From 5644f4186577bf14a870a2840488141973f84d00 Mon Sep 17 00:00:00 2001
From: Hannu Hartikainen <hannu.hartikainen@gmail.com>
Date: Tue, 8 Nov 2022 12:25:43 +0200
Subject: [PATCH] Add lexer for BQN (#691)

Based on the Vim syntax highlighting by Marshall Lochbaum[[0]], with number
parsing from PrismJS highlighter by Christopher Rodriguez[[1]].

The lexed types are selected to be as descriptive as possible while
retaining similar groupings to the Vim highlighter, so the highlighted
code looks familiar to BQN users.

[0]: https://github.com/mlochbaum/BQN/blob/a436a71a083f410fd58d86e8d228470c68c24b91/editors/vim/syntax/bqn.vim
[1]: https://github.com/PrismJS/prism/commit/859f99a042e2f9c072a882b4cf9bf5f1f7804fa9
---
 README.md                    |   2 +-
 lexers/embedded/bqn.xml      |  83 +++++++++++
 lexers/testdata/bqn.actual   |  31 +++++
 lexers/testdata/bqn.expected | 258 +++++++++++++++++++++++++++++++++++
 4 files changed, 373 insertions(+), 1 deletion(-)
 create mode 100644 lexers/embedded/bqn.xml
 create mode 100644 lexers/testdata/bqn.actual
 create mode 100644 lexers/testdata/bqn.expected

diff --git a/README.md b/README.md
index 3a879a8c3..2fa78bf41 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,7 @@ translators for Pygments lexers and styles.
 Prefix | Language
 :----: | --------
 A | ABAP, ABNF, ActionScript, ActionScript 3, Ada, Angular2, ANTLR, ApacheConf, APL, AppleScript, Arduino, Awk
-B | Ballerina, Base Makefile, Bash, Batchfile, BibTeX, Bicep, BlitzBasic, BNF, Brainfuck
+B | Ballerina, Base Makefile, Bash, Batchfile, BibTeX, Bicep, BlitzBasic, BNF, Brainfuck, BQN
 C | C, C#, C++, Caddyfile, Caddyfile Directives, Cap'n Proto, Cassandra CQL, Ceylon, CFEngine3, cfstatement, ChaiScript, Chapel, Cheetah, Clojure, CMake, COBOL, CoffeeScript, Common Lisp, Coq, Crystal, CSS, Cython
 D | D, Dart, Diff, Django/Jinja, Docker, DTD, Dylan
 E | EBNF, Elixir, Elm, EmacsLisp, Erlang
diff --git a/lexers/embedded/bqn.xml b/lexers/embedded/bqn.xml
new file mode 100644
index 000000000..c1090ea5a
--- /dev/null
+++ b/lexers/embedded/bqn.xml
@@ -0,0 +1,83 @@
+<lexer>
+  <config>
+    <name>BQN</name>
+    <alias>bqn</alias>
+    <filename>*.bqn</filename>
+  </config>
+  <rules>
+    <state name="root">
+      <rule pattern="\s+">
+        <token type="TextWhitespace"/>
+      </rule>
+      <rule pattern="\A#!.+$">
+        <token type="CommentPreproc"/>
+      </rule>
+      <rule pattern="#.*$">
+        <token type="CommentSingle"/>
+      </rule>
+      <rule pattern="&quot;(?:[^&quot;]|&quot;&quot;)*&quot;">
+        <token type="LiteralString"/>
+      </rule>
+      <rule pattern="[{}]">
+        <token type="KeywordPseudo"/>
