nepc.y

使用yacc和lex编写的cmm语言的词法分析和语法分析程序.

%{
#include "nepc.h"
#include "nepc.c"  /* routines for parse */
#include "lex.yy.c"
%}

%union{
    INT iValue;
    FLT fValue;
    char * pStr;
    nodeType *nPtr;
};

%token <iValue> INTEGER
%token <fValue> FLOAT
%token <pStr> VARIABLE
%token <pStr> STRING
%token <iValue> ACOS ASIN ATAN CEIL COS COSH EXP FABS FLOOR 
%token <iValue> LOG LOG10 POW10 SIN SINH SQRT TAN TANH

%type <nPtr> stmt expr stmt_list function

%token EXIT ERASE CLEAR LIST HELP DEC HEX OCT
%token WHILE IF PRINT

%nonassoc IFX
%nonassoc ELSE

%left OR
%left AND
%left GE LE EQ NE '>' '<'
%left '+' '-'
%left '*' '/' '%'
%left PP SS
%nonassoc UMINUS


%%
program:
    init parsed EXIT        { freeSymTable(); exit(0); }
  ;
init: /* NULL*/             { initSymTable(); WAITINPUT;} 
  ;
parsed:
    parsed stmt             { free(interpret($2)); freeNode($2); WAITINPUT; }
  | parsed error separator  { yyerrok; WAITINPUT;}
  | /* NULL */
  ;

stmt:
    separator               { $$ = opr(';', 2, NULL, NULL);  }
  | expr separator          { $$ = opr(PRINT, 1, $1); }
  | PRINT expr separator    { $$ = opr(PRINT, 1, $2); }
  | VARIABLE '=' expr separator     { $$ = (($3 == NULL)?NULL:(symname_install($1),opr('=', 2, var($1), $3)));}
  | WHILE '(' expr ')' stmt         { $$ = opr(WHILE, 2, $3, $5);  }
  | IF '(' expr ')' stmt %prec IFX  { $$ = opr(IF, 2, $3, $5); }
  | IF '(' expr ')' stmt ELSE stmt  { $$ = opr(IF, 3, $3, $5, $7); }
  | '{' stmt_list '}'       { $$ = $2; }
  | CMD                     { $$ = NULL; }
  ;

CMD:
    ERASE       { freeSymTable(); printf(">> All variables erased!\n"); }
  | HELP        {
                       printf(">> COMMANDS:\n");
                       printf("> help: Display this help section.\n");
                       printf("> clear/cls: Clear the screen.\n");
                       printf("> dec: Decimal mode to display numbers or variables.\n");
                       printf("> hex: Hexadecimal mode to display numbers or variables.\n");
                       printf("> oct: Octal mode to display numbers or variables.\n");
                       printf("> list/ls: List the values of variables.\n");
                       printf("> erase: Reset all variables to 0.\n");
                       printf("> exit/quit: Quit this program.\n");
                       printf("> functions supported: acos,asin,atan,ceil,cos,cosh,exp,\n");
                       printf(">   fabs,floor,log,log10,sin,sinh,sqrt,tan,tanh.\n"); 
                }
  | LIST        {
                    int i;
                    symType * p;
                    for(i=0;i<symtop;i++)
                    {   
                        p=&symtab[i];
                        if(symtab[i].type==typeInt)
                        {
                            printf("\tINT %s = ", p->name);
                            PRINTINT(p);
                        }
                        else if(symtab[i].type==typeFlt)
                        {
                            printf("\tFLT %s = ", p->name);
                            PRINTFLT(p);
                        }
                        else if(symtab[i].type==typeStr)
                        {
                            printf("\tSTR %s = ", p->name);
                            PRINTSTR(p);
                        }
                        printf("\n");
                    }
                }
   | CLEAR      { printf("\033[2J\033[1;1H\n"); }
   | HEX        { dflag=HEX_ON; printf(">> HEX display mode on!\n"); }
   | DEC        { dflag=DEC_ON; printf(">> DEC display mode on!\n"); }
   | OCT        { dflag=OCT_ON; printf(">> OCT display mode on!\n"); }
   ;

stmt_list:
    stmt                    { $$ = $1; }
  | stmt_list stmt          { $$ = opr(';', 2, $1, $2); }
 
  ;

separator:
    ';'
  ;
expr:
    INTEGER                 { $$ = con_int($1); }
  | FLOAT                   { $$ = con_flt($1); }
  | STRING                  { $$ = con_str($1); }
  | VARIABLE                { $$ = var($1); }
  | '-' expr %prec UMINUS   { $$ = opr(UMINUS, 1, $2); }
  | VARIABLE PP             { $$ = ((var($1)==NULL) ? NULL: opr(PP, 1, var($1))); }
  | VARIABLE SS             { $$ = ((var($1)==NULL) ? NULL: opr(SS, 1, var($1))); }
  | expr '+' expr           { $$ = opr('+', 2, $1, $3); }
  | expr '-' expr           { $$ = opr('-', 2, $1, $3); }
  | expr '*' expr           { $$ = opr('*', 2, $1, $3); }
  | expr '/' expr           { $$ = opr('/', 2, $1, $3); }
  | expr '<' expr           { $$ = opr('<', 2, $1, $3); }
  | expr '>' expr           { $$ = opr('>', 2, $1, $3); }
  | expr '%' expr           { $$ = opr('%', 2, $1, $3); }
  | expr AND expr           { $$ = opr(AND, 2, $1, $3); }
  | expr OR expr            { $$ = opr(OR, 2, $1, $3); }
  | expr GE expr            { $$ = opr(GE, 2, $1, $3); }
  | expr LE expr            { $$ = opr(LE, 2, $1, $3); }
  | expr NE expr            { $$ = opr(NE, 2, $1, $3); }
  | expr EQ expr            { $$ = opr(EQ, 2, $1, $3); }
  | '(' expr ')'            { $$ = $2; }
  | function                { $$ = $1; }
  ;

function:
    ACOS '(' expr ')'       { $$ = opr(ACOS,1,$3); }
  | ASIN '(' expr ')'       { $$ = opr(ASIN,1,$3); }
  | ATAN '(' expr ')'       { $$ = opr(ATAN,1,$3);; }
  | CEIL '(' expr ')'       { $$ = opr(CEIL,1,$3); }
  | COS  '(' expr ')'       { $$ = opr(COS,1,$3); }
  | COSH '(' expr ')'       { $$ = opr(COSH,1,$3); }
  | EXP '(' expr ')'        { $$ = opr(EXP,1,$3); }
  | FABS '(' expr ')'       { $$ = opr(FABS,1,$3); }
  | FLOOR '(' expr ')'      { $$ = opr(FLOOR,1,$3); }
  | LOG '(' expr ')'        { $$ = opr(LOG,1,$3); }
  | LOG10 '(' expr ')'      { $$ = opr(LOG10,1,$3); }
  | SIN '(' expr ')'        { $$ = opr(SIN,1,$3); }
  | SINH '(' expr ')'       { $$ = opr(SINH,1,$3); }
  | SQRT '(' expr ')'       { $$ = opr(SQRT,1,$3); }
  | TAN '(' expr ')'        { $$ = opr(TAN,1,$3); }
  | TANH '(' expr ')'       { $$ = opr(TANH,1,$3); }
  ;

%%

void yyerror(char *s) 
{
    fprintf(stdout, "%s\n", s);
}