Updated D lexer from maXmo.

Feature Request #2793782.
Supports more forms of strings and numbers and has more keyword lists.

1 files changed, 323 insertions, 285 deletions

diff --git a/src/LexD.cxx b/src/LexD.cxx
index 850642111..4c4bcb343 100644
--- a/src/LexD.cxx
+++ b/src/LexD.cxx
@@ -25,20 +25,20 @@
 using namespace Scintilla;
 #endif
 
-/*/ Nested comments require keeping the value of the nesting level for every
-    position in the document.  But since scintilla always styles line by line,
-    we only need to store one value per line. The non-negative number indicates
-    nesting level at the end of the line.
-/*/
+/* Nested comments require keeping the value of the nesting level for every
+   position in the document.  But since scintilla always styles line by line,
+   we only need to store one value per line. The non-negative number indicates
+   nesting level at the end of the line.
+*/
 
-// We use custom qualifiers since it is not clear what D allows.
+// Underscore, letter, digit and universal alphas from C99 Appendix D.
 
 static bool IsWordStart(int ch) {
-	return isascii(ch) && (isalpha(ch) || ch == '_');
+	return (isascii(ch) && (isalpha(ch) || ch == '_')) || !isascii(ch);
 }
 
 static bool IsWord(int ch) {
-	return isascii(ch) && (isalnum(ch) || ch == '_');
+	return (isascii(ch) && (isalnum(ch) || ch == '_')) || !isascii(ch);
 }
 
 static bool IsDoxygen(int ch) {
@@ -51,311 +51,349 @@ static bool IsDoxygen(int ch) {
 	return false;
 }
 
+static bool IsStringSuffix(int ch) {
+	return ch == 'c' || ch == 'w' || ch == 'd';
+}
 
-static void ColouriseDoc(unsigned int startPos, int length, int initStyle, 
-    WordList *keywordlists[], Accessor &styler, bool caseSensitive) {
 
-    WordList &keywords = *keywordlists[0];
-    WordList &keywords2 = *keywordlists[1];
-    WordList &keywords3 = *keywordlists[2];
-    WordList &keywords4 = *keywordlists[3];
+static void ColouriseDoc(unsigned int startPos, int length, int initStyle,
+	WordList *keywordlists[], Accessor &styler, bool caseSensitive) {
 
-    int styleBeforeDCKeyword = SCE_D_DEFAULT;
+	WordList &keywords  = *keywordlists[0];
+	WordList &keywords2 = *keywordlists[1];
+	WordList &keywords3 = *keywordlists[2]; //doxygen
+	WordList &keywords4 = *keywordlists[3];
+	WordList &keywords5 = *keywordlists[4];
+	WordList &keywords6 = *keywordlists[5];
+	WordList &keywords7 = *keywordlists[6];
 
-    StyleContext sc(startPos, length, initStyle, styler);
+	int styleBeforeDCKeyword = SCE_D_DEFAULT;
 
-    int curLine = styler.GetLine(startPos);
-    int curNcLevel = curLine > 0? styler.GetLineState(curLine-1): 0;
+	StyleContext sc(startPos, length, initStyle, styler);
 
-    for (; sc.More(); sc.Forward()) {
+	int curLine = styler.GetLine(startPos);
+	int curNcLevel = curLine > 0? styler.GetLineState(curLine-1): 0;
+	bool numFloat = false; // Float literals have '+' and '-' signs
+	bool numHex = false;
 
-        if (sc.atLineStart) {
-            if (sc.state == SCE_D_STRING) {
-                // Prevent SCE_D_STRINGEOL from leaking back to previous line which
-                // ends with a line continuation by locking in the state upto this position.
-                sc.SetState(SCE_D_STRING);
-            }
-            curLine = styler.GetLine(sc.currentPos);
-            styler.SetLineState(curLine, curNcLevel);
-        }
+	for (; sc.More(); sc.Forward()) {
 
-        // Handle line continuation generically.
-        if (sc.ch == '\\') {
-            if (sc.chNext == '\n' || sc.chNext == '\r') {
-                sc.Forward();
-                if (sc.ch == '\r' && sc.chNext == '\n') {
-                    sc.Forward();
-                }
-                continue;
-            }
-        }
+		if (sc.atLineStart) {
+			curLine = styler.GetLine(sc.currentPos);
+			styler.SetLineState(curLine, curNcLevel);
+		}
 
