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Edit File: cursesf.h
// * This makes emacs happy -*-Mode: C++;-*- // vile:cppmode /**************************************************************************** * Copyright 2019-2021,2022 Thomas E. Dickey * * Copyright 1998-2012,2014 Free Software Foundation, Inc. * * * * Permission is hereby granted, free of charge, to any person obtaining a * * copy of this software and associated documentation files (the * * "Software"), to deal in the Software without restriction, including * * without limitation the rights to use, copy, modify, merge, publish, * * distribute, distribute with modifications, sublicense, and/or sell * * copies of the Software, and to permit persons to whom the Software is * * furnished to do so, subject to the following conditions: * * * * The above copyright notice and this permission notice shall be included * * in all copies or substantial portions of the Software. * * * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * * THE USE OR OTHER DEALINGS IN THE SOFTWARE. * * * * Except as contained in this notice, the name(s) of the above copyright * * holders shall not be used in advertising or otherwise to promote the * * sale, use or other dealings in this Software without prior written * * authorization. * ****************************************************************************/ /**************************************************************************** * Author: Juergen Pfeifer, 1997 * ****************************************************************************/ // $Id: cursesf.h,v 1.39 2022/08/20 20:52:15 tom Exp $ #ifndef NCURSES_CURSESF_H_incl #define NCURSES_CURSESF_H_incl 1 #include <cursesp.h> #ifndef __EXT_QNX #include <string.h> #endif extern "C" { # include <form.h> } // // ------------------------------------------------------------------------- // The abstract base class for builtin and user defined Fieldtypes. // ------------------------------------------------------------------------- // class NCURSES_CXX_IMPEXP NCursesFormField; // forward declaration // Class to represent builtin field types as well as C++ written new // fieldtypes (see classes UserDefineFieldType... class NCURSES_CXX_IMPEXP NCursesFieldType { friend class NCursesFormField; protected: FIELDTYPE* fieldtype; inline void OnError(int err) const THROW2(NCursesException const, NCursesFormException) { if (err!=E_OK) THROW(new NCursesFormException (err)); } NCursesFieldType(FIELDTYPE *f) : fieldtype(f) { } virtual ~NCursesFieldType() {} // Set the fields f fieldtype to this one. virtual void set(NCursesFormField& f) = 0; public: NCursesFieldType() : fieldtype(STATIC_CAST(FIELDTYPE*)(0)) { } NCursesFieldType& operator=(const NCursesFieldType& rhs) { if (this != &rhs) { *this = rhs; } return *this; } NCursesFieldType(const NCursesFieldType& rhs) : fieldtype(rhs.fieldtype) { } }; // // ------------------------------------------------------------------------- // The class representing a forms field, wrapping the lowlevel FIELD struct // ------------------------------------------------------------------------- // class NCURSES_CXX_IMPEXP NCursesFormField { friend class NCursesForm; protected: FIELD *field; // lowlevel structure NCursesFieldType* ftype; // Associated field type // Error handler inline void OnError (int err) const THROW2(NCursesException const, NCursesFormException) { if (err != E_OK) THROW(new NCursesFormException (err)); } public: // Create a 'Null' field. Can be used to delimit a field list NCursesFormField() : field(STATIC_CAST(FIELD*)(0)), ftype(STATIC_CAST(NCursesFieldType*)(0)) { } // Create a new field NCursesFormField (int rows, int ncols, int first_row = 0, int first_col = 0, int offscreen_rows = 0, int additional_buffers = 0) : field(0), ftype(STATIC_CAST(NCursesFieldType*)(0)) { field = ::new_field(rows, ncols, first_row, first_col, offscreen_rows, additional_buffers); if (!field) OnError(errno); } NCursesFormField& operator=(const NCursesFormField& rhs) { if (this != &rhs) { *this = rhs; } return *this; } NCursesFormField(const NCursesFormField& rhs) : field(rhs.field), ftype(rhs.ftype) { } virtual ~NCursesFormField () THROWS(NCursesException); // Duplicate the field at a new position inline NCursesFormField* dup(int first_row, int first_col) { NCursesFormField* f = new NCursesFormField(); if (!f) OnError(E_SYSTEM_ERROR); else { f->ftype = ftype; f->field = ::dup_field(field,first_row,first_col); if (!f->field) OnError(errno); } return f; } // Link the field to a new location inline NCursesFormField* link(int first_row, int first_col) { NCursesFormField* f = new NCursesFormField(); if (!f) OnError(E_SYSTEM_ERROR); else { f->ftype = ftype; f->field = ::link_field(field,first_row,first_col); if (!f->field) OnError(errno); } return f; } // Get the lowlevel field representation inline FIELD* get_field() const { return field; } // Retrieve info about the field inline void info(int& rows, int& ncols, int& first_row, int& first_col, int& offscreen_rows, int& additional_buffers) const { OnError(::field_info(field, &rows, &ncols, &first_row, &first_col, &offscreen_rows, &additional_buffers)); } // Retrieve info about the fields dynamic properties. inline void dynamic_info(int& dynamic_rows, int& dynamic_cols, int& max_growth) const { OnError(::dynamic_field_info(field, &dynamic_rows, &dynamic_cols, &max_growth)); } // For a dynamic field you may set the maximum growth limit. // A zero means unlimited growth. inline void set_maximum_growth(int growth = 0) { OnError(::set_max_field(field,growth)); } // Move the field to a new position inline void move(int row, int col) { OnError(::move_field(field,row,col)); } // Mark the field to start a new page inline void new_page(bool pageFlag = FALSE) { OnError(::set_new_page(field,pageFlag)); } // Retrieve whether or not the field starts a new page. inline bool is_new_page() const { return ::new_page(field); } // Set the justification for the field inline void set_justification(int just) { OnError(::set_field_just(field,just)); } // Retrieve the fields justification inline int justification() const { return ::field_just(field); } // Set the foreground attribute for the field inline void set_foreground(chtype foreground) { OnError(::set_field_fore(field,foreground)); } // Retrieve the fields foreground attribute inline chtype fore() const { return ::field_fore(field); } // Set the background attribute for the field inline void set_background(chtype background) { OnError(::set_field_back(field,background)); } // Retrieve the fields background attribute inline chtype back() const { return ::field_back(field); } // Set the padding character for the field inline void set_pad_character(int padding) { OnError(::set_field_pad(field, padding)); } // Retrieve the fields padding character inline int pad() const { return ::field_pad(field); } // Switch on the fields options inline void options_on (Field_Options opts) { OnError (::field_opts_on (field, opts)); } // Switch off the fields options inline void options_off (Field_Options opts) { OnError (::field_opts_off (field, opts)); } // Retrieve the fields options inline Field_Options options () const { return ::field_opts (field); } // Set the fields options inline void set_options (Field_Options opts) { OnError (::set_field_opts (field, opts)); } // Mark the field as changed inline void set_changed(bool changeFlag = TRUE) { OnError(::set_field_status(field,changeFlag)); } // Test whether or not the field is marked as changed inline bool changed() const { return ::field_status(field); } // Return the index of the field in the field array of a form // or -1 if the field is not associated to a form inline int (index)() const { return ::field_index(field); } // Store a value in a fields buffer. The default buffer is nr. 0 inline void set_value(const char *val, int buffer = 0) { OnError(::set_field_buffer(field,buffer,val)); } // Retrieve the value of a fields buffer. The default buffer is nr. 0 inline char* value(int buffer = 0) const { return ::field_buffer(field,buffer); } // Set the validation type of the field. inline void set_fieldtype(NCursesFieldType& f) { ftype = &f; f.set(*this); // A good friend may do that... } // Retrieve the validation type of the field. inline NCursesFieldType* fieldtype() const { return ftype; } }; // This