@@ -65,3 +65,4 @@ web/assets/*.h[eb]x
 *.com.dbg
 hex.js
 hex.wasm
+lib/*.html

@@ -38,6 +38,7 @@ ./hex -b scripts/test.hex
 	./hex scripts/test.hbx
 
 web: playground utils.hbx hex
+	./hex scripts/doc.hex lib/utils.hex lib/utils.html
 	./hex -b scripts/web.hex
 	./hex scripts/web.hex
 

@@ -393,7 +393,7 @@ ) "ends" ::
 
 ;;; fmt
 ;; s1 q -> s2
-;; Substitutes %:$0%% to %%$9%% placeholders in %:s1%% with items in %:q%%.
+;; Substitutes %:$\{0\}%% to %%$\{9\}%% placeholders in %:s1%% with items in %:q%%.
 (
   "_fmt_q" :
   "_fmt_s" :
@@ -403,7 +403,7 @@ ("[symbol fmt] Only a maximum of 10 placeholders are supported" throw)
   when
   (_fmt_c _fmt_q len <)
     (
-      _fmt_s "$" _fmt_c str cat _fmt_q _fmt_c get gsub "_fmt_s" :
+      _fmt_s "${" _fmt_c str cat "}" cat _fmt_q _fmt_c get gsub "_fmt_s" :
       _fmt_c 0x1 + "_fmt_c" :
     )
   while

@@ -0,0 +1,87 @@ 
+#!/usr/bin/env hex
+"./lib/utils.hbx" read "utils.hbx" !
+
+(args len 0x3 <) 
+    ("ERROR: no input file specified." puts 0x1 exit)
+when
+
+args 0x2 get "INFILE" : 
+
+(args len 0x4 <) 
+    ("ERROR: no output file specified." puts 0x1 exit)
+when
+
+args 0x3 get "OUTFILE" : 
+
+
+"*** Processing ${0}..." (INFILE) fmt puts 
+
+INFILE read "\n" split "LINES" :
+
+"" "PREV" :
+"" "OUT"  :
+LINES
+    (
+        "LINE" :
+        (LINE ";;;;; " begins)
+            (
+                ("h3" PREV ==)
+                    ; Paragraph after title
+                    (
+                        LINE ";;;;; " "" sub () cons "<p>${0}</p>\n" swap fmt OUT swap cat "OUT" :
+                        "p" "PREV" :
+                    )
+                    ; H3
+                    (
+                        LINE ";;;;; " "" sub () cons "<h3>${0}</h2>\n" swap fmt OUT swap cat "OUT" :
+                        "h3" "PREV" :
+                    )
+                if
+            )
+        when 
+        (LINE ";;;; " begins)
+            (
+                ("h4" PREV ==)
+                    ; Paragraph after title
+                    (
+                        LINE ";;;; " "" sub () cons "<p>${0}</p>\n" swap fmt OUT swap cat "OUT" :
+                        "p" "PREV" :
+                    )
+                    ; H4
+                    (
+                        LINE ";;;; " "" sub () cons "<h4>${0}</h3>\n" swap fmt OUT swap cat "OUT" :
+                        "h4" "PREV" :
+                    )
+                if
+            )
+        when 
+        (LINE ";;; " begins)
+            (
+                LINE ";;; " "" sub () cons "<h5 id=\"${0}-symbol\"><code><span class=\"hex-symbol\">${0}</span></code> Symbol</h5><a href=\"top\"></a>\n" swap fmt OUT swap cat "OUT" :
+                "sym" "PREV" :
+            )
+        when
+        (LINE ";; " begins "sig" PREV == and)
+            (
+                LINE ";; " "" sub () cons "<p>${0}</p>\n" swap fmt OUT swap cat "OUT" :
+                "desc" "PREV" :
+            )
+        when
+        (LINE ";; " begins "sym" PREV == and)
+            (
+                LINE ";; " "" sub () cons "<p><mark>${0}</mark></p>\n" swap fmt "->" "→" sub OUT swap cat "OUT" :
+                "sig" "PREV" :
+            )
+        when
+        "LINE" #
+    )
+each
+
+"*** Writing output to ${0}..." (OUTFILE) fmt puts
+OUT OUTFILE write
+"*** Done!" puts
+
+"OUT"       #
+"PREV"      #
+"LINES"     #
+"INFILE"      #

@@ -355,10 +355,10 @@ ((0x1 0x4 0x5) min 0x1 ==)
     ((0x1 0x4 0x5) max 0x5 ==)
     ;190
 
-    ("$0, $1!" ("hello" "world") fmt "hello, world!" ==)
+    ("${0}, ${1}!" ("hello" "world") fmt "hello, world!" ==)
     (("" ("a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m" "n") fmt) (error) try "[symbol fmt] Only a maximum of 10 placeholders are supported" ==)
-    ("This is a $0, and another $0, and yet another $0" ("test") fmt "This is a test, and another test, and yet another test" ==)
-    ("$0, $2, $1!" ("first" "third") fmt "first, $2, third!" ==)
+    ("This is a ${0}, and another ${0}, and yet another ${0}" ("test") fmt "This is a test, and another test, and yet another test" ==)
+    ("${0}, ${2}, ${1}!" ("first" "third") fmt "first, ${2}, third!" ==)
     ;194
 
     (0x0 "_a" : (0x1 0x2 0x3) (_a + "_a" :) each _a 0x6 == "_a" #)

@@ -38,6 +38,8 @@ "$:"
     "$$"
     "%:"
     "%%"
+    "\{"
+    "\}"
 ) "highlight-delimiters" :
 
 (
@@ -50,6 +52,8 @@ "<span class=\"hex-symbol\">"
     "</span>"
     "<code>"
     "</code>"
+    "{"
+    "}"
 ) "highlight-replacements" :
 
 ; Highlight syntax in text
@@ -190,6 +194,9 @@ changelog-content highlight
 "CHANGELOG.md" write
 "*** Done!" puts
 
+; Read reference docs
+"lib/utils.html" read "lib_utils_docs" :
+
 ;;;;; Write web site contents
 "*** Generating hex web site..." puts
 0x0 "_c" :
@@ -206,6 +213,8 @@ "release" meta-release process-tag
         "year" meta-year process-tag
         "changelog-toc" changelog-toc process-tag
         "releases" releases-content process-tag 
+        ; Replace files
+        "@@@lib/utils.html@@@" lib_utils_docs sub
         "new-content" :
         ; Replace symbols with links
         0x0 "_i" :

@@ -7058,7 +7058,7 @@ 
     hex_register_symbols(ctx);
     hex_create_docs(ctx->docs);
 
-    char *file;
+    char *file = NULL;
     int generate_bytecode = 0;
 
     if (argc > 1)
@@ -7115,7 +7115,11 @@ }
             }
             else
             {
-                file = arg;
+                if (!file)
+                {
+                    file = arg;
+                }
+                // Ignore extra arguments
             }
         }
         if (file)

@@ -358,7 +358,7 @@ 
     hex_register_symbols(ctx);
     hex_create_docs(ctx->docs);
 
-    char *file;
+    char *file = NULL;
     int generate_bytecode = 0;
 
     if (argc > 1)
@@ -415,7 +415,11 @@ }
             }
             else
             {
-                file = arg;
+                if (!file)
+                {
+                    file = arg;
+                }
+                // Ignore extra arguments
             }
         }
         if (file)

@@ -8,4 +8,6 @@ To pre-load this file, you can start hex like this:</p>
   <pre><code>hex -l utils.hbx</code></pre>
   </p>
 
+  @@@lib/utils.html@@@
+
 </article>