bpo-36390: IDLE: Refactor formatting methods from editor.py.

* Create module for indent, dedent, comment, uncomment, tabify, and untabify. * Add tests for new module.
python · terryjreedy · Jul 17, 2019 · Mar 21, 2019 · Jul 11, 2019 · Jul 17, 2019
commit d07fa50acbdb56e9aa2b947895ec0e1352d666a5
diff --git a/Lib/idlelib/editor.py b/Lib/idlelib/editor.py
@@ -55,6 +55,7 @@ class EditorWindow(object):
     from idlelib.codecontext import CodeContext
     from idlelib.paragraph import FormatParagraph
     from idlelib.parenmatch import ParenMatch
+    from idlelib.formatregion import FormatRegion
     from idlelib.rstrip import Rstrip
     from idlelib.squeezer import Squeezer
     from idlelib.zoomheight import ZoomHeight
@@ -170,13 +171,14 @@ def __init__(self, flist=None, filename=None, key=None, root=None):
         text.bind("<<smart-backspace>>",self.smart_backspace_event)
         text.bind("<<newline-and-indent>>",self.newline_and_indent_event)
         text.bind("<<smart-indent>>",self.smart_indent_event)
-        text.bind("<<indent-region>>",self.indent_region_event)
-        text.bind("<<dedent-region>>",self.dedent_region_event)
-        text.bind("<<comment-region>>",self.comment_region_event)
-        text.bind("<<uncomment-region>>",self.uncomment_region_event)
-        text.bind("<<tabify-region>>",self.tabify_region_event)
-        text.bind("<<untabify-region>>",self.untabify_region_event)
-        text.bind("<<toggle-tabs>>",self.toggle_tabs_event)
+        self.fregion = fregion = self.FormatRegion(self)
+        text.bind("<<indent-region>>", fregion.indent_region_event)
+        text.bind("<<dedent-region>>", fregion.dedent_region_event)
+        text.bind("<<comment-region>>", fregion.comment_region_event)
+        text.bind("<<uncomment-region>>", fregion.uncomment_region_event)
+        text.bind("<<tabify-region>>", fregion.tabify_region_event)
+        text.bind("<<untabify-region>>", fregion.untabify_region_event)
+        text.bind("<<toggle-tabs>>", self.toggle_tabs_event)
         text.bind("<<change-indentwidth>>",self.change_indentwidth_event)
         text.bind("<Left>", self.move_at_edge_if_selection(0))
         text.bind("<Right>", self.move_at_edge_if_selection(1))
@@ -1280,7 +1282,7 @@ def smart_indent_event(self, event):
         try:
             if first and last:
                 if index2line(first) != index2line(last):
-                    return self.indent_region_event(event)
+                    return self.fregion.indent_region_event(event)
                 text.delete(first, last)
                 text.mark_set("insert", first)
             prefix = text.get("insert linestart", "insert")
@@ -1414,72 +1416,6 @@ def inner(offset, _startinde
8000
x=startindex,
             return _icis(_startindex + "+%dc" % offset)
         return inner
 
-    def indent_region_event(self, event):
-        head, tail, chars, lines = self.get_region()
-        for pos in range(len(lines)):
-            line = lines[pos]
-            if line:
-                raw, effective = classifyws(line, self.tabwidth)
-                effective = effective + self.indentwidth
-                lines[pos] = self._make_blanks(effective) + line[raw:]
-        self.set_region(head, tail, chars, lines)
-        return "break"
-
-    def dedent_region_event(self, event):
-        head, tail, chars, lines = self.get_region()
-        for pos in range(len(lines)):
-            line = lines[pos]
-            if line:
-                raw, effective = classifyws(line, self.tabwidth)
-                effective = max(effective - self.indentwidth, 0)
-                lines[pos] = self._make_blanks(effective) + line[raw:]
-        self.set_region(head, tail, chars, lines)
-        return "break"
-
-    def comment_region_event(self, event):
-        head, tail, chars, lines = self.get_region()
-        for pos in range(len(lines) - 1):
-            line = lines[pos]
-            lines[pos] = '##' + line
-        self.set_region(head, tail, chars, lines)
-        return "break"
-
-    def uncomment_region_event(self, event):
-        head, tail, chars, lines = self.get_region()
-        for pos in range(len(lines)):
-            line = lines[pos]
-            if not line:
-                continue
-            if line[:2] == '##':
-                line = line[2:]
-            elif line[:1] == '#':
-                line = line[1:]
-            lines[pos] = line
-        self.set_region(head, tail, chars, lines)
-        return "break"
-
-    def tabify_region_event(self, event):
-        head, tail, chars, lines = self.get_region()
-        tabwidth = self._asktabwidth()
-        if tabwidth is None: return
-        for pos in range(len(lines)):
-            line = lines[pos]
-            if line:
-                raw, effective = classifyws(line, tabwidth)
-                ntabs, nspaces = divmod(effective, tabwidth)
-                lines[pos] = '\t' * ntabs + ' ' * nspaces + line[raw:]
-        self.set_region(head, tail, chars, lines)
-        return "break"
-
-    def untabify_region_event(self, event):
-        head, tail, chars, lines = self.get_region()
-        tabwidth = self._asktabwidth()
-        if tabwidth is None: return
-        for pos in range(len(lines)):
-            lines[pos] = lines[pos].expandtabs(tabwidth)
-        self.set_region(head, tail, chars, lines)
-        return "break"
-
     def toggle_tabs_event(self, event):
         if self.askyesno(
               "Toggle tabs",
@@ -1514,33 +1450,6 @@ def change_indentwidth_event(self, event):
             self.indentwidth = new
         return "break"
 
