Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <pre><code>/* ref: http://msdn2.microsoft.com/en-us/library/y39145bk(vs.80).aspx C language Tokens token: keyword identifier constant string-literal operator punctuator operator: one of [ ] ( ) . –&gt; ++ &amp; * + – ~ ! sizeof/ % &lt;&lt; &gt;&gt; &lt;&gt; &lt;= &gt;= == != ^ | &amp;&amp; !!? := *= /= %= += –= &lt;&lt;= &gt;&gt;= &amp;= ^= |=, # ## assignment-operator: one of = *= /= %= += –= &lt;&lt;= &gt;&gt;= &amp;= ^= |= punctuator: one of [ ] ( ) { } * , : = ; ... # * This is a generalized program working for any kind of input( input C program). * It fails to recognise stdio.h in "#include&lt;stdio.h&gt;" as one token. * Instead it identifies stdio as Identifier, . as dot operator , h as Identifier. * this is becoz i considered .(dot) as a separator b/w tokens of structure variables ex: struct book { int price; }b1; b1.price; //here dot is used as seperator b/w b1 token and price token......... This program is not exactly correct....... It neither parses the comments nor the header files..... At first time if u get an error saying "Abnormal program termination" simply reduce the TableSize macro value. Becoz TC cannot allocated more global memory... */ #include&lt;stdio.h&gt; #include&lt;string.h&gt; #include&lt;conio.h&gt; //=============================================================================================== #define true 1 #define false 0 //simple macros for moving back and front in the file #define MoveFront(units) fseek(fp,+(units),SEEK_CUR) #define MoveBack(units) fseek(fp,-(units),SEEK_CUR) //Token Table size #define TableSize 9144 //=============================================================================================== //used to open the file int FileOpen(const char * path); //Core function which splits the given program in to tokens.... int CreateTokens(); //forms the token string based on the starting(start) of file pointer //position and ending(end) of file pointer position of the token void GetToken(int start,int end); //recognises whether the formed token as keyword,identifier, numeric constant,....... void IdentifyTokenType(int index); int EOFReached(); //=============================================================================================== //Keywords are arranged in such a way that most frequently used onces come first..... //So that the comparison b/w retrieved tokens and keywords become more efficient.... const char *keywords[]= { "int", "char", "double", "float", "if", "else", "for", "while", "return", "switch", "case", "break", "do", "default", "void", "struct", "long", "const", "static", "union", "enum", "register", "short", "unsigned", "continue", "goto", "sizeof", "signed", "auto", "volatile", "typedef", "extern", }; //=============================================================================================== const char *preprocess[]= { "#define", "#include", // here rest of the preprocessors can be included too............. }; //=============================================================================================== struct TokenEntry { int start, //start contains starting of token's file pointer position.... end; //end contains one more than the ending of token's file pointer position.... char * type; //Type of the token ,whether it is identifier ,keyword,numeric constant.... }tokenTable[TableSize]; //TableSize is the TC limit of TokenArray :( //=============================================================================================== struct DelimEntry { char * delim; //delimiters .... "[","{".... char * type; //delimiter's name ................"LSquare","LBrace".... }; //=============================================================================================== //These are the delimiters in C language........