Support fallback strategies by setting array in config

Makefile

@@ -9,6 +9,7 @@ SRC_FILES := \
 	$(SRC_DIR)/highlight.zsh \
 	$(SRC_DIR)/widgets.zsh \
 	$(SRC_DIR)/strategies/*.zsh \
+	$(SRC_DIR)/fetch.zsh \
 	$(SRC_DIR)/async.zsh \
 	$(SRC_DIR)/start.zsh
 

README.md

@@ -2,7 +2,7 @@
 
 _[Fish](http://fishshell.com/)-like fast/unobtrusive autosuggestions for zsh._
 
-It suggests commands as you type, based on command history.
+It suggests commands as you type.
 
 Requirements: Zsh v4.3.11 or later
 
@@ -39,10 +39,13 @@ Set `ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE` to configure the style that the suggestion
 
 ### Suggestion Strategy
 
-Set `ZSH_AUTOSUGGEST_STRATEGY` to choose the strategy for generating suggestions. There are currently two to choose from:
+`ZSH_AUTOSUGGEST_STRATEGY` is an array that specifies how suggestions should be generated. The strategies in the array are tried successively until a suggestion is found. There are currently three built-in strategies to choose from:
 
-- `default`: Chooses the most recent match.
-- `match_prev_cmd`: Chooses the most recent match whose preceding history item matches the most recently executed command ([more info](src/strategies/match_prev_cmd.zsh)). Note that this strategy won't work as expected with ZSH options that don't preserve the history order such as `HIST_IGNORE_ALL_DUPS` or `HIST_EXPIRE_DUPS_FIRST`.
+- `history`: Chooses the most recent match from history.
+- `match_prev_cmd`: Like `history`, but chooses the most recent match whose preceding history item matches the most recently executed command ([more info](src/strategies/match_prev_cmd.zsh)). Note that this strategy won't work as expected with ZSH options that don't preserve the history order such as `HIST_IGNORE_ALL_DUPS` or `HIST_EXPIRE_DUPS_FIRST`.
+- `completion`: (experimental) Chooses a suggestion based on what tab-completion would suggest.
+
+For example, setting `ZSH_AUTOSUGGEST_STRATEGY=(history completion)` will first try to find a suggestion from your history, but, if it can't find a match, will find a suggestion from the completion engine.
 
 
 ### Widget Mapping

spec/integrations/zle_input_stack_spec.rb

@@ -2,7 +2,7 @@ describe 'using `zle -U`' do
   let(:before_sourcing) do
     -> do
       session.
-        run_command('_zsh_autosuggest_strategy_test() { sleep 1; _zsh_autosuggest_strategy_default "$1" }').
+        run_command('_zsh_autosuggest_strategy_test() { sleep 1; _zsh_autosuggest_strategy_history "$1" }').
         run_command('foo() { zle -U - "echo hello" }; zle -N foo; bindkey ^B foo')
     end
   end

spec/options/strategy_spec.rb

@@ -1,20 +1,45 @@
 describe 'a suggestion for a given prefix' do
-  let(:options) { ['_zsh_autosuggest_strategy_default() { suggestion="echo foo" }'] }
+  let(:history_strategy) { '_zsh_autosuggest_strategy_history() { suggestion="history" }' }
+  let(:foobar_strategy) { '_zsh_autosuggest_strategy_foobar() { [[ "foobar baz" = $1* ]] && suggestion="foobar baz" }' }
+  let(:foobaz_strategy) { '_zsh_autosuggest_strategy_foobaz() { [[ "foobaz bar" = $1* ]] && suggestion="foobaz bar" }' }
 
-  it 'is determined by calling the default strategy function' do
-    session.send_string('e')
-    wait_for { session.content }.to eq('echo foo')
+  let(:options) { [ history_strategy ] }
+
+  it 'by default is determined by calling the `history` strategy function' do
+    session.send_string('h')
+    wait_for { session.content }.to eq('history')
+  end
+
+  context 'when ZSH_AUTOSUGGEST_STRATEGY is set to an array' do
+    let(:options) { [
+      foobar_strategy,
+      foobaz_strategy,
+      'ZSH_AUTOSUGGEST_STRATEGY=(foobar foobaz)'
+    ] }
+
+    it 'is determined by the first strategy function to return a suggestion' do
+      session.send_string('foo')
+      wait_for { session.content }.to eq('foobar baz')
+
+      session.send_string('baz')
+      wait_for { session.content }.to eq('foobaz bar')
+    end
   end
 
-  context 'when ZSH_AUTOSUGGEST_STRATEGY is set' do
+  context 'when ZSH_AUTOSUGGEST_STRATEGY is set to a string' do
     let(:options) { [
-      '_zsh_autosuggest_strategy_custom() { suggestion="echo foo" }',
-      'ZSH_AUTOSUGGEST_STRATEGY=custom'
+      foobar_strategy,
+      foobaz_strategy,
+      'ZSH_AUTOSUGGEST_STRATEGY="foobar foobaz"'
     ] }
 
-    it 'is determined by calling the specified strategy function' do
-      session.send_string('e')
-      wait_for { session.content }.to eq('echo foo')
+    it 'is determined by the first strategy function to return a suggestion' do
+      session.send_string('foo')
+      wait_for { session.content }.to eq('foobar baz')
+
+      session.send_string('baz')
+      wait_for { session.content }.to eq('foobaz bar')
     end
   end
 end
+

src/async.zsh

@@ -35,7 +35,7 @@ _zsh_autosuggest_async_server() {
 		# Run suggestion search in the background
 		(
 			local suggestion
-			_zsh_autosuggest_strategy_$ZSH_AUTOSUGGEST_STRATEGY "$query"
+			_zsh_autosuggest_fetch_suggestion "$query"
 			echo -n -E "$suggestion"$'\0'
 		) &
 

src/config.zsh

@@ -11,7 +11,9 @@ ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE='fg=8'
 # Prefix to use when saving original versions of bound widgets
 ZSH_AUTOSUGGEST_ORIGINAL_WIDGET_PREFIX=autosuggest-orig-
 
-ZSH_AUTOSUGGEST_STRATEGY=default
+# Strategies to use to fetch a suggestion
+# Will try each strategy in order until a suggestion is returned
+ZSH_AUTOSUGGEST_STRATEGY=(history)
 
 # Widgets that clear the suggestion
 ZSH_AUTOSUGGEST_CLEAR_WIDGETS=(

src/fetch.zsh

@@ -0,0 +1,23 @@
+
+#--------------------------------------------------------------------#
+# Fetch Suggestion                                                   #
+#--------------------------------------------------------------------#
+# Loops through all specified strategies and returns a suggestion
+# from the first strategy to provide one.
+#
+
+_zsh_autosuggest_fetch_suggestion() {
+	typeset -g suggestion
+	local -a strategies
+
+	# Ensure we are working with an array
+	strategies=(${=ZSH_AUTOSUGGEST_STRATEGY})
+
+	for strategy in $strategies; do
+		# Try to get a suggestion from this strategy
+		_zsh_autosuggest_strategy_$strategy "$1"
+
+		# Break once we've found a suggestion
+		[[ -n "$suggestion" ]] && break
+	done
+}

src/strategies/default.zsh

@@ -1,17 +0,0 @@
-
-#--------------------------------------------------------------------#
-# Default Suggestion Strategy                                        #
-#--------------------------------------------------------------------#
-# Will provide suggestions from your history. If no matches are found
-# in history, will provide a suggestion from the completion engine.
-#
-
-_zsh_autosuggest_strategy_default() {
-	typeset -g suggestion
-
-	_zsh_autosuggest_strategy_history "$1"
-
-	if [[ -z "$suggestion" ]]; then
-		_zsh_autosuggest_strategy_completion "$1"
-	fi
-}