are the built-in hook functions in this C++ binding. In C++ we use // virtual member functions (see below On_..._Init and On_..._Termination) // to provide this functionality in an object oriented manner. extern "C" { void _nc_xx_frm_init(FORM *); void _nc_xx_frm_term(FORM *); void _nc_xx_fld_init(FORM *); void _nc_xx_fld_term(FORM *); } // // ------------------------------------------------------------------------- // The class representing a form, wrapping the lowlevel FORM struct // ------------------------------------------------------------------------- // class NCURSES_CXX_IMPEXP NCursesForm : public NCursesPanel { protected: FORM* form; // the lowlevel structure private: NCursesWindow* sub; // the subwindow object bool b_sub_owner; // is this our own subwindow? bool b_framed; // has the form a border? bool b_autoDelete; // Delete fields when deleting form? NCursesFormField** my_fields; // The array of fields for this form // This structure is used for the form's user data field to link the // FORM* to the C++ object and to provide extra space for a user pointer. typedef struct { void* m_user; // the pointer for the user's data const NCursesForm* m_back; // backward pointer to C++ object const FORM* m_owner; } UserHook; // Get the backward pointer to the C++ object from a FORM static inline NCursesForm* getHook(const FORM *f) { UserHook* hook = reinterpret_cast<UserHook*>(::form_userptr(f)); assert(hook != 0 && hook->m_owner==f); return const_cast<NCursesForm*>(hook->m_back); } friend void _nc_xx_frm_init(FORM *); friend void _nc_xx_frm_term(FORM *); friend void _nc_xx_fld_init(FORM *); friend void _nc_xx_fld_term(FORM *); // Calculate FIELD* array for the menu FIELD** mapFields(NCursesFormField* nfields[]); protected: // internal routines inline void set_user(void *user) { UserHook* uptr = reinterpret_cast<UserHook*>(::form_userptr (form)); assert (uptr != 0 && uptr->m_back==this && uptr->m_owner==form); uptr->m_user = user; } inline void *get_user() { UserHook* uptr = reinterpret_cast<UserHook*>(::form_userptr (form)); assert (uptr != 0 && uptr->m_back==this && uptr->m_owner==form); return uptr->m_user; } void InitForm (NCursesFormField* Fields[], bool with_frame, bool autoDeleteFields); inline void OnError (int err) const THROW2(NCursesException const, NCursesFormException) { if (err != E_OK) THROW(new NCursesFormException (err)); } // this wraps the form_driver call. virtual int driver (int c) ; // 'Internal' constructor, builds an object without association to a // field array. NCursesForm( int nlines, int ncols, int begin_y = 0, int begin_x = 0) : NCursesPanel(nlines, ncols, begin_y, begin_x), form (STATIC_CAST(FORM*)(0)), sub(0), b_sub_owner(0), b_framed(0), b_autoDelete(0), my_fields(0) { } public: // Create form for the default panel. NCursesForm (NCursesFormField* Fields[], bool with_frame=FALSE, // reserve space for a frame? bool autoDelete_Fields=FALSE) // do automatic cleanup? : NCursesPanel(), form(0), sub(0), b_sub_owner(0), b_framed(0), b_autoDelete(0), my_fields(0) { InitForm(Fields, with_frame, autoDelete_Fields); } // Create a form in a panel with the given position and size. NCursesForm (NCursesFormField* Fields[], int nlines, int ncols, int begin_y, int begin_x, bool with_frame=FALSE, // reserve space for a frame? bool autoDelete_Fields=FALSE) // do automatic cleanup? : NCursesPanel(nlines, ncols, begin_y, begin_x), form(0), sub(0), b_sub_owner(0), b_framed(0), b_autoDelete(0), my_fields(0) { InitForm(Fields, with_frame, autoDelete_Fields); } NCursesForm& operator=(const NCursesForm& rhs) { if (this != &rhs) { *this = rhs; NCursesPanel::operator=(rhs); } return *this; } NCursesForm(const NCursesForm& rhs) : NCursesPanel(rhs), form(rhs.form), sub(rhs.sub), b_sub_owner(rhs.b_sub_owner), b_framed(rhs.b_framed), b_autoDelete(rhs.b_autoDelete), my_fields(rhs.my_fields) { } virtual ~NCursesForm() THROWS(NCursesException); // Set the default attributes for the form virtual void setDefaultAttributes(); // Retrieve current field of the form. inline NCursesFormField* current_field() const { return my_fields[::field_index(::current_field(form))]; } // Set the forms subwindow