text: // Scintilla source code edit control
  /** @file LexBasic.cxx
   ** Lexer for BlitzBasic and PureBasic.
   **/
  // Copyright 1998-2003 by Neil Hodgson <neilh@scintilla.org>
  // The License.txt file describes the conditions under which this software may be distributed.
  
  // This tries to be a unified Lexer/Folder for all the BlitzBasic/BlitzMax/PurBasic basics
  // and derivatives. Once they diverge enough, might want to split it into multiple
  // lexers for more code clearity.
  //
  // Mail me (elias <at> users <dot> sf <dot> net) for any bugs.
  
  // Folding only works for simple things like functions or types.
  
  // You may want to have a look at my ctags lexer as well, if you additionally to coloring
  // and folding need to extract things like label tags in your editor.
  
  #include <stdlib.h>
  #include <string.h>
  #include <stdio.h>
  #include <stdarg.h>
  #include <assert.h>
  
  #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"
  
  #ifdef SCI_NAMESPACE
  using namespace Scintilla;
  #endif
  
  /* Bits:
   * 1  - whitespace
   * 2  - operator
   * 4  - identifier
   * 8  - decimal digit
   * 16 - hex digit
   * 32 - bin digit
   */
  static int character_classification[128] =
  {
      0,  0,  0,  0,  0,  0,  0,  0,  0,  1,  1,  0,  0,  1,  0,  0,
      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
      1,  2,  0,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2,  10, 2,
      60, 60, 28, 28, 28, 28, 28, 28, 28, 28, 2,  2,  2,  2,  2,  2,
      2,  20, 20, 20, 20, 20, 20, 4,  4,  4,  4,  4,  4,  4,  4,  4,
      4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  2,  2,  2,  2,  4,
      2,  20, 20, 20, 20, 20, 20, 4,  4,  4,  4,  4,  4,  4,  4,  4,
      4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  2,  2,  2,  2,  0
  };
  
  static bool IsSpace(int c) {
  	return c < 128 && (character_classification[c] & 1);
  }
  
  static bool IsOperator(int c) {
  	return c < 128 && (character_classification[c] & 2);
  }
  
  static bool IsIdentifier(int c) {
  	return c < 128 && (character_classification[c] & 4);
  }
  
  static bool IsDigit(int c) {
  	return c < 128 && (character_classification[c] & 8);
  }
  
  static bool IsHexDigit(int c) {
  	return c < 128 && (character_classification[c] & 16);
  }
  
  static bool IsBinDigit(int c) {
  	return c < 128 && (character_classification[c] & 32);
  }
  
  static int LowerCase(int c)
  {
  	if (c >= 'A' && c <= 'Z')
  		return 'a' + c - 'A';
  	return c;
  }
  
  static void ColouriseBasicDoc(unsigned int startPos, int length, int initStyle,
                             WordList *keywordlists[], Accessor &styler, char comment_char) {
  	bool wasfirst = true, isfirst = true; // true if first token in a line
  	styler.StartAt(startPos);
  
  	StyleContext sc(startPos, length, initStyle, styler);
  
  	// Can't use sc.More() here else we miss the last character
  	for (; ; sc.Forward()) {
  		if (sc.state == SCE_B_IDENTIFIER) {
  			if (!IsIdentifier(sc.ch)) {
  				// Labels
  				if (wasfirst && sc.Match(':')) {
  					sc.ChangeState(SCE_B_LABEL);
  					sc.ForwardSetState(SCE_B_DEFAULT);
  				} else {
  					char s[100];
  					int kstates[4] = {
  						SCE_B_KEYWORD,
  						SCE_B_KEYWORD2,
  						SCE_B_KEYWORD3,
  						SCE_B_KEYWORD4,
  					};
  					sc.GetCurrentLowered(s, sizeof(s));
  					for (int i = 0; i < 4; i++) {
  						if (keywordlists[i]->InList(s)) {
  							sc.ChangeState(kstates[i]);
  						}
  					}
  					// Types, must set them as operator else they will be
  					// matched as number/constant
  					if (sc.Match('.') || sc.Match('$') || sc.Match('%') ||
  						sc.Match('#')) {
  						sc.SetState(SCE_B_OPERATOR);
  					} else {
  						sc.SetState(SCE_B_DEFAULT);
  					}
  				}
  			}
  		} else if (sc.state == SCE_B_OPERATOR) {
  			if (!IsOperator(sc.ch) || sc.Match('#'))
  				sc.SetState(SCE_B_DEFAULT);
  		} else if (sc.state == SCE_B_LABEL) {
  			if (!IsIdentifier(sc.ch))
  				sc.SetState(SCE_B_DEFAULT);
  		} else if (sc.state == SCE_B_CONSTANT) {
  			if (!IsIdentifier(sc.ch))
  				sc.SetState(SCE_B_DEFAULT);
  		} else if (sc.state == SCE_B_NUMBER) {
  			if (!IsDigit(sc.ch))
  				sc.SetState(SCE_B_DEFAULT);
  		} else if (sc.state == SCE_B_HEXNUMBER) {
  			if (!IsHexDigit(sc.ch))
  				sc.SetState(SCE_B_DEFAULT);
  		} else if (sc.state == SCE_B_BINNUMBER) {
  			if (!IsBinDigit(sc.ch))
  				sc.SetState(SCE_B_DEFAULT);
  		} else if (sc.state == SCE_B_STRING) {
  			if (sc.ch == '"') {
  				sc.ForwardSetState(SCE_B_DEFAULT);
  			}
  			if (sc.atLineEnd) {
  				sc.ChangeState(SCE_B_ERROR);
  				sc.SetState(SCE_B_DEFAULT);
  			}
  		} else if (sc.state == SCE_B_COMMENT || sc.state == SCE_B_PREPROCESSOR) {
  			if (sc.atLineEnd) {
  				sc.SetState(SCE_B_DEFAULT);
  			}
  		}
  
