text: // Scintilla source code edit control
  /** @file LexVerilog.cxx
   ** Lexer for Verilog.
   ** Written by Avi Yegudin, based on C++ lexer by Neil Hodgson
   **/
  // Copyright 1998-2002 by Neil Hodgson <neilh@scintilla.org>
  // The License.txt file describes the conditions under which this software may be distributed.
  
  #include <stdlib.h>
  #include <string.h>
  #include <stdio.h>
  #include <stdarg.h>
  #include <assert.h>
  #include <ctype.h>
  
  #include <string>
  #include <vector>
  #include <map>
  #include <algorithm>
  
  #include "ILexer.h"
  #include "Scintilla.h"
  #include "SciLexer.h"
  
  #include "WordList.h"
  #include "LexAccessor.h"
  #include "Accessor.h"
  #include "StyleContext.h"
  #include "CharacterSet.h"
  #include "LexerModule.h"
  
  #include "OptionSet.h"
  #include "SubStyles.h"
  
  #ifdef SCI_NAMESPACE
  using namespace Scintilla;
  #endif
  
  namespace {
  	// Use an unnamed namespace to protect the functions and classes from name conflicts
  
  struct PPDefinition {
  	int line;
  	std::string key;
  	std::string value;
  	bool isUndef;
  	std::string arguments;
  	PPDefinition(int line_, const std::string &key_, const std::string &value_, bool isUndef_ = false, std::string arguments_="") :
  		line(line_), key(key_), value(value_), isUndef(isUndef_), arguments(arguments_) {
  	}
  };
  
  class LinePPState {
  	int state;
  	int ifTaken;
  	int level;
  	bool ValidLevel() const {
  		return level >= 0 && level < 32;
  	}
  	int maskLevel() const {
  		return 1 << level;
  	}
  public:
  	LinePPState() : state(0), ifTaken(0), level(-1) {
  	}
  	bool IsInactive() const {
  		return state != 0;
  	}
  	bool CurrentIfTaken() const {
  		return (ifTaken & maskLevel()) != 0;
  	}
  	void StartSection(bool on) {
  		level++;
  		if (ValidLevel()) {
  			if (on) {
  				state &= ~maskLevel();
  				ifTaken |= maskLevel();
  			} else {
  				state |= maskLevel();
  				ifTaken &= ~maskLevel();
  			}
  		}
  	}
  	void EndSection() {
  		if (ValidLevel()) {
  			state &= ~maskLevel();
  			ifTaken &= ~maskLevel();
  		}
  		level--;
  	}
  	void InvertCurrentLevel() {
  		if (ValidLevel()) {
  			state ^= maskLevel();
  			ifTaken |= maskLevel();
  		}
  	}
  };
  
  // Hold the preprocessor state for each line seen.
  // Currently one entry per line but could become sparse with just one entry per preprocessor line.
  class PPStates {
  	std::vector<LinePPState> vlls;
  public:
  	LinePPState ForLine(int line) const {
  		if ((line > 0) && (vlls.size() > static_cast<size_t>(line))) {
  			return vlls[line];
  		} else {
  			return LinePPState();
  		}
  	}
  	void Add(int line, LinePPState lls) {
  		vlls.resize(line+1);
  		vlls[line] = lls;
  	}
  };
  
  // Options used for LexerVerilog
  struct OptionsVerilog {
  	bool foldComment;
  	bool foldPreprocessor;
  	bool foldPreprocessorElse;
  	bool foldCompact;
  	bool foldAtElse;
  	bool foldAtModule;
  	bool trackPreprocessor;
  	bool updatePreprocessor;
  	bool portStyling;
  	bool allUppercaseDocKeyword;
  	OptionsVerilog() {
  		foldComment = false;
  		foldPreprocessor = false;
  		foldPreprocessorElse = false;
  		foldCompact = false;
  		foldAtElse = false;
  		foldAtModule = false;
  		// for backwards compatibility, preprocessor functionality is disabled by default
  		trackPreprocessor = false;
  		updatePreprocessor = false;
  		// for backwards compatibility, treat input/output/inout as regular keywords
  		portStyling = false;
  		// for backwards compatibility, don't treat all uppercase identifiers as documentation keywords
  		allUppercaseDocKeyword = false;
  	}
  };
  
  struct OptionSetVerilog : public OptionSet<OptionsVerilog> {
  	OptionSetVerilog() {
  		DefineProperty("fold.comment", &OptionsVerilog::foldComment,
  			"This option enables folding multi-line comments when using the Verilog lexer.");
  		DefineProperty("fold.preprocessor", &OptionsVerilog::foldPreprocessor,
  			"This option enables folding preprocessor directives when using the Verilog lexer.");
  		DefineProperty("fold.compact", &OptionsVerilog::foldCompact);
  		DefineProperty("fold.at.else", &OptionsVerilog::foldAtElse,
  			"This option enables folding on the else line of an if statement.");
  		DefineProperty("fold.verilog.flags", &OptionsVerilog::foldAtModule,
  			"This option enables folding module definitions. Typically source files "
  			"contain only one module definition so this option is somewhat useless.");
  		DefineProperty("lexer.verilog.track.preprocessor", &OptionsVerilog::trackPreprocessor,
  			"Set to 1 to interpret `if/`else/`endif to grey out code that is not active.");
  		DefineProperty("lexer.verilog.update.preprocessor", &OptionsVerilog::updatePreprocessor,
  			"Set to 1 to update preprocessor definitions when `define, `undef, or `undefineall found.");
  		DefineProperty("lexer.verilog.portstyling", &OptionsVerilog::portStyling,
  			"Set to 1 to style input, output, and inout ports differently from regular keywords.");
  		DefineProperty("lexer.verilog.allupperkeywords", &OptionsVerilog::allUppercaseDocKeyword,
  			"Set to 1 to style identifiers that are all uppercase as documentation keyword.");
  		DefineProperty("lexer.verilog.fold.preprocessor.else", &OptionsVerilog::foldPreprocessorElse,
  			"This option enables folding on `else and `elsif preprocessor directives.");
  	}
  };
  