-        // Determine if the current state should terminate.
-        switch (sc.state) {
-            case SCE_D_OPERATOR:
-                sc.SetState(SCE_D_DEFAULT);
-                break;
-            case SCE_D_NUMBER:
-                // We accept almost anything because of hex. and number suffixes
-                if (!IsWord(sc.ch) && sc.ch != '.') {
-                    sc.SetState(SCE_D_DEFAULT);
-                }
-                break;
-            case SCE_D_IDENTIFIER:
-                if (!IsWord(sc.ch)) {
-                    char s[1000];
-                    if (caseSensitive) {
-                        sc.GetCurrent(s, sizeof(s));
-                    } else {
-                        sc.GetCurrentLowered(s, sizeof(s));
-                    }
-                    if (keywords.InList(s)) {
-                        sc.ChangeState(SCE_D_WORD);
-                    } else if (keywords2.InList(s)) {
-                        sc.ChangeState(SCE_D_WORD2);
-                    } else if (keywords4.InList(s)) {
-                        sc.ChangeState(SCE_D_TYPEDEF);
-                    }
-                    sc.SetState(SCE_D_DEFAULT);
-                }
-                break;
-            case SCE_D_COMMENT:
-                if (sc.Match('*', '/')) {
-                    sc.Forward();
-                    sc.ForwardSetState(SCE_D_DEFAULT);
-                }
-                break;
-            case SCE_D_COMMENTDOC:
-                if (sc.Match('*', '/')) {
-                    sc.Forward();
-                    sc.ForwardSetState(SCE_D_DEFAULT);
-                } else if (sc.ch == '@' || sc.ch == '\\') { // JavaDoc and Doxygen support
-                    // Verify that we have the conditions to mark a comment-doc-keyword
-                    if ((IsASpace(sc.chPrev) || sc.chPrev == '*') && (!IsASpace(sc.chNext))) {
-                        styleBeforeDCKeyword = SCE_D_COMMENTDOC;
-                        sc.SetState(SCE_D_COMMENTDOCKEYWORD);
-                    }
-                }
-                break;
-            case SCE_D_COMMENTLINE:
-                if (sc.atLineStart) {
-                    sc.SetState(SCE_D_DEFAULT);
-                }
-                break;
-            case SCE_D_COMMENTLINEDOC:
-                if (sc.atLineStart) {
-                    sc.SetState(SCE_D_DEFAULT);
-                } else if (sc.ch == '@' || sc.ch == '\\') { // JavaDoc and Doxygen support
-                    // Verify that we have the conditions to mark a comment-doc-keyword
-                    if ((IsASpace(sc.chPrev) || sc.chPrev == '/' || sc.chPrev == '!') && (!IsASpace(sc.chNext))) {
-                        styleBeforeDCKeyword = SCE_D_COMMENTLINEDOC;
-                        sc.SetState(SCE_D_COMMENTDOCKEYWORD);
-                    }
-                }
-                break;
-            case SCE_D_COMMENTDOCKEYWORD:
-                if ((styleBeforeDCKeyword == SCE_D_COMMENTDOC) && sc.Match('*', '/')) {
-                    sc.ChangeState(SCE_D_COMMENTDOCKEYWORDERROR);
-                    sc.Forward();
-                    sc.ForwardSetState(SCE_D_DEFAULT);
-                } else if (!IsDoxygen(sc.ch)) {
-                    char s[100];
-                    if (caseSensitive) {
-                        sc.GetCurrent(s, sizeof(s));
-                    } else {
-                        sc.GetCurrentLowered(s, sizeof(s));
-                    }
