP server + Agent Skill) design
stdio transport (no HTTP port), mlr mcp terminal in the main binary,
SDK-vs-handroll decision, tool list, in-process vs subprocess split,
run-tool safety (--no-shell prerequisite), single-sourced skill, tests.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Add mlr mcp: MCP server + agent playbook; --no-shell gate (#2098 PR7)
New terminal `mlr mcp` runs a Model Context Protocol server over stdio
(spawned by MCP clients; no network port), exposing five tools --
list_capabilities, which, validate_dsl, describe_data, run -- plus an
agent playbook as MCP prompt/resource. Catalog tools are served
in-process from the help registries; the rest subprocess this same
binary with MLR_ERRORS_JSON=1, a timeout, and an output cap.
Prerequisite: a new --no-shell flag / MLR_NO_SHELL env var (one-way
gate) disables the DSL system/exec functions, piped redirects, and
--prepipe/--prepipex; the MCP server sets it on the commands it runs
unless started with --allow-shell.
Adds the github.com/modelcontextprotocol/go-sdk dependency.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Force LF checkout for the embedded SKILL.md (Windows CI fix)
go:embed embeds checkout bytes, so a CRLF checkout on Windows made the
embedded playbook differ per platform and failed
TestPlaybookHasFrontmatter. Pin the file to eol=lf in .gitattributes.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Move no-shell test DSL into per-case mlr files (Windows CI fix)
Inline single-quoted DSL in cmd files is mangled by the Windows shell
(single quotes are not quote characters there); the harness's
put -f ${CASEDIR}/mlr pattern avoids shell quoting entirely.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
* Tier-2 structured verb options: OptionSpec, initial migration (#2098)
PR 3 of the AI-friendly roadmap (plans/plan-2098-llm.md).
Infrastructure:
- Add OptionSpec{Flag,Arg,Type,Desc,Repeatable,Values} to
pkg/transformers/aaa_record_transformer.go alongside TransformerSetup.
Type is one of: bool, string, int, float, csv-list, regex, filename,
format, enum. For type=="enum", Values lists the valid choices.
- Add Options []OptionSpec to TransformerSetup (nil = not yet migrated).
- Emit Options in VerbInfoForJSON (omitempty so unmigrated verbs stay
backward-compatible; agents check key presence for Tier-2 availability).
UsageText is always present as the Tier-1 prose fallback.
- Add VerbOptionsNilCheck() in aaa_verb_options_check.go: progress report
of migrated vs. unmigrated verbs, analogous to FLAG_TABLE.NilCheck().
- Wire verb-options-nil-check into mlr help (internal/docgen section).
Initial migration (5/70 verbs):
- nothing: empty Options (no verb-specific options, explicitly migrated)
- cat: -n (bool), -N (string), -g (csv-list), --filename, --filenum (bool)
- head: -g (csv-list), -n (int)
- tail: -g (csv-list), -n (int)
- tee: -a, -p (bool)
Tests:
- 5 new unit tests in aaa_transformer_json_test.go covering migrated/
unmigrated paths, field population, JSON round-trip, and key-presence.
- Regression test case 0003: mlr help verb-options-nil-check golden output.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
* Migrate all 70 verbs to structured OptionSpec; bump catalog schema to v2
Completes the Tier-2 migration started in the previous commit. Every verb
in TRANSFORMER_LOOKUP_TABLE now has a non-nil Options field.
- Workflow-migrated all 65 remaining verbs. Each Setup var now carries
Options: []OptionSpec{...} with Flag/Arg/Type/Desc fields. Verbs with
no verb-specific options (altkv, check, group-like, nothing, etc.) use
an empty slice to signal "migrated but no options."
- Drop `omitempty` from VerbInfoForJSON.Options: empty slices were silently
dropped, making migrated-no-option verbs indistinguishable from unmigrated
ones in JSON. Without omitempty: null=unmigrated, []=migrated-no-options,
[...]= migrated-with-options. Bump catalogSchemaVersion 1→2 for this shape
change.
- Replace the two "unmigrated-verb" unit tests (which used stats1 as an
example) with TestAllVerbsFullyMigrated (asserts every verb has non-nil
Options) and TestAllVerbsHaveOptionsKeyInJSON (asserts every migrated
verb emits the "options" key in JSON).