  const char styleSubable[] = {0};
  
  }
  
  class LexerVerilog : public ILexerWithSubStyles {
  	CharacterSet setWord;
  	WordList keywords;
  	WordList keywords2;
  	WordList keywords3;
  	WordList keywords4;
  	WordList keywords5;
  	WordList ppDefinitions;
  	PPStates vlls;
  	std::vector<PPDefinition> ppDefineHistory;
  	struct SymbolValue {
  		std::string value;
  		std::string arguments;
  		SymbolValue(const std::string &value_="", const std::string &arguments_="") : value(value_), arguments(arguments_) {
  		}
  		SymbolValue &operator = (const std::string &value_) {
  			value = value_;
  			arguments.clear();
  			return *this;
  		}
  		bool IsMacro() const {
  			return !arguments.empty();
  		}
  	};
  	typedef std::map<std::string, SymbolValue> SymbolTable;
  	SymbolTable preprocessorDefinitionsStart;
  	OptionsVerilog options;
  	OptionSetVerilog osVerilog;
  	enum { activeFlag = 0x40 };
  	SubStyles subStyles;
  
  	// states at end of line (EOL) during fold operations:
  	//		foldExternFlag: EOL while parsing an extern function/task declaration terminated by ';'
  	//		foldWaitDisableFlag: EOL while parsing wait or disable statement, terminated by "fork" or '('
  	//		typdefFlag: EOL while parsing typedef statement, terminated by ';'
  	enum {foldExternFlag = 0x01, foldWaitDisableFlag = 0x02, typedefFlag = 0x04};
  	// map using line number as key to store fold state information
  	std::map<int, int> foldState;
  
  public:
  	LexerVerilog() :
  		setWord(CharacterSet::setAlphaNum, "._", 0x80, true),
  		subStyles(styleSubable, 0x80, 0x40, activeFlag) {
  		}
  	virtual ~LexerVerilog() {}
  	int SCI_METHOD Version() const {
  		return lvSubStyles;
  	}
  	void SCI_METHOD Release() {
  		delete this;
  	}
  	const char* SCI_METHOD PropertyNames() {
  		return osVerilog.PropertyNames();
  	}
  	int SCI_METHOD PropertyType(const char* name) {
  		return osVerilog.PropertyType(name);
  	}
  	const char* SCI_METHOD DescribeProperty(const char* name) {
  		return osVerilog.DescribeProperty(name);
  	}
  	int SCI_METHOD PropertySet(const char* key, const char* val) {
  	    return osVerilog.PropertySet(&options, key, val);
  	}
  	const char* SCI_METHOD DescribeWordListSets() {
  		return osVerilog.DescribeWordListSets();
  	}
  	int SCI_METHOD WordListSet(int n, const char* wl);
  	void SCI_METHOD Lex(unsigned int startPos, int length, int initStyle, IDocument *pAccess);
  	void SCI_METHOD Fold(unsigned int startPos, int length, int initStyle, IDocument *pAccess);
  	void* SCI_METHOD PrivateCall(int, void*) {
  		return 0;
  	}
  	int SCI_METHOD LineEndTypesSupported() {
  		return SC_LINE_END_TYPE_UNICODE;
  	}
  	int SCI_METHOD AllocateSubStyles(int styleBase, int numberStyles) {
  		return subStyles.Allocate(styleBase, numberStyles);
  	}
  	int SCI_METHOD SubStylesStart(int styleBase) {
  		return subStyles.Start(styleBase);
  	}
  	int SCI_METHOD SubStylesLength(int styleBase) {
  		return subStyles.Length(styleBase);
  	}
  	int SCI_METHOD StyleFromSubStyle(int subStyle) {
  		int styleBase = subStyles.BaseStyle(MaskActive(subStyle));
  		int active = subStyle & activeFlag;
  		return styleBase | active;
  	}
  	int SCI_METHOD PrimaryStyleFromStyle(int style) {
  		return MaskActive(style);
   	}
  	void SCI_METHOD FreeSubStyles() {
  		subStyles.Free();
  	}
  	void SCI_METHOD SetIdentifiers(int style, const char *identifiers) {
  		subStyles.SetIdentifiers(style, identifiers);
  	}
  	int SCI_METHOD DistanceToSecondaryStyles() {
  		return activeFlag;
  	}
  	const char * SCI_METHOD GetSubStyleBases() {
  		return styleSubable;
  	}
  	static ILexer* LexerFactoryVerilog() {
  		return new LexerVerilog();
  	}
  	static int MaskActive(int style) {
  		return style & ~activeFlag;
  	}
  	std::vector<std::string> Tokenize(const std::string &expr) const;
  };
  