-                    if (!IsASpace(sc.ch) || !keywords3.InList(s + 1)) {
-                        sc.ChangeState(SCE_D_COMMENTDOCKEYWORDERROR);
-                    }
-                    sc.SetState(styleBeforeDCKeyword);
-                }
-                break;
-            case SCE_D_COMMENTNESTED:
-                if (sc.Match('+', '/')) {
-                    if (curNcLevel > 0)
-                        curNcLevel -= 1;
-                    curLine = styler.GetLine(sc.currentPos);
-                    styler.SetLineState(curLine, curNcLevel);
-                    sc.Forward();
-                    if (curNcLevel == 0) {
-                        sc.ForwardSetState(SCE_D_DEFAULT);
-		    }
-                }
-                else if (sc.Match('/','+')) {
-                    curNcLevel += 1;
-                    curLine = styler.GetLine(sc.currentPos);
-                    styler.SetLineState(curLine, curNcLevel);
-                    sc.Forward();
-                }
-                break;
-            case SCE_D_STRING:
-                if (sc.atLineEnd) {
-                    sc.ChangeState(SCE_D_STRINGEOL);
-                } else if (sc.ch == '\\') {
-                    if (sc.chNext == '\"' || sc.chNext == '\'' || sc.chNext == '\\') {
-                        sc.Forward();
-                    }
-                } else if (sc.ch == '\"') {
-                    sc.ForwardSetState(SCE_D_DEFAULT);
-                }
-                break;
-            case SCE_D_CHARACTER:
-                if (sc.atLineEnd) {
-                    sc.ChangeState(SCE_D_STRINGEOL);
-                } else if (sc.ch == '\\') {
-                    if (sc.chNext == '\"' || sc.chNext == '\'' || sc.chNext == '\\') {
-                        sc.Forward();
-                    }
-                } else if (sc.ch == '\'') {
-                    sc.ForwardSetState(SCE_D_DEFAULT);
-                }
-                break;
-            case SCE_D_STRINGEOL:
-                if (sc.atLineStart) {
-                    sc.SetState(SCE_D_DEFAULT);
-                }
-                break;
-        }
+		// Determine if the current state should terminate.
+		switch (sc.state) {
+			case SCE_D_OPERATOR:
+				sc.SetState(SCE_D_DEFAULT);
+				break;
+			case SCE_D_NUMBER:
+				// We accept almost anything because of hex. and number suffixes
+				if (isascii(sc.ch) && (isalnum(sc.ch) || sc.ch == '_')) {
+					continue;
+				} else if (sc.ch == '.' && sc.chNext != '.' && !numFloat) {
+					// Don't parse 0..2 as number.
+					numFloat=true;
+					continue;
+				} else if ( ( sc.ch == '-' || sc.ch == '+' ) && (		/*sign and*/
+					( !numHex && ( sc.chPrev == 'e' || sc.chPrev == 'E' ) ) || /*decimal or*/
+					( sc.chPrev == 'p' || sc.chPrev == 'P' ) ) ) {		/*hex*/
+					// Parse exponent sign in float literals: 2e+10 0x2e+10
+					continue;
+				} else {
+					sc.SetState(SCE_D_DEFAULT);
+				}
+				break;
+			case SCE_D_IDENTIFIER:
+				if (!IsWord(sc.ch)) {
+					char s[1000];
+					if (caseSensitive) {
+						sc.GetCurrent(s, sizeof(s));
+					} else {
+						sc.GetCurrentLowered(s, sizeof(s));
+					}
+					if (keywords.InList(s)) {
+						sc.ChangeState(SCE_D_WORD);
+					} else if (keywords2.InList(s)) {
+						sc.ChangeState(SCE_D_WORD2);
+					} else if (keywords4.InList(s)) {
+						sc.ChangeState(SCE_D_TYPEDEF);
+					} else if (keywords5.InList(s)) {
+						sc.ChangeState(SCE_D_WORD5);
+					} else if (keywords6.InList(s)) {
+						sc.ChangeState(SCE_D_WORD6);