src/widgets.zsh

@@ -97,7 +97,7 @@ _zsh_autosuggest_fetch() {
 		_zsh_autosuggest_async_request "$BUFFER"
 	else
 		local suggestion
-		_zsh_autosuggest_strategy_$ZSH_AUTOSUGGEST_STRATEGY "$BUFFER"
+		_zsh_autosuggest_fetch_suggestion "$BUFFER"
 		_zsh_autosuggest_suggest "$suggestion"
 	fi
 }

zsh-autosuggestions.zsh

@@ -47,7 +47,9 @@ ZSH_AUTOSUGGEST_HIGHLIGHT_STYLE='fg=8'
 # Prefix to use when saving original versions of bound widgets
 ZSH_AUTOSUGGEST_ORIGINAL_WIDGET_PREFIX=autosuggest-orig-
 
-ZSH_AUTOSUGGEST_STRATEGY=default
+# Strategies to use to fetch a suggestion
+# Will try each strategy in order until a suggestion is returned
+ZSH_AUTOSUGGEST_STRATEGY=(history)
 
 # Widgets that clear the suggestion
 ZSH_AUTOSUGGEST_CLEAR_WIDGETS=(
@@ -381,7 +383,7 @@ _zsh_autosuggest_fetch() {
 		_zsh_autosuggest_async_request "$BUFFER"
 	else
 		local suggestion
-		_zsh_autosuggest_strategy_$ZSH_AUTOSUGGEST_STRATEGY "$BUFFER"
+		_zsh_autosuggest_fetch_suggestion "$BUFFER"
 		_zsh_autosuggest_suggest "$suggestion"
 	fi
 }
@@ -619,23 +621,6 @@ _zsh_autosuggest_strategy_completion() {
 	suggestion="${1[1,$i-1]}$completion"
 }
 
-#--------------------------------------------------------------------#
-# Default Suggestion Strategy                                        #
-#--------------------------------------------------------------------#
-# Will provide suggestions from your history. If no matches are found
-# in history, will provide a suggestion from the completion engine.
-#
-
-_zsh_autosuggest_strategy_default() {
-	typeset -g suggestion
-
-	_zsh_autosuggest_strategy_history "$1"
-
-	if [[ -z "$suggestion" ]]; then
-		_zsh_autosuggest_strategy_completion "$1"
-	fi
-}
-
 #--------------------------------------------------------------------#
 # History Suggestion Strategy                                        #
 #--------------------------------------------------------------------#
@@ -720,6 +705,29 @@ _zsh_autosuggest_strategy_match_prev_cmd() {
 	typeset -g suggestion="$history[$histkey]"
 }
 
+#--------------------------------------------------------------------#
+# Fetch Suggestion                                                   #
+#--------------------------------------------------------------------#
+# Loops through all specified strategies and returns a suggestion
+# from the first strategy to provide one.
+#
+
+_zsh_autosuggest_fetch_suggestion() {
+	typeset -g suggestion
+	local -a strategies
+
+	# Ensure we are working with an array
+	strategies=(${=ZSH_AUTOSUGGEST_STRATEGY})
+
+	for strategy in $strategies; do
+		# Try to get a suggestion from this strategy
+		_zsh_autosuggest_strategy_$strategy "$1"
+
+		# Break once we've found a suggestion
+		[[ -n "$suggestion" ]] && break
+	done
+}
+
 #--------------------------------------------------------------------#
 # Async                                                              #
 #--------------------------------------------------------------------#
@@ -756,7 +764,7 @@ _zsh_autosuggest_async_server() {
 		# Run suggestion search in the background
 		(
 			local suggestion
-			_zsh_autosuggest_strategy_$ZSH_AUTOSUGGEST_STRATEGY "$query"
+			_zsh_autosuggest_fetch_suggestion "$query"
 			echo -n -E "$suggestion"$'\0'
 		) &