  int SCI_METHOD LexerVerilog::WordListSet(int n, const char *wl) {
  	WordList *wordListN = 0;
  	switch (n) {
  	case 0:
  		wordListN = &keywords;
  		break;
  	case 1:
  		wordListN = &keywords2;
  		break;
  	case 2:
  		wordListN = &keywords3;
  		break;
  	case 3:
  		wordListN = &keywords4;
  		break;
  	case 4:
  		wordListN = &keywords5;
  		break;
  	case 5:
  		wordListN = &ppDefinitions;
  		break;
  	}
  	int firstModification = -1;
  	if (wordListN) {
  		WordList wlNew;
  		wlNew.Set(wl);
  		if (*wordListN != wlNew) {
  			wordListN->Set(wl);
  			firstModification = 0;
  			if (n == 5) {
  				// Rebuild preprocessorDefinitions
  				preprocessorDefinitionsStart.clear();
  				for (int nDefinition = 0; nDefinition < ppDefinitions.Length(); nDefinition++) {
  					const char *cpDefinition = ppDefinitions.WordAt(nDefinition);
  					const char *cpEquals = strchr(cpDefinition, '=');
  					if (cpEquals) {
  						std::string name(cpDefinition, cpEquals - cpDefinition);
  						std::string val(cpEquals+1);
  						size_t bracket = name.find('(');
  						size_t bracketEnd = name.find(')');
  						if ((bracket != std::string::npos) && (bracketEnd != std::string::npos)) {
  							// Macro
  							std::string args = name.substr(bracket + 1, bracketEnd - bracket - 1);
  							name = name.substr(0, bracket);
  							preprocessorDefinitionsStart[name] = SymbolValue(val, args);
  						} else {
  							preprocessorDefinitionsStart[name] = val;
  						}
  					} else {
  						std::string name(cpDefinition);
  						std::string val("1");
  						preprocessorDefinitionsStart[name] = val;
  					}
  				}
  			}
  		}
  	}
  	return firstModification;
  }
  
  static inline bool IsAWordChar(const int ch) {
  	return (ch < 0x80) && (isalnum(ch) || ch == '_' || ch == '\''|| ch == '$');
  }
  
  static inline bool IsAWordStart(const int ch) {
  	return (ch < 0x80) && (isalnum(ch) || ch == '_' || ch == '$');
  }
  
  static inline bool AllUpperCase(const char *a) {
  	while (*a) {
  		if (*a >= 'a' && *a <= 'z') return false;
  		a++;
  	}
  	return true;
  }
  
  // Functor used to truncate history
  struct After {
  	int line;
  	explicit After(int line_) : line(line_) {}
  	bool operator()(PPDefinition &p) const {
  		return p.line > line;
  	}
  };
  
  static std::string GetRestOfLine(LexAccessor &styler, int start, bool allowSpace) {
  	std::string restOfLine;
  	int i =0;
  	char ch = styler.SafeGetCharAt(start, '\n');
  	int endLine = styler.LineEnd(styler.GetLine(start));
  	while (((start+i) < endLine) && (ch != '\r')) {
  		char chNext = styler.SafeGetCharAt(start + i + 1, '\n');
  		if (ch == '/' && (chNext == '/' || chNext == '*'))
  			break;
  		if (allowSpace || (ch != ' '))
  			restOfLine += ch;
  		i++;
  		ch = chNext;
  	}
  	return restOfLine;
  }
  
  static bool IsSpaceOrTab(int ch) {
  	return ch == ' ' || ch == '\t';
  }
  
  void SCI_METHOD LexerVerilog::Lex(unsigned int startPos, int length, int initStyle, IDocument *pAccess)
  {
  	LexAccessor styler(pAccess);
  
  	const int kwOther=0, kwDot=0x100, kwInput=0x200, kwOutput=0x300, kwInout=0x400;
  	int lineState = kwOther;
  	bool continuationLine = false;
  
  	int curLine = styler.GetLine(startPos);
  	if (curLine > 0) lineState = styler.GetLineState(curLine - 1);
  
  	// Do not leak onto next line
  	if (initStyle == SCE_V_STRINGEOL)
  		initStyle = SCE_V_DEFAULT;
  
  	if ((MaskActive(initStyle) == SCE_V_PREPROCESSOR) ||
  			(MaskActive(initStyle) == SCE_V_COMMENTLINE) ||
  			(MaskActive(initStyle) == SCE_V_COMMENTLINEBANG)) {
  		// Set continuationLine if last character of previous line is '\'
  		if (curLine > 0) {
  			int endLinePrevious = styler.LineEnd(curLine - 1);
  			if (endLinePrevious > 0) {
  				continuationLine = styler.SafeGetCharAt(endLinePrevious-1) == '\\';
  			}
  		}
  	}
  
  	StyleContext sc(startPos, length, initStyle, styler);
  	LinePPState preproc = vlls.ForLine(curLine);
  
  	bool definitionsChanged = false;
  
  	// Truncate ppDefineHistory before current line
  
  	if (!options.updatePreprocessor)
  		ppDefineHistory.clear();
  
  	std::vector<PPDefinition>::iterator itInvalid = std::find_if(ppDefineHistory.begin(), ppDefineHistory.end(), After(curLine-1));
  	if (itInvalid != ppDefineHistory.end()) {
  		ppDefineHistory.erase(itInvalid, ppDefineHistory.end());
  		definitionsChanged = true;
  	}
  