- Regenerate test/cases/cli-help/0003/expout: now reads
"Verb options migration: 70/70 migrated."
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
* remove a transitional helper
* git rms
* Render verb usage Options blocks from structured OptionSpec
Each verb's usage message and its Tier-2 OptionSpec list previously
duplicated the option text. New WriteVerbOptions (aaa_verb_usage.go)
renders the "Options:" block from the specs: aligned flag column,
descriptions word-wrapped at 80, uniform trailing -h|--help line.
- OptionSpec gains Aliases (JSON "aliases") so long-form spellings
like join's --lk|--left-keep-field-names survive in both outputs
- All 70 verbs migrated; options literals hoisted to package-level
vars (usage funcs can't reference their Setup var without a Go
init cycle)
- Hand-written per-option details the specs had condensed away are
merged into Desc, enriching the JSON catalog
- Non-option prose (examples, cross-references, dynamic accumulator
listings) kept verbatim
- Regenerated the six usage-embedding regression expectations and
the two affected doc pages
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Fix pre-existing usage-text bugs surfaced by the OptionSpec migration
- gap: usage said "One of -f or -g is required" but the parser takes
-n or -g
- seqgen: drop description line copy-pasted from cat ("Passes input
records directly to output...") which contradicted "Discards the
input record stream"
- utf8-to-latin1: description read inverted ("from Latin-1 to UTF-8")
- sec2gmtdate: usage said "../c/mlr" instead of "mlr"
- top: document the accepted-but-undocumented --max flag
- stats2: add linreg-pca to the -a enum values, matching the runtime
accumulator table
Regression expectations and docs regenerated accordingly.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Fix check usage sentence order; stats1 usage blank line to usage stream
- check: the description's second and third lines were swapped,
reading "Consumes records without printing any output, / Useful for
doing a well-formatted check on input data. / with the exception
that warnings are printed to stderr."
- stats1: a bare fmt.Println() in the usage func wrote its blank line
to process stdout instead of the usage output stream
Regression expectation and docs regenerated.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
* refine the plan
* Fix all staticcheck lint findings (uncapped)
golangci-lint's default max-same-issues=3 was hiding most of the backlog:
the true pre-fix count was 69 staticcheck findings, not 34. This fixes all
of them, driving staticcheck to zero:
- ST1023/QF1011 (37): omit explicit types inferred from the RHS
- S1009/S1031 (15): drop redundant nil checks before len()/range
- SA9003 (9): remove comment-only empty branches, keeping the comments
- QF1007 (3): merge conditional assignment into declaration
- QF1006 (3): lift break conditions into loop conditions
- QF1001 (3): apply De Morgan's law / name the negated predicate
Also updates plans/lintfixes.md with the cap discovery and the corrected
errcheck picture (1202 uncapped, ~949 of them fmt.Fprint*).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
* Drive errcheck to zero: config for bulk categories, propagate real errors
Adds .golangci.yml with errcheck exclude-functions for fmt.Fprint* (usage
printers), (*bufio.Writer).Write/WriteString (sticky errors, surfaced at the
now-checked final Flush), and (*strings.Builder).WriteString; pins
max-issues-per-linter/max-same-issues to 0 so CI reports true counts.
Real error paths now propagate instead of being dropped:
- Finalize{Reader,Writer}Options in join/put/filter/split/tee and the
repl/script entry points: 'mlr join -i badformat' now errors instead of
silently using wrong separators
- final output-stream Flush in pkg/stream: write failure no longer exits 0
- DSL emit/print/dump redirect writes, matching their sibling branches
- CSV writer WriteCSVRecordMaybeColorized, close-time Flush in file output
handlers, ENV[...] Setenv, REPL record-write and redirect-close errors
- termcvt write-side Close before rename (had "TODO: check return status")
The rest are deliberate ignores, marked with _ = and a comment where the
reason isn't obvious: unset-of-missing-path no-ops, read-side closes,
mid-stream FlushOnEveryRecord, init-time strftime registrations, in-memory
usage-capture pipes, and regtest-harness env/temp-file teardown.
golangci-lint now reports 0 issues on ./cmd/mlr ./pkg/... with all caps off.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Found with golang.org/x/tools/cmd/deadcode (rooted at cmd/mlr + tests)
and staticcheck U1000; each finding verified by hand before deletion.
