Show a bool as true or false, and make the examples' flags bools

aup and Pure now have a bool (Pure 016): a view or column may be one.
vega_text writes it as true or false, as a string's interpolation does, so
every surface shows the same words: the CLI, the TUI's cells, speech and
the web surface's JSON (a value's text) and page. An app that wants other
words picks them with a conditional (if t.done { "done" } else { "" }).

The flags of the examples are bools: todo's done and urgent, today's done,
the stopwatch's running. vega.when takes the bool as it took the number.

bools checks a bool field and a bool column on the CLI, the TUI, speech
and the web surface: true and false, never 1 and 0.

1 files changed, 5 insertions, 2 deletions

diff --git a/surfaces/screen.c b/surfaces/screen.c
index f079bd5..51181a5 100644
--- a/surfaces/screen.c
+++ b/surfaces/screen.c
@@ -163,10 +163,13 @@ bool vega_text(PureApp *app, uint32_t view, size_t row, char out[VEGA_TEXT], siz
     ++evaluations;
     *length = 0;
     out[0] = 0;
-    if (m->view_type[view] == PURE_VIEW_NUM) {
+    if (m->view_type[view] == PURE_VIEW_NUM || m->view_type[view] == PURE_VIEW_BOOL) {
         double value;
         if (!(column ? pure_app_cell(app, view, row, &value) : pure_app_view(app, view, &value))) return false;
-        *length = pure_format_number(value, out);
+        if (m->view_type[view] == PURE_VIEW_BOOL) { /* a bool is written true or false, as a string shows it */
+            *length = value ? 4 : 5;
+            memcpy(out, value ? "true" : "false", *length);
+        } else *length = pure_format_number(value, out);
         out[*length] = 0;
         return true;
     }