diff --git a/tools/lemon/lemon.c b/tools/lemon/lemon.c
index f560f10964..a70220572f 100644
--- a/tools/lemon/lemon.c
+++ b/tools/lemon/lemon.c
@@ -17,6 +17,14 @@
 #include <stdlib.h>
 #include <assert.h>
 
+#define ISSPACE(X) isspace((unsigned char)(X))
+#define ISDIGIT(X) isdigit((unsigned char)(X))
+#define ISALNUM(X) isalnum((unsigned char)(X))
+#define ISALPHA(X) isalpha((unsigned char)(X))
+#define ISUPPER(X) isupper((unsigned char)(X))
+#define ISLOWER(X) islower((unsigned char)(X))
+
+
 #ifndef __WIN32__
 #   if defined(_WIN32) || defined(WIN32)
 #	define __WIN32__
@@ -1494,7 +1502,7 @@ int main(int argc, char **argv)
   while( lem.symbols[i-1]->type==MULTITERMINAL ){ i--; }
   assert( strcmp(lem.symbols[i-1]->name,"{default}")==0 );
   lem.nsymbol = i - 1;
-  for(i=1; isupper(lem.symbols[i]->name[0]); i++);
+  for(i=1; ISUPPER(lem.symbols[i]->name[0]); i++);
   lem.nterminal = i;
 
   /* Generate a reprint of the grammar, if requested on the command line */
@@ -2028,7 +2036,7 @@ static void parseonetoken(struct pstate *psp)
     case WAITING_FOR_DECL_OR_RULE:
       if( x[0]=='%' ){
         psp->state = WAITING_FOR_DECL_KEYWORD;
-      }else if( islower(x[0]) ){
+      }else if( ISLOWER(x[0]) ){
         psp->lhs = Symbol_new(x);
         psp->nrhs = 0;
         psp->lhsalias = 0;
@@ -2058,7 +2066,7 @@ to follow the previous rule.");
       }
       break;
     case PRECEDENCE_MARK_1:
-      if( !isupper(x[0]) ){
+      if( !ISUPPER(x[0]) ){
         ErrorMsg(psp->filename,psp->tokenlineno,
           "The precedence symbol must be a terminal.");
         psp->errorcnt++;
@@ -2098,7 +2106,7 @@ to follow the previous rule.");
       }
       break;
     case LHS_ALIAS_1:
-      if( isalpha(x[0]) ){
+      if( ISALPHA(x[0]) ){
         psp->lhsalias = x;
         psp->state = LHS_ALIAS_2;
       }else{
@@ -2163,11 +2171,11 @@ to follow the previous rule.");
 	  }else{
             psp->lastrule->next = rp;
             psp->lastrule = rp;
-	  }
+          }
           psp->prevrule = rp;
-	}
+        }
         psp->state = WAITING_FOR_DECL_OR_RULE;
-      }else if( isalpha(x[0]) ){
+      }else if( ISALPHA(x[0]) ){
         if( psp->nrhs>=MAXRHS ){
           ErrorMsg(psp->filename,psp->tokenlineno,
             "Too many symbols on RHS of rule beginning at \"%s\".",
@@ -2195,7 +2203,7 @@ to follow the previous rule.");
         msp->subsym = (struct symbol **) realloc(msp->subsym,
           sizeof(struct symbol*)*msp->nsubsym);
         msp->subsym[msp->nsubsym-1] = Symbol_new(&x[1]);
-        if( islower(x[1]) || islower(msp->subsym[0]->name[0]) ){
+        if( ISLOWER(x[1]) || ISLOWER(msp->subsym[0]->name[0]) ){
           ErrorMsg(psp->filename,psp->tokenlineno,
             "Cannot form a compound containing a non-terminal");
           psp->errorcnt++;
@@ -2210,7 +2218,7 @@ to follow the previous rule.");
       }
       break;
     case RHS_ALIAS_1:
-      if( isalpha(x[0]) ){
+      if( ISALPHA(x[0]) ){
         psp->alias[psp->nrhs-1] = x;
         psp->state = RHS_ALIAS_2;
       }else{
@@ -2232,7 +2240,7 @@ to follow the previous rule.");
       }
       break;
     case WAITING_FOR_DECL_KEYWORD:
-      if( isalpha(x[0]) ){
+      if( ISALPHA(x[0]) ){
         psp->declkeyword = x;
         psp->declargslot = 0;
         psp->decllinenoslot = 0;
@@ -2312,7 +2320,7 @@ to follow the previous rule.");
       }
       break;
     case WAITING_FOR_DESTRUCTOR_SYMBOL:
-      if( !isalpha(x[0]) ){
+      if( !ISALPHA(x[0]) ){
         ErrorMsg(psp->filename,psp->tokenlineno,
           "Symbol name missing after %%destructor keyword");
         psp->errorcnt++;
@@ -2326,7 +2334,7 @@ to follow the previous rule.");