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Replaces 100+ if/else-if chains on a single variable with tagged switch
statements across 72 files. The bulk are transformer option-parsing loops
(switch on opt string), plus a handful of value-dispatch sites in mlrval,
dsl/cst, repl, lib, auxents, and bifs. One case (surv.go) required a
labeled break to preserve the loop-exit behavior of the original else branch.
Fixes staticcheck QF1003 findings.
Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
* Add JSON index and mlr which capability router (#2098)
PR 2 of the AI-friendly roadmap (plans/plan-2098-llm.md):
- `mlr help --as-json --index` emits a lightweight [{kind,name,summary}]
index across all 651 catalog items (verbs, functions, flags, keywords),
sorted by kind then name. Agents use this as a cheap first call to pick
a verb before fetching its full entry.
- `mlr which "<query>"` is a new terminal that tokenizes a natural-language
query, scores every catalog item (name match +20/token, body match +5/token),
and returns ranked JSON [{kind,name,score,summary}]. Exit code 0 means a
confident match (at least one token hit the item name); exit code 2 means
low confidence. Agents branch on the exit code rather than parsing prose.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
* Move mlr which into pkg/terminals/help, deduplicate firstLine
pkg/terminals/which/ was a misplaced package: it imported the same four
catalog registries as pkg/terminals/help/ and duplicated the firstLine
helper. Moving the logic into help/entry_which.go fixes both issues:
- WhichMain and all which helpers now live alongside the other --as-json
catalog machinery in pkg/terminals/help/
- indexFirstLine (entry_json.go) and firstLine (which/entry.go) collapse
into a single firstLine shared by both files
- pkg/terminals/terminals.go calls help.WhichMain directly; the
pkg/terminals/which/ package is deleted
No behavior change.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
* Fix five Go-purity issues found in code review
1. Exit-code false positive: whichScore now returns (int, bool) where the
bool records whether any token hit the item name. WhichMain uses
results[0].nameHit for exit-code 0, so 4 body-only token hits (4×5=20)
no longer incorrectly signal a confident match.
2. Flag Summary inconsistency: whichSearch was setting Summary: fl.Help
directly for flags while using firstLine(...) for functions and keywords.
Changed to firstLine(fl.Help) so all four kinds behave consistently.
3+5. kindOrder/whichKindRank duplication: the verb<function<flag<keyword
ordering was encoded twice — as a local map[string]int in buildIndex and
as a switch in whichKindRank. Replaced both with a single package-level
kindRank() function. The map lookup also silently returned 0 (= verb rank)
for unknown kinds; the switch correctly returns 4 (sorts last).
4. extractIndexFlag/extractAsJSONFlag duplication: both had identical loop
bodies differing only in the sentinel string. Introduced a generic
extractFlag(args, flag) helper; both are now one-liners.
Also promoted whichStopwords to a package-level var so whichTokenize does
not allocate a new map on every call.
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
---------
Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
Emit Miller's existing help catalog (verbs, functions, flags, keywords)
as structured JSON so AI agents and tooling can model Miller's surface
without scraping prose. The --json token may appear anywhere on a
`mlr help ...` command line; plain text help is unchanged.
mlr help --json # full catalog
mlr help verb cat --json # one or more verbs
mlr help function splitax --json # one or more functions
mlr help flag --ifs --json # one or more flags
mlr help keyword ENV --json # one or more keywords
Functions and flags serialize fully (name/class/arity/help/examples;
section/name/alt_names/arg/help). Verbs carry a summary, ignores_input,
and captured raw usage_text as a Tier-1 fallback, since per-verb options
are prose-only today (each verb hand-writes its UsageFunc). Structured
verb options are a planned follow-on (see #2098).
This is a serialization layer over the existing registries -- no
refactor of the text-help path.
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
* initial attempt
* fix bash
* fix zsh
* Add shell-completion docs page
Documents the new 'mlr completion {bash,zsh}' feature: the then-chain
context model, install instructions for bash and zsh (including the macOS
bash-3.2 'eval' caveat and zsh compinit self-init), and examples of
context-aware completion. Added to the nav under "Miller in more detail".
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* Add enum value completion for format and separator flags
Completes the argument value for arg-taking main flags whose values are a
known set: file-format names for -i/-o/--io, separator aliases for
--ifs/--ofs/--ips/etc., and regex-separator aliases for --ifs-regex/--ips-regex.