  	SymbolTable preprocessorDefinitions = preprocessorDefinitionsStart;
  	for (std::vector<PPDefinition>::iterator itDef = ppDefineHistory.begin(); itDef != ppDefineHistory.end(); ++itDef) {
  		if (itDef->isUndef)
  			preprocessorDefinitions.erase(itDef->key);
  		else
  			preprocessorDefinitions[itDef->key] = SymbolValue(itDef->value, itDef->arguments);
  	}
  
  	int activitySet = preproc.IsInactive() ? activeFlag : 0;
  	int lineEndNext = styler.LineEnd(curLine);
  	bool isEscapedId = false;    // true when parsing an escaped Identifier
  
  	for (; sc.More(); sc.Forward()) {
  		if (sc.atLineStart) {
  			if (sc.state == SCE_V_STRING) {
  				// Prevent SCE_V_STRINGEOL from leaking back to previous line
  				sc.SetState(SCE_V_STRING);
  			}
  			if ((MaskActive(sc.state) == SCE_V_PREPROCESSOR) && (!continuationLine)) {
  				sc.SetState(SCE_V_DEFAULT|activitySet);
  			}
  			if (preproc.IsInactive()) {
  				activitySet = activeFlag;
  				sc.SetState(sc.state | activitySet);
  			}
  		}
  
  		if (sc.atLineEnd) {
  			curLine++;
  			lineEndNext = styler.LineEnd(curLine);
  			vlls.Add(curLine, preproc);
  			// Update the line state, so it can be seen by next line
  			styler.SetLineState(curLine, lineState);
  			isEscapedId = false;    // EOL terminates an escaped Identifier
  		}
  
  		// Handle line continuation generically.
  		if (sc.ch == '\\') {
  			if (static_cast<int>((sc.currentPos+1)) >= lineEndNext) {
  				curLine++;
  				lineEndNext = styler.LineEnd(curLine);
  				vlls.Add(curLine, preproc);
  				// Update the line state, so it can be seen by next line
  				styler.SetLineState(curLine, lineState);
  				sc.Forward();
  				if (sc.ch == '\r' && sc.chNext == '\n') {
  					// Even in UTF-8, \r and \n are separate
  					sc.Forward();
  				}
  				continuationLine = true;
  				sc.Forward();
  				continue;
  			}
  		}
  
  		// for comment keyword
  		if (MaskActive(sc.state) == SCE_V_COMMENT_WORD && !IsAWordChar(sc.ch)) {
  			char s[100];
  			int state = lineState & 0xff;
  			sc.GetCurrent(s, sizeof(s));
  			if (keywords5.InList(s)) {
  				sc.ChangeState(SCE_V_COMMENT_WORD|activitySet);
  			} else {
  				sc.ChangeState(state|activitySet);
  			}
  			sc.SetState(state|activitySet);
  		}
  
  		const bool atLineEndBeforeSwitch = sc.atLineEnd;
  
  		// Determine if the current state should terminate.
  		switch (MaskActive(sc.state)) {
  			case SCE_V_OPERATOR:
  				sc.SetState(SCE_V_DEFAULT|activitySet);
  				break;
  			case SCE_V_NUMBER:
  				if (!(IsAWordChar(sc.ch) || (sc.ch == '?'))) {
  					sc.SetState(SCE_V_DEFAULT|activitySet);
  				}
  				break;
  			case SCE_V_IDENTIFIER:
  				if (!isEscapedId &&(!IsAWordChar(sc.ch) || (sc.ch == '.'))) {
  					char s[100];
  					lineState &= 0xff00;
  					sc.GetCurrent(s, sizeof(s));
  					if (options.portStyling && (strcmp(s, "input") == 0)) {
  						lineState = kwInput;
  						sc.ChangeState(SCE_V_INPUT|activitySet);
  					} else if (options.portStyling && (strcmp(s, "output") == 0)) {
  						lineState = kwOutput;
  						sc.ChangeState(SCE_V_OUTPUT|activitySet);
  					} else if (options.portStyling && (strcmp(s, "inout") == 0)) {
  						lineState = kwInout;
  						sc.ChangeState(SCE_V_INOUT|activitySet);
  					} else if (lineState == kwInput) {
  						sc.ChangeState(SCE_V_INPUT|activitySet);
  					} else if (lineState == kwOutput) {
  						sc.ChangeState(SCE_V_OUTPUT|activitySet);
  					} else if (lineState == kwInout) {
  						sc.ChangeState(SCE_V_INOUT|activitySet);
  					} else if (lineState == kwDot) {
  						lineState = kwOther;
  						if (options.portStyling)
  							sc.ChangeState(SCE_V_PORT_CONNECT|activitySet);
  					} else if (keywords.InList(s)) {
  						sc.ChangeState(SCE_V_WORD|activitySet);
  					} else if (keywords2.InList(s)) {
  						sc.ChangeState(SCE_V_WORD2|activitySet);
  					} else if (keywords3.InList(s)) {
  						sc.ChangeState(SCE_V_WORD3|activitySet);
  					} else if (keywords4.InList(s)) {
  						sc.ChangeState(SCE_V_USER|activitySet);
  					} else if (options.allUppercaseDocKeyword && AllUpperCase(s)) {
  						sc.ChangeState(SCE_V_USER|activitySet);
  					}
  					sc.SetState(SCE_V_DEFAULT|activitySet);
  				}
  				break;
  			case SCE_V_PREPROCESSOR:
  				if (!IsAWordChar(sc.ch) || sc.atLineEnd) {
  					sc.SetState(SCE_V_DEFAULT|activitySet);
  				}
  				break;
  			case SCE_V_COMMENT:
  				if (sc.Match('*', '/')) {
  					sc.Forward();
  					sc.ForwardSetState(SCE_V_DEFAULT|activitySet);
  				} else if (IsAWordStart(sc.ch)) {
  					lineState = sc.state | (lineState & 0xff00);
  					sc.SetState(SCE_V_COMMENT_WORD|activitySet);
  				}
  				break;
  			case SCE_V_COMMENTLINE:
  			case SCE_V_COMMENTLINEBANG:
  				if (sc.atLineStart) {
  					sc.SetState(SCE_V_DEFAULT|activitySet);
  				} else if (IsAWordStart(sc.ch)) {
  					lineState = sc.state | (lineState & 0xff00);
  					sc.SetState(SCE_V_COMMENT_WORD|activitySet);
  				}
  				break;
  			case SCE_V_STRING:
  				if (sc.ch == '\\') {
  					if (sc.chNext == '\"' || sc.chNext == '\'' || sc.chNext == '\\') {
  						sc.Forward();
  					}
  				} else if (sc.ch == '\"') {
  					sc.ForwardSetState(SCE_V_DEFAULT|activitySet);
  				} else if (sc.atLineEnd) {
  					sc.ChangeState(SCE_V_STRINGEOL|activitySet);
  					sc.ForwardSetState(SCE_V_DEFAULT|activitySet);
  				}
  				break;
  		}
  