  		if (sc.atLineStart)
  			isfirst = true;
  
  		if (sc.state == SCE_B_DEFAULT || sc.state == SCE_B_ERROR) {
  			if (isfirst && sc.Match('.')) {
  				sc.SetState(SCE_B_LABEL);
  			} else if (isfirst && sc.Match('#')) {
  				wasfirst = isfirst;
  				sc.SetState(SCE_B_IDENTIFIER);
  			} else if (sc.Match(comment_char)) {
  				// Hack to make deprecated QBASIC '$Include show
  				// up in freebasic with SCE_B_PREPROCESSOR.
  				if (comment_char == '\'' && sc.Match(comment_char, '$'))
  					sc.SetState(SCE_B_PREPROCESSOR);
  				else
  					sc.SetState(SCE_B_COMMENT);
  			} else if (sc.Match('"')) {
  				sc.SetState(SCE_B_STRING);
  			} else if (IsDigit(sc.ch)) {
  				sc.SetState(SCE_B_NUMBER);
  			} else if (sc.Match('$')) {
  				sc.SetState(SCE_B_HEXNUMBER);
  			} else if (sc.Match('%')) {
  				sc.SetState(SCE_B_BINNUMBER);
  			} else if (sc.Match('#')) {
  				sc.SetState(SCE_B_CONSTANT);
  			} else if (IsOperator(sc.ch)) {
  				sc.SetState(SCE_B_OPERATOR);
  			} else if (IsIdentifier(sc.ch)) {
  				wasfirst = isfirst;
  				sc.SetState(SCE_B_IDENTIFIER);
  			} else if (!IsSpace(sc.ch)) {
  				sc.SetState(SCE_B_ERROR);
  			}
  		}
  
  		if (!IsSpace(sc.ch))
  			isfirst = false;
  
  		if (!sc.More())
  			break;
  	}
  	sc.Complete();
  }
  
  static int CheckBlitzFoldPoint(char const *token, int &level) {
  	if (!strcmp(token, "function") ||
  		!strcmp(token, "type")) {
  		level |= SC_FOLDLEVELHEADERFLAG;
  		return 1;
  	}
  	if (!strcmp(token, "end function") ||
  		!strcmp(token, "end type")) {
  		return -1;
  	}
  	return 0;
  }
  
  static int CheckPureFoldPoint(char const *token, int &level) {
  	if (!strcmp(token, "procedure") ||
  		!strcmp(token, "enumeration") ||
  		!strcmp(token, "interface") ||
  		!strcmp(token, "structure")) {
  		level |= SC_FOLDLEVELHEADERFLAG;
  		return 1;
  	}
  	if (!strcmp(token, "endprocedure") ||
  		!strcmp(token, "endenumeration") ||
  		!strcmp(token, "endinterface") ||
  		!strcmp(token, "endstructure")) {
  		return -1;
  	}
  	return 0;
  }
  
  static int CheckFreeFoldPoint(char const *token, int &level) {
  	if (!strcmp(token, "function") ||
  		!strcmp(token, "sub") ||
  		!strcmp(token, "type")) {
  		level |= SC_FOLDLEVELHEADERFLAG;
  		return 1;
  	}
  	if (!strcmp(token, "end function") ||
  		!strcmp(token, "end sub") ||
  		!strcmp(token, "end type")) {
  		return -1;
  	}
  	return 0;
  }
  
