From 2a511a65767aaae2a2d4e5307f1b3e8e7acee077 Mon Sep 17 00:00:00 2001
From: Andrew Whatson <whatson@gmail.com>
Date: Wed, 29 May 2019 00:01:45 +1000
Subject: [PATCH 1/2] Add +prescient option for :completion ivy

This provides an alternative backend for filtering and sorting ivy
searches. Uses prescient instead of flx for fuzzy completion when both
+prescient and +fuzzy are selected.
---
 modules/completion/company/config.el |  1 +
 modules/completion/ivy/README.org    |  4 +++-
 modules/completion/ivy/config.el     | 30 +++++++++++++++++++++++++++-
 modules/completion/ivy/packages.el   |  6 ++++--
 4 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/modules/completion/company/config.el b/modules/completion/company/config.el
index 3e582e242..226b64ee9 100644
--- a/modules/completion/company/config.el
+++ b/modules/completion/company/config.el
@@ -47,6 +47,7 @@
 (def-package! company-prescient
   :hook (company-mode . company-prescient-mode)
   :config
+  ;; NOTE prescient config duplicated with `ivy'
   (setq prescient-save-file (concat doom-cache-dir "prescient-save.el"))
   (prescient-persist-mode +1))
 
diff --git a/modules/completion/ivy/README.org b/modules/completion/ivy/README.org
index 9feb2af27..ab34d25b5 100644
--- a/modules/completion/ivy/README.org
+++ b/modules/completion/ivy/README.org
@@ -37,7 +37,8 @@ lighter, simpler and faster in many cases.
 #+end_quote
 
 ** Module Flags
-+ =+fuzzy= Enables the fuzzy method for ivy searches.
++ =+fuzzy= Enables fuzzy completion for Ivy searches.
++ =+prescient= Enables prescient filtering and sorting for Ivy searches.
 + =+childframe= Causes Ivy to display in a floating child frame, above Emacs.
   *This requires GUI Emacs 26.1+*
 + =+icons= Enables file icons for switch-{buffer,project}/find-file counsel
@@ -53,6 +54,7 @@ lighter, simpler and faster in many cases.
 + [[https://github.com/mhayashi1120/Emacs-wgrep][wgrep]]
 + [[https://github.com/DarwinAwardWinner/amx][amx]]
 + [[https://github.com/lewang/flx][flx]]* (=+fuzzy=)
++ [[https://github.com/raxod502/prescient.el][prescient]]* (=+prescient=)
 + [[https://github.com/tumashu/ivy-posframe][ivy-posframe]]* (=+childframe=)
 + [[https://github.com/asok/all-the-icons-ivy][all-the-icons-ivy]]* (=+icons=)
 
diff --git a/modules/completion/ivy/config.el b/modules/completion/ivy/config.el
index 032943a3d..677c5a77e 100644
--- a/modules/completion/ivy/config.el
+++ b/modules/completion/ivy/config.el
@@ -294,7 +294,8 @@ immediately runs it on the current candidate (ending the ivy session)."
 
 
 (def-package! flx
-  :when (featurep! +fuzzy)
+  :when (and (featurep! +fuzzy)
+             (not (featurep! +prescient)))
   :defer t  ; is loaded by ivy
   :init
   (setq ivy-re-builders-alist
@@ -307,6 +308,33 @@ immediately runs it on the current candidate (ending the ivy session)."
         ivy-initial-inputs-alist nil))
 
 
+(def-package! ivy-prescient
+  :hook (ivy-mode . ivy-prescient-mode)
+  :when (featurep! +prescient)
+  :init
+  (setq prescient-filter-method (if (featurep! +fuzzy)
+                                    '(literal regexp initialism fuzzy)
+                                  '(literal regexp initialism))
+        ivy-prescient-enable-filtering nil ;; we do this ourselves
+        ivy-initial-inputs-alist nil
+        ivy-re-builders-alist
+        '((counsel-ag . +ivy-prescient-non-fuzzy)
+          (counsel-rg . +ivy-prescient-non-fuzzy)
+          (counsel-grep . +ivy-prescient-non-fuzzy)
+          (swiper . +ivy-prescient-non-fuzzy)
+          (swiper-isearch . +ivy-prescient-non-fuzzy)
+          (t . ivy-prescient-re-builder)))
+
+  :config
+  (defun +ivy-prescient-non-fuzzy (str)
+    (let ((prescient-filter-method '(literal regexp)))
+      (ivy-prescient-re-builder str)))
+
+  ;; NOTE prescient config duplicated with `company'
+  (setq prescient-save-file (concat doom-cache-dir "prescient-save.el"))
+  (prescient-persist-mode +1))
+
+
 ;; Used by `counsel-M-x'
 (setq amx-save-file (concat doom-cache-dir "amx-items"))
 
diff --git a/modules/completion/ivy/packages.el b/modules/completion/ivy/packages.el
index a61af857e..e804e9ead 100644
--- a/modules/completion/ivy/packages.el
+++ b/modules/completion/ivy/packages.el
@@ -10,8 +10,10 @@
 (package! ivy-rich)
 (package! wgrep)
 
-(when (featurep! +fuzzy)
-  (package! flx))
+(if (featurep! +prescient)
+    (package! ivy-prescient)
+  (when (featurep! +fuzzy)
+    (package! flx)))
 
 (when (and EMACS26+ (featurep! +childframe))
   (package! ivy-posframe))

From 9f4352006f7a07ad29cdcb1bd613cff5cddbb2ba Mon Sep 17 00:00:00 2001
From: Andrew Whatson <whatson@gmail.com>
Date: Wed, 29 May 2019 00:10:21 +1000
Subject: [PATCH 2/2] Increase ivy-flx-limit for improved fuzzy behavior

The default setting of 200 is too low for common use-cases like
`describe-function`, `describe-variable` or `counsel-projectile`.

This has a performance impact, but it's barely noticeable on a fast
machine. If performance is not acceptable, set `ivy-flx-limit` lower or
consider disabling the `+fuzzy` feature entirely.
---
 modules/completion/ivy/config.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/modules/completion/ivy/config.el b/modules/completion/ivy/config.el
index 677c5a77e..ce3e192f6 100644
--- a/modules/completion/ivy/config.el
+++ b/modules/completion/ivy/config.el
@@ -305,7 +305,8 @@ immediately runs it on the current candidate (ending the ivy session)."
           (swiper . ivy--regex-plus)
           (swiper-isearch . ivy--regex-plus)
           (t . ivy--regex-fuzzy))
-        ivy-initial-inputs-alist nil))
+        ivy-initial-inputs-alist nil
+        ivy-flx-limit 10000))
 
 
 (def-package! ivy-prescient