  		if (sc.atLineEnd && !atLineEndBeforeSwitch) {
  			// State exit processing consumed characters up to end of line.
  			curLine++;
  			lineEndNext = styler.LineEnd(curLine);
  			vlls.Add(curLine, preproc);
  			// Update the line state, so it can be seen by next line
  			styler.SetLineState(curLine, lineState);
  			isEscapedId = false;    // EOL terminates an escaped Identifier
  		}
  
  		// Determine if a new state should be entered.
  		if (MaskActive(sc.state) == SCE_V_DEFAULT) {
  			if (IsADigit(sc.ch) || (sc.ch == '\'') || (sc.ch == '.' && IsADigit(sc.chNext))) {
  				sc.SetState(SCE_V_NUMBER|activitySet);
  			} else if (IsAWordStart(sc.ch)) {
  				sc.SetState(SCE_V_IDENTIFIER|activitySet);
  			} else if (sc.Match('/', '*')) {
  				sc.SetState(SCE_V_COMMENT|activitySet);
  				sc.Forward();	// Eat the * so it isn't used for the end of the comment
  			} else if (sc.Match('/', '/')) {
  				if (sc.Match("//!"))	// Nice to have a different comment style
  					sc.SetState(SCE_V_COMMENTLINEBANG|activitySet);
  				else
  					sc.SetState(SCE_V_COMMENTLINE|activitySet);
  			} else if (sc.ch == '\"') {
  				sc.SetState(SCE_V_STRING|activitySet);
  			} else if (sc.ch == '`') {
  				sc.SetState(SCE_V_PREPROCESSOR|activitySet);
  				// Skip whitespace between ` and preprocessor word
  				do {
  					sc.Forward();
  				} while ((sc.ch == ' ' || sc.ch == '\t') && sc.More());
  				if (sc.atLineEnd) {
  					sc.SetState(SCE_V_DEFAULT|activitySet);
  					styler.SetLineState(curLine, lineState);
  				} else {
  					if (options.trackPreprocessor) {
  						if (sc.Match("ifdef") || sc.Match("ifndef")) {
  							bool isIfDef = sc.Match("ifdef");
  							int i = isIfDef ? 5 : 6;
  							std::string restOfLine = GetRestOfLine(styler, sc.currentPos + i + 1, false);
  							bool foundDef = preprocessorDefinitions.find(restOfLine) != preprocessorDefinitions.end();
  							preproc.StartSection(isIfDef == foundDef);
  						} else if (sc.Match("else")) {
  							if (!preproc.CurrentIfTaken()) {
  								preproc.InvertCurrentLevel();
  								activitySet = preproc.IsInactive() ? activeFlag : 0;
  								if (!activitySet) {
  									sc.ChangeState(SCE_V_PREPROCESSOR|activitySet);
  								}
  							} else if (!preproc.IsInactive()) {
  								preproc.InvertCurrentLevel();
  								activitySet = preproc.IsInactive() ? activeFlag : 0;
  								if (!activitySet) {
  									sc.ChangeState(SCE_V_PREPROCESSOR|activitySet);
  								}
  							}
  						} else if (sc.Match("elsif")) {
  							// Ensure only one chosen out of `if .. `elsif .. `elsif .. `else .. `endif
  							if (!preproc.CurrentIfTaken()) {
  								// Similar to `ifdef
  								std::string restOfLine = GetRestOfLine(styler, sc.currentPos + 6, true);
  								bool ifGood = preprocessorDefinitions.find(restOfLine) != preprocessorDefinitions.end();
  								if (ifGood) {
  									preproc.InvertCurrentLevel();
  									activitySet = preproc.IsInactive() ? activeFlag : 0;
  									if (!activitySet)
  										sc.ChangeState(SCE_V_PREPROCESSOR|activitySet);
  								}
  							} else if (!preproc.IsInactive()) {
  								preproc.InvertCurrentLevel();
  								activitySet = preproc.IsInactive() ? activeFlag : 0;
  								if (!activitySet)
  									sc.ChangeState(SCE_V_PREPROCESSOR|activitySet);
  							}
  						} else if (sc.Match("endif")) {
  							preproc.EndSection();
  							activitySet = preproc.IsInactive() ? activeFlag : 0;
  							sc.ChangeState(SCE_V_PREPROCESSOR|activitySet);
  						} else if (sc.Match("define")) {
  							if (options.updatePreprocessor && !preproc.IsInactive()) {
  								std::string restOfLine = GetRestOfLine(styler, sc.currentPos + 6, true);
  								size_t startName = 0;
  								while ((startName < restOfLine.length()) && IsSpaceOrTab(restOfLine[startName]))
  									startName++;
  								size_t endName = startName;
  								while ((endName < restOfLine.length()) && setWord.Contains(static_cast<unsigned char>(restOfLine[endName])))
  									endName++;
  								std::string key = restOfLine.substr(startName, endName-startName);
  								if ((endName < restOfLine.length()) && (restOfLine.at(endName) == '(')) {
  									// Macro
  									size_t endArgs = endName;
  									while ((endArgs < restOfLine.length()) && (restOfLine[endArgs] != ')'))
  										endArgs++;
  									std::string args = restOfLine.substr(endName + 1, endArgs - endName - 1);
  									size_t startValue = endArgs+1;
  									while ((startValue < restOfLine.length()) && IsSpaceOrTab(restOfLine[startValue]))
  										startValue++;
  									std::string value;
  									if (startValue < restOfLine.length())
  										value = restOfLine.substr(startValue);
  									preprocessorDefinitions[key] = SymbolValue(value, args);
  									ppDefineHistory.push_back(PPDefinition(curLine, key, value, false, args));
  									definitionsChanged = true;
  								} else {
  									// Value
  									size_t startValue = endName;
  									while ((startValue < restOfLine.length()) && IsSpaceOrTab(restOfLine[startValue]))
  										startValue++;
  									std::string value = restOfLine.substr(startValue);
  									preprocessorDefinitions[key] = value;
  									ppDefineHistory.push_back(PPDefinition(curLine, key, value));
  									definitionsChanged = true;
  								}
  							}
  						} else if (sc.Match("undefineall")) {
  							if (options.updatePreprocessor && !preproc.IsInactive()) {
  								// remove all preprocessor definitions
  								std::map<std::string, SymbolValue>::iterator itDef;
  								for(itDef = preprocessorDefinitions.begin(); itDef != preprocessorDefinitions.end(); ++itDef) {
  									ppDefineHistory.push_back(PPDefinition(curLine, itDef->first, "", true));
  								}
  								preprocessorDefinitions.clear();
  								definitionsChanged = true;
  							}
  						} else if (sc.Match("undef")) {
  							if (options.updatePreprocessor && !preproc.IsInactive()) {
  								std::string restOfLine = GetRestOfLine(styler, sc.currentPos + 5, true);
  								std::vector<std::string> tokens = Tokenize(restOfLine);
  								std::string key;
  								if (tokens.size() >= 1) {
  									key = tokens[0];
  									preprocessorDefinitions.erase(key);
  									ppDefineHistory.push_back(PPDefinition(curLine, key, "", true));
  									definitionsChanged = true;
  								}
  							}
  						}
  					}
  				}
  			} else if (sc.ch == '\\') {
  				// escaped identifier, everything is ok up to whitespace
  				isEscapedId = true;
  				sc.SetState(SCE_V_IDENTIFIER|activitySet);
  			} else if (isoperator(static_cast<char>(sc.ch)) || sc.ch == '@' || sc.ch == '#') {
  				sc.SetState(SCE_V_OPERATOR|activitySet);
  				if (sc.ch == '.') lineState = kwDot;
  				if (sc.ch == ';') lineState = kwOther;
  			}
  		}
  		if (isEscapedId && isspacechar(sc.ch)) {
  			isEscapedId = false;
  		}
  	}
  	if (definitionsChanged) {
  		styler.ChangeLexerState(startPos, startPos + length);
  	}
  	sc.Complete();
  }
  
  static bool IsStreamCommentStyle(int style) {
  	return style == SCE_V_COMMENT;
  }
  
  static bool IsCommentLine(int line, LexAccessor &styler) {
  	int pos = styler.LineStart(line);
  	int eolPos = styler.LineStart(line + 1) - 1;
  	for (int i = pos; i < eolPos; i++) {
  		char ch = styler[i];
  		char chNext = styler.SafeGetCharAt(i + 1);
  		int style = styler.StyleAt(i);
  		if (ch == '/' && chNext == '/' &&
  		   (style == SCE_V_COMMENTLINE || style == SCE_V_COMMENTLINEBANG)) {
  			return true;
  		} else if (!IsASpaceOrTab(ch)) {
  			return false;
  		}
  	}
  	return false;
  }
  
