refactor error object

include/picrin.h

@@ -81,6 +81,7 @@ typedef struct {
   pic_sym sCONS, sCAR, sCDR, sNILP;
   pic_sym sADD, sSUB, sMUL, sDIV, sMINUS;
   pic_sym sEQ, sLT, sLE, sGT, sGE, sNOT;
+  pic_sym sREAD, sFILE;
 
   pic_sym rDEFINE, rLAMBDA, rIF, rBEGIN, rQUOTE, rSETBANG;
   pic_sym rDEFINE_SYNTAX, rIMPORT, rEXPORT;
@@ -104,7 +105,7 @@ typedef struct {
   struct pic_reader *reader;
 
   jmp_buf *jmp;
-  struct pic_error *err;
+  pic_value err;
   struct pic_jmpbuf *try_jmps;
   size_t try_jmp_size, try_jmp_idx;
 
@@ -206,7 +207,7 @@ noreturn void pic_abort(pic_state *, const char *);
 noreturn void pic_errorf(pic_state *, const char *, ...);
 void pic_warnf(pic_state *, const char *, ...);
 pic_str *pic_get_backtrace(pic_state *);
-void pic_print_backtrace(pic_state *, struct pic_error *);
+void pic_print_backtrace(pic_state *);
 
 /* obsoleted */
 static inline void pic_warn(pic_state *pic, const char *msg)

include/picrin/error.h

@@ -34,18 +34,14 @@ struct pic_jmpbuf {
 void pic_push_try(pic_state *, struct pic_proc *);
 void pic_pop_try(pic_state *);
 
-noreturn void pic_throw(pic_state *, short, const char *, pic_value);
-noreturn void pic_throw_error(pic_state *, struct pic_error *);
+noreturn void pic_raise(pic_state *, pic_value);
+noreturn void pic_throw(pic_state *, pic_sym, const char *, pic_list);
+noreturn void pic_error(pic_state *, const char *, pic_list);
 
 struct pic_error {
   PIC_OBJECT_HEADER
-  enum pic_error_kind {
-    PIC_ERROR_OTHER,
-    PIC_ERROR_FILE,
-    PIC_ERROR_READ,
-    PIC_ERROR_RAISED
-  } type;
-  struct pic_string *msg;
+  pic_sym type;
+  pic_str *msg;
   pic_value irrs;
   pic_str *stack;
 };

include/picrin/value.h

@@ -142,6 +142,7 @@ struct pic_blob;
 
 struct pic_proc;
 struct pic_port;
+struct pic_error;
 
 /* set aliases to basic types */
 typedef pic_value pic_list;