  static void FoldBasicDoc(unsigned int startPos, int length,
  	Accessor &styler, int (*CheckFoldPoint)(char const *, int &)) {
  	int line = styler.GetLine(startPos);
  	int level = styler.LevelAt(line);
  	int go = 0, done = 0;
  	int endPos = startPos + length;
  	char word[256];
  	int wordlen = 0;
  	int i;
          bool foldCompact = styler.GetPropertyInt("fold.compact", 1) != 0;
  	// Scan for tokens at the start of the line (they may include
  	// whitespace, for tokens like "End Function"
  	for (i = startPos; i < endPos; i++) {
  		int c = styler.SafeGetCharAt(i);
  		if (!done && !go) {
  			if (wordlen) { // are we scanning a token already?
  				word[wordlen] = static_cast<char>(LowerCase(c));
  				if (!IsIdentifier(c)) { // done with token
  					word[wordlen] = '\0';
  					go = CheckFoldPoint(word, level);
  					if (!go) {
  						// Treat any whitespace as single blank, for
  						// things like "End   Function".
  						if (IsSpace(c) && IsIdentifier(word[wordlen - 1])) {
  							word[wordlen] = ' ';
  							if (wordlen < 255)
  								wordlen++;
  						}
  						else // done with this line
  							done = 1;
  					}
  				} else if (wordlen < 255) {
  					wordlen++;
  				}
  			} else { // start scanning at first non-whitespace character
  				if (!IsSpace(c)) {
  					if (IsIdentifier(c)) {
  						word[0] = static_cast<char>(LowerCase(c));
  						wordlen = 1;
  					} else // done with this line
  						done = 1;
  				}
  			}
  		}
  		if (c == '\n') { // line end
  			if (!done && wordlen == 0 && foldCompact) // line was only space
  				level |= SC_FOLDLEVELWHITEFLAG;
  			if (level != styler.LevelAt(line))
  				styler.SetLevel(line, level);
  			level += go;
  			line++;
  			// reset state
  			wordlen = 0;
  			level &= ~SC_FOLDLEVELHEADERFLAG;
  			level &= ~SC_FOLDLEVELWHITEFLAG;
  			go = 0;
  			done = 0;
  		}
  	}
  }
  
  static void ColouriseBlitzBasicDoc(unsigned int startPos, int length, int initStyle,
                             WordList *keywordlists[], Accessor &styler) {
  	ColouriseBasicDoc(startPos, length, initStyle, keywordlists, styler, ';');
  }
  
  static void ColourisePureBasicDoc(unsigned int startPos, int length, int initStyle,
                             WordList *keywordlists[], Accessor &styler) {
  	ColouriseBasicDoc(startPos, length, initStyle, keywordlists, styler, ';');
  }
  
  static void ColouriseFreeBasicDoc(unsigned int startPos, int length, int initStyle,
                             WordList *keywordlists[], Accessor &styler) {
  	ColouriseBasicDoc(startPos, length, initStyle, keywordlists, styler, '\'');
  }
  
  static void FoldBlitzBasicDoc(unsigned int startPos, int length, int,
  	WordList *[], Accessor &styler) {
  	FoldBasicDoc(startPos, length, styler, CheckBlitzFoldPoint);
  }
  
  static void FoldPureBasicDoc(unsigned int startPos, int length, int,
  	WordList *[], Accessor &styler) {
  	FoldBasicDoc(startPos, length, styler, CheckPureFoldPoint);
  }
  
  static void FoldFreeBasicDoc(unsigned int startPos, int length, int,
  	WordList *[], Accessor &styler) {
  	FoldBasicDoc(startPos, length, styler, CheckFreeFoldPoint);
  }
  
  static const char * const blitzbasicWordListDesc[] = {
  	"BlitzBasic Keywords",
  	"user1",
  	"user2",
  	"user3",
  	0
  };
  
  static const char * const purebasicWordListDesc[] = {
  	"PureBasic Keywords",
  	"PureBasic PreProcessor Keywords",
  	"user defined 1",
  	"user defined 2",
  	0
  };
  
  static const char * const freebasicWordListDesc[] = {
  	"FreeBasic Keywords",
  	"FreeBasic PreProcessor Keywords",
  	"user defined 1",
  	"user defined 2",
  	0
  };
  
  LexerModule lmBlitzBasic(SCLEX_BLITZBASIC, ColouriseBlitzBasicDoc, "blitzbasic",
  	FoldBlitzBasicDoc, blitzbasicWordListDesc);
  
  LexerModule lmPureBasic(SCLEX_PUREBASIC, ColourisePureBasicDoc, "purebasic",
  	FoldPureBasicDoc, purebasicWordListDesc);
  
  LexerModule lmFreeBasic(SCLEX_FREEBASIC, ColouriseFreeBasicDoc, "freebasic",
  	FoldFreeBasicDoc, freebasicWordListDesc);
  
  