cm_scan.l

小型编译系统的源代码

%{
#include "globals.h"
#include "util.h"
#include "scan.h"
#include "symtab.h"

char tokenString[MAXTOKENLEN+1];

/* set NO_PARSE to TRUE to get a scanner-only compiler */
#define NO_PARSE FALSE
/* set NO_ANALYZE to TRUE to get a parser-only compiler */
#define NO_ANALYZE FALSE

/* set NO_CODE to TRUE to get a compiler that does not
 * generate code
 */
#define NO_CODE FALSE

#include "util.h"
#if NO_PARSE
#include "scan.h"
#else
#include "parse.h"
#if !NO_ANALYZE
#include "analyze.h"
#if !NO_CODE
#include "cgen.h"
#endif
#endif
#endif

/* allocate global variables */
int lineno = 1;
FILE *source;
FILE *listing;
FILE *code;

/* allocate and set tracing flags */
int TraceScan = FALSE;
int TraceParse = FALSE;
int TraceAnalyze = FALSE;
int TraceCode = FALSE;

int Error = FALSE;

%}

id          [a-zA-Z_]+[a-zA-Z0-9_]*
num         (-?[1-9]+[0-9]*)|(-?[1-9])|0
floatnum		(-?[1-9]+[0-9]*\.[0-9]+)|(-?0\.[0-9]+)
constchar		'.'
newline     \n
whitespace  [ \t]+

%%

"int"       {return INT;}
"char"      {return CHAR;}
"float"     {return FLOAT;}
"void"      {return VOID;}
"if"        {return IF;}
"else"      {return ELSE;}
"while"     {return WHILE;}
"for"       {return FOR;}
"return"    {return RETURN;}
"=="        {return EQ;}
"<="        {return LE;}
">="        {return GE;}
"!="        {return NE;}
"="         {return ASSIGN;}
"<"         {return LT;}
">"         {return GT;}
"+"         {return PLUS;}
"-"         {return MINUS;}
"*"         {return TIMES;}
"/"         {return OVER;}
";"         {return SEMICOLON;}
","         {return COMMA;}
"("         {return LPAREN;}
")"         {return RPAREN;}
"["         {return LBRACKET;}
"]"         {return RBRACKET;}
"{"         {return LBRACE;}
"}"         {return RBRACE;}
"||"        {return OR;}
"&&"        {return AND;}
"!"         {return NOT;}
"/*"        {
                char c;
                LABEL:
                do
                {
                    c = input();
                    if( c == '\n')
                    	lineno++;
                }while(c != '*');
                
                do
                {
                    c = input();
                    if(c == '/')
                        break;
                    if( c == '\n')
                    	lineno++;
                    if(c != '*')
                        goto LABEL;
                }while(c == '*');
            }
{id}        {strncpy(tokenString,yytext,MAXTOKENLEN);	return ID;}
{num}       {strncpy(tokenString,yytext,MAXTOKENLEN);	return NUM;}
{floatnum}	{strncpy(tokenString,yytext,MAXTOKENLEN);	return FLOATNUM;}
{constchar}	{strncpy(tokenString,yytext,MAXTOKENLEN);	return CONSTCHAR;}
{newline}   {lineno++;}
{whitespace} {/* skip whitespace */}
.           {return ERROR;}

%%

int main( int argc, char * argv[] )
{ 
  TreeNode * syntaxTree;
  char pgm[120]; /* source code file name */
  
	if (argc != 2 && argc != 3)
  { 
		fprintf(stderr, "usage: CMinusC <filename>\n");
    exit(1);
  }

  if(argc == 3)
	{
		if(strpbrk(argv[2], "S") != 0)
			TraceScan = TRUE;
		if(strpbrk(argv[2], "P") != 0)
			TraceParse = TRUE;
		if(strpbrk(argv[2], "A") != 0)
			TraceAnalyze = TRUE;
		if(strpbrk(argv[2], "C") != 0)
			TraceCode = TRUE;
	}
  strcpy(pgm, argv[1]) ;
  if (strchr(pgm, '.') == NULL)
    strcat(pgm, ".cm");

  yyin = fopen(pgm,"r");
  if (yyin == NULL)
  {
		fprintf(stderr,"File %s not found\n",pgm);
    exit(1);
  }
	source = yyin;

  listing = stdout; /* send listing to screen */
  fprintf(listing,"\nC-Minus COMPILATION: %s\n", pgm);
#if NO_PARSE
  while (getToken() != ENDFILE);
#else
  syntaxTree = parse();
  if (TraceParse) 
	{
    fprintf(listing,"\nSyntax tree:\n");
    printTree(syntaxTree);
  }
#if !NO_ANALYZE
  if (! Error)
  { 
		if (TraceAnalyze) 
			fprintf(listing,"\nBuilding Symbol Table...\n");
    buildSymtab(syntaxTree);
    st_reset();
		if (TraceAnalyze) 
		{
			fprintf(listing,"\nSyntax tree:\n");
		  printTree(syntaxTree);
	  }
	}

	if(! Error)
	{
		if (TraceAnalyze) 
			fprintf(listing,"\nChecking Types...\n");
	   typeCheck(syntaxTree);
	  st_reset();
		if (TraceAnalyze) 
			fprintf(listing,"\nType Checking Finished\n");
	}
#if !NO_CODE
  if (! Error)
  { 
		char * codefile;
    int fnlen = strcspn(pgm,".");
    codefile = (char *) calloc(fnlen+4, sizeof(char));
    
		strncpy(codefile,pgm,fnlen);
    strcat(codefile,".p");
    code = fopen(codefile,"w");
    if (code == NULL)
    {
			printf("Unable to open %s\n",codefile);
      exit(1);
    }
    codeGen(syntaxTree,codefile);
    st_reset();
    fclose(code);
  }
#endif
#endif
#endif

	fclose(source);
  return 0;
}

int getToken()
{ 
	static int firstTime = TRUE;
  int currentToken;
  if (firstTime)
  { 
		firstTime = FALSE;
    lineno++;
    yyin = source;
    yyout = listing;
  }

  currentToken = yylex();
  if(currentToken == 0)
  	currentToken = ENDFILE;
  strncpy(tokenString,yytext,MAXTOKENLEN);
  if (TraceScan)
	{
    fprintf(listing,"\t%d: ",lineno);
    printToken(currentToken,tokenString);
  }
  return currentToken;
}

int yywrap()
{
    return 1;
}