void setSubWindow(NCursesWindow& sub); // Set these fields for the form inline void setFields(NCursesFormField* Fields[]) { OnError(::set_form_fields(form,mapFields(Fields))); } // Remove the form from the screen inline void unpost (void) { OnError (::unpost_form (form)); } // Post the form to the screen if flag is true, unpost it otherwise inline void post(bool flag = TRUE) { OnError (flag ? ::post_form(form) : ::unpost_form (form)); } // Decorations inline void frame(const char *title=NULL, const char* btitle=NULL) NCURSES_OVERRIDE { if (b_framed) NCursesPanel::frame(title,btitle); else OnError(E_SYSTEM_ERROR); } inline void boldframe(const char *title=NULL, const char* btitle=NULL) NCURSES_OVERRIDE { if (b_framed) NCursesPanel::boldframe(title,btitle); else OnError(E_SYSTEM_ERROR); } inline void label(const char *topLabel, const char *bottomLabel) NCURSES_OVERRIDE { if (b_framed) NCursesPanel::label(topLabel,bottomLabel); else OnError(E_SYSTEM_ERROR); } // ----- // Hooks // ----- // Called after the form gets repositioned in its window. // This is especially true if the form is posted. virtual void On_Form_Init(); // Called before the form gets repositioned in its window. // This is especially true if the form is unposted. virtual void On_Form_Termination(); // Called after the field became the current field virtual void On_Field_Init(NCursesFormField& field); // Called before this field is left as current field. virtual void On_Field_Termination(NCursesFormField& field); // Calculate required window size for the form. void scale(int& rows, int& ncols) const { OnError(::scale_form(form,&rows,&ncols)); } // Retrieve number of fields in the form. int count() const { return ::field_count(form); } // Make the page the current page of the form. void set_page(int pageNum) { OnError(::set_form_page(form, pageNum)); } // Retrieve current page number int page() const { return ::form_page(form); } // Switch on the forms options inline void options_on (Form_Options opts) { OnError (::form_opts_on (form, opts)); } // Switch off the forms options inline void options_off (Form_Options opts) { OnError (::form_opts_off (form, opts)); } // Retrieve the forms options inline Form_Options options () const { return ::form_opts (form); } // Set the forms options inline void set_options (Form_Options opts) { OnError (::set_form_opts (form, opts)); } // Are there more data in the current field after the data shown inline bool data_ahead() const { return ::data_ahead(form); } // Are there more data in the current field before the data shown inline bool data_behind() const { return ::data_behind(form); } // Position the cursor to the current field inline void position_cursor () { OnError (::pos_form_cursor (form)); } // Set the current field inline void set_current(NCursesFormField& F) { OnError (::set_current_field(form, F.field)); } // Provide a default key virtualization. Translate the keyboard // code c into a form request code. // The default implementation provides a hopefully straightforward // mapping for the most common keystrokes and form requests. virtual int virtualize(int c); // Operators inline NCursesFormField* operator[](int i) const { if ( (i < 0) || (i >= ::field_count (form)) ) OnError (E_BAD_ARGUMENT); return my_fields[i]; } // Perform the menu's operation // Return the field where you left the form. virtual NCursesFormField* operator()(void); // Exception handlers. The default is a Beep. virtual void On_Request_Denied(int c) const; virtual void On_Invalid_Field(int c) const; virtual void On_Unknown_Command(int c) const; }; // // ------------------------------------------------------------------------- // This is the typical C++ typesafe way to allow to attach // user data to a field of a form. Its assumed that the user // data belongs to some class T. Use T as template argument // to create a UserField. // ------------------------------------------------------------------------- template<class T> class NCURSES_CXX_IMPEXP NCursesUserField : public NCursesFormField { public: NCursesUserField (int rows, int ncols, int first_row = 0, int first_col = 0, const T* p_UserData = STATIC_CAST(T*)(0), int