  // 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 {".
  void SCI_METHOD LexerVerilog::Fold(unsigned int startPos, int length, int initStyle, IDocument *pAccess)
  {
  	LexAccessor styler(pAccess);
  	bool foldAtBrace  = 1;
  	bool foldAtParenthese  = 1;
  
  	int lineCurrent = styler.GetLine(startPos);
  	// Move back one line to be compatible with LexerModule::Fold behavior, fixes problem with foldComment behavior
  	if (lineCurrent > 0) {
  		lineCurrent--;
  		int newStartPos = styler.LineStart(lineCurrent);
  		length += startPos - newStartPos;
  		startPos = newStartPos;
  		initStyle = 0;
  		if (startPos > 0) {
  			initStyle = styler.StyleAt(startPos - 1);
  		}
  	}
  	unsigned int endPos = startPos + length;
  	int visibleChars = 0;
  	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 = MaskActive(styler.StyleAt(startPos));
  	int style = MaskActive(initStyle);
  
  	// restore fold state (if it exists) for prior line
  	int stateCurrent = 0;
  	std::map<int,int>::iterator foldStateIterator = foldState.find(lineCurrent-1);
  	if (foldStateIterator != foldState.end()) {
  		stateCurrent = foldStateIterator->second;
  	}
  
  	// remove all foldState entries after lineCurrent-1
  	foldStateIterator = foldState.upper_bound(lineCurrent-1);
  	if (foldStateIterator != foldState.end()) {
  		foldState.erase(foldStateIterator, foldState.end());
  	}
  