(Not all of them are called as Delimiters...) struct DelimEntry const DelimTable[]= { //Single Character Delimiters //Set 1 {"[","LSquare"}, //0 {"]","RSquare"}, //1 {"(","LParen"}, {")","RParen"}, {"{","LBrace"}, {"}","RBrace"}, {",","Comma"}, {";","SemiColon"}, {":","Colon"}, {"?","QuestionMark"}, {"~","BitwiseNOT"}, {".","Dot"}, //11 //Singles in triple character delimiters.... //Set 2 //When ever u encounter a Set 2 character .... //U cannot confirm it as "Singles in triple character delimiters" //U need to check for its next character also..... //similarly When ever u encounter a Set 3 character .... //U need to check for its next character also..... // {"&lt;","LessThan"}, //12 {"&gt;","GreaterThan"}, {"&amp;","BitwiseAND"}, {"|","BitwiseOR"}, {"^","XOR"}, {"=","Assignment"}, {"!","Not"}, {"%","Remainder"}, {"-","Minus"}, {"+","Plus"}, {"*","Multiply"}, {"/","DividedBy"}, //23 //Doubles in triple character delimiters.... //Set 3 {"&lt;&lt;","LeftShift"}, //24 {"&lt;=","LessThanOrEqual"}, {"&gt;&gt;","RightShift"}, {"&gt;=","GreaterThanOrEqual"}, {"&amp;&amp;","LogicalAND"}, {"&amp;=","BitwiseANDEqual"}, {"||","LogicalOR"}, {"|=","BitwiseOREqual"}, {"^=","XOREqual"}, {"==","LogicalEqual"}, {"!=","LogicalNotEqual"}, {"%=","RemainderEquals"}, {"-=","MinusEquals"}, {"-&gt;","PointerArrow"}, {"--","DecrementOperator"}, {"++","IncrementOperator"}, {"+=","PlusEquals"}, {"*=","MultiplyEquals"}, {"/=","DividedByEquals"}, //42 //Triples in triple character delimiters.... //Set 4 {"&lt;&lt;=","LeftShiftEquals"}, //43 {"&gt;&gt;=","RightShiftEquals"}, //44 }; //=============================================================================================== FILE * fp = NULL; int index; //Variable used to iterate over the tokenTable Array.......... char buf[200]; //temporary variable to hold the token string........ //=============================================================================================== main(int argc , char *argv[] ) { int i; if(!FileOpen(argv[1])){ printf("\nUnable to Open the File : %s",argv[1]); return; } if(!CreateTokens()){ //It is the problem of TC ..... :( printf("\nUnable to Create Tokens - May be the given program contains tokens more than the maximum token table size"); return; } //Printing the Created Tokens.......... printf("\n%-5s %-16s %-18s %-8s %-8s\n","No","Token","Token Type","Begin","End"); printf("============================================================"); for(i=0 ; i&lt;index;i++){ GetToken(tokenTable[i].start,tokenTable[i].end); IdentifyTokenType(i); printf("\n%-5d %-16s %-18s %-6d %-6d",i,buf,tokenTable[i].type,tokenTable[i].start,tokenTable[i].end); } } //=============================================================================================== void IdentifyTokenType(int index) { int no,i; if(strcmp(tokenTable[index].type ,"Unknown")==0) { //determining keywords present in tokens no = sizeof(keywords)/sizeof(int); for(i = 0;i&lt;no;i++) if(strcmp(buf,keywords[i]) == 0){ tokenTable[index].type = "Keyword"; return; } //determining identifiers present in tokens if((buf[0]&gt;='a'&amp;&amp;buf[0]&lt;='z')|| (buf[0]&gt;='A'&amp;&amp;buf[0]&lt;='Z')||buf[0] == '_'){ tokenTable[index].type = "Identifier"; return; } //determining Preprocessor directives.. no = sizeof(preprocess)/sizeof(int); for(i = 0;i&lt;no;i++) if(strcmp(buf,preprocess[i]) == 0){ tokenTable[index].type = "Preprocessor"; return; } //Determining String Literals if(buf[0] == '"' &amp;&amp; buf[strlen(buf)-1] == '"'){ tokenTable[index].type = "String Literal"; return; } //Determining Char Literals //Determining Numeric constants for(i=0;buf[i]!='\0';i++) if(!