+					} else if (keywords7.InList(s)) {
+						sc.ChangeState(SCE_D_WORD7);
+					}
+					sc.SetState(SCE_D_DEFAULT);
+				}
+				break;
+			case SCE_D_COMMENT:
+				if (sc.Match('*', '/')) {
+					sc.Forward();
+					sc.ForwardSetState(SCE_D_DEFAULT);
+				}
+				break;
+			case SCE_D_COMMENTDOC:
+				if (sc.Match('*', '/')) {
+					sc.Forward();
+					sc.ForwardSetState(SCE_D_DEFAULT);
+				} else if (sc.ch == '@' || sc.ch == '\\') { // JavaDoc and Doxygen support
+					// Verify that we have the conditions to mark a comment-doc-keyword
+					if ((IsASpace(sc.chPrev) || sc.chPrev == '*') && (!IsASpace(sc.chNext))) {
+						styleBeforeDCKeyword = SCE_D_COMMENTDOC;
+						sc.SetState(SCE_D_COMMENTDOCKEYWORD);
+					}
+				}
+				break;
+			case SCE_D_COMMENTLINE:
+				if (sc.atLineStart) {
+					sc.SetState(SCE_D_DEFAULT);
+				}
+				break;
+			case SCE_D_COMMENTLINEDOC:
+				if (sc.atLineStart) {
+					sc.SetState(SCE_D_DEFAULT);
+				} else if (sc.ch == '@' || sc.ch == '\\') { // JavaDoc and Doxygen support
+					// Verify that we have the conditions to mark a comment-doc-keyword
+					if ((IsASpace(sc.chPrev) || sc.chPrev == '/' || sc.chPrev == '!') && (!IsASpace(sc.chNext))) {
+						styleBeforeDCKeyword = SCE_D_COMMENTLINEDOC;
+						sc.SetState(SCE_D_COMMENTDOCKEYWORD);
+					}
+				}
+				break;
+			case SCE_D_COMMENTDOCKEYWORD:
+				if ((styleBeforeDCKeyword == SCE_D_COMMENTDOC) && sc.Match('*', '/')) {
+					sc.ChangeState(SCE_D_COMMENTDOCKEYWORDERROR);
+					sc.Forward();
+					sc.ForwardSetState(SCE_D_DEFAULT);
+				} else if (!IsDoxygen(sc.ch)) {
+					char s[100];
+					if (caseSensitive) {
+						sc.GetCurrent(s, sizeof(s));
+					} else {
+						sc.GetCurrentLowered(s, sizeof(s));
+					}
+					if (!IsASpace(sc.ch) || !keywords3.InList(s + 1)) {
+						sc.ChangeState(SCE_D_COMMENTDOCKEYWORDERROR);
+					}
+					sc.SetState(styleBeforeDCKeyword);
+				}
+				break;
+			case SCE_D_COMMENTNESTED:
+				if (sc.Match('+', '/')) {
+					if (curNcLevel > 0)
+						curNcLevel -= 1;
+					curLine = styler.GetLine(sc.currentPos);
+					styler.SetLineState(curLine, curNcLevel);
+					sc.Forward();
+					if (curNcLevel == 0) {
+						sc.ForwardSetState(SCE_D_DEFAULT);
+					}
+				} else if (sc.Match('/','+')) {
+					curNcLevel += 1;
+					curLine = styler.GetLine(sc.currentPos);
+					styler.SetLineState(curLine, curNcLevel);
+					sc.Forward();
+				}
+				break;
+			case SCE_D_STRING:
+				if (sc.ch == '\\') {
+					if (sc.chNext == '"' || sc.chNext == '\\') {
+						sc.Forward();
+					}
+				} else if (sc.ch == '"') {
+					if(IsStringSuffix(sc.chNext))
+						sc.Forward();
+					sc.ForwardSetState(SCE_D_DEFAULT);
+				}
+				break;
+			case SCE_D_CHARACTER:
+				if (sc.atLineEnd) {
+					sc.ChangeState(SCE_D_STRINGEOL);
+				} else if (sc.ch == '\\') {
+					if (sc.chNext == '\'' || sc.chNext == '\\') {
+						sc.Forward();
+					}
+				} else if (sc.ch == '\'') {
+					// Char has no suffixes
+					sc.ForwardSetState(SCE_D_DEFAULT);
+				}
+				break;
+			case SCE_D_STRINGEOL:
+				if (sc.atLineStart) {
+					sc.SetState(SCE_D_DEFAULT);
+				}
+				break;
+			case SCE_D_STRINGB:
+				if (sc.ch == '`') {
+					if(IsStringSuffix(sc.chNext))
+						sc.Forward();
+					sc.ForwardSetState(SCE_D_DEFAULT);
+				}
+				break;
+			case SCE_D_STRINGR:
+				if (sc.ch == '"') {
+					if(IsStringSuffix(sc.chNext))
+						sc.Forward();
+					sc.ForwardSetState(SCE_D_DEFAULT);
+				}
+				break;
+		}
 
-        // Determine if a new state should be entered.
-        if (sc.state == SCE_D_DEFAULT) {
-            if (IsADigit(sc.ch) || (sc.ch == '.' && IsADigit(sc.chNext))) {
-                    sc.SetState(SCE_D_NUMBER);
-            } else if (IsWordStart(sc.ch)) {
-                    sc.SetState(SCE_D_IDENTIFIER);
-            } else if (sc.Match('/','+')) {
-                curNcLevel += 1;
-		curLine = styler.GetLine(sc.currentPos);
-                styler.SetLineState(curLine, curNcLevel);
-                sc.SetState(SCE_D_COMMENTNESTED);
-                sc.Forward();
-            } else if (sc.Match('/', '*')) {
-                if (sc.Match("/**") || sc.Match("/*!")) {   // Support of Qt/Doxygen doc. style
-                    sc.SetState(SCE_D_COMMENTDOC);
-                } else {
-                    sc.SetState(SCE_D_COMMENT);
-                }
-                sc.Forward();   // Eat the * so it isn't used for the end of the comment
-            } else if (sc.Match('/', '/')) {
-                if ((sc.Match("///") && !sc.Match("////")) || sc.Match("//!"))
-                    // Support of Qt/Doxygen doc. style
-                    sc.SetState(SCE_D_COMMENTLINEDOC);
-                else
-                    sc.SetState(SCE_D_COMMENTLINE);
-            } else if (sc.ch == '\"') {
-                sc.SetState(SCE_D_STRING);
-            } else if (sc.ch == '\'') {
-                sc.SetState(SCE_D_CHARACTER);
-            } else if (isoperator(static_cast<char>(sc.ch))) {
-                sc.SetState(SCE_D_OPERATOR);
-            }
-        }
-    }
-    sc.Complete();
+		// Determine if a new state should be entered.
+		if (sc.state == SCE_D_DEFAULT) {
+			if (IsADigit(sc.ch) || (sc.ch == '.' && IsADigit(sc.chNext))) {
+				sc.SetState(SCE_D_NUMBER);
+				numFloat = sc.ch == '.';
+				// Remember hex literal
+				numHex = sc.ch == '0' && ( sc.chNext == 'x' || sc.chNext == 'X' );
+			} else if ( (sc.ch == 'r' || sc.ch == 'x' || sc.ch == 'q')
+				&& sc.chNext == '"' ) {
+				// Limited support for hex and delimited strings: parse as r""
+				sc.SetState(SCE_D_STRINGR);
+				sc.Forward();
+			} else if (IsWordStart(sc.ch) || sc.ch == '$') {
+				sc.SetState(SCE_D_IDENTIFIER);
+			} else if (sc.Match('/','+')) {
+				curNcLevel += 1;
+				curLine = styler.GetLine(sc.currentPos);
+				styler.SetLineState(curLine, curNcLevel);
+				sc.SetState(SCE_D_COMMENTNESTED);
+				sc.Forward();
+			} else if (sc.Match('/', '*')) {
+				if (sc.Match("/**") || sc.Match("/*!")) {   // Support of Qt/Doxygen doc. style
+					sc.SetState(SCE_D_COMMENTDOC);
+				} else {
+					sc.SetState(SCE_D_COMMENT);
+				}
+				sc.Forward();   // Eat the * so it isn't used for the end of the comment
+			} else if (sc.Match('/', '/')) {
+				if ((sc.Match("///") && !sc.Match("////")) || sc.Match("//!"))
+					// Support of Qt/Doxygen doc. style
+					sc.SetState(SCE_D_COMMENTLINEDOC);
+				else
+					sc.SetState(SCE_D_COMMENTLINE);
+			} else if (sc.ch == '"') {
+				sc.SetState(SCE_D_STRING);
+			} else if (sc.ch == '\'') {
+				sc.SetState(SCE_D_CHARACTER);
+			} else if (sc.ch == '`') {
+				sc.SetState(SCE_D_STRINGB);
+			} else if (isoperator(static_cast<char>(sc.ch))) {
+				sc.SetState(SCE_D_OPERATOR);
+				if (sc.ch == '.' && sc.chNext == '.') sc.Forward(); // Range operator
+			}
+		}
+	}
+	sc.Complete();
 }
 
