Added intra-field navigation sample

[Damien Ruscoe]

I have created a sample application to demonstrate navigation within a
field. This maybe suitable for ncurses_programs as well as being added
to the documentation (
http://invisible-island.net/ncurses/NCURSES-Programming-HOWTO.html#INTRAFIELDNAVREQ
) as a sample.

Critique wanted please :)

Damien



--- new    2017-01-01 21:44:33.417336100 +0000
+++ form_field_navigation.c    2017-01-01 21:50:13.564662100 +0000
@@ -0,0 +1,107 @@
+#include <form.h>
+
+int main()
+{    FIELD *fields[2];
+    FORM  *my_form;
+    int ch;
+
+    /* Initialize curses */
+    initscr();
+    cbreak();
+    noecho();
+    keypad(stdscr, TRUE);
+
+    int rows = 10, columns = 25, max = 200;
+    FIELD *field = new_field(rows, columns, 4, 28, 0, 0);
+
+    /* Set field options */
+    set_field_back(field, A_UNDERLINE);     /* Print a line for the
option     */
+    field_opts_off(field, O_AUTOSKIP);      /* Don't go to next field
when this */
+                                            /* Field is filled up         */
+    field_opts_off(field, O_STATIC);        /* Allow the field to be
resizable */
+    set_max_field(field, max);
+
+    char *sample_buffer = "There's a line I have that our family was
designed more " \
+                          "for public than for private. But there are
definitely " \
+                          "some things that are only mine. I am
someone who dreams " \
+                          "at night, and you don't know what I'm dreaming.";
+    set_field_buffer(field, 0, sample_buffer);
+
+    /* Initialize the fields */
+    fields[0] = field;
+    fields[1] = NULL;
+
+    /* Create the form and post it */
+    my_form = new_form(fields);
+    post_form(my_form);
+    refresh();
+
+    mvprintw(4,  10, "Multi-line Text:");
+    refresh();
+
+    /* Loop through to get user requests */
+    while((ch = getch()) != KEY_F(1))
+    {    switch(ch)
+        {
+            case KEY_RIGHT:
+            case 'l':
+                form_driver(my_form, REQ_NEXT_CHAR);
+                break;
+            case KEY_LEFT:
+            case 'h':
+                form_driver(my_form, REQ_PREV_CHAR);
+                break;
+            case KEY_DOWN:
+            case 'j':
+                form_driver(my_form, REQ_DOWN_CHAR);
+                break;
+            case KEY_UP:
+            case 'k':
+                form_driver(my_form, REQ_UP_CHAR);
+                break;
+            case KEY_HOME:
+            case '0':
+                form_driver(my_form, REQ_BEG_LINE);
+                break;
+            case KEY_END:
+            case '$':
+                form_driver(my_form, REQ_END_LINE);
+                break;
+            case 'L':
+                form_driver(my_form, REQ_RIGHT_CHAR);
+                break;
+            case 'H':
+                form_driver(my_form, REQ_LEFT_CHAR);
+                break;
+            case 'J':
+                form_driver(my_form, REQ_NEXT_LINE);
+                break;
+            case 'K':
+                form_driver(my_form, REQ_PREV_LINE);
+                break;
+            case 'w':
+                form_driver(my_form, REQ_NEXT_WORD);
+                break;
+            case 'b':
+                form_driver(my_form, REQ_PREV_WORD);
+                break;
+            case 'g':
+                form_driver(my_form, REQ_BEG_FIELD);
+                break;
+            case 'G':
+                form_driver(my_form, REQ_END_FIELD);
+                break;
+
+            default:
+                break;
+        }
+    }
+
+    /* Un post form and free the memory */
+    unpost_form(my_form);
+    free_form(my_form);
+    free_field(fields[0]);
+
+    endwin();
+    return 0;
+}