Rework indentation

- Change continued field values to support Python indentation.  This
  is useful when the value is using something like format (but only
  applies to naked field keys).

- Don't move back to the start of the line when in a continued field
  value.

- When on the first line of block, only indent to main offset.

- Move to current indentation if point is before it.  Unless there is
  one possible value for indentation, don't adjust indentation any
  further.

3 files changed, 359 insertions, 51 deletions

diff --git a/NEWS b/NEWS
index e2dd498..c456238 100644
--- a/NEWS
+++ b/NEWS
@@ -10,7 +10,9 @@
 - Indentation for field values starting on the line below a field key
   is now supported.  New variable `snakemake-indent-value-offset'
   controls the offset for the value and replaces the variable
-  `snakemake-indent-run-offset'.
+  `snakemake-indent-run-offset'.  If these values are continued on
+  another line, indentation cycling now includes a step that indents
+  according to Python mode.
 
 * v0.2.0
 
diff --git a/snakemake-mode.el b/snakemake-mode.el
index cb928d5..51c5c30 100644
--- a/snakemake-mode.el
+++ b/snakemake-mode.el
@@ -122,13 +122,16 @@ rule blocks (or on a blank line directly below), call
     (python-indent-line-function)))
 
 (defun snakemake-indent-rule-line ()
-  "Indent rule line.
+  "Indent line of a rule or subworkflow block.
+
+Indent according the the first case below that is true.
 
 - At the top of rule block
 
   Remove all indentation.
 
-- At a rule field key ('input', 'output',...)
+- At a rule field key ('input', 'output',...) or on the first
+  field line of the block
 
   Indent the line to `snakemake-indent-field-offset'.
 
@@ -139,20 +142,27 @@ rule blocks (or on a blank line directly below), call
 
 - On any 'run' field value line except for the first value line.
 
-  Indent with `python-indent-line-function'.
+  Indent according to Python mode.
+
+- Before the current indentation
+
+  Move point to the current indentation.
 
 - Otherwise
 
-  Alternate between no indentation,
-  `snakemake-indent-field-offset', and the column of the previous
-  field value."
-  (save-excursion
-    (let ((start-indent (current-indentation)))
+  Cycle between indenting to `snakemake-indent-field-offset',
+  indenting to the column of the previous field value.  If within
+  a field value for a naked field key, add a step that indents
+  according to Python mode."
+  (let ((start-col (current-column))
+        (start-indent (current-indentation)))
+    (save-excursion
       (beginning-of-line)
       (cond
        ((looking-at-p (concat "^\\s-*" snakemake-rule-or-subworkflow-re))
         (delete-horizontal-space))
-       ((looking-at-p (concat "^\\s-*" snakemake-field-key-re))
+       ((or (looking-at-p (concat "^\\s-*" snakemake-field-key-re))
+            (snakemake-first-field-line-p))
         (delete-horizontal-space)
         (indent-to snakemake-indent-field-offset))
        ((snakemake-below-naked-field-p)
@@ -161,17 +171,36 @@ rule blocks (or on a blank line directly below), call
                       snakemake-indent-value-offset)))
        ((snakemake-run-field-line-p)
         (python-indent-line-function))
-       ((< start-indent snakemake-indent-field-offset)
-        (delete-horizontal-space)
-        (indent-to snakemake-indent-field-offset))
-       (t
+       ((>= start-col start-indent)
         (let ((prev-col (snakemake-previous-field-value-column)))
           (when prev-col
-            (delete-horizontal-space)
-            (when (< start-indent prev-col)
-              (indent-to prev-col))))))))
-  (when (< (current-column) (current-indentation))
-    (forward-to-indentation 0)))
+            (cond
+             ((and (snakemake-naked-field-line-p)
+                   (or (and (= start-indent 0)
+                            (not (looking-at-p "^\\s-*$")))
+                       (= start-indent prev-col)))
+              (let (last-command)
+                ;; ^ Don't let `python-indent-line' do clever things
+                ;; when indent command is repeated.
+                (python-indent-line-function))
+              (when (= (current-column) start-indent)
+                (delete-horizontal-space)
+                (indent-to snakemake-indent-value-offset)))
+             ((= start-indent snakemake-indent-field-offset)
+              (delete-horizontal-space)
+              (indent-to prev-col))
+             (t
+              (delete-horizontal-space)
+              (indent-to snakemake-indent-field-offset))))))))
+    (when (< (current-column) (current-indentation))
+      (forward-to-indentation 0))))
+
+(defun snakemake-first-field-line-p ()
+  "Return non-nil if point is on first field line of block."
+  (save-excursion
+    (forward-line -1)
+    (beginning-of-line)
+    (looking-at-p (concat snakemake-rule-or-subworkflow-re))))
 
