providers/import: Add panic function

providers/import/import.go

@@ -1,5 +1,7 @@
 package impor
 
+import "fmt"
+import "errors"
 import "strings"
 import "html/template"
 import "git.tebibyte.media/sashakoshka/step"
@@ -22,6 +24,7 @@ func (this *Provider) FuncMapFor (document *step.Document) template.FuncMap {
 		document: document,
 	}
 	return template.FuncMap {
+		"panic":       stat.funcPanic,
 		"execute":     stat.funcExecute,
 		"include":     stat.funcInclude,
 		"includeHTML": stat.funcIncludeHTML,
@@ -32,6 +35,14 @@ type state struct {
 	document *step.Document
 }
 
+func (this *state) funcPanic (message any) (string, error) {
+	if err, ok := message.(error); ok {
+		return "", err
+	} else {
+		return "", errors.New(fmt.Sprint(message))
+	}
+}
+
 func (this *state) funcExecute (name string, data any) (step.ExecutionResult, error) {
 	document, err := this.document.Environment().Parse(name)
 	if err != nil { return step.ExecutionResult { }, err }