(buf[i]&gt;='0'&amp;&amp;buf[i]&lt;='9'))return; tokenTable[index].type = "Numeric Constant"; return; } } //=============================================================================================== void GetToken(int start,int end) { int i=0; fseek(fp,start,SEEK_SET); while(i&lt;end-start) buf[i++] = fgetc(fp); buf[i] = '\0'; //Trim trailing newline chars.... for(i--;i&gt;=0;i--) if(buf[i] == '\n')buf[i] = '\0'; } //=============================================================================================== int EOFReached() { return feof(fp) != 0; } //=============================================================================================== //Implements the state machine for splitting the given program(input) in to tokens............... int CreateTokens() { int i=0,j=0,k=0; char c[4]={'\0','\0','\0','\0'}; //Array holding temporary characters..... do{ //state1 c[0] = fgetc(fp); //-------- //Path A if(c[0] == ' ' || c[0] == '\t' || c[0] == '\n' || EOFReached()) goto End; /* //-------- Skipping the comments..... if(c[0] == '/') { c[1] = fgetc(fp); //Skipping // type of comments.............. if(c[1] == '/') { do c[2] = fgetc(fp); while(c[2]!='\n'&amp;&amp;!EOFReached()); goto End; } //Skipping /* type of comments.............. else if(c[1] == '*') { do{ c[1] = fgetc(fp); c[2] = fgetc(fp); ungetc(c[2],fp); }while((c[1] != '*' || c[2] != '/')&amp;&amp;!EOFReached()); goto End; } MoveBack(1); } */ MoveBack(1); tokenTable[index].start = ftell(fp); MoveFront(1); //String literals if(c[0] == '"'){ do{ c[1] = fgetc(fp); if(c[1] =='\\') { fgetc(fp); c[1] = fgetc(fp);} //skip \" character in b/w a string literal }while(c[1] != '"'&amp;&amp;!EOFReached()); tokenTable[index].type = "Unknown"; tokenTable[index++].end = ftell(fp); goto End; } //-------- for(i=0;i&lt;12;i++) { if(strcmp(DelimTable[i].delim,c) == 0) //Path B { tokenTable[index].type = DelimTable[i].type; tokenTable[index++].end = ftell(fp); goto End; } } //-------- for(i=12;i&lt;24;i++) { //Checking for single char in triples if(strcmp(DelimTable[i].delim,c) == 0) //Path C { c[1] = fgetc(fp); //State 2 for(j=24;j&lt;43&amp;&amp;!EOFReached();j++) { //Checking for double char in triples if(strcmp(DelimTable[j].delim,c) == 0) //Path E { c[2] = fgetc(fp); //State 3 for(k=43;k&lt;45&amp;&amp; !EOFReached();k++) { //Checking for triplets in triples if(strcmp(DelimTable[k].delim,c) == 0) //Path G { tokenTable[index].type = DelimTable[k].type; tokenTable[index++].end = ftell(fp); goto End; } } //Path F if(!EOFReached())MoveBack(1); tokenTable[index].type = DelimTable[j].type; tokenTable[index++].end = ftell(fp); goto End; } } //Path D if(!EOFReached())MoveBack(1); tokenTable[index].type = DelimTable[i].type; tokenTable[index++].end = ftell(fp); goto End; } } //--------- do{ //Path H c[0] = fgetc(fp); //State 4 //Path I //Checking for White Spaces if(c[0] == ' ' || c[0] == '\t' || c[0] == '\n' ||EOFReached()) { if(!EOFReached()) MoveBack(1); tokenTable[index].type = "Unknown"; tokenTable[index++].end = ftell(fp); goto End; } //Checking for Single char Delims //Checking for Single char Delims in triplets for(i=0;i&lt;24;i++) if(strcmp(DelimTable[i].delim,c) == 0) { MoveBack(1); tokenTable[index].type = "Unknown"; tokenTable[index++].end = ftell(fp); goto End; } }while(!feof(fp)); End: c[0] = c[1] = c[2] = c[3] = '\0'; }while((!feof(fp))&amp;&amp;index&lt;TableSize); //Tokens May(Not) be Ready return index &lt; TableSize; } //=============================================================================================== int FileOpen(const char *path) { fp = fopen(path,"r"); if(fp == NULL) return false; return true; } //=============================================================================================== </code></pre> <p>Hope this helps you........</p>
    singulars
    1. This table or related slice is empty.
    1. POerror in coding a lexer in c
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USVineel Kumar Reddy
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. CO`#` and `##` are only operators inside a preprocessor macro definition. Also, I would be amazed if this answer helped anyone. Too much code, too little explanation.
      singulars
      1. PO
      1. USChris Lutz
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload