Codebase list jlex / HEAD sample.lex
HEAD

Tree @HEAD (Download .tar.gz)

sample.lex @HEAD — raw · history · blame 

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
import java.lang.System;

class Sample {
    public static void main(String argv[]) throws java.io.IOException {
	Yylex yy = new Yylex(System.in);
	Yytoken t;
	while ((t = yy.yylex()) != null)
	    System.out.println(t);
    }
}

class Utility {
  public static void ASSERT
    (
     boolean expr
     )
      { 
	if (false == expr) {
	  throw (new Error("Error: Assertion failed."));
	}
      }
  
  private static final String errorMsg[] = {
    "Error: Unmatched end-of-comment punctuation.",
    "Error: Unmatched start-of-comment punctuation.",
    "Error: Unclosed string.",
    "Error: Illegal character."
    };
  
  public static final int E_ENDCOMMENT = 0; 
  public static final int E_STARTCOMMENT = 1; 
  public static final int E_UNCLOSEDSTR = 2; 
  public static final int E_UNMATCHED = 3; 

  public static void error
    (
     int code
     )
      {
	System.out.println(errorMsg[code]);
      }
}

class Yytoken {
  Yytoken 
    (
     int index,
     String text,
     int line,
     int charBegin,
     int charEnd
     )
      {
	m_index = index;
	m_text = new String(text);
	m_line = line;
	m_charBegin = charBegin;
	m_charEnd = charEnd;
      }

  public int m_index;
  public String m_text;
  public int m_line;
  public int m_charBegin;
  public int m_charEnd;
  public String toString() {
      return "Token #"+m_index+": "+m_text+" (line "+m_line+")";
  }
}

%%

%{
  private int comment_count = 0;
%} 
%line
%char
%state COMMENT

ALPHA=[A-Za-z]
DIGIT=[0-9]
NONNEWLINE_WHITE_SPACE_CHAR=[\ \t\b\012]
WHITE_SPACE_CHAR=[\n\ \t\b\012]
STRING_TEXT=(\\\"|[^\n\"]|\\{WHITE_SPACE_CHAR}+\\)*
COMMENT_TEXT=([^/*\n]|[^*\n]"/"[^*\n]|[^/\n]"*"[^/\n]|"*"[^/\n]|"/"[^*\n])*


%% 

<YYINITIAL> "," { return (new Yytoken(0,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> ":" { return (new Yytoken(1,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> ";" { return (new Yytoken(2,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "(" { return (new Yytoken(3,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> ")" { return (new Yytoken(4,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "[" { return (new Yytoken(5,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "]" { return (new Yytoken(6,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "{" { return (new Yytoken(7,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "}" { return (new Yytoken(8,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "." { return (new Yytoken(9,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "+" { return (new Yytoken(10,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "-" { return (new Yytoken(11,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "*" { return (new Yytoken(12,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "/" { return (new Yytoken(13,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "=" { return (new Yytoken(14,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "<>" { return (new Yytoken(15,yytext(),yyline,yychar,yychar+2)); }
<YYINITIAL> "<"  { return (new Yytoken(16,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "<=" { return (new Yytoken(17,yytext(),yyline,yychar,yychar+2)); }
<YYINITIAL> ">"  { return (new Yytoken(18,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> ">=" { return (new Yytoken(19,yytext(),yyline,yychar,yychar+2)); }
<YYINITIAL> "&"  { return (new Yytoken(20,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> "|"  { return (new Yytoken(21,yytext(),yyline,yychar,yychar+1)); }
<YYINITIAL> ":=" { return (new Yytoken(22,yytext(),yyline,yychar,yychar+2)); }

<YYINITIAL> {NONNEWLINE_WHITE_SPACE_CHAR}+ { }

<YYINITIAL,COMMENT> \n { }

<YYINITIAL> "/*" { yybegin(COMMENT); comment_count = comment_count + 1; }

<COMMENT> "/*" { comment_count = comment_count + 1; }
<COMMENT> "*/" { 
	comment_count = comment_count - 1; 
	Utility.ASSERT(comment_count >= 0);
	if (comment_count == 0) {
    		yybegin(YYINITIAL);
	}
}
<COMMENT> {COMMENT_TEXT} { }

<YYINITIAL> \"{STRING_TEXT}\" {
	String str =  yytext().substring(1,yytext().length() - 1);
	
	Utility.ASSERT(str.length() == yytext().length() - 2);
	return (new Yytoken(40,str,yyline,yychar,yychar + str.length()));
}
<YYINITIAL> \"{STRING_TEXT} {
	String str =  yytext().substring(1,yytext().length());

	Utility.error(Utility.E_UNCLOSEDSTR);
	Utility.ASSERT(str.length() == yytext().length() - 1);
	return (new Yytoken(41,str,yyline,yychar,yychar + str.length()));
} 
<YYINITIAL> {DIGIT}+ { 
	return (new Yytoken(42,yytext(),yyline,yychar,yychar + yytext().length()));
}	
<YYINITIAL> {ALPHA}({ALPHA}|{DIGIT}|_)* {
	return (new Yytoken(43,yytext(),yyline,yychar,yychar + yytext().length()));
}	
<YYINITIAL,COMMENT> . {
        System.out.println("Illegal character: <" + yytext() + ">");
	Utility.error(Utility.E_UNMATCHED);
}