+      </rule>
+      <rule pattern="[⟨⟩\[\]‿]">
+        <token type="KeywordPseudo"/>
+      </rule>
+      <rule pattern="[()]">
+        <token type="Punctuation"/>
+      </rule>
+      <rule pattern="[:;?]">
+        <token type="Punctuation"/>
+      </rule>
+      <rule pattern="[⋄,]">
+        <token type="KeywordPseudo"/>
+      </rule>
+      <rule pattern="[←⇐↩→]">
+        <token type="Text"/>
+      </rule>
+      <rule pattern="'.'">
+        <token type="LiteralStringChar"/>
+      </rule>
+      <rule pattern="[˙˜˘¨⌜⁼´˝`]">
+        <token type="Operator"/>
+      </rule>
+      <rule pattern="[∘○⊸⟜⌾⊘◶⎉⚇⍟⎊]">
+        <token type="OperatorWord"/>
+      </rule>
+      <rule pattern="[𝔽𝔾𝕎𝕏𝕊+\-×÷⋆√⌊⌈|¬∧∨&lt;&gt;≠=≤≥≡≢⊣⊢⥊∾≍⋈↑↓↕«»⌽⍉/⍋⍒⊏⊑⊐⊒∊⍷⊔!⍕⍎]">
+        <token type="NameFunction"/>
+      </rule>
+      <rule pattern="[𝕗𝕘𝕨𝕩𝕤]">
+        <token type="Name"/>
+      </rule>
+      <rule pattern="·">
+        <token type="NameConstant"/>
+      </rule>
+      <rule pattern="@">
+        <token type="LiteralStringChar"/>
+      </rule>
+      <rule pattern="\d+(?:\.\d+)?[eE]¯?\d+">
+        <token type="LiteralNumber"/>
+      </rule>
+      <rule pattern="[¯∞π]?(?:\d*\.?\b\d+(?:e[+¯]?\d+|E[+¯]?\d+)?|¯|∞|π)(?:j¯?(?:(?:\d+(?:\.\d+)?|\.\d+)(?:e[+¯]?\d+|E[+¯]?\d+)?|¯|∞|π))?">
+        <token type="LiteralNumber"/>
+      </rule>
+      <rule pattern="(•?[a-z][A-Z_a-z0-9π∞¯]*|𝕣)">
+        <token type="Name"/>
+      </rule>
+      <rule pattern="•?[A-Z][A-Z_a-z0-9π∞¯]*">
+        <token type="NameFunction"/>
+      </rule>
+      <rule pattern="(•?_[A-Za-z][A-Z_a-z0-9π∞¯]*|_𝕣)">
+        <token type="Operator"/>
+      </rule>
+      <rule pattern="(•?_[A-Za-z][A-Z_a-z0-9π∞¯]*_|_𝕣_)">
+        <token type="OperatorWord"/>
+      </rule>
+      <rule pattern="\.">
+        <token type="Text"/>
+      </rule>
+    </state>
+  </rules>
+</lexer>
\ No newline at end of file
diff --git a/lexers/testdata/bqn.actual b/lexers/testdata/bqn.actual
new file mode 100644
index 000000000..064a2d093
--- /dev/null
+++ b/lexers/testdata/bqn.actual
@@ -0,0 +1,31 @@
+#! /usr/bin/env bqn
+
+# From BQN documentation / quick start:
+# https://mlochbaum.github.io/BQN/doc/quick.html
+
+# Case conversion utilities
+case ← {
+  diff ← -´ "Aa"
+  Lower ⇐ -⟜diff
+  Upper ⇐ Lower⁼
+}
+
+hw ← <˘ 2‿∘ ⥊ "helloworld"
+hw case.Upper⌾(⊑¨)↩
+•Out hw ↩ ∾ ⥊⍉ [hw, ", "‿"!"]  # Hello, World!
+
+# Split at spaces and repeated characters
+Split ← {
+  !1==𝕩 ⋄ (!2=•Type)¨𝕩
+  Proc ← {
+    · 𝕊 ' ': spl⇐1 ;             # Space: break and delete it
+    prev Fn cur: ⟨spl,str⟩⇐
+      spl←0 ⋄ str←⟨cur⟩          # Include and don't break...
