add hoc
diff --git a/src/cmd/hoc/hoc.h b/src/cmd/hoc/hoc.h
new file mode 100644
index 0000000..3cdc18a
--- /dev/null
+++ b/src/cmd/hoc/hoc.h
@@ -0,0 +1,83 @@
+typedef void (*Inst)(void);
+#define STOP (Inst) 0
+
+typedef struct Symbol Symbol;
+typedef union Datum Datum;
+typedef struct Formal Formal;
+typedef struct Saveval Saveval;
+typedef struct Fndefn Fndefn;
+typedef union Symval Symval;
+
+union Symval { /* value of a symbol */
+ double val; /* VAR */
+ double (*ptr)(double); /* BLTIN */
+ Fndefn *defn; /* FUNCTION, PROCEDURE */
+ char *str; /* STRING */
+};
+
+struct Symbol { /* symbol table entry */
+ char *name;
+ long type;
+ Symval u;
+ struct Symbol *next; /* to link to another */
+};
+Symbol *install(char*, int, double), *lookup(char*);
+
+union Datum { /* interpreter stack type */
+ double val;
+ Symbol *sym;
+};
+
+struct Saveval { /* saved value of variable */
+ Symval val;
+ long type;
+ Saveval *next;
+};
+
+struct Formal { /* formal parameter */
+ Symbol *sym;
+ Saveval *save;
+ Formal *next;
+};
+
+struct Fndefn { /* formal parameter */
+ Inst *code;
+ Formal *formals;
+ int nargs;
+};
+
+extern Formal *formallist(Symbol*, Formal*);
+extern double Fgetd(int);
+extern int moreinput(void);
+extern void restore(Symbol*);
+extern void restoreall(void);
+extern void execerror(char*, char*);
+extern void define(Symbol*, Formal*), verify(Symbol*);
+extern Datum pop(void);
+extern void initcode(void), push(Datum), xpop(void), constpush(void);
+extern void varpush(void);
+#define div hocdiv
+extern void eval(void), add(void), sub(void), mul(void), div(void), mod(void);
+extern void negate(void), power(void);
+extern void addeq(void), subeq(void), muleq(void), diveq(void), modeq(void);
+
+extern Inst *progp, *progbase, prog[], *code(Inst);
+extern void assign(void), bltin(void), varread(void);
+extern void prexpr(void), prstr(void);
+extern void gt(void), lt(void), eq(void), ge(void), le(void), ne(void);
+extern void and(void), or(void), not(void);
+extern void ifcode(void), whilecode(void), forcode(void);
+extern void call(void), arg(void), argassign(void);
+extern void funcret(void), procret(void);
+extern void preinc(void), predec(void), postinc(void), postdec(void);
+extern void execute(Inst*);
+extern void printtop(void);
+
+extern double Log(double), Log10(double), Gamma(double), Sqrt(double), Exp(double);
+extern double Asin(double), Acos(double), Sinh(double), Cosh(double), integer(double);
+extern double Pow(double, double);
+
+extern void init(void);
+extern int yyparse(void);
+extern void execerror(char*, char*);
+extern void *emalloc(unsigned);
