mruby-compiler: rename operator field to op for c++ compatibility

Rename mrb_ast_op_asgn_node.operator field to op to avoid conflict with
C++ operator keyword. Update all references including macro definitions
and field access code.

Co-authored-by: Claude <noreply@anthropic.com>

mrbgems/mruby-compiler/core/codegen.c

@@ -4533,7 +4533,7 @@ gen_op_asgn_var(codegen_scope *s, node *varnode, int val)
   struct mrb_ast_op_asgn_node *op_asgn_n = op_asgn_node(varnode);
   node *lhs = op_asgn_n->lhs;
   node *rhs = op_asgn_n->rhs;
-  mrb_sym sym = op_asgn_n->operator;
+  mrb_sym sym = op_asgn_n->op;
   mrb_int len;
   const char *name = mrb_sym_name_len(s->mrb, sym, &len);
   int vsp = -1;

mrbgems/mruby-compiler/core/node.h

@@ -337,7 +337,7 @@ struct mrb_ast_masgn_node {
 struct mrb_ast_op_asgn_node {
   struct mrb_ast_var_header header;  /* 8 bytes */
   struct mrb_ast_node *lhs;          /* Left-hand side (target) */
-  mrb_sym operator;                  /* Assignment operator (e.g., +=, -=, etc.) */
+  mrb_sym op;                        /* Assignment operator (e.g., +=, -=, etc.) */
   struct mrb_ast_node *rhs;          /* Right-hand side (value) */
 };
 
@@ -495,7 +495,7 @@ struct mrb_ast_super_node {
 #define MASGN_NODE_RHS(n) (masgn_node(n)->rhs)
 
 #define OP_ASGN_NODE_LHS(n) (op_asgn_node(n)->lhs)
-#define OP_ASGN_NODE_OP(n) (op_asgn_node(n)->operator)
+#define OP_ASGN_NODE_OP(n) (op_asgn_node(n)->op)
 #define OP_ASGN_NODE_RHS(n) (op_asgn_node(n)->rhs)
 
 /* Expression node value access macros */

mrbgems/mruby-compiler/core/parse.y

@@ -1574,7 +1574,7 @@ new_op_asgn(parser_state *p, node *a, mrb_sym op, node *b)
   struct mrb_ast_op_asgn_node *n = (struct mrb_ast_op_asgn_node*)parser_alloc_var(p, total_size, class);
   init_var_header(&n->header, p, NODE_OP_ASGN, class);
   n->lhs = a;
-  n->operator = op;
+  n->op = op;
   n->rhs = b;
   return cons_head((node*)NODE_VARIABLE, (node*)n);
 }

mrbgems/mruby-compiler/core/y.tab.c

@@ -1636,7 +1636,7 @@ new_op_asgn(parser_state *p, node *a, mrb_sym op, node *b)
   struct mrb_ast_op_asgn_node *n = (struct mrb_ast_op_asgn_node*)parser_alloc_var(p, total_size, class);
   init_var_header(&n->header, p, NODE_OP_ASGN, class);
   n->lhs = a;
-  n->operator = op;
+  n->op = op;
   n->rhs = b;
   return cons_head((node*)NODE_VARIABLE, (node*)n);
 }