+      { prev=cur ? spl+↩1 ; @ }  # except at equal characters
+  }
+  GV‿GS ← {𝕏¨}¨ ⟨ {⟨s⇐str⟩:s;""}
+                  {𝕩.spl} ⟩
+  r ← Proc{»𝔽¨⊢} 𝕩
+  (∾¨ GV ⊔˜ ·+`GS) r
+}
+•Show Split hw  # ⟨ "Hel" "lo," "World!" ⟩
diff --git a/lexers/testdata/bqn.expected b/lexers/testdata/bqn.expected
new file mode 100644
index 000000000..19ce024a0
--- /dev/null
+++ b/lexers/testdata/bqn.expected
@@ -0,0 +1,258 @@
+[
+  {"type":"CommentPreproc","value":"#! /usr/bin/env bqn"},
+  {"type":"TextWhitespace","value":"\n\n"},
+  {"type":"CommentSingle","value":"# From BQN documentation / quick start:"},
+  {"type":"TextWhitespace","value":"\n"},
+  {"type":"CommentSingle","value":"# https://mlochbaum.github.io/BQN/doc/quick.html"},
+  {"type":"TextWhitespace","value":"\n\n"},
+  {"type":"CommentSingle","value":"# Case conversion utilities"},
+  {"type":"TextWhitespace","value":"\n"},
+  {"type":"Name","value":"case"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Text","value":"←"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"{"},
+  {"type":"TextWhitespace","value":"\n  "},
+  {"type":"Name","value":"diff"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Text","value":"←"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"-"},
+  {"type":"Operator","value":"´"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"LiteralString","value":"\"Aa\""},
+  {"type":"TextWhitespace","value":"\n  "},
+  {"type":"NameFunction","value":"Lower"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Text","value":"⇐"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"-"},
+  {"type":"OperatorWord","value":"⟜"},
+  {"type":"Name","value":"diff"},
+  {"type":"TextWhitespace","value":"\n  "},
+  {"type":"NameFunction","value":"Upper"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Text","value":"⇐"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"Lower"},
+  {"type":"Operator","value":"⁼"},
+  {"type":"TextWhitespace","value":"\n"},
+  {"type":"KeywordPseudo","value":"}"},
+  {"type":"TextWhitespace","value":"\n\n"},
+  {"type":"Name","value":"hw"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Text","value":"←"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"\u003c"},
+  {"type":"Operator","value":"˘"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"LiteralNumber","value":"2"},
+  {"type":"KeywordPseudo","value":"‿"},
+  {"type":"OperatorWord","value":"∘"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"⥊"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"LiteralString","value":"\"helloworld\""},
+  {"type":"TextWhitespace","value":"\n"},
+  {"type":"Name","value":"hw"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Name","value":"case"},
+  {"type":"Text","value":"."},
+  {"type":"NameFunction","value":"Upper"},
+  {"type":"OperatorWord","value":"⌾"},
+  {"type":"Punctuation","value":"("},
+  {"type":"NameFunction","value":"⊑"},
+  {"type":"Operator","value":"¨"},
+  {"type":"Punctuation","value":")"},
+  {"type":"Text","value":"↩"},
+  {"type":"TextWhitespace","value":"\n"},
+  {"type":"NameFunction","value":"•Out"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Name","value":"hw"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Text","value":"↩"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"∾"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"⥊⍉"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"["},
+  {"type":"Name","value":"hw"},
+  {"type":"KeywordPseudo","value":","},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"LiteralString","value":"\", \""},
+  {"type":"KeywordPseudo","value":"‿"},
+  {"type":"LiteralString","value":"\"!\""},
+  {"type":"KeywordPseudo","value":"]"},
+  {"type":"TextWhitespace","value":"  "},
+  {"type":"CommentSingle","value":"# Hello, World!"},
+  {"type":"TextWhitespace","value":"\n\n"},
+  {"type":"CommentSingle","value":"# Split at spaces and repeated characters"},
+  {"type":"TextWhitespace","value":"\n"},
+  {"type":"NameFunction","value":"Split"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Text","value":"←"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"{"},
+  {"type":"TextWhitespace","value":"\n  "},
+  {"type":"NameFunction","value":"!"},
+  {"type":"LiteralNumber","value":"1"},
+  {"type":"NameFunction","value":"=="},
+  {"type":"Name","value":"𝕩"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"⋄"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Punctuation","value":"("},
+  {"type":"NameFunction","value":"!"},
+  {"type":"LiteralNumber","value":"2"},
+  {"type":"NameFunction","value":"=•Type"},
+  {"type":"Punctuation","value":")"},
+  {"type":"Operator","value":"¨"},
+  {"type":"Name","value":"𝕩"},
+  {"type":"TextWhitespace","value":"\n  "},
+  {"type":"NameFunction","value":"Proc"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Text","value":"←"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"{"},
+  {"type":"TextWhitespace","value":"\n    "},
+  {"type":"NameConstant","value":"·"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"𝕊"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"LiteralStringChar","value":"' '"},
