Fixes for Word motions in Standard Mode

Added helper in buffer, and tweaks to fix more standard mode issues;
needs a unit test or two.

Author: cmaughan

NOTES.md

@@ -1,8 +1,9 @@
  Assumptions in the code / Design decisions:
 
- - All ASCII for now, now UTF8
- - The cursor is only ever on a valid buffer location.  This can be the hidden CR of the line, or the 0 at the end.
+ - All ASCII for now, no real UTF8
+ - The cursor is only ever on a valid buffer location.  This can be the hidden CR of the line,
+   or the 0 at the end.
  - Even if the loaded buffer doesn't 0 terminate, it is terminated and then removed at save time if necessary.
  - Internally every thing is a '\n'; '\r\n' is converted and converted back if necessary.  Mixed files aren't supported, you'll just get a '\n' file
  - The window converts the entire buffer to a list of visible character lines.  This is used to handle wrapping, and let the user jump around in a wrapped buffer file.
- - Cursor is on the virtual line in the wrapped buffer, and can be off screen?
+ - Cursor is on the virtual line in the wrapped buffer, and can be off screen; but ScrollTo will find it

TODO.md

@@ -3,6 +3,7 @@ Delete everything; iterator bug. ?How to repro
 
 #### Window
 - Finish HSplit 
+- Finish Tab management
 
 #### General
 - Finish cut/paste to OS buffer
@@ -15,16 +16,9 @@ Delete everything; iterator bug. ?How to repro
 - 'R'/'r' overstrike
 
 #### Standard Mode
+- Ctrl + Shift Select word motions
 
 #### Syntax Highlight
-- Generalize the token matching into the base class for easy 
-implementation of c like languages
-- Add multilinne highlight via a hierarchy table?
 
 #### Tests
-- Add standard mode unit tests
-- Test syntax highlighting
-
-#### Future
-- UTF 8?
-- Standalone editor tool so I can dogfood it
+- Add tests for syntax highlighting

src/buffer.cpp

@@ -35,6 +35,15 @@ inline bool IsSpace(const char ch)
 {
     return ch == ' ';
 }
+inline bool IsSpaceOrTerminal(const char ch)
+{
+    return ch == ' ' || ch == 0 || ch == '\n';
+}
+inline bool IsNewlineOrEnd(const char ch)
+{
+    return ch == '\n' || ch == 0;
+}
+
 using fnMatch = std::function<bool>(const char);
 
 } // namespace
@@ -229,6 +238,70 @@ BufferRange ZepBuffer::AWordMotion(BufferLocation start, uint32_t searchType) co
     return r;
 }
 
+// Implements the ctrl + motion of a standard editor.
+// This is a little convoluted; perhaps the logic can be simpler!
+// Playing around with CTRL+ arrows and shift in an app like notepad will teach you that the rules for how far to jump
+// depend on what you are over, and which direction you are going.....
+// The unit tests are designed to enforce the behavior here
+BufferRange ZepBuffer::StandardCtrlMotion(BufferLocation visual_start, BufferLocation cursor, SearchDirection searchDir) const
+{
+    auto IsWord = IsWORDChar;
+    auto searchType = SearchType::WORD;
+    MotionBegin(cursor, searchType, SearchDirection::Forward);
+
+    auto lineEnd = GetLinePos(cursor, LineLocation::LineLastNonCR);
+    auto current = std::min(lineEnd, Clamp(cursor));
+
+    BufferRange r;
+    r.first = current;
+    r.second = current;
+
+    if (searchDir == SearchDirection::Forward)
+    {
+        // Skip space
+        Skip(IsSpaceOrTerminal, current, searchDir);
+        if (Skip(IsWORDChar, current, searchDir))
+        {
+            if (Skip(IsSpace, current, searchDir))
+            {
+                if (current > visual_start)
+                {
+                    current--;
+                }
+            }
+        }
+        // Forward jumping, step back before word
+        if (current != cursor &&
+            current > visual_start && 
+            (m_gapBuffer[current] == '\n' ||
+            m_gapBuffer[current] == 0))
+        {
+            current--;
+        }
+    }
+    else
+    {
+        // If on the first char of a new word, skip back
+        if (current > 0 && IsWORDChar(m_gapBuffer[current]) &&
+            !IsWORDChar(m_gapBuffer[current - 1]))
+        {
+            current--;
+        }
+
+        // Skip a space
+        Skip(IsSpaceOrTerminal, current, searchDir);
+
+        // Back to the beginning of the next word
+        if (Skip(IsWORDChar, current, searchDir))
+        {
+            current++;
+        }
+    }
+    r.second = Clamp(current);
+   
+    return r;
+}
+
 BufferRange ZepBuffer::InnerWordMotion(BufferLocation start, uint32_t searchType) const
 {
     auto IsWordOrSpace = searchType == SearchType::Word ? IsWordOrSepChar : IsWORDOrSepChar;

src/buffer.h

@@ -102,6 +102,7 @@ class ZepBuffer : public ZepComponent
     BufferLocation ChangeWordMotion(BufferLocation start, uint32_t searchType, SearchDirection dir) const;
     BufferRange AWordMotion(BufferLocation start, uint32_t searchType) const;
     BufferRange InnerWordMotion(BufferLocation start, uint32_t searchType) const;
+    BufferRange StandardCtrlMotion(BufferLocation visual_start, BufferLocation cursor, SearchDirection searchDir) const;
 
     bool Delete(const BufferLocation& startOffset, const BufferLocation& endOffset, const BufferLocation& cursorAfter = BufferLocation{ -1 });
     bool Insert(const BufferLocation& startOffset, const std::string& str, const BufferLocation& cursorAfter = BufferLocation{ -1 });