some more logs

The previous commit was super useful. The links are not actually being
lost when I exit pensieve. Instead, they're somehow not being set in
some code path that I haven't tracked down yet.

The important thing is, I've been missing things because I wasn't
running it from a terminal. prints (that the links are empty) were
disappearing that would have helped diagnose it. Lesson learned: always
send error prints to the log as well. At least there we have a hope of
spotting them.

Once we start emitting prints to the log, also include the function
name. On errors so far we've not bothered because the default LOVE error
handler shows the stack trace. However the logs don't record the stack,
and we might go looking at them long after the app crashes. The print
doesn't need function names, but the log does so we'll just
lowest-common-denominator both.

commands.lua

@@ -235,7 +235,7 @@ function keychord_press_on_command_palette(chord, key)
     -- clean up some columns if possible
     if Cursor_pane.col < 45 then
       while #Surface > 50 do
-        print('dropping '..Surface[#Surface].name)
+        print_and_log('keychord_press (palette) return: dropping '..Surface[#Surface].name)
         love.filesystem.append(Overflow_file, os.date('%Y-%m-%d %H:%M:%S ')..Surface[#Surface].name..'\n')
         table.remove(Surface)
       end
@@ -543,7 +543,7 @@ function run_command(cmd, args)
   elseif cmd == 'cursor to previous word' then
     command.send_key_to_current_pane('M-left', 'left')
   else
-    print(('not implemented yet: %s'):format(function_name))
+    print_and_log(('run_command: not implemented yet: %s'):format(function_name))
   end
 end
 
@@ -591,7 +591,7 @@ function create_column(column_name)
     -- a column on the surface, but there's no file backing it. You can still
     -- edit it later and create a file for it. But if you just quit, the
     -- column will silently disappear after restart.
-    print('file not found: '..column_name)
+    print_and_log('create_column: file not found: '..column_name)
   else
     -- delegate to one of various helpers based on the column name
     local column = {name=column_name}
@@ -1211,7 +1211,7 @@ function command.rename_link(args)
   else
     target = Links[pane.id][from]
   end
-  print('renaming link', from, 'of', pane, 'to', to)
+  print_and_log('renaming link', from, 'of', pane, 'to', to)
   if Links[pane.id][to] and not array.find(Non_unique_edges, to) then
     add_error(('%s already has a %s note'):format(pane.id, to))
     return
@@ -1248,7 +1248,7 @@ function command.clear_link(rel)
   if type(Links[pane.id][rel]) == 'table' then
     add_error(('%s is a non-unique link; clearing all such links'):format(rel))
   end
-  print(('clearing link %s of %s (used to point to %s)'):format(rel, pane.id, Links[pane.id][rel]))
+  print_and_log(('clearing link %s of %s (used to point to %s)'):format(rel, pane.id, Links[pane.id][rel]))
   Links[pane.id][rel] = nil
   schedule_save(pane)
   stop_editing(pane)
@@ -1586,7 +1586,7 @@ end
 function new_pane()
   local t = os.time()
   local id = os.date('%Y/%m/%d/%H-%M-%S', t)
-  print('creating directory '..Directory..dirname(id))
+  print_and_log('new_pane: creating directory '..Directory..dirname(id))
   local status = love.filesystem.createDirectory(Directory..dirname(id))
   assert(status)
   Links[id] = {}

errors.lua

@@ -1,5 +1,6 @@
 function add_error(err)
   print(err)
+  log(2, 'add_error: '..err)
   table.insert(Error_log.lines, {mode='text', data=err})
   table.insert(Error_log.line_cache, {})
   Current_error = err

file.lua

@@ -104,7 +104,7 @@ function load_drawing(infile_next_line)
     elseif shape.mode == 'deleted' then
       -- ignore
     else
-      print(shape.mode)
+      print_and_log('load_drawing: '..shape.mode)
       assert(false)
     end
     table.insert(drawing.shapes, shape)
@@ -139,7 +139,7 @@ function store_drawing(outfile, drawing)
     elseif shape.mode == 'deleted' then
       -- ignore
     else
-      print(shape.mode)
+      print_and_log('store_drawing: '..shape.mode)
       assert(false)
     end
   end
@@ -160,8 +160,7 @@ function save_links(id)
   local links_filename = Directory..id..'.json'
   log(2, 'save_links: '..id)
   if empty(Links[id]) then
-    log(2, 'save_links: no links; getting rid of .json if it exists')
-    print('no links; getting rid of .json if it exists')
+    print_and_log('save_links: no links; getting rid of .json if it exists')
     love.filesystem.remove(links_filename)
     return
   end
@@ -232,7 +231,7 @@ function load_drawing_from_array(iter, a, i)
     elseif shape.mode == 'deleted' then
       -- ignore
     else
-      print(shape.mode)
+      print_and_log('load_drawing_from_array: '..shape.mode)
       assert(false)
     end
     table.insert(drawing.shapes, shape)

run.lua

@@ -140,8 +140,8 @@ function run.initialize(arg)
   end
 
   love.window.setTitle('pensieve.love')
-  print('reading notes from '..love.filesystem.getSaveDirectory()..'/'..Directory)
-  print('put any notes there (and make frequent backups)')
+  print_and_log('reading notes from '..love.filesystem.getSaveDirectory()..'/'..Directory)
+  print_and_log('put any notes there (and make frequent backups)')
 
   if Settings.width then
     run.load_settings()
@@ -166,6 +166,11 @@ function run.initialize(arg)
   end
 end
 
+function print_and_log(s)
+  print(s)
+  log(3, s)
+end
+
 function run.load_settings()
   -- determine default dimensions and flags
   App.screen.width, App.screen.height, App.screen.flags = love.window.getMode()
@@ -261,7 +266,7 @@ function refresh_pane_height(pane)
       -- nothing
       y = y + Drawing.pixels(line.h, Display_settings.column_width) + Drawing_padding_height
     else
-      print(line.mode)
+      print_and_log('refresh_pane_height: '..line.mode)
       assert(false)
     end
   end
@@ -362,7 +367,7 @@ function run.draw()
       end
     end
   else
-    print(Display_settings.mode)
+    print_and_log('run.draw: '..Display_settings.mode)
     assert(false)
   end
   if Grab_pane then
@@ -639,7 +644,7 @@ function run.mouse_press(x,y, mouse_button)
       end
     end
   else
-    print(Display_settings.mode)
+    print_and_log('run.mouse_press: '..Display_settings.mode)
     assert(false)
   end
 end
@@ -753,7 +758,7 @@ function run.text_input(t)
       end
     end
   else
-    print(Display_settings.mode)
+    print_and_log('run.text_input: '..Display_settings.mode)
     assert(false)
   end
 end
@@ -825,7 +830,7 @@ function run.keychord_press(chord, key)
       keychord_press_in_maximize_mode(chord, key)
     end
   else
-    print(Display_settings.mode)
+    print_and_log('run.keychord_press: '..Display_settings.mode)
     assert(false)
   end
 end
@@ -1114,12 +1119,12 @@ end
 
 function keychord_press_in_maximize_mode(chord, key)
   if Cursor_pane.col < 1 then
-    print('no current note to edit')
+    print_and_log('keychord_press (maximized): no current note to edit')
     return
   end
   local pane = Surface[Cursor_pane.col][Cursor_pane.row]
   if pane == nil then
-    print('no current note to edit')
+    print_and_log('keychord_press (maximized): no current note to edit')
     return
   end
   if pane.editable then