refactor: move non-symbols in ex_eval.h to ex_eval_defs.h (#19739)

This avoids including ex_eval.h in any other header, thus preventing
future circular includes.

src/nvim/ex_eval_defs.h

@@ -0,0 +1,77 @@
+#ifndef NVIM_EX_EVAL_DEFS_H
+#define NVIM_EX_EVAL_DEFS_H
+
+#include "nvim/pos.h"           // for linenr_T
+
+/// There is no CSF_IF, the lack of CSF_WHILE, CSF_FOR and CSF_TRY means ":if"
+/// was used.
+enum {
+  CSF_TRUE     = 0x0001,  ///< condition was TRUE
+  CSF_ACTIVE   = 0x0002,  ///< current state is active
+  CSF_ELSE     = 0x0004,  ///< ":else" has been passed
+  CSF_WHILE    = 0x0008,  ///< is a ":while"
+  CSF_FOR      = 0x0010,  ///< is a ":for"
+
+  CSF_TRY      = 0x0100,  ///< is a ":try"
+  CSF_FINALLY  = 0x0200,  ///< ":finally" has been passed
+  CSF_THROWN   = 0x0800,  ///< exception thrown to this try conditional
+  CSF_CAUGHT   = 0x1000,  ///< exception caught by this try conditional
+  CSF_FINISHED = 0x2000,  ///< CSF_CAUGHT was handled by finish_exception()
+  CSF_SILENT   = 0x4000,  ///< "emsg_silent" reset by ":try"
+};
+// Note that CSF_ELSE is only used when CSF_TRY and CSF_WHILE are unset
+// (an ":if"), and CSF_SILENT is only used when CSF_TRY is set.
+
+/// What's pending for being reactivated at the ":endtry" of this try
+/// conditional:
+enum {
+  CSTP_NONE      = 0,   ///< nothing pending in ":finally" clause
+  CSTP_ERROR     = 1,   ///< an error is pending
+  CSTP_INTERRUPT = 2,   ///< an interrupt is pending
+  CSTP_THROW     = 4,   ///< a throw is pending
+  CSTP_BREAK     = 8,   ///< ":break" is pending
+  CSTP_CONTINUE  = 16,  ///< ":continue" is pending
+  CSTP_RETURN    = 24,  ///< ":return" is pending
+  CSTP_FINISH    = 32,  ///< ":finish" is pending
+};
+
+/// A list of error messages that can be converted to an exception.  "throw_msg"
+/// is only set in the first element of the list.  Usually, it points to the
+/// original message stored in that element, but sometimes it points to a later
+/// message in the list.  See cause_errthrow() below.
+typedef struct msglist msglist_T;
+struct msglist {
+  char *msg;        ///< original message
+  char *throw_msg;  ///< msg to throw: usually original one
+  msglist_T *next;  ///< next of several messages in a row
+};
+
+/// The exception types.
+typedef enum {
+  ET_USER,       ///< exception caused by ":throw" command
+  ET_ERROR,      ///< error exception
+  ET_INTERRUPT,  ///< interrupt exception triggered by Ctrl-C
+} except_type_T;
+
+/// Structure describing an exception.
+/// (don't use "struct exception", it's used by the math library).
+typedef struct vim_exception except_T;
+struct vim_exception {
+  except_type_T type;   ///< exception type
+  char *value;          ///< exception value
+  msglist_T *messages;  ///< message(s) causing error exception
+  char *throw_name;     ///< name of the throw point
+  linenr_T throw_lnum;  ///< line number of the throw point
+  except_T *caught;     ///< next exception on the caught stack
+};
+
+/// Structure to save the error/interrupt/exception state between calls to
+/// enter_cleanup() and leave_cleanup().  Must be allocated as an automatic
+/// variable by the (common) caller of these functions.
+typedef struct cleanup_stuff cleanup_T;
+struct cleanup_stuff {
+  int pending;          ///< error/interrupt/exception state
+  except_T *exception;  ///< exception value
+};
+
+#endif  // NVIM_EX_EVAL_DEFS_H