  	for (unsigned int i = startPos; i < endPos; i++) {
  		char ch = chNext;
  		chNext = styler.SafeGetCharAt(i + 1);
  		int stylePrev = style;
  		style = styleNext;
  		styleNext = MaskActive(styler.StyleAt(i + 1));
  		bool atEOL = (ch == '\r' && chNext != '\n') || (ch == '\n');
  		if (options.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 (options.foldComment && atEOL && IsCommentLine(lineCurrent, styler))
  		{
  			if (!IsCommentLine(lineCurrent - 1, styler)
  			    && IsCommentLine(lineCurrent + 1, styler))
  				levelNext++;
  			else if (IsCommentLine(lineCurrent - 1, styler)
  			         && !IsCommentLine(lineCurrent+1, styler))
  				levelNext--;
  		}
  		if (options.foldComment && (style == SCE_V_COMMENTLINE)) {
  			if ((ch == '/') && (chNext == '/')) {
  				char chNext2 = styler.SafeGetCharAt(i + 2);
  				if (chNext2 == '{') {
  					levelNext++;
  				} else if (chNext2 == '}') {
  					levelNext--;
  				}
  			}
  		}
  		if (options.foldPreprocessor && (style == SCE_V_PREPROCESSOR)) {
  			if (ch == '`') {
  				unsigned int j = i + 1;
  				while ((j < endPos) && IsASpaceOrTab(styler.SafeGetCharAt(j))) {
  					j++;
  				}
  				if (styler.Match(j, "if")) {
  					if (options.foldPreprocessorElse) {
  						// Measure the minimum before a begin to allow
  						// folding on "end else begin"
  						if (levelMinCurrent > levelNext) {
  							levelMinCurrent = levelNext;
  						}
  					}
  					levelNext++;
  				} else if (options.foldPreprocessorElse && styler.Match(j, "else")) {
  					levelNext--;
  					if (levelMinCurrent > levelNext) {
  						levelMinCurrent = levelNext;
  					}
  					levelNext++;
  				} else if (options.foldPreprocessorElse && styler.Match(j, "elsif")) {
  					levelNext--;
  					// Measure the minimum before a begin to allow
  					// folding on "end else begin"
  					if (levelMinCurrent > levelNext) {
  						levelMinCurrent = levelNext;
  					}
  					levelNext++;
  				} else if (styler.Match(j, "endif")) {
  					levelNext--;
  				}
  			}
  		}
  		if (style == SCE_V_OPERATOR) {
  			if (foldAtParenthese) {
  				if (ch == '(') {
  					levelNext++;
  				} else if (ch == ')') {
  					levelNext--;
  				}
  			}
  			// semicolons terminate external declarations
  			if (ch == ';') {
  				// extern and pure virtual declarations terminated by semicolon
  				if (stateCurrent & foldExternFlag) {
  					levelNext--;
  					stateCurrent &= ~foldExternFlag;
  				}
  				// wait and disable statements terminated by semicolon
  				if (stateCurrent & foldWaitDisableFlag) {
  					stateCurrent &= ~foldWaitDisableFlag;
  				}
  				// typedef statements terminated by semicolon
  				if (stateCurrent & typedefFlag) {
  					stateCurrent &= ~typedefFlag;
  				}
  			}
  			// wait and disable statements containing '(' will not contain "fork" keyword, special processing is not needed
  			if (ch == '(') {
  				if (stateCurrent & foldWaitDisableFlag) {
  					stateCurrent &= ~foldWaitDisableFlag;
  				}
  			}
  		}
  		if (style == SCE_V_OPERATOR) {
  			if (foldAtBrace) {
  				if (ch == '{') {
  					levelNext++;
  				} else if (ch == '}') {
  					levelNext--;
  				}
  			}
  		}
  		if (style == SCE_V_WORD && stylePrev != SCE_V_WORD) {
  			unsigned int j = i;
  			if (styler.Match(j, "case") ||
  				styler.Match(j, "casex") ||
  				styler.Match(j, "casez") ||
  				styler.Match(j, "covergroup") ||
  				styler.Match(j, "function") ||
  				styler.Match(j, "generate") ||
  				styler.Match(j, "interface") ||
  				styler.Match(j, "package") ||
  				styler.Match(j, "primitive") ||
  				styler.Match(j, "program") ||
  				styler.Match(j, "sequence") ||
  				styler.Match(j, "specify") ||
  				styler.Match(j, "table") ||
  				styler.Match(j, "task") ||
  				(styler.Match(j, "module") && options.foldAtModule)) {
