implement input_filename/0 function (close #90)

cli/cli.go

@@ -225,6 +225,14 @@ Synopsis:
 		gojq.WithVariables(cli.argnames),
 		gojq.WithFunction("debug", 0, 0, cli.funcDebug),
 		gojq.WithFunction("stderr", 0, 0, cli.funcStderr),
+		gojq.WithFunction("input_filename", 0, 0,
+			func(interface{}, []interface{}) interface{} {
+				if fname := iter.Name(); fname != "" {
+					return fname
+				}
+				return nil
+			},
+		),
 		gojq.WithInputIter(iter),
 	)
 	if err != nil {

cli/inputs.go

@@ -64,6 +64,7 @@ func (ir *inputReader) getContents(offset *int64, line *int) string {
 type inputIter interface {
 	gojq.Iter
 	io.Closer
+	Name() string
 }
 
 type jsonInputIter struct {
@@ -114,6 +115,10 @@ func (i *jsonInputIter) Close() error {
 	return nil
 }
 
+func (i *jsonInputIter) Name() string {
+	return i.fname
+}
+
 type nullInputIter struct {
 	err error
 }
@@ -135,6 +140,10 @@ func (i *nullInputIter) Close() error {
 	return nil
 }
 
+func (i *nullInputIter) Name() string {
+	return ""
+}
+
 type filesInputIter struct {
 	newIter func(io.Reader, string) inputIter
 	fnames  []string
@@ -186,13 +195,21 @@ func (i *filesInputIter) Close() error {
 	return nil
 }
 
+func (i *filesInputIter) Name() string {
+	if i.file != nil {
+		return i.file.Name()
+	}
+	return ""
+}
+
 type rawInputIter struct {
 	scanner *bufio.Scanner
+	fname   string
 	err     error
 }
 
-func newRawInputIter(r io.Reader, _ string) inputIter {
-	return &rawInputIter{scanner: bufio.NewScanner(r)}
+func newRawInputIter(r io.Reader, fname string) inputIter {
+	return &rawInputIter{scanner: bufio.NewScanner(r), fname: fname}
 }
 
 func (i *rawInputIter) Next() (interface{}, bool) {
@@ -214,6 +231,10 @@ func (i *rawInputIter) Close() error {
 	return nil
 }
 
+func (i *rawInputIter) Name() string {
+	return i.fname
+}
+
 type streamInputIter struct {
 	stream *jsonStream
 	ir     *inputReader
@@ -262,6 +283,10 @@ func (i *streamInputIter) Close() error {
 	return nil
 }
 
+func (i *streamInputIter) Name() string {
+	return i.fname
+}
+
 type yamlInputIter struct {
 	dec   *yaml.Decoder
 	ir    *inputReader
@@ -296,6 +321,10 @@ func (i *yamlInputIter) Close() error {
 	return nil
 }
 
+func (i *yamlInputIter) Name() string {
+	return i.fname
+}
+
 type slurpInputIter struct {
 	iter inputIter
 	err  error
@@ -334,6 +363,10 @@ func (i *slurpInputIter) Close() error {
 	return nil
 }
 
+func (i *slurpInputIter) Name() string {
+	return i.iter.Name()
+}
+
 type slurpRawInputIter struct {
 	iter inputIter
 	err  error
@@ -371,3 +404,7 @@ func (i *slurpRawInputIter) Close() error {
 	}
 	return nil
 }
+
+func (i *slurpRawInputIter) Name() string {
+	return i.iter.Name()
+}

cli/test.yaml

@@ -4134,6 +4134,95 @@
     "debug/0"
     "stderr/0"
 
+- name: input_filename function with stdin input
+  args:
+    - 'input_filename'
+  input: '0 1 2'
+  expected: |
+    "<stdin>"
+    "<stdin>"
+    "<stdin>"
+
+- name: input_filename function with null input option
+  args:
+    - -n
+    - 'input_filename'
+  input: '0'
+  expected: |
+    null
+
+- name: input_filename function with raw strings input option
+  args:
+    - --raw-input
+    - 'input_filename'
+  input: |
+    1
+    2
+    3
+  expected: |
+    "<stdin>"
+    "<stdin>"
+    "<stdin>"
+
+- name: input_filename function with slurp option
+  args:
+    - --slurp
+    - 'input_filename'
+  input: |
+    1
+    2
+    3
+  expected: |
+    "<stdin>"
+
+- name: input_filename function with input and slurp option
+  args:
+    - --raw-input
+    - --slurp
+    - 'input_filename'
+  input: |
+    1
+    2
+    3
+  expected: |
+    "<stdin>"
+
+- name: input_filename function with json file arguments
+  args:
+    - 'input_filename'
+    - 'testdata/1.json'
+    - 'testdata/2.json'
+  input: '0'
+  expected: |
+    "testdata/1.json"
+    "testdata/2.json"
+
+- name: input_filename function with yaml input option
+  args:
+    - --yaml-input
+    - 'input_filename'
+  input: '0'
+  expected: |
+    "<stdin>"
+
+- name: input_filename function with yaml file arguments
+  args:
+    - --yaml-input
+    - 'input_filename'
+    - 'testdata/1.yaml'
+  input: '0'
+  expected: |
+    "testdata/1.yaml"
+    "testdata/1.yaml"
+    "testdata/1.yaml"
+
+- name: input_filename in builtins
+  args:
+    - 'builtins[] | select(test("input_filename"))'
+  input: 'null'
+  expected: |
+    "input_filename/0"
+
 - name: halt function
   args:
     - 'def f($n): if $n > 0 then $n, f($n - 1) else halt end; f(.), .'