offscreen_rows = 0, int additional_buffers = 0) : NCursesFormField (rows, ncols, first_row, first_col, offscreen_rows, additional_buffers) { if (field) OnError(::set_field_userptr(field, STATIC_CAST(void *)(p_UserData))); } virtual ~NCursesUserField() THROWS(NCursesException) {}; inline const T* UserData (void) const { return reinterpret_cast<const T*>(::field_userptr (field)); } inline virtual void setUserData(const T* p_UserData) { if (field) OnError (::set_field_userptr (field, STATIC_CAST(void *)(p_UserData))); } }; // // ------------------------------------------------------------------------- // The same mechanism is used to attach user data to a form // ------------------------------------------------------------------------- // template<class T> class NCURSES_CXX_IMPEXP NCursesUserForm : public NCursesForm { protected: // 'Internal' constructor, builds an object without association to a // field array. NCursesUserForm( int nlines, int ncols, int begin_y = 0, int begin_x = 0, const T* p_UserData = STATIC_CAST(T*)(0)) : NCursesForm(nlines,ncols,begin_y,begin_x) { if (form) set_user (const_cast<void *>(reinterpret_cast<const void*> (p_UserData))); } public: NCursesUserForm (NCursesFormField* Fields[], const T* p_UserData = STATIC_CAST(T*)(0), bool with_frame=FALSE, bool autoDelete_Fields=FALSE) : NCursesForm (Fields, with_frame, autoDelete_Fields) { if (form) set_user (const_cast<void *>(reinterpret_cast<const void*>(p_UserData))); }; NCursesUserForm (NCursesFormField* Fields[], int nlines, int ncols, int begin_y = 0, int begin_x = 0, const T* p_UserData = STATIC_CAST(T*)(0), bool with_frame=FALSE, bool autoDelete_Fields=FALSE) : NCursesForm (Fields, nlines, ncols, begin_y, begin_x, with_frame, autoDelete_Fields) { if (form) set_user (const_cast<void *>(reinterpret_cast<const void*> (p_UserData))); }; virtual ~NCursesUserForm() THROWS(NCursesException) { }; inline T* UserData (void) { return reinterpret_cast<T*>(get_user ()); }; inline virtual void setUserData (const T* p_UserData) { if (form) set_user (const_cast<void *>(reinterpret_cast<const void*>(p_UserData))); } }; // // ------------------------------------------------------------------------- // Builtin Fieldtypes // ------------------------------------------------------------------------- // class NCURSES_CXX_IMPEXP Alpha_Field : public NCursesFieldType { private: int min_field_width; void set(NCursesFormField& f) NCURSES_OVERRIDE { OnError(::set_field_type(f.get_field(),fieldtype,min_field_width)); } public: explicit Alpha_Field(int width) : NCursesFieldType(TYPE_ALPHA), min_field_width(width) { } }; class NCURSES_CXX_IMPEXP Alphanumeric_Field : public NCursesFieldType { private: int min_field_width; void set(NCursesFormField& f) NCURSES_OVERRIDE { OnError(::set_field_type(f.get_field(),fieldtype,min_field_width)); } public: explicit Alphanumeric_Field(int width) : NCursesFieldType(TYPE_ALNUM), min_field_width(width) { } }; class NCURSES_CXX_IMPEXP Integer_Field : public NCursesFieldType { private: int precision; long lower_limit, upper_limit; void set(NCursesFormField& f) NCURSES_OVERRIDE { OnError(::set_field_type(f.get_field(),fieldtype, precision,lower_limit,upper_limit)); } public: Integer_Field(int prec, long low=0L, long high=0L) : NCursesFieldType(TYPE_INTEGER), precision(prec), lower_limit(low), upper_limit(high) { } }; class NCURSES_CXX_IMPEXP Numeric_Field : public NCursesFieldType { private: int precision; double lower_limit, upper_limit; void set(NCursesFormField& f) NCURSES_OVERRIDE { OnError(::set_field_type(f.get_field(),fieldtype, precision,lower_limit,upper_limit)); } public: Numeric_Field(int prec, double low=0.0, double high=0.0) : NCursesFieldType(TYPE_NUMERIC), precision(prec), lower_limit(low), upper_limit(high) { } }; class NCURSES_CXX_IMPEXP Regular_Expression_Field : public NCursesFieldType { private: char* regex; void set(NCursesFormField& f) NCURSES_OVERRIDE { OnError(::set_field_type(f.get_field(),fieldtype,regex)); } void copy_regex(const char *source) { regex = new char[1 + ::strlen(source)]; (::strcpy)(regex, source); } public: explicit Regular_Expression_Field(const char *expr) : NCursesFieldType(TYPE_REGEXP), regex(NULL) { copy_regex(expr); } Regular_Expression_Field& operator=(const Regular_Expression_Field& rhs) { if (this != &rhs) { *this = rhs; copy_regex(rhs.regex); NCursesFieldType::operator=(rhs); } return *this; } Regular_Expression_Field(const Regular_Expression_Field& rhs) : NCursesFieldType(rhs), regex(NULL) { copy_regex(rhs.regex); } ~Regular_Expression_Field() { delete[] regex; } }; class NCURSES_CXX_IMPEXP Enumeration_Field : public NCursesFieldType { private: const char** list; int case_sensitive; int non_unique_matches; void set(NCursesFormField& f) NCURSES_OVERRIDE { OnError(::set_field_type(f.get_field(),fieldtype, list,case_sensitive,non_unique_matches)); } public: Enumeration_Field(const char* enums[], bool case_sens=FALSE, bool non_unique=FALSE) : NCursesFieldType(TYPE_ENUM), list(enums), case_sensitive(case_sens ? -1 : 0), non_unique_matches(non_unique ? -1 : 0) { } Enumeration_Field& operator=(const Enumeration_Field& rhs) { if (this != &rhs) { *this = rhs; NCursesFieldType::operator=(rhs); } return *this; } Enumeration_Field(const Enumeration_Field& rhs) : NCursesFieldType(rhs), list(rhs.list), case_sensitive(rhs.case_sensitive), non_unique_matches(rhs.non_unique_matches) { } }; class NCURSES_CXX_IMPEXP IPV4_Address_Field : public NCursesFieldType { private: void set(NCursesFormField& f) NCURSES_OVERRIDE { OnError(::set_field_type(f.get_field(),fieldtype)); } public: IPV4_Address_Field() : NCursesFieldType(TYPE_IPV4) { } }; extern "C" { bool _nc_xx_fld_fcheck(FIELD *, const void*); bool _nc_xx_fld_ccheck(int c, const void *); void* _nc_xx_fld_makearg(va_list*); } // // ------------------------------------------------------------------------- // Abstract base class for User-Defined Fieldtypes // ------------------------------------------------------------------------- // class NCURSES_CXX_IMPEXP UserDefinedFieldType : public NCursesFieldType { friend class UDF_Init; // Internal helper to set up statics private: // For all C++ defined fieldtypes we need only one generic lowlevel // FIELDTYPE* element. static FIELDTYPE* generic_fieldtype; protected: // This are the functions required by the low level libforms functions // to construct a fieldtype. friend bool _nc_xx_fld_fcheck(FIELD *, const void*); friend bool _nc_xx_fld_ccheck(int c, const void *); friend void* _nc_xx_fld_makearg(va_list*); void set(NCursesFormField& f) NCURSES_OVERRIDE { OnError(::set_field_type(f.get_field(),fieldtype,&f)); } protected: // Redefine this function to do a field validation. The argument // is a reference to the field you should validate. virtual bool field_check(NCursesFormField& f) = 0; // Redefine this function to do a character validation. The argument // is the character to be validated. virtual bool char_check (int c) = 0; public: UserDefinedFieldType(); }; extern "C" { bool _nc_xx_next_choice(FIELD*, const void *); bool _nc_xx_prev_choice(FIELD*, const void *); } // // ------------------------------------------------------------------------- // Abstract base class for User-Defined Fieldtypes with Choice functions // ------------------------------------------------------------------------- // class NCURSES_CXX_IMPEXP UserDefinedFieldType_With_Choice : public UserDefinedFieldType { friend class UDF_Init; // Internal helper to set up statics private: // For all C++ defined fieldtypes with choice functions we need only one // generic lowlevel FIELDTYPE* element. static FIELDTYPE* generic_fieldtype_with_choice; // This are the functions required by the low level libforms functions // to construct a fieldtype with choice functions. friend bool _nc_xx_next_choice(FIELD*, const void *); friend bool _nc_xx_prev_choice(FIELD*, const void *); protected: // Redefine this function to do the retrieval of the next choice value. // The argument is a reference to the field tobe examined. virtual bool next (NCursesFormField& f) = 0; // Redefine this function to do the retrieval of the previous choice value. // The argument is a reference to the field tobe examined. virtual bool previous(NCursesFormField& f) = 0; public: UserDefinedFieldType_With_Choice(); }; #endif /* NCURSES_CURSESF_H_incl */