 (defun snakemake-in-rule-or-subworkflow-block-p ()
   "Return non-nil if point is in block or on first blank line following one."
@@ -191,6 +220,22 @@ rule blocks (or on a blank line directly below), call
     (beginning-of-line)
     (looking-at-p (concat snakemake-field-key-indented-re "\\s-*$"))))
 
+(defun snakemake-naked-field-line-p ()
+  "Return non-nil if point is on any line of naked field key.
+This function assumes that point is in a rule or subworkflow
+block (which includes being on a blank line immediately below a
+block)."
+  (save-excursion
+    (let ((rule-start (save-excursion
+                        (end-of-line)
+                        (re-search-backward snakemake-rule-or-subworkflow-re
+                                            nil t))))
+      (end-of-line)
+      (and (re-search-backward snakemake-field-key-indented-re
+                               rule-start t)
+           (goto-char (match-end 0))
+           (looking-at-p "\\s-*$")))))
+
 (defun snakemake-run-field-line-p ()
   "Return non-nil if point is on any line below a run field key.
 This function assumes that point is in a rule or subworkflow
diff --git a/test-snakemake-mode.el b/test-snakemake-mode.el
index b48b128..859c28a 100644
--- a/test-snakemake-mode.el
+++ b/test-snakemake-mode.el
@@ -49,10 +49,13 @@ Also, mute messages."
 (def-edebug-spec org-test-with-temp-text (form body))
 
 
-(ert-deftest test-snakemake-mode/indentation ()
-  "Test `snakemake-indent-line'."
+
+;;; Indentation
 
-  ;; At top of rule block
+(ert-deftest test-snakemake-mode/indentation-at-rule-block ()
+  "Test `snakemake-indent-line' at top of rule block."
+
+  ;; Always shift first line of block to column 0.
   (should
    (string=
     "rule abc:"
@@ -60,18 +63,51 @@ Also, mute messages."
         "rule abc:"
       (snakemake-indent-line)
       (buffer-string))))
-
-  ;; At top of rule block, repeated
   (should
    (string=
     "rule abc:"
     (snakemake-with-temp-text
-        "rule abc:"
+        "     rule abc:"
       (snakemake-indent-line)
+      (buffer-string))))
+
+  ;; Don't move point if beyond column 0.
+  (should
+   (string=
+    "rule abc:  "
+    (snakemake-with-temp-text
+        "    rule abc:  <point>"
       (snakemake-indent-line)
       (buffer-string))))
+  (should
+   (string=
+    "rule "
+    (snakemake-with-temp-text
+        "    rule <point>abc:  <point>"
+      (snakemake-indent-line)
+      (buffer-substring (point-min) (point))))))
 
-  ;; Below a rule block
+(ert-deftest test-snakemake-mode/indentation-outside-rule ()
+  "Test `snakemake-indent-line' outside rule block."
+  ;; Use standard Python mode indentation outside of rule blocks.
+  (should
+   (string=
+    "
+def ok():
+    "
+    (snakemake-with-temp-text
+        "
+def ok():
+<point>"
+      (snakemake-indent-line)
+      (buffer-string)))))
+
+(ert-deftest test-snakemake-mode/indentation-field-key ()
+  "Test `snakemake-indent-line' on field key line."
+
+  ;; Always indent first line to `snakemake-indent-field-offset'.
+  ;; Move point to `snakemake-indent-field-offset' if it is before any
+  ;; text on the line.
   (should
    (string=
     "
@@ -83,8 +119,6 @@ rule abc:
 <point>"
       (snakemake-indent-line)
       (buffer-string))))
-
-  ;; Below a rule block, repeated
   (should
    (string=
     "
@@ -97,35 +131,93 @@ rule abc:
       (snakemake-indent-line)
       (snakemake-indent-line)
       (buffer-string))))
+  (should
+   (string=
+    "
+rule abc:
+    text"
+    (snakemake-with-temp-text
+        "
+rule abc:
+text<point>"
+      (snakemake-indent-line)
+      (buffer-substring (point-min) (point)))))
+  (should
+   (string=
+    "
+rule abc:
+    te"
+    (snakemake-with-temp-text
+        "
+rule abc:
+te<point>xt"
+      (snakemake-indent-line)
+      (buffer-substring (point-min) (point)))))
 
