improv(defaults): backspace instead of tab

A comfortable key with no mnemonic value is a perfectly acceptable
default, but an antimnemonic is less so.

Closes #165

Author: ggandor

README.md

@@ -31,15 +31,15 @@ need to do that.
   those are guaranteed non-conflicting letters, disappearing on the next
   keypress.
 - Else: type the label character. If there are more matches than available
-  labels, you can switch between groups, using `<space>` and `<tab>`.
+  labels, you can switch between groups, using `<space>` and `<backspace>`.
 
 Character pairs give you full coverage of the screen:
 
 - `s{char}<space>` jumps to a character before the end of the line.
 - `s<space><space>` jumps to any EOL position, including empty lines.
 
 At any stage, `<enter>` consistently jumps to the next available target
-(`<tab>` steps back):
+(`<backspace>` steps back):
 
 - `s<enter>...` repeats the previous search.
 - `s{char}<enter>...` can be used as a multiline substitute for `fFtT` motions.
@@ -144,10 +144,6 @@ See `:h leap-custom-mappings` for more.
 -- the default whitespace group.
 require('leap').opts.equivalence_classes = { ' \t\r\n', '([{', ')]}', '\'"`' }
 
--- Override some old defaults - use backspace instead of tab (see issue #165).
-require('leap').opts.special_keys.prev_target = '<backspace>'
-require('leap').opts.special_keys.prev_group = '<backspace>'
-
 -- Use the traversal keys to repeat the previous motion without explicitly
 -- invoking Leap.
 require('leap.user').set_repeat_keys('<enter>', '<backspace>')

doc/leap.txt

@@ -46,7 +46,7 @@ USAGE                                                               *leap-usage*
   keypress (|leap.opts.safe_labels|). *leap-autojump*
 
 • Else: type the label character. If there are more matches than available
-  labels, you can switch between groups, using `<space>` and `<tab>`.
+  labels, you can switch between groups, using `<space>` and `<backspace>`.
 
 If a |language-mapping| ('keymap') is active, Leap waits for keymapped
 sequences as needed and searches for the keymapped result as expected.
@@ -77,7 +77,7 @@ be used as a multiline substitute for `fFtT` motions.
 
 If the search is directional, `<enter>` can also traverse through the rest of
 the targets, moving on to the next one on each subsequent keypress
-(`s<enter><enter>...`). If you overshoot, `<tab>`
+(`s<enter><enter>...`). If you overshoot, `<backspace>`
 (|leap.opts.special_keys.prev_target|) can revert the jump(s).
 
 There is a convenience function in the `user` module to set keys that behave
@@ -316,9 +316,9 @@ right-hand keys to get a better balance for the whole sequence on average.
 `special_keys =` >
     {
       next_target = '<enter>',
-      prev_target = '<tab>',
+      prev_target = { '<backspace>', '<tab>' },
       next_group = '<space>',
-      prev_group = '<tab>',
+      prev_group = { '<backspace>', '<tab>' },
     }
 
 Meta-keys accepted at runtime. Each one can be a table too, with a list of

fnl/leap/opts.fnl

@@ -14,9 +14,9 @@
                              "J" "K" "L" "H" "O" "D" "W" "E" "I" "M" "B" "U"
                              "Y" "V" "R" "G" "T" "A" "Q" "P" "C" "X" "Z" "?"]
                     :special_keys {:next_target "<enter>"
-                                   :prev_target "<tab>"
+                                   :prev_target ["<backspace>" "<tab>"]
                                    :next_group "<space>"
-                                   :prev_group "<tab>"}}
+                                   :prev_group ["<backspace>" "<tab>"]}}
           ; Will be updated by `leap` on invocation.
           :current_call {}})