Implement exponentiation (**) operator

include/ph7int.h

@@ -1403,6 +1403,7 @@ enum ph7_vm_op {
 	PH7_OP_BITNOT,       /* Bitwise not '~' */
 	PH7_OP_LNOT,         /* Logical not '!' */
 	PH7_OP_MUL,          /* Multiplication '*' */
+	PH7_OP_POW,          /* POW '**' */
 	PH7_OP_DIV,          /* Division '/' */
 	PH7_OP_MOD,          /* Modulus '%' */
 	PH7_OP_ADD,          /* Add '+' */
@@ -1437,6 +1438,7 @@ enum ph7_vm_op {
 	PH7_OP_ADD_STORE,    /* Add and store '+=' */
 	PH7_OP_SUB_STORE,    /* Sub and store '-=' */
 	PH7_OP_MUL_STORE,    /* Mul and store '*=' */
+	PH7_OP_POW_STORE,    /* Pow and store '**=' */
 	PH7_OP_DIV_STORE,    /* Div and store '/=' */
 	PH7_OP_MOD_STORE,    /* Mod and store '%=' */
 	PH7_OP_SHL_STORE,    /* Shift left and store '>>=' */
@@ -1479,6 +1481,7 @@ enum ph7_expr_id {
 	EXPR_OP_TYPECAST,  /* Type cast [i.e: (int),(float),(string)...] */
 	EXPR_OP_IS,        /* is */
 	EXPR_OP_LOGNOT,    /* logical not ! */
+	EXPR_OP_POW,       /* Exponentiation '**' */
 	EXPR_OP_MUL,       /* Multiplication */
 	EXPR_OP_DIV,       /* division */
 	EXPR_OP_MOD,       /* Modulus */
@@ -1505,6 +1508,7 @@ enum ph7_expr_id {
 	EXPR_OP_ADD_ASSIGN, /* Combined operator: += */
 	EXPR_OP_SUB_ASSIGN, /* Combined operator: -= */
 	EXPR_OP_MUL_ASSIGN, /* Combined operator: *= */
+	EXPR_OP_POW_ASSIGN, /* Combined operator: **= */
 	EXPR_OP_DIV_ASSIGN, /* Combined operator: /= */
 	EXPR_OP_MOD_ASSIGN, /* Combined operator: %= */
 	EXPR_OP_AND_ASSIGN, /* Combined operator: &= */