Automatically convert some unicode characters to their LaTeX command

dollar.rkt

@@ -6,7 +6,9 @@
          scribble/latex-properties
          scriblib/render-cond
          racket/runtime-path
-         setup/collects)
+         setup/collects
+         "katex-convert-unicode.rkt"
+         racket/list)
 
 (provide $
          $$
@@ -190,13 +192,15 @@ EOTEX
   (make-element math-inline-style-mathjax `("$" ,@strs "$")))
 
 (define ($-katex strs)
-  (make-element math-inline-style-katex strs))
+  (make-element math-inline-style-katex
+                (map katex-convert-unicode (flatten strs))))
 
 (define ($$-mathjax strs)
   (make-element math-display-style-mathjax `("\\[" ,@strs "\\]")))
 
 (define ($$-katex strs)
-  (make-element math-display-style-katex strs))
+  (make-element math-display-style-katex
+                (map katex-convert-unicode (flatten strs))))
 
 (define $-html-handler (make-parameter $-katex))
 (define $$-html-handler (make-parameter $$-katex))

katex-convert-unicode.rkt

@@ -0,0 +1,95 @@
+#lang racket/base
+(require racket/string)
+
+(provide katex-convert-unicode)
+
+(define (literal-alternatives→regexp literal-alternatives)
+  (string-append "("
+                 (string-join (map regexp-quote literal-alternatives) "|")
+                 ")"))
+
+(define (string-replace* str sym→*)
+  (define →* (map (λ (x)
+                    (cons (symbol->string (car x))
+                          (cadr x)))
+                  sym→*))
+  (define hash→* (make-immutable-hash →*))
+  (regexp-replace* (literal-alternatives→regexp (map car →*))
+                   str
+                   (λ (found . _)
+                     (hash-ref hash→* found))))
+
+(define (katex-convert-unicode str)
+  (if (string? str)
+      (string-replace*
+       str
+       '([₀ "_0"]
+         [₁ "_1"]
+         [₂ "_2"]
+         [₃ "_3"]
+         [₄ "_4"]
+         [₅ "_5"]
+         [₆ "_6"]
+         [₇ "_7"]
+         [₈ "_8"]
+         [₉ "_9"]
+         [ᵢ "_i"]
+         [ⱼ "_j"]
+         [ₖ "_k"]
+         [ₗ "_l"]
+         [ₘ "_m"]
+         [ₙ "_n"]
+         [ₒ "_o"]
+         [⁰ "^0"]
+         [¹ "^1"]
+         [² "^2"]
+         [³ "^3"]
+         [⁴ "^4"]
+         [⁵ "^5"]
+         [⁶ "^6"]
+         [⁷ "^7"]
+         [⁸ "^8"]
+         [⁹ "^9"]
+         [ⁱ "^i"]
+         [ʲ "^j"]
+         [ᵏ "^k"]
+         [ˡ "^l"]
+         [ᵐ "^m"]
+         [ⁿ "^n"]
+         [ᵒ "^o"]
+         [⊆ "\\subseteq" "\\ensuremath{\\subseteq}"]
+         [⊂ "\\subset" "\\ensuremath{\\subset}"]
+         [⊇ "\\supseteq" "\\ensuremath{\\supseteq}"]
+         [⊃ "\\supset" "\\ensuremath{\\supset}"]
+         [→ "\\rightarrow" "\\ensuremath{\\rightarrow}"]
+         [⇒ "\\Rightarrow" "\\ensuremath{\\Rightarrow}"]
+         [← "\\leftarrow" "\\ensuremath{\\leftarrow}"]
+         [⇐ "\\Leftarrow" "\\ensuremath{\\Leftarrow}"]
+         [↔ "\\leftrightarrow" "\\ensuremath{\\leftrightarrow}"]
+         [⇔ "\\Leftrightarrow" "\\ensuremath{\\Leftrightarrow}"]
+         ;; Partially extracted from my .XCompose generator
+         [ñ "\\tilde{n}" "{\\ifmmode\\tilde{n}\\else\\~{n}\\fi}"]
+         [Ñ "\\tilde{N}" "{\\ifmmode\\tilde{N}\\else\\~{N}\\fi}"]
+         [⋆ "\\star" "\\ensuremath{\\star}"]
+         [⍣ "\\ddot{\\star}}" "\\ensuremath{\\ddot{\\star}}"]
+         [⃰ "^*" "^*"]
+         [⟨ "\\langle" "\\ensuremath{\\mathsmaller{\\raisemath{.15ex}{\\langle}}}"]
+         [⟩ "\\rangle" "\\ensuremath{\\mathsmaller{\\raisemath{.15ex}{\\rangle}}}"]
+         [⋯ "\\cdots"]
+         [⋮ "\\vdots"]
+         [⋰ "\\iddots"]
+         [⋱ "\\ddots"]
+         [⧺ "\\mathbin{+\\mkern-6.5mu+}" "\\ensuremath{\\mathbin{+\\mkern-6.5mu+}}"]
+         [∅ "\\emptyset" "\\ensuremath{\\emptyset}"]
+         [ı⃗ "\\vec{\\i}}" "\\ensuremath{\\vec{\\i}"]
+         [⊕ "\\oplus" "\\ensuremath{\\oplus}"]
+         [⊖ "\\ominus" "\\ensuremath{\\ominus}"]
+         [⋓ "\\Cup" "\\ensuremath{\\Cup}"]
+         ;[ₗ "\\ensuremath{_{l}}"]
+         [∷ "::"]
+         [Λ "\\Lambda" "\\ensuremath{\\Lambda}"]
+         [∀ "\\forall"]
+         [∃ "\\exists"]
+         [≡ "\\equiv"]
+         [≢ "\not\\equiv"]))
+      str))