From 31a156ec14f3414e34d3ba53e49dfd5b9db6589a Mon Sep 17 00:00:00 2001
From: be5invis <belleve@typeof.net>
Date: Sat, 21 Nov 2020 13:10:38 -0800
Subject: [PATCH] Add more alternative exclamation-related ligation sets
 (`exeqeq-alt-1`, `eqexeq-alt-1`, `eqexeq-dl-alt-1`) (#748).

---
 README.md                           |  3 +++
 changes/4.0.0.md                    |  1 +
 font-src/glyphs/symbol/ligation.ptl |  4 ++++
 font-src/otl/gsub-ligation.ptl      | 12 ++++++++++++
 params/ligation-set.toml            | 12 ++++++++++++
 5 files changed, 32 insertions(+)
 create mode 100644 changes/4.0.0.md

diff --git a/README.md b/README.md
index d016a11d1..4ad935b64 100644
--- a/README.md
+++ b/README.md
@@ -368,8 +368,11 @@ Subsection `ligations` is used to customize the ligation set assigned to `calt`
   - `eqeq`: Enable ligation for `==` and `===`.
   - `ineq`: Enable ligation for `<=` and `>=`.
   - `exeqeq`: Enable special ligation for `!==` with triple lines.
+  - `exeqeq-alt-1`: Enable special ligation for `!==` with triple lines, and a dot at below for distinction.
   - `eqexeq`: Enable special ligation for `=!=` with triple lines.
+  - `eqexeq-alt-1`: Enable special ligation for `=!=` with triple lines and a dot at below for distinction.
   - `eqexeq-dl`: Enable special ligation for `=!=` with double lines.
+  - `eqexeq-dl-alt-1`: Enable special ligation for `=!=` with double lines, and a dot at below for distinction.
   - `exeq`: Enable ligation for `!=` and `!==`.
   - `exeq-alt-1`: Enable ligation for `!=` and `!==` with a dot at below for distinction.
   - `tildeeq`: Enable ligation for `~=` as inequality.
diff --git a/changes/4.0.0.md b/changes/4.0.0.md
new file mode 100644
index 000000000..d6a814e5c
--- /dev/null
+++ b/changes/4.0.0.md
@@ -0,0 +1 @@
+ * Add more alternative exclamation-related ligation sets (`exeqeq-alt-1`, `eqexeq-alt-1`, `eqexeq-dl-alt-1`) (#748).
\ No newline at end of file
diff --git a/font-src/glyphs/symbol/ligation.ptl b/font-src/glyphs/symbol/ligation.ptl
index d6a30b714..88eb669f9 100644
--- a/font-src/glyphs/symbol/ligation.ptl
+++ b/font-src/glyphs/symbol/ligation.ptl
@@ -255,6 +255,10 @@ glyph-block Symbol-Ligation : begin
 		notGlyph.generic 'equal.fc.neg3-alt-1' null 'equal.fc' (shift -- (Width * 1.0)) (F -- exSlash2)
 		notGlyph.generic 'equal.fc.neg4-alt-1' null 'equal.fc' (shift -- (Width * 1.5)) (F -- exSlash2)
 
+		notGlyph.generic 'ident.fc.neg-alt-1'  null 'ident.fc' (shift -- (Width * 0.5)) (F -- exSlash2)
+		notGlyph.generic 'ident.fc.neg3-alt-1' null 'ident.fc' (shift -- (Width * 1.0)) (F -- exSlash2)
+		notGlyph.generic 'ident.fc.neg4-alt-1' null 'ident.fc' (shift -- (Width * 1.5)) (F -- exSlash2)
+
 	do "<| , |> and <>"
 		glyph-block-import Symbol-Math-Relation : LessShape GreaterShape
 
diff --git a/font-src/otl/gsub-ligation.ptl b/font-src/otl/gsub-ligation.ptl
index d54a8c751..3fd9c45ec 100644
--- a/font-src/otl/gsub-ligation.ptl
+++ b/font-src/otl/gsub-ligation.ptl
@@ -790,14 +790,26 @@ define [buildLigationsImpl sink para featureName mappedFeature rankedLookups] :
 				equal       ~> {'equal.cc'}
 				equal       ~> {'equal.cf'}
 		piecewise
+			[hasLG 'exeqeq-alt-1'] : chain-rule
+				exclam      ~> {'ident.fc.neg3-alt-1'}
+				equal       ~> {'ident.cc'}
+				equal       ~> {'ident.cf'}
 			[hasLG 'exeqeq'] : chain-rule
 				exclam      ~> {'ident.fc.neg3'}
 				equal       ~> {'ident.cc'}
 				equal       ~> {'ident.cf'}
+			[hasLG 'eqexeq-alt-1'] : chain-rule
+				equal       ~> {'ident.fc.neg3-alt-1'}
+				exclam      ~> {'ident.cc'}
+				equal       ~> {'ident.cf'}
 			[hasLG 'eqexeq'] : chain-rule
 				equal       ~> {'ident.fc.neg3'}
 				exclam      ~> {'ident.cc'}
 				equal       ~> {'ident.cf'}
+			[hasLG 'eqexeq-dl-alt-1'] : chain-rule
+				equal       ~> {'equal.fc.neg3-alt-1'}
+				exclam      ~> {'equal.cc'}
+				equal       ~> {'equal.cf'}
 			[hasLG 'eqexeq-dl'] : chain-rule
 				equal       ~> {'equal.fc.neg3'}
 				exclam      ~> {'equal.cc'}
diff --git a/params/ligation-set.toml b/params/ligation-set.toml
index 079c578c6..0dff8e4d7 100644
--- a/params/ligation-set.toml
+++ b/params/ligation-set.toml
@@ -30,14 +30,26 @@ desc = 'Enable ligation for `<=` and `>=`'
 ligGroup =  "exeqeq"
 desc = 'Enable special ligation for `!==` with triple lines'
 
+[simple.exeqeq-alt-1]
+ligGroup =  "exeqeq-alt-1"
+desc = 'Enable special ligation for `!==` with triple lines, and a dot at below for distinction'
+
 [simple.eqexeq]
 ligGroup =  "eqexeq"
 desc = 'Enable special ligation for `=!=` with triple lines'
 
+[simple.eqexeq-alt-1]
+ligGroup =  "eqexeq-alt-1"
+desc = 'Enable special ligation for `=!=` with triple lines and a dot at below for distinction'
+
 [simple.eqexeq-dl]
 ligGroup =  "eqexeq-dl"
 desc = 'Enable special ligation for `=!=` with double lines'
 
+[simple.eqexeq-dl-alt-1]
+ligGroup =  "eqexeq-dl-alt-1"
+desc = 'Enable special ligation for `=!=` with double lines, and a dot at below for distinction'
+
 [simple.exeq]
 ligGroup =  "exeq"
 desc = 'Enable ligation for `!=` and `!==`'