 static bool IsStreamCommentStyle(int style) {
-    return style == SCE_D_COMMENT ||
-        style == SCE_D_COMMENTDOC ||
-        style == SCE_D_COMMENTDOCKEYWORD ||
-        style == SCE_D_COMMENTDOCKEYWORDERROR;
+	return style == SCE_D_COMMENT ||
+		style == SCE_D_COMMENTDOC ||
+		style == SCE_D_COMMENTDOCKEYWORD ||
+		style == SCE_D_COMMENTDOCKEYWORDERROR;
 }
 
 // Store both the current line's fold level and the next lines in the
 // level store to make it easy to pick up with each increment
 // and to make it possible to fiddle the current level for "} else {".
 static void FoldDoc(unsigned int startPos, int length, int initStyle, Accessor &styler) {
-    bool foldComment = styler.GetPropertyInt("fold.comment") != 0;
-    bool foldCompact = styler.GetPropertyInt("fold.compact", 1) != 0;
+	bool foldComment = styler.GetPropertyInt("fold.comment") != 0;
+	bool foldCompact = styler.GetPropertyInt("fold.compact", 1) != 0;
 
-    // property lexer.d.fold.at.else 
-    //	This option enables D folding on a "} else {" line of an if statement. 
-    bool foldAtElse = styler.GetPropertyInt("lexer.d.fold.at.else",
+	// property lexer.d.fold.at.else
+	//  This option enables D folding on a "} else {" line of an if statement.
+	bool foldAtElse = styler.GetPropertyInt("lexer.d.fold.at.else",
 		styler.GetPropertyInt("fold.at.else", 0)) != 0;
-    unsigned int endPos = startPos + length;
-    int visibleChars = 0;
-    int lineCurrent = styler.GetLine(startPos);
-    int levelCurrent = SC_FOLDLEVELBASE;
-    if (lineCurrent > 0)
-        levelCurrent = styler.LevelAt(lineCurrent-1) >> 16;
-    int levelMinCurrent = levelCurrent;
-    int levelNext = levelCurrent;
-    char chNext = styler[startPos];
-    int styleNext = styler.StyleAt(startPos);
-    int style = initStyle;
-    for (unsigned int i = startPos; i < endPos; i++) {
-        char ch = chNext;
-        chNext = styler.SafeGetCharAt(i + 1);
-        int stylePrev = style;
-        style = styleNext;
-        styleNext = styler.StyleAt(i + 1);
-        bool atEOL = (ch == '\r' && chNext != '\n') || (ch == '\n');
-        if (foldComment && IsStreamCommentStyle(style)) {
-            if (!IsStreamCommentStyle(stylePrev)) {
-                levelNext++;
-            } else if (!IsStreamCommentStyle(styleNext) && !atEOL) {
-                // Comments don't end at end of line and the next character may be unstyled.
-                levelNext--;
-            }
-        }
-        if (style == SCE_D_OPERATOR) {
-            if (ch == '{') {
-                // Measure the minimum before a '{' to allow
-                // folding on "} else {"
-                if (levelMinCurrent > levelNext) {
-                    levelMinCurrent = levelNext;
-                }
-                levelNext++;
-            } else if (ch == '}') {
-                levelNext--;
-            }
-        }
-        if (atEOL) {
-            if (foldComment) {	// Handle nested comments
-		int nc;
-                nc =  styler.GetLineState(lineCurrent);
-                nc -= lineCurrent>0? styler.GetLineState(lineCurrent-1): 0;
-                levelNext += nc;
-	    }
-            int levelUse = levelCurrent;
-            if (foldAtElse) {
-                levelUse = levelMinCurrent;
-            }
-            int lev = levelUse | levelNext << 16;
-            if (visibleChars == 0 && foldCompact)
-                lev |= SC_FOLDLEVELWHITEFLAG;
-            if (levelUse < levelNext)
-                lev |= SC_FOLDLEVELHEADERFLAG;
-            if (lev != styler.LevelAt(lineCurrent)) {
-                styler.SetLevel(lineCurrent, lev);
-            }
-            lineCurrent++;
-            levelCurrent = levelNext;
-            levelMinCurrent = levelCurrent;
-            visibleChars = 0;
-        }
-        if (!IsASpace(ch))
-            visibleChars++;
-    }
+	unsigned int endPos = startPos + length;
+	int visibleChars = 0;
+	int lineCurrent = styler.GetLine(startPos);
+	int levelCurrent = SC_FOLDLEVELBASE;
+	if (lineCurrent > 0)
+		levelCurrent = styler.LevelAt(lineCurrent-1) >> 16;
+	int levelMinCurrent = levelCurrent;
+	int levelNext = levelCurrent;
+	char chNext = styler[startPos];
+	int styleNext = styler.StyleAt(startPos);
+	int style = initStyle;
+	for (unsigned int i = startPos; i < endPos; i++) {
+		char ch = chNext;
+		chNext = styler.SafeGetCharAt(i + 1);
+		int stylePrev = style;
+		style = styleNext;
+		styleNext = styler.StyleAt(i + 1);
+		bool atEOL = (ch == '\r' && chNext != '\n') || (ch == '\n');
+		if (foldComment && IsStreamCommentStyle(style)) {
+			if (!IsStreamCommentStyle(stylePrev)) {
+				levelNext++;
+			} else if (!IsStreamCommentStyle(styleNext) && !atEOL) {
+				// Comments don't end at end of line and the next character may be unstyled.
+				levelNext--;
+			}
+		}
+		if (style == SCE_D_OPERATOR) {
+			if (ch == '{') {
+				// Measure the minimum before a '{' to allow
+				// folding on "} else {"
+				if (levelMinCurrent > levelNext) {
+					levelMinCurrent = levelNext;
+				}
+				levelNext++;
+			} else if (ch == '}') {
+				levelNext--;
+			}
+		}
+		if (atEOL) {
+			if (foldComment) {  // Handle nested comments
+				int nc;
+				nc =  styler.GetLineState(lineCurrent);
+				nc -= lineCurrent>0? styler.GetLineState(lineCurrent-1): 0;
+				levelNext += nc;
+			}
+			int levelUse = levelCurrent;
+			if (foldAtElse) {
+				levelUse = levelMinCurrent;
+			}
+			int lev = levelUse | levelNext << 16;
+			if (visibleChars == 0 && foldCompact)
+				lev |= SC_FOLDLEVELWHITEFLAG;
+			if (levelUse < levelNext)
+				lev |= SC_FOLDLEVELHEADERFLAG;
+			if (lev != styler.LevelAt(lineCurrent)) {
+				styler.SetLevel(lineCurrent, lev);
+			}
+			lineCurrent++;
+			levelCurrent = levelNext;
+			levelMinCurrent = levelCurrent;
+			visibleChars = 0;
+		}
+		if (!IsASpace(ch))
+			visibleChars++;
+	}
 }
 
 static void FoldDDoc(unsigned int startPos, int length, int initStyle,
-    WordList *[], Accessor &styler) {
-        FoldDoc(startPos, length, initStyle, styler);
+	WordList *[], Accessor &styler) {
+		FoldDoc(startPos, length, initStyle, styler);
 }
 
 static const char * const dWordLists[] = {
-            "Primary keywords and identifiers",
-            "Secondary keywords and identifiers",
-            "Documentation comment keywords",
-            "Type definitions and aliases",
-            0,
-        };
+			"Primary keywords and identifiers",
+			"Secondary keywords and identifiers",
+			"Documentation comment keywords",
+			"Type definitions and aliases",
+			"Keywords 5",
+			"Keywords 6",
+			"Keywords 7",
+			0,
+		};
 
-static void ColouriseDDoc(unsigned int startPos, int length, 
-    int initStyle, WordList *keywordlists[], Accessor &styler) {
-        ColouriseDoc(startPos, length, initStyle, keywordlists, styler, true);
+static void ColouriseDDoc(unsigned int startPos, int length,
+	int initStyle, WordList *keywordlists[], Accessor &styler) {
+		ColouriseDoc(startPos, length, initStyle, keywordlists, styler, true);
 }
 
 LexerModule lmD(SCLEX_D, ColouriseDDoc, "d", FoldDDoc, dWordLists);