-  ;; At rule field key.
+  ;; Always indent field key to `snakemake-indent-field-offset'.
+  ;; Move point to `snakemake-indent-field-offset' if it is before any
+  ;; text on the line.
   (should
    (string=
     "
 rule abc:
+    input: 'infile'
     output:"
     (snakemake-with-temp-text
         "
 rule abc:
+    input: 'infile'
 <point>output:"
       (snakemake-indent-line)
       (buffer-string))))
-
-  ;; At rule field key, repeated
   (should
    (string=
     "
 rule abc:
+    input: 'infile'
     output:"
     (snakemake-with-temp-text
         "
 rule abc:
+    input: 'infile'
 <point>output:"
       (snakemake-indent-line)
       (snakemake-indent-line)
       (buffer-string))))
+  (should
+   (string=
+    "
+rule abc:
+    input: 'infile'
+    output:  "
+    (snakemake-with-temp-text
+        "
+rule abc:
+    input: 'infile'
+output:  <point>"
+      (snakemake-indent-line)
+      (buffer-string))))
+  (should
+   (string=
+    "
+rule abc:
+    input: 'infile'
+    "
+    (snakemake-with-temp-text
+        "
+rule abc:
+    input: 'infile'
+<point>  output:"
+      (snakemake-indent-line)
+      (buffer-substring (point-min) (point))))))
 
-  ;; Below a naked rule field key
+(ert-deftest test-snakemake-mode/indentation-field-value ()
+  "Test `snakemake-indent-line' on field value line."
+
+  ;; Always indent line below naked field key to
+  ;; `snakemake-indent-field-offset' +
+  ;; `snakemake-indent-value-offset'.  Move point to to this position
+  ;; as well if it is before any text on the line.
   (should
    (string=
     "
@@ -139,8 +231,6 @@ rule abc:
 <point>"
       (snakemake-indent-line)
       (buffer-string))))
-
-  ;; Below a naked rule field key, repeated
   (should
    (string=
     "
@@ -155,8 +245,72 @@ rule abc:
       (snakemake-indent-line)
       (snakemake-indent-line)
       (buffer-string))))
+  (should
+   (string=
+    "
+rule abc:
+    output:
+        "
+    (snakemake-with-temp-text
+        "
+rule abc:
+    output:
+              <point>"
+      (snakemake-indent-line)
+      (buffer-string))))
 
-  ;; Below a filled rule field key
+  ;; Add step with Python indentation for non-blank lines under naked
+  ;; field keys.  Field keys with values starting on the same line do
+  ;; not use Python indentation because this is invalid syntax in
+  ;; Snakemake.
+  (should
+   (string=
+    "
+rule abc:
+    output: 'file{}{}'.format('one',
+    'two'"
+    (snakemake-with-temp-text
+        "
+rule abc:
+    output: 'file{}{}'.format('one',
+<point>'two'"
+      (snakemake-indent-line)
+      (buffer-string))))
+  (should
+   (string=
+    "
+rule abc:
+    output:
+        'file{}{}'.format('one',
+                          'two'"
+    (snakemake-with-temp-text
+        "
+rule abc:
+    output:
+        'file{}{}'.format('one',
+<point>'two'"
+      (snakemake-indent-line)
+      (buffer-string))))
+  (should
+   (string=
+    "
+rule abc:
+    output:
+        'file{}{}'.format('one',
+    "
+    (snakemake-with-temp-text
+        "
+rule abc:
+    output:
+        'file{}{}'.format('one',
+<point>"
+      (snakemake-indent-line)
+      (buffer-string))))
+
+  ;; On non-naked field key cycle indentation between
+  ;; `snakemake-indent-field-offset' and column of previous field
+  ;; value.  If point is before any text on the line, move it to the
+  ;; start of the text instead.
   (should
    (string=
     "
@@ -170,8 +324,6 @@ rule abc:
 <point>"
       (snakemake-indent-line)
       (buffer-string))))
-
-  ;; Below a filled rule field key, repeated once
   (should
    (string=
     "
@@ -186,8 +338,6 @@ rule abc:
       (snakemake-indent-line)
       (snakemake-indent-line)
       (buffer-string))))
-
-  ;; Below a filled rule field key, repeated twice
   (should
    (string=
     "
@@ -203,37 +353,94 @@ rule abc:
       (snakemake-indent-line)
       (snakemake-indent-line)
       (buffer-string))))
-
-  ;; Body of a run field
   (should
    (string=
     "
 rule abc:
-    run:
-        with this:
-            "
+    output: 'file'
+    'text'"
     (snakemake-with-temp-text
         "
 rule abc:
-    run:
-        with this:
-<point>"
+    output: 'file'
+<point>'text'"
       (snakemake-indent-line)
       (buffer-string))))
-
-  ;; Outside a rule block
   (should
    (string=
     "
-def ok():
+rule abc:
+    output: 'file'
+            'text'"
+    (snakemake-with-temp-text
+        "
+rule abc:
+    output: 'file'
+<point>'text'"
+      (snakemake-indent-line)
+      (snakemake-indent-line)
+      (buffer-string))))
+  (should
+   (string=
     "
+rule abc:
+    output: 'file'
+    'text' "
     (snakemake-with-temp-text
         "
-def ok():
+rule abc:
+    output: 'file'
+'text' <point>"
+      (snakemake-indent-line)
+      (buffer-string))))
+  (should
+   (string=
+    "
+rule abc:
+    output: 'file'
+  "
+    (snakemake-with-temp-text
+        "
+rule abc:
+    output: 'file'
+<point>  'text'"
+      (snakemake-indent-line)
+      (buffer-substring (point-min) (point)))))
+  (should
+   (string=
+    "
+rule abc:
+    output: 'file'
+    'text'"
+    (snakemake-with-temp-text
+        "
+rule abc:
+    output: 'file'
+<point>  'text'"
+      (snakemake-indent-line)
+      (snakemake-indent-line)
+      (buffer-string))))
+
+  ;; Indent body of run field according to Python mode.
+  (should
+   (string=
+    "
+rule abc:
+    run:
+        with this:
+            "
+    (snakemake-with-temp-text
+        "
+rule abc:
+    run:
+        with this:
 <point>"
       (snakemake-indent-line)
       (buffer-string)))))
 
+
+;;; Other
+
 (ert-deftest test-snakemake-mode/in-rule-block ()
   "Test `snakemake-in-rule-or-subworkflow-block-p'"
 
@@ -283,6 +490,25 @@ subworkflow otherworkflow:
     snakefile: '../path/to/otherworkflow/Snakefile'"
     (should (snakemake-in-rule-or-subworkflow-block-p))))
 
+(ert-deftest test-snakemake-mode/first-field-line-p ()
+  "Test `snakemake-first-field-line-p'."
+  (snakemake-with-temp-text
+      "
+rule abc:
+<point>"
+    (should (snakemake-first-field-line-p)))
+  (snakemake-with-temp-text
+      "
+rule abc:
+<point>    output: 'file'"
+    (should (snakemake-first-field-line-p)))
+  (snakemake-with-temp-text
+      "
+rule abc:
+    output:
+<point>"
+    (should-not (snakemake-first-field-line-p))))
+
 (ert-deftest test-snakemake-mode/below-naked-field-p ()
   "Test `snakemake-below-naked-field-p'."
   (snakemake-with-temp-text
@@ -303,6 +529,41 @@ rule abc:
     output: <point>"
     (should-not (snakemake-below-naked-field-p))))
 
+(ert-deftest test-snakemake-mode/naked-field-line-p ()
+  "Test `snakemake-naked-field-line-p'."
+  (snakemake-with-temp-text
+      "
+rule abc:
+    output:
+<point>"
+    (should (snakemake-naked-field-line-p)))
+  (snakemake-with-temp-text
+      "
+rule abc:
+    output:
+        'file',
+         <point>"
+    (should (snakemake-naked-field-line-p)))
+  (snakemake-with-temp-text
+      "
+rule abc:
+    output: <point>"
+    (should (snakemake-naked-field-line-p)))
+  (snakemake-with-temp-text
+      "
+rule abc:
+    output: 'file'
+<point>"
+    (should-not (snakemake-naked-field-line-p)))
+  (snakemake-with-temp-text
+      "
+rule abc:
+    input:
+        'infile'
+    output: 'file'
+<point>"
+    (should-not (snakemake-naked-field-line-p))))
+
 (ert-deftest test-snakemake-mode/run-field-line-p ()
   "Test `snakemake-run-field-line-p'."
   (snakemake-with-temp-text