Add $filename command and test it (fix #23)

Author: Alistair Turnbull

nancy/__init__.py

@@ -478,6 +478,15 @@ def expand(self, args: Optional[list[bytes]], input: Optional[bytes]) -> bytes:
 
         return strip_final_newline(self._expand.expand(input))
 
+    def filename(self, args: Optional[list[bytes]], input: Optional[bytes]) -> bytes:
+        if args is None or len(args) != 1:
+            raise ValueError("$filename needs exactly one argument")
+        if input is not None:
+            raise ValueError("$filename does not take an input")
+        debug(command_to_str(b"filename", args, input))
+
+        return bytes(self._expand.file_arg(args[0]))
+
     def paste(self, args: Optional[list[bytes]], input: Optional[bytes]) -> bytes:
         if args is None or len(args) != 1:
             raise ValueError("$paste needs exactly one argument")

tests/test-files/filename-expected/filenames

@@ -0,0 +1,4 @@
+in A
+B from A: filename-src/b.in
+In B
+A from B: filename-src/a.in

tests/test-files/filename-expected/subdir/filenames

@@ -0,0 +1,5 @@
+In subdir/A
+super A from A: filename-src/a.in
+B from A: filename-src/b.in
+In B
+A from B: filename-src/subdir/a.in

tests/test-files/filename-input.nancy.txt

@@ -0,0 +1 @@
+$filename(foo){}

tests/test-files/filename-no-arg.nancy.txt

@@ -0,0 +1 @@
+$filename

tests/test-files/filename-src/a.in

@@ -0,0 +1,2 @@
+in A
+B from A: $filename(b.in)

tests/test-files/filename-src/b.in

@@ -0,0 +1,2 @@
+In B
+A from B: $filename(a.in)

tests/test-files/filename-src/filenames.nancy

@@ -0,0 +1,2 @@
+$include(a.in)
+$include(b.in)

tests/test-files/filename-src/subdir/a.in

@@ -0,0 +1,3 @@
+In subdir/A
+super A from A: $filename(a.in)
+B from A: $filename(b.in)

tests/test-files/filename-src/subdir/filenames.nancy

@@ -0,0 +1,2 @@
+$include(a.in)
+$include(b.in)