-    def get_region(self):
-        text = self.text
-        first, last = self.get_selection_indices()
-        if first and last:
-            head = text.index(first + " linestart")
-            tail = text.index(last + "-1c lineend +1c")
-        else:
-            head = text.index("insert linestart")
-            tail = text.index("insert lineend +1c")
-        chars = text.get(head, tail)
-        lines = chars.split("\n")
-        return head, tail, chars, lines
-
-    def set_region(self, head, tail, chars, lines):
-        text = self.text
-        newchars = "\n".join(lines)
-        if newchars == chars:
-            text.bell()
-            return
-        text.tag_remove("sel", "1.0", "end")
-        text.mark_set("insert", head)
-        text.undo_block_start()
-        text.delete(head, tail)
-        text.insert(head, newchars)
-        text.undo_block_stop()
-        text.tag_add("sel", head, "insert")
-
     # Make string that displays as n leading blanks.
 
     def _make_blanks(self, n):
@@ -1562,15 +1471,6 @@ def reindent_to(self, column):
             text.insert("insert", self._make_blanks(column))
         text.undo_block_stop()
 
-    def _asktabwidth(self):
-        return self.askinteger(
-            "Tab width",
-            "Columns per tab? (2-16)",
-            parent=self.text,
-            initialvalue=self.indentwidth,
-            minvalue=2,
-            maxvalue=16)
-
     # Guess indentwidth from text content.
     # Return guessed indentwidth.  This should not be believed unless
     # it's in a reasonable range (e.g., it will be 0 if no indented

