Support for multiple ligature'd fonts

Refactors the ligature configuration to support more than just Iosevka
(uses Fira Code as the second font).

modules/ui/pretty-code/autoload/autoload.el

@@ -0,0 +1,27 @@
+;;; ui/pretty-code/autoload.el -*- lexical-binding: t; -*-
+
+;;;###autoload
+(defvar +pretty-code-enabled-modes t
+  "List of major modes in which `prettify-symbols-mode' should be enabled.
+If t, enable it everywhere. If the first element is 'not, enable it in any mode
+besides what is listed.")
+
+
+;;;###autoload
+(defun +pretty-code|init-pretty-symbols ()
+  "Enabled `prettify-symbols-mode'.
+
+If the current major mode is disabled in `+pretty-code-enabled-modes', this
+function does nothing. Otherwise, it sets the value of
+`prettify-code-symbols-alist' according to `+pretty-code-symbols-alist' for the
+current major mode."
+  (when (or (eq +pretty-code-enabled-modes 't)
+            (if (eq (car +pretty-code-enabled-modes 'not))
+                (not (memq major-mode (cdr +pretty-code-enabled-modes)))
+              (memq major-mode +pretty-code-enabled-modes)))
+    (setq prettify-symbols-alist
+          (append (alist-get major-mode +pretty-code-symbols-alist)
+                  (default-value 'prettify-symbols-alist)))
+    (when prettify-symbols-mode
+      (prettify-symbols-mode -1))
+    (prettify-symbols-mode +1)))

modules/ui/pretty-code/autoload/settings.el

@@ -0,0 +1,67 @@
+;;; ui/pretty-code/settings.el -*- lexical-binding: t; -*-
+
+;;;###autoload
+(defvar +pretty-code-symbols
+  '(;; org
+    :name          "»"
+    :src_block     "»"
+    :src_block_end " "
+    ;; Functional
+    :lambda        "λ"
+    :def           "ƒ"
+    :composition   "∘"
+    :map           "↦"
+    ;; Types
+    :null          "∅"
+    :true          "𝕋"
+    :false         "𝔽"
+    :int           "ℤ"
+    :float         "ℝ"
+    :str           "𝕊"
+    :bool          "𝔹"
+    ;; Flow
+    :not           "￢"
+    :in            "∈"
+    :not-in        "∉"
+    :and           "∧"
+    :or            "∨"
+    :for           "∀"
+    :some          "∃"
+    :return        "⟼"
+    :yield         "⟻"
+    ;; Other
+    :tuple         "⨂"
+    :pipe          "" ;; FIXME: find a non-private char
+    :dot           "•")
+  "Options plist for `set-pretty-symbols!'.
+
+This should not contain any symbols from the Unicode Private Area! There is no
+universal way of getting the correct symbol as that area varies from font to
+font.")
+
+;;;###autoload
+(defvar +pretty-code-symbols-alist nil
+  "An alist containing a mapping of major modes to its value for
+`prettify-symbols-alist'.")
+
+
+;;;###autoload
+(defun set-pretty-symbols! (modes &rest rest)
+  (dolist (mode (doom-enlist modes))
+    (if (null (car-safe rest))
+        (setq var nil)
+      (let (results merge key alist)
+        (while rest
+          (setq key (pop rest))
+          (pcase key
+            (:merge (setq merge t))
+            (:alist (setq results (append (pop rest) results)))
+            (_
+             (unless (plist-member +pretty-code-symbols key)
+               (user-error "Invalid keyword in set-pretty-symbols!: %s" key))
+             (let* ((sym (pop rest))
+                    (char (plist-get +pretty-code-symbols key)))
+               (push (cons sym char) results)))))
+        (unless merge
+          (assq-delete-all mode +pretty-code-symbols-alist))
+        (push (cons mode results) +pretty-code-symbols-alist)))))