+  {"type":"Punctuation","value":":"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Name","value":"spl"},
+  {"type":"Text","value":"⇐"},
+  {"type":"LiteralNumber","value":"1"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Punctuation","value":";"},
+  {"type":"TextWhitespace","value":"             "},
+  {"type":"CommentSingle","value":"# Space: break and delete it"},
+  {"type":"TextWhitespace","value":"\n    "},
+  {"type":"Name","value":"prev"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"Fn"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Name","value":"cur"},
+  {"type":"Punctuation","value":":"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"⟨"},
+  {"type":"Name","value":"spl"},
+  {"type":"KeywordPseudo","value":","},
+  {"type":"Name","value":"str"},
+  {"type":"KeywordPseudo","value":"⟩"},
+  {"type":"Text","value":"⇐"},
+  {"type":"TextWhitespace","value":"\n      "},
+  {"type":"Name","value":"spl"},
+  {"type":"Text","value":"←"},
+  {"type":"LiteralNumber","value":"0"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"⋄"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Name","value":"str"},
+  {"type":"Text","value":"←"},
+  {"type":"KeywordPseudo","value":"⟨"},
+  {"type":"Name","value":"cur"},
+  {"type":"KeywordPseudo","value":"⟩"},
+  {"type":"TextWhitespace","value":"          "},
+  {"type":"CommentSingle","value":"# Include and don't break..."},
+  {"type":"TextWhitespace","value":"\n      "},
+  {"type":"KeywordPseudo","value":"{"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Name","value":"prev"},
+  {"type":"NameFunction","value":"="},
+  {"type":"Name","value":"cur"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Punctuation","value":"?"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Name","value":"spl"},
+  {"type":"NameFunction","value":"+"},
+  {"type":"Text","value":"↩"},
+  {"type":"LiteralNumber","value":"1"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Punctuation","value":";"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"LiteralStringChar","value":"@"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"}"},
+  {"type":"TextWhitespace","value":"  "},
+  {"type":"CommentSingle","value":"# except at equal characters"},
+  {"type":"TextWhitespace","value":"\n  "},
+  {"type":"KeywordPseudo","value":"}"},
+  {"type":"TextWhitespace","value":"\n  "},
+  {"type":"NameFunction","value":"GV"},
+  {"type":"KeywordPseudo","value":"‿"},
+  {"type":"NameFunction","value":"GS"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Text","value":"←"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"{"},
+  {"type":"NameFunction","value":"𝕏"},
+  {"type":"Operator","value":"¨"},
+  {"type":"KeywordPseudo","value":"}"},
+  {"type":"Operator","value":"¨"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"⟨"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"{⟨"},
+  {"type":"Name","value":"s"},
+  {"type":"Text","value":"⇐"},
+  {"type":"Name","value":"str"},
+  {"type":"KeywordPseudo","value":"⟩"},
+  {"type":"Punctuation","value":":"},
+  {"type":"Name","value":"s"},
+  {"type":"Punctuation","value":";"},
+  {"type":"LiteralString","value":"\"\""},
+  {"type":"KeywordPseudo","value":"}"},
+  {"type":"TextWhitespace","value":"\n                  "},
+  {"type":"KeywordPseudo","value":"{"},
+  {"type":"Name","value":"𝕩"},
+  {"type":"Text","value":"."},
+  {"type":"Name","value":"spl"},
+  {"type":"KeywordPseudo","value":"}"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"KeywordPseudo","value":"⟩"},
+  {"type":"TextWhitespace","value":"\n  "},
+  {"type":"Name","value":"r"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Text","value":"←"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"Proc"},
+  {"type":"KeywordPseudo","value":"{"},
+  {"type":"NameFunction","value":"»𝔽"},
+  {"type":"Operator","value":"¨"},
+  {"type":"NameFunction","value":"⊢"},
+  {"type":"KeywordPseudo","value":"}"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Name","value":"𝕩"},
+  {"type":"TextWhitespace","value":"\n  "},
+  {"type":"Punctuation","value":"("},
+  {"type":"NameFunction","value":"∾"},
+  {"type":"Operator","value":"¨"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"GV"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"⊔"},
+  {"type":"Operator","value":"˜"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameConstant","value":"·"},
+  {"type":"NameFunction","value":"+"},
+  {"type":"Operator","value":"`"},
+  {"type":"NameFunction","value":"GS"},
+  {"type":"Punctuation","value":")"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Name","value":"r"},
+  {"type":"TextWhitespace","value":"\n"},
+  {"type":"KeywordPseudo","value":"}"},
+  {"type":"TextWhitespace","value":"\n"},
+  {"type":"NameFunction","value":"•Show"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"NameFunction","value":"Split"},
+  {"type":"TextWhitespace","value":" "},
+  {"type":"Name","value":"hw"},
+  {"type":"TextWhitespace","value":"  "},
+  {"type":"CommentSingle","value":"# ⟨ \"Hel\" \"lo,\" \"World!\" ⟩"},
+  {"type":"TextWhitespace","value":"\n"}
+]