       }
       break;
     case WAITING_FOR_DATATYPE_SYMBOL:
-      if( !isalpha(x[0]) ){
+      if( !ISALPHA(x[0]) ){
         ErrorMsg(psp->filename,psp->tokenlineno,
           "Symbol name missing after %%type keyword");
         psp->errorcnt++;
@@ -2351,7 +2359,7 @@ to follow the previous rule.");
     case WAITING_FOR_PRECEDENCE_SYMBOL:
       if( x[0]=='.' ){
         psp->state = WAITING_FOR_DECL_OR_RULE;
-      }else if( isupper(x[0]) ){
+      }else if( ISUPPER(x[0]) ){
         struct symbol *sp;
         sp = Symbol_new(x);
         if( sp->prec>=0 ){
@@ -2369,7 +2377,7 @@ to follow the previous rule.");
       }
       break;
     case WAITING_FOR_DECL_ARG:
-      if( x[0]=='{' || x[0]=='\"' || isalnum(x[0]) ){
+      if( x[0]=='{' || x[0]=='\"' || ISALNUM(x[0]) ){
         const char *zOld, *zNew;
         char *zBuf, *z;
         int nOld, n, nLine, nNew, nBack;
@@ -2430,7 +2438,7 @@ to follow the previous rule.");
     case WAITING_FOR_FALLBACK_ID:
       if( x[0]=='.' ){
         psp->state = WAITING_FOR_DECL_OR_RULE;
-      }else if( !isupper(x[0]) ){
+      }else if( !ISUPPER(x[0]) ){
         ErrorMsg(psp->filename, psp->tokenlineno,
           "%%fallback argument \"%s\" should be a token", x);
         psp->errorcnt++;
@@ -2451,7 +2459,7 @@ to follow the previous rule.");
     case WAITING_FOR_WILDCARD_ID:
       if( x[0]=='.' ){
         psp->state = WAITING_FOR_DECL_OR_RULE;
-      }else if( !isupper(x[0]) ){
+      }else if( !ISUPPER(x[0]) ){
         ErrorMsg(psp->filename, psp->tokenlineno,
           "%%wildcard argument \"%s\" should be a token", x);
         psp->errorcnt++;
@@ -2467,7 +2475,7 @@ to follow the previous rule.");
       }
       break;
     case WAITING_FOR_CLASS_ID:
-      if( !islower(x[0]) ){
+      if( !ISLOWER(x[0]) ){
         ErrorMsg(psp->filename, psp->tokenlineno,
           "%%token_class must be followed by an identifier: ", x);
         psp->errorcnt++;
@@ -2486,12 +2494,12 @@ to follow the previous rule.");
     case WAITING_FOR_CLASS_TOKEN:
       if( x[0]=='.' ){
         psp->state = WAITING_FOR_DECL_OR_RULE;
-      }else if( isupper(x[0]) || ((x[0]=='|' || x[0]=='/') && isupper(x[1])) ){
+      }else if( ISUPPER(x[0]) || ((x[0]=='|' || x[0]=='/') && ISUPPER(x[1])) ){
         struct symbol *msp = psp->tkclass;
         msp->nsubsym++;
         msp->subsym = (struct symbol **) realloc(msp->subsym,
           sizeof(struct symbol*)*msp->nsubsym);
-        if( !isupper(x[0]) ) x++;
+        if( !ISUPPER(x[0]) ) x++;
         msp->subsym[msp->nsubsym-1] = Symbol_new(x);
       }else{
         ErrorMsg(psp->filename, psp->tokenlineno,
@@ -2524,7 +2532,7 @@ static void preprocess_input(char *z){
   for(i=0; z[i]; i++){
     if( z[i]=='\n' ) lineno++;
     if( z[i]!='%' || (i>0 && z[i-1]!='\n') ) continue;
-    if( strncmp(&z[i],"%endif",6)==0 && isspace(z[i+6]) ){
+    if( strncmp(&z[i],"%endif",6)==0 && ISSPACE(z[i+6]) ){
       if( exclude ){
         exclude--;
         if( exclude==0 ){
@@ -2532,13 +2540,13 @@ static void preprocess_input(char *z){
         }
       }
       for(j=i; z[j] && z[j]!='\n'; j++) z[j] = ' ';
-    }else if( (strncmp(&z[i],"%ifdef",6)==0 && isspace(z[i+6]))
-          || (strncmp(&z[i],"%ifndef",7)==0 && isspace(z[i+7])) ){
+    }else if( (strncmp(&z[i],"%ifdef",6)==0 && ISSPACE(z[i+6]))
+          || (strncmp(&z[i],"%ifndef",7)==0 && ISSPACE(z[i+7])) ){
       if( exclude ){
         exclude++;
       }else{
-        for(j=i+7; isspace(z[j]); j++){}
-        for(n=0; z[j+n] && !isspace(z[j+n]); n++){}
+        for(j=i+7; ISSPACE(z[j]); j++){}
+        for(n=0; z[j+n] && !ISSPACE(z[j+n]); n++){}
         exclude = 1;
         for(k=0; k<nDefine; k++){
