some updates for yacc stuff

bc/bc_parse.l

@@ -0,0 +1,46 @@
+%{
+  #include <string.h>
+  #include "y.tab.h"
+%}
+
+%%
+
+"/*"(\.)*"*/"             ;
+\n                        return NEWLINE;
+\".\"                     yylval.string=strdup(yytext); return STRING;
+[ \t]                     ;
+\\\n                      ;
+[0-9A-F]*(\.)?[0-9A-F]*   yylval.number=atof(yytext); return NUMBER;
+auto                      return AUTO;
+break                     return BREAK;
+define                    return DEFINE;
+ibase                     return IBASE;
+if                        return IF;
+for                       return FOR;
+length                    return LENGTH;
+obase                     return OBASE;
+quit                      return QUIT;
+return                    return RETURN;
+scale                     return SCALE;
+sqrt                      return SQRT;
+while                     return WHILE;
+[a-z]                     yylval.letter_op=yytext[0]; return LETTER
+[-+*/%^]?=                return ASSIGN_OP;
+=-                        ;
+[*/%]                     yylval.letter_op=yytext[0]; return MUL_OP;
+([=<>]?(=)?)|!=           return REL_OP;
+\+\+|--                   yylval.num_op=strcmp(yytext, "++"); return INCR_DECR;
+"("                       return OPAREN;
+")"                       return CPAREN;
+,                         return COMMA;
+"+"                       return PLUS;
+-                         return MINUS;
+;                         return SEMICOLON;
+"["                       return OSQR;
+"]"                       return CSQR;
+"^"                       return CARET;
+"{"                       return OCURL;
+"}"                       return CCURL;
+<<EOF>>                   return EOF;
+
+%%