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132 lines
3.3 KiB
Go
132 lines
3.3 KiB
Go
package transformers
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import (
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"fmt"
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"os"
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"strings"
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"github.com/johnkerl/miller/v6/pkg/cli"
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"github.com/johnkerl/miller/v6/pkg/lib"
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"github.com/johnkerl/miller/v6/pkg/types"
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)
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// ----------------------------------------------------------------
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const verbNameLabel = "label"
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var LabelSetup = TransformerSetup{
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Verb: verbNameLabel,
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UsageFunc: transformerLabelUsage,
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ParseCLIFunc: transformerLabelParseCLI,
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IgnoresInput: false,
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}
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func transformerLabelUsage(
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o *os.File,
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) {
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fmt.Fprintf(o, "Usage: %s %s [options] {new1,new2,new3,...}\n", "mlr", verbNameLabel)
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fmt.Fprintf(o, "Given n comma-separated names, renames the first n fields of each record to\n")
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fmt.Fprintf(o, "have the respective name. (Fields past the nth are left with their original\n")
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fmt.Fprintf(o, "names.) Particularly useful with --inidx or --implicit-csv-header, to give\n")
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fmt.Fprintf(o, "useful names to otherwise integer-indexed fields.\n")
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fmt.Fprintf(o, "\n")
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fmt.Fprintf(o, "Options:\n")
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fmt.Fprintf(o, "-h|--help Show this message.\n")
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}
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func transformerLabelParseCLI(
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pargi *int,
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argc int,
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args []string,
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_ *cli.TOptions,
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doConstruct bool, // false for first pass of CLI-parse, true for second pass
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) IRecordTransformer {
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// Skip the verb name from the current spot in the mlr command line
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argi := *pargi
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argi++
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for argi < argc /* variable increment: 1 or 2 depending on flag */ {
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opt := args[argi]
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if !strings.HasPrefix(opt, "-") {
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break // No more flag options to process
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}
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if args[argi] == "--" {
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break // All transformers must do this so main-flags can follow verb-flags
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}
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argi++
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if opt == "-h" || opt == "--help" {
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transformerLabelUsage(os.Stdout)
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os.Exit(0)
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} else {
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transformerLabelUsage(os.Stderr)
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os.Exit(1)
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}
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}
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// Get the label field names from the command line
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if argi >= argc {
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transformerLabelUsage(os.Stderr)
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os.Exit(1)
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}
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newNames := lib.SplitString(args[argi], ",")
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argi++
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*pargi = argi
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if !doConstruct { // All transformers must do this for main command-line parsing
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return nil
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}
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transformer, err := NewTransformerLabel(
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newNames,
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)
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if err != nil {
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fmt.Fprint(os.Stderr, err)
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os.Exit(1)
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// TODO: return nil to caller and have it exit, maybe
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}
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return transformer
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}
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// ----------------------------------------------------------------
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type TransformerLabel struct {
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newNames []string
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}
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func NewTransformerLabel(
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newNames []string,
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) (*TransformerLabel, error) {
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// TODO: make this a library function.
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uniquenessChecker := make(map[string]bool)
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for _, newName := range newNames {
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_, ok := uniquenessChecker[newName]
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if ok {
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return nil, fmt.Errorf(`mlr label: labels must be unique; got duplicate "%s"`, newName)
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}
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uniquenessChecker[newName] = true
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}
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tr := &TransformerLabel{
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newNames: newNames,
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}
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return tr, nil
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}
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// ----------------------------------------------------------------
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func (tr *TransformerLabel) Transform(
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inrecAndContext *types.RecordAndContext,
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outputRecordsAndContexts *types.List[*types.RecordAndContext],
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inputDownstreamDoneChannel <-chan bool,
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outputDownstreamDoneChannel chan<- bool,
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) {
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HandleDefaultDownstreamDone(inputDownstreamDoneChannel, outputDownstreamDoneChannel)
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if !inrecAndContext.EndOfStream {
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inrec := inrecAndContext.Record
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inrec.Label(tr.newNames)
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}
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outputRecordsAndContexts.PushBack(inrecAndContext) // including end-of-stream marker
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}
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