[gtksourceview/gtksourceview-4-8] lean.lang: add LEAN language specification

[Christian Hergert <chergert src gnome org>]

commit 9992d0a3018946af3668edcfdc1d373542911703
Author: Christian Hergert <christian hergert me>
Date:   Fri Sep 17 20:48:11 2021 +0000

    lean.lang: add LEAN language specification
    
    add syntax highlighting for Lean
    
    https://leanprover.github.io/about/
    
    See merge request GNOME/gtksourceview!208
    
    (cherry picked from commit e990defcb67fc320d0b08eb225bc543f8ff4ee9e)
    
    2e892ab3 add syntax highlighting for Lean
    dadc8e3a lean.lang: add more keywords
    993e3479 add an example Lean file

 data/language-specs/lean.lang       | 163 ++++++++++++++++++++++++++++++++++++
 tests/syntax-highlighting/file.lean |  15 ++++
 2 files changed, 178 insertions(+)
---
diff --git a/data/language-specs/lean.lang b/data/language-specs/lean.lang
new file mode 100644
index 00000000..2cb0e051
--- /dev/null
+++ b/data/language-specs/lean.lang
@@ -0,0 +1,163 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+ This file is part of GtkSourceView
+
+ Authors: Elias Aebi
+ Copyright (C) 2021 Elias Aebi
+
+ GtkSourceView is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ GtkSourceView is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this library; if not, see <http://www.gnu.org/licenses/>.
+
+-->
+<language id="lean" name="Lean" version="2.0" _section="Source">
+  <metadata>
+    <property name="mimetypes">text/x-lean</property>
+    <property name="globs">*.lean</property>
+    <property name="line-comment-start">--</property>
+    <property name="block-comment-start">/-</property>
+    <property name="block-comment-end">-/</property>
+  </metadata>
+
+  <styles>
+    <style id="comment" name="Comment" map-to="def:comment"/>
+    <style id="command" name="Command" map-to="def:preprocessor"/>
+    <style id="keyword" name="Keyword" map-to="def:keyword"/>
+    <style id="string" name="String" map-to="def:string"/>
+    <style id="character" name="Character" map-to="def:character"/>
+    <style id="escaped-character" name="Escaped Character" map-to="def:special-char"/>
+    <style id="numeric" name="Numeric" map-to="def:number"/>
+    <style id="boolean" name="Boolean" map-to="def:boolean"/>
+  </styles>
+
+  <definitions>
+    <context id="line-comment" style-ref="comment" end-at-line-end="true" class="comment" 
class-disabled="no-spell-check">
+      <start>--</start>
+      <include>
+        <context ref="def:in-comment"/>
+      </include>
+    </context>
+
+    <context id="block-comment" style-ref="comment" class="comment" class-disabled="no-spell-check">
+      <start>/-</start>
+      <end>-/</end>
+      <include>
+        <context ref="def:in-comment"/>
+        <context ref="block-comment"/>
+      </include>
+    </context>
+
+    <context id="command" style-ref="command">
+      <match extended="true">
+        ^\s*\#(
+            check(_failure)?
+          | eval
+          | print
+          | reduce
+        )
+      </match>
+    </context>
+
+    <context id="keyword" style-ref="keyword">
+      <keyword>axiom</keyword>
+      <keyword>break</keyword>
+      <keyword>class</keyword>
+      <keyword>continue</keyword>
+      <keyword>def</keyword>
+      <keyword>do</keyword>
+      <keyword>else</keyword>
+      <keyword>end</keyword>
+      <keyword>example</keyword>
+      <keyword>for</keyword>
+      <keyword>fun</keyword>
+      <keyword>if</keyword>
+      <keyword>in</keyword>
+      <keyword>inductive</keyword>
+      <keyword>instance</keyword>
+      <keyword>let</keyword>
+      <keyword>match</keyword>
+      <keyword>mut</keyword>
+      <keyword>namespace</keyword>
+      <keyword>open</keyword>
+      <keyword>return</keyword>
+      <keyword>section</keyword>
+      <keyword>structure</keyword>
+      <keyword>then</keyword>
+      <keyword>theorem</keyword>
+      <keyword>universe</keyword>
+      <keyword>variable</keyword>
+      <keyword>where</keyword>
+      <keyword>with</keyword>
+      <keyword>λ</keyword>
+    </context>
+
+    <define-regex id="string-escape" extended="true">
+      \\(
+          \\
+        | \"
+        | \'
+        | n
+        | t
+        | x[0-9a-fA-F]{2}
+      )
+    </define-regex>
+
+    <context id="string" style-ref="string" end-at-line-end="true" class="string" 
class-disabled="no-spell-check">
+      <start>"</start>
+      <end>"</end>
+      <include>
+        <context style-ref="escaped-character">
+          <match>\%{string-escape}</match>
+        </context>
+      </include>
+    </context>
+
+    <context id="character" style-ref="character" end-at-line-end="true">
+      <start>'</start>
+      <end>'</end>
+      <include>
+        <context style-ref="escaped-character">
+          <match>\%{string-escape}</match>
+        </context>
+      </include>
+    </context>
+
+    <context id="numeric" style-ref="numeric">
+      <match extended="true">
+          0[bB][0-1]+
+        | 0[oO][0-7]+
+        | 0[xX][0-9a-fA-F]+
+        | [0-9]+
+      </match>
+    </context>
+
+    <context id="boolean" style-ref="boolean">
+      <keyword>true</keyword>
+      <keyword>false</keyword>
+    </context>
+
+    <context id="lean" class="no-spell-check">
+      <include>
+        <context ref="line-comment"/>
+        <context ref="block-comment"/>
+        <context ref="command"/>
+        <context ref="keyword"/>
+        <context ref="string"/>
+        <context ref="character"/>
+        <context ref="numeric"/>
+        <context ref="boolean"/>
+      </include>
+    </context>
+
+  </definitions>
+</language>
diff --git a/tests/syntax-highlighting/file.lean b/tests/syntax-highlighting/file.lean
new file mode 100644
index 00000000..5b92b00a
--- /dev/null
+++ b/tests/syntax-highlighting/file.lean
@@ -0,0 +1,15 @@
+-- line comment
+
+/-
+  block comment
+  /- nested block comment -/
+-/
+
+def main : IO Unit :=
+  let a := 1
+  let b := 0b1
+  let c := 0x1
+  let d := '1'
+  IO.println "Hello World"
+
+#eval main