Other arg-taking flags continue to fall back to filename completion.
Candidate sets come from new cli getters (GetFileFormatNames,
GetSeparatorAliasNames, GetSeparatorRegexAliasNames) that read the same maps
Miller uses at runtime, so there is no separate list to keep in sync. The
command-line walk now records which flag a value position belongs to.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* Include format-conversion keystroke-savers in bare-dash completion
Reverts the suppression of --c2j/--x2y-style flags from 'mlr -<TAB>'. The full
set of main flags (297) is now offered, matching what is valid on the command
line. GetFlagNames no longer takes an includeSuppressed argument.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* Complete terminal subcommands and top-level help/version flags
'mlr <TAB>' now offers subcommand names (help, version, repl, regtest, script,
completion, terminal-list) alongside verb names, and 'mlr -<TAB>' offers the
top-level terminal flags (-h, --help, --version, --bare-version, and the help
shorthands -g/-l/-L/-f/-F/-k/-K). Subcommand names are offered only as the
first non-flag token, where they are valid.
To let the completion engine know these names without an import cycle
(pkg/terminals imports pkg/terminals/completion), the canonical terminal names
and version-flag spellings are factored into a new leaf package
pkg/terminals/registry, imported by pkg/terminals, pkg/climain, and completion.
The help-flag spellings come from a new help.GetTerminalFlagNames derived from
the existing shorthand table, so nothing drifts.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* Complete 'mlr help' topics and topic arguments
'mlr help <TAB>' now completes help topics (flags, verb, function, keyword,
list-verbs, ...), and topics that take a name argument complete it too:
'mlr help verb <TAB>' -> verb names, 'mlr help function <TAB>' -> function
names, 'mlr help keyword <TAB>' -> keyword names, 'mlr help flag <TAB>' ->
flag names. 'mlr completion <TAB>' completes bash/zsh.
A terminal subcommand consumes the rest of the command line, so the walk now
returns a ctxTerminalArgs context carrying the terminal name and the words
typed after it. New getters supply the candidate names without drift:
help.GetTopicNames, help.GetFunctionNames/GetKeywordNames (wrapping new
cst.BuiltinFunctionManager.GetBuiltinFunctionNames and cst.GetKeywordNames).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* docs-neaten
* Move flag-value-candidate logic into pkg/cli; fix verb-flag collision
The mapping of which flags take a format/separator/regex-separator argument is
flag metadata, so it now lives with the flags in pkg/cli as
cli.FlagValueCandidates, alongside the existing GetFileFormatNames /
GetSeparatorAliasNames getters, replacing the maps that were in
pkg/terminals/completion/value_completion.go (now removed).
This also fixes a bug: value completion now applies only to main flags, not to
identically-spelled verb flags. Previously 'mlr uniq -o <TAB>' offered file
formats because uniq's -o (an output field name) collided with the main -o
format flag; it now correctly falls back to filename completion.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
* Default to "cat" verb when none is supplied (#2029)
Invocations like 'mlr --j2y' or 'mlr --c2p' previously failed with
"no verb supplied", forcing users to type the trailing 'cat'
explicitly for pure format conversions. Default the verb to 'cat'
in that case. Bare 'mlr' with no flags, no verb, and no files
still prints the main usage banner.
This handles flag-only invocations (e.g. 'mlr --c2j < input.csv'
or 'mlr --c2j --from input.csv'). File names without a preceding
verb are still parsed as verb candidates and continue to error if
not found; that broader change is out of scope here.
* Use ${MLR} substitution for bare-mlr regression case (#2029)
The regtester only substitutes the mlr executable when the cmd
starts with "mlr " (with a trailing space). The bare-mlr usage-banner
test had a cmd of just "mlr", so on CI -- which invokes regtest with
a relative path like 'test/../mlr' -- the test shelled out to a
literal 'mlr' that isn't on PATH and failed with exit 127.
Switch the cmd to ${MLR} (the regtester's explicit substitution
token) so the case runs the right binary in any invocation context.
* 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
The io/ioutil package has been deprecated as of Go 1.16 [1]. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.
[1]: https://golang.org/doc/go1.16#ioutil
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
* Absent-handling with short-circuiting operators `&&` and `||`
* add a missing file
* artifacts from make dev
* type-errors
* doc content
* artifacts from make dev