           if( strncmp(azDefine[k],&z[j],n)==0 && lemonStrlen(azDefine[k])==n ){
@@ -2636,7 +2644,7 @@ void Parse(struct lemon *gp)
   lineno = 1;
   for(cp=filebuf; (c= *cp)!=0; ){
     if( c=='\n' ) lineno++;              /* Keep track of the line number */
-    if( isspace(c) ){ cp++; continue; }  /* Skip all white space */
+    if( ISSPACE(c) ){ cp++; continue; }  /* Skip all white space */
     if( c=='/' && cp[1]=='/' ){          /* Skip C++ style comments */
       cp+=2;
       while( (c= *cp)!=0 && c!='\n' ) cp++;
@@ -2706,15 +2714,15 @@ void Parse(struct lemon *gp)
       }else{
         nextcp = cp+1;
       }
-    }else if( isalnum(c) ){          /* Identifiers */
-      while( (c= *cp)!=0 && (isalnum(c) || c=='_') ) cp++;
+    }else if( ISALNUM(c) ){          /* Identifiers */
+      while( (c= *cp)!=0 && (ISALNUM(c) || c=='_') ) cp++;
       nextcp = cp;
     }else if( c==':' && cp[1]==':' && cp[2]=='=' ){ /* The operator "::=" */
       cp += 3;
       nextcp = cp;
-    }else if( (c=='/' || c=='|') && isalpha(cp[1]) ){
+    }else if( (c=='/' || c=='|') && ISALPHA(cp[1]) ){
       cp += 2;
-      while( (c = *cp)!=0 && (isalnum(c) || c=='_') ) cp++;
+      while( (c = *cp)!=0 && (ISALNUM(c) || c=='_') ) cp++;
       nextcp = cp;
     }else{                          /* All other (one character) operators */
       cp++;
@@ -3169,7 +3177,7 @@ PRIVATE void tplt_xfer(char *name, FILE *in, FILE *out, int *lineno)
     if( name ){
       for(i=0; line[i]; i++){
         if( line[i]=='P' && strncmp(&line[i],"Parse",5)==0
-          && (i==0 || !isalpha(line[i-1]))
+          && (i==0 || !ISALPHA(line[i-1]))
         ){
           if( i>iStart ) fprintf(out,"%.*s",i-iStart,&line[iStart]);
           fprintf(out,"%s",name);
@@ -3413,9 +3421,9 @@ PRIVATE void translate_code(struct lemon *lemp, struct rule *rp){
 
   /* This const cast is wrong but harmless, if we're careful. */
   for(cp=(char *)rp->code; *cp; cp++){
-    if( isalpha(*cp) && (cp==rp->code || (!isalnum(cp[-1]) && cp[-1]!='_')) ){
+    if( ISALPHA(*cp) && (cp==rp->code || (!ISALNUM(cp[-1]) && cp[-1]!='_')) ){
       char saved;
-      for(xp= &cp[1]; isalnum(*xp) || *xp=='_'; xp++);
+      for(xp= &cp[1]; ISALNUM(*xp) || *xp=='_'; xp++);
       saved = *xp;
       *xp = 0;
       if( rp->lhsalias && strcmp(cp,rp->lhsalias)==0 ){
@@ -3579,9 +3587,9 @@ void print_stack_union(
     cp = sp->datatype;
     if( cp==0 ) cp = lemp->vartype;
     j = 0;
-    while( isspace(*cp) ) cp++;
+    while( ISSPACE(*cp) ) cp++;
     while( *cp ) stddt[j++] = *cp++;
-    while( j>0 && isspace(stddt[j-1]) ) j--;
+    while( j>0 && ISSPACE(stddt[j-1]) ) j--;
     stddt[j] = 0;
     if( lemp->tokentype && strcmp(stddt, lemp->tokentype)==0 ){
       sp->dtnum = 0;
@@ -3792,8 +3800,8 @@ void ReportTable(
   if( lemp->arg && lemp->arg[0] ){
     size_t i;
     i = lemonStrlen(lemp->arg);
-    while( i>=1 && isspace(lemp->arg[i-1]) ) i--;
-    while( i>=1 && (isalnum(lemp->arg[i-1]) || lemp->arg[i-1]=='_') ) i--;
+    while( i>=1 && ISSPACE(lemp->arg[i-1]) ) i--;
+    while( i>=1 && (ISALNUM(lemp->arg[i-1]) || lemp->arg[i-1]=='_') ) i--;
     fprintf(out,"#define %sARG_SDECL %s;\n",name,lemp->arg);  lineno++;
     fprintf(out,"#define %sARG_PDECL ,%s\n",name,lemp->arg);  lineno++;
     fprintf(out,"#define %sARG_FETCH %s = yypParser->%s\n",
@@ -4603,7 +4611,7 @@ struct symbol *Symbol_new(const char *x)
     sp = (struct symbol *)calloc(1, sizeof(struct symbol) );
     MemoryCheck(sp);
     sp->name = Strsafe(x);
-    sp->type = isupper(*x) ? TERMINAL : NONTERMINAL;
+    sp->type = ISUPPER(*x) ? TERMINAL : NONTERMINAL;
     sp->rule = 0;
     sp->fallback = 0;
     sp->prec = -1;