diff --git a/Lib/idlelib/formatregion.py b/Lib/idlelib/formatregion.py
@@ -0,0 +1,178 @@
+"""Format a selected region of text.
+
+Several formatting options are available:
+indent, deindent, comment, uncomment, tabify, and untabify.
+"""
+from tkinter.simpledialog import askinteger
+
+
+def classifyws(s, tabwidth):
+    """Classify leading whitespace in a string.
+
+    Count the number of actual spaces and tabs at the beginning of
+    the string.  Also count the tabwidth number of spaces that a
+    tab would expand to.
+
+    Return a tuple of (number of raw leading whitespace characters,
+        number of leading characters after expanding tabs).
+    """
+    raw = effective = 0
+    for ch in s:
+        if ch == ' ':
+            raw = raw + 1
+            effective = effective + 1
+        elif ch == '\t':
+            raw = raw + 1
+            effective = (effective // tabwidth + 1) * tabwidth
+        else:
+            break
+    return raw, effective
+
+
+class FormatRegion:
+    "Format selected text."
+
+    def __init__(self, editwin):
+        self.editwin = editwin
+
+    def get_region(self):
+        """Return line information about the selected text region.
+
+        If text is selected, the first and last indices will be
+        for the selection.  If there is no text selected, the
+        indices will be the current cursor location.
+
+        Return a tuple containing (first index, last index,
+            string representation of text, list of text lines).
+        """
+        text = self.editwin.text
+        first, last = self.editwin.get_selection_indices()
+        if first and last:
+            head = text.index(first + " linestart")
+            tail = text.index(last + "-1c lineend +1c")
+        else:
+            head = text.index("insert linestart")
+            tail = text.index("insert lineend +1c")
+        chars = text.get(head, tail)
+        lines = chars.split("\n")
+        return head, tail, chars, lines
+
+    def set_region(self, head, tail, chars, lines):
+        """Replace the text between the given indices.
+
+        Args:
+            head: Starting index of text to replace.
+            tail: Ending index of text to replace.
+            chars: Expected to be string of current text
+                between head and tail.
+                lines: List of new lines to insert between head
+                and tail.
+        """
+        text = self.editwin.text
+        newchars = "\n".join(lines)
+        if newchars == chars:
+            text.bell()
+            return
+        text.tag_remove("sel", "1.0", "end")
+        text.mark_set("insert", head)
+        text.undo_block_start()
+        text.delete(head, tail)
+        text.insert(head, newchars)
+        text.undo_block_stop()
+        text.tag_add("sel", head, "insert")
+
+    def indent_region_event(self, event=None):
+        "Indent region by indentwidth spaces."
+        head, tail, chars, lines = self.get_region()
+        for pos in range(len(lines)):
+            line = lines[pos]
+            if line:
+                raw, effective = classifyws(line, self.editwin.tabwidth)
+                effective = effective + self.editwin.indentwidth
+                lines[pos] = self.editwin._make_blanks(effective) + line[raw:]
+        self.set_region(head, tail, chars, lines)
+        return "break"
+
+    def dedent_region_event(self, event=None):
+        "Dedent region by indentwidth spaces."
+        head, tail, chars, lines = self.get_region()
+        for pos in range(len(lines)):
+            line = lines[pos]
+            if line:
+                raw, effective = classifyws(line, self.editwin.tabwidth)
+                effective = max(effective - self.editwin.indentwidth, 0)
+                lines[pos] = self.editwin._make_blanks(effective) + line[raw:]
+        self.set_region(head, tail, chars, lines)
+        return "break"
+
+    def comment_region_event(self, event=None):
+        """Comment out each line in region.
+
+        ## is appended to the beginning of each line to comment it out.
+        """
+        head, tail, chars, lines = self.get_region()
+        for pos in range(len(lines) - 1):
+            line = lines[pos]
+            lines[pos] = '##' + line
+        self.set_region(head, tail, chars, lines)
+        return "break"
+
+    def uncomment_region_event(self, event=None):
+        """Uncomment each line in region.
+
+        Remove ## or # in the first positions of a line.  If the comment
+        is not in the beginning position, this command will have no effect.
+        """
+        head, tail, chars, lines = self.get_region()
+        for pos in range(len(lines)):
+            line = lines[pos]
+            if not line:
+                continue
+            if line[:2] == '##':
+                line = line[2:]
+            elif line[:1] == '#':
+                line = line[1:]
+            lines[pos] = line
+        self.set_region(head, tail, chars, lines)
+        return "break"
+
+    def tabify_region_event(self, event=None):
+        "Convert leading spaces to tabs for each line in selected region."
+        head, tail, chars, lines = self.get_region()
+        tabwidth = self._asktabwidth()
+        if tabwidth is None:
+            return
+        for pos in range(len(lines)):
+            line = lines[pos]
+            if line:
+                raw, effective = classifyws(line, tabwidth)
+                ntabs, nspaces = divmod(effective, tabwidth)
+                lines[pos] = '\t' * ntabs + ' ' * nspaces + line[raw:]
+        self.set_region(head, tail, chars, lines)
+        return "break"
+
+    def untabify_region_event(self, event=None):
+        "Expand tabs to spaces for each line in region."
+        head, tail, chars, lines = self.get_region()
+        tabwidth = self._asktabwidth()
+        if tabwidth is None:
+            return
+        for pos in range(len(lines)):
+            lines[pos] = lines[pos].expandtabs(tabwidth)
+        self.set_region(head, tail, chars, lines)
+        return "break"
+
+    def _asktabwidth(self):
+        "Return value for tab width."
+        return askinteger(
+            "Tab width",
+            "Columns per tab? (2-16)",
+            parent=self.editwin.text,
+            initialvalue=self.editwin.indentwidth,
+            minvalue=2,
+            maxvalue=16)
+
+
+if __name__ == "__main__":
+    from unittest import main
+    main('idlelib.idle_test.test_formatregion', verbosity=2, exit=False)