  				levelNext++;
  			} else if (styler.Match(j, "begin")) {
  				// Measure the minimum before a begin to allow
  				// folding on "end else begin"
  				if (levelMinCurrent > levelNext) {
  					levelMinCurrent = levelNext;
  				}
  				levelNext++;
  			} else if (styler.Match(j, "class")) {
  				// class does not introduce a block when used in a typedef statement
  				if (!(stateCurrent & typedefFlag))
  					levelNext++;
  			} else if (styler.Match(j, "fork")) {
  				// fork does not introduce a block when used in a wait or disable statement
  				if (stateCurrent & foldWaitDisableFlag) {
  					stateCurrent &= ~foldWaitDisableFlag;
  				} else
  					levelNext++;
  			} else if (styler.Match(j, "endcase") ||
  				styler.Match(j, "endclass") ||
  				styler.Match(j, "endfunction") ||
  				styler.Match(j, "endgenerate") ||
  				styler.Match(j, "endgroup") ||
  				styler.Match(j, "endinterface") ||
  				styler.Match(j, "endpackage") ||
  				styler.Match(j, "endprimitive") ||
  				styler.Match(j, "endprogram") ||
  				styler.Match(j, "endsequence") ||
  				styler.Match(j, "endspecify") ||
  				styler.Match(j, "endtable") ||
  				styler.Match(j, "endtask") ||
  				styler.Match(j, "join") ||
  				styler.Match(j, "join_any") ||
  				styler.Match(j, "join_none") ||
  				(styler.Match(j, "endmodule") && options.foldAtModule) ||
  				(styler.Match(j, "end") && !IsAWordChar(styler.SafeGetCharAt(j + 3)))) {
  				levelNext--;
  			} else if (styler.Match(j, "extern") ||
  				styler.Match(j, "pure")) {
  				// extern and pure virtual functions/tasks are terminated by ';' not endfunction/endtask
  				stateCurrent |= foldExternFlag;
  			} else if (styler.Match(j, "disable") ||
  				styler.Match(j, "wait")) {
  				// fork does not introduce a block when used in a wait or disable statement
  				stateCurrent |= foldWaitDisableFlag;
  			} else if (styler.Match(j, "typedef")) {
  				stateCurrent |= typedefFlag;
  			}
  		}
  		if (atEOL) {
  			int levelUse = levelCurrent;
  			if (options.foldAtElse||options.foldPreprocessorElse) {
  				levelUse = levelMinCurrent;
  			}
  			int lev = levelUse | levelNext << 16;
  			if (visibleChars == 0 && options.foldCompact)
  				lev |= SC_FOLDLEVELWHITEFLAG;
  			if (levelUse < levelNext)
  				lev |= SC_FOLDLEVELHEADERFLAG;
  			if (stateCurrent) {
  				foldState[lineCurrent] = stateCurrent;
  			}
  			if (lev != styler.LevelAt(lineCurrent)) {
  				styler.SetLevel(lineCurrent, lev);
  			}
  			lineCurrent++;
  			levelCurrent = levelNext;
  			levelMinCurrent = levelCurrent;
  			visibleChars = 0;
  		}
  		if (!isspacechar(ch))
  			visibleChars++;
  	}
  }
  
  std::vector<std::string> LexerVerilog::Tokenize(const std::string &expr) const {
  	// Break into tokens
  	std::vector<std::string> tokens;
  	const char *cp = expr.c_str();
  	while (*cp) {
  		std::string word;
  		if (setWord.Contains(static_cast<unsigned char>(*cp))) {
  			// Identifiers and numbers
  			while (setWord.Contains(static_cast<unsigned char>(*cp))) {
  				word += *cp;
  				cp++;
  			}
  		} else if (IsSpaceOrTab(*cp)) {
  			while (IsSpaceOrTab(*cp)) {
  				cp++;
  			}
  			continue;
  		} else {
  			// Should handle strings, characters, and comments here
  			word += *cp;
  			cp++;
  		}
  		tokens.push_back(word);
  	}
  	return tokens;
  }
  
  static const char * const verilogWordLists[] = {
              "Primary keywords and identifiers",
              "Secondary keywords and identifiers",
              "System Tasks",
              "User defined tasks and identifiers",
              "Documentation comment keywords",
              "Preprocessor definitions",
              0,
          };
  
  LexerModule lmVerilog(SCLEX_VERILOG, LexerVerilog::LexerFactoryVerilog, "verilog", verilogWordLists);
  