Add new restructureOrLines match target + update join command to use it

src/vm/commands/command.ts

@@ -26,6 +26,15 @@ export const joinDestructured = (val: StrDestructured['value']): string =>
         .map(part => `${part.prefix || ''}${part.value}`)
         .join('')
 
+export const destructureToLines = (val: string): StrDestructured['value'] => val
+    .split('\n')
+    .map((line, idx) => {
+        if ( idx ) {
+            return { prefix: '\n', value: line }
+        }
+        return { value: line }
+    })
+
 export type StrRVal =
     { term: 'string', value: string, literal?: true }
     | { term: 'int', value: number }

src/vm/commands/join.ts

@@ -20,7 +20,7 @@ export class Join extends Command<{ with?: StrTerm }> {
 
     execute(vm: StrVM, data: { with?: StrTerm }): Awaitable<StrVM> {
         return vm.replaceContextMatchingTerm(ctx => ({
-            restructure: parts => {
+            restructureOrLines: parts => {
                 if ( data.with ) {
                     return parts
                         .map(part => part.value)