Added go template processor

textfilters.go

@@ -10,6 +10,8 @@ import (
 	"strconv"
 	"strings"
 
+	"text/template"
+
 	"gopkg.in/yaml.v3"
 	"ucl.lmika.dev/ucl"
 )
@@ -24,11 +26,20 @@ type TextProcessor struct {
 	// Analyses the supplied text. This is used for extracting information from the text input. The result
 	// will be displayed in the status bar. Multiple selected regions will be returned as a single string separated by line numbers.
 	Analyze TextAnalyzer
+
+	// FilterWithArg requests some input from the user. If the user supplies it, it will return a text filter
+	// to process the input.
+	FilterWithArg *FilterWithArg
 }
 
 type TextFilter func(ctx context.Context, input string) (resp TextFilterResponse, err error)
 type TextAnalyzer func(ctx context.Context, input string) (resp string, err error)
 
+type FilterWithArg struct {
+	Label     string
+	OnConfirm func(ctx context.Context, input string) (filter TextFilter, err error)
+}
+
 type TextFilterResponse struct {
 	Output string
 	Append bool
@@ -165,6 +176,45 @@ var TextFilters = map[string]TextProcessor{
 		},
 	},
 
+	"template-each-line": {
+		Label:       "Lines: Go Template…",
+		Description: "Evaluates the input as a Go template and replaces each line with the result.",
+		FilterWithArg: &FilterWithArg{
+			Label: "Template",
+			OnConfirm: func(ctx context.Context, prompt string) (filter TextFilter, err error) {
+				tmpl, err := template.New("").Parse(prompt)
+				if err != nil {
+					return nil, err
+				}
+
+				return func(ctx context.Context, input string) (resp TextFilterResponse, err error) {
+					var (
+						dst     bytes.Buffer
+						dstLine bytes.Buffer
+					)
+					scnr := bufio.NewScanner(strings.NewReader(input))
+					isFirst := true
+					for scnr.Scan() {
+						if isFirst {
+							isFirst = false
+						} else {
+							dst.WriteString("\n")
+						}
+
+						dstLine.Reset()
+						line := scnr.Text()
+						if err := tmpl.Execute(&dstLine, line); err != nil {
+							return TextFilterResponse{}, err
+						}
+						dst.WriteString(dstLine.String())
+					}
+
+					return TextFilterResponse{Output: dst.String()}, nil
+				}, nil
+			},
+		},
+	},
+
 	"ucl-evaluate": {
 		Label:       "UCL: Evaluate",
 		Description: "Evaluates the input as a UCL expression and displays the result in the status bar.",