add "insert command char" button to DrRacket (closes #104)

drracket-buttons.rkt

@@ -0,0 +1,32 @@
+#lang racket/base
+
+(require racket/runtime-path
+         racket/gui/base
+         racket/class)
+
+(provide make-drracket-buttons)
+
+(module test racket/base) ; suppress testing by `raco test`
+
+(define-runtime-path html-png-path "server-extras/cmd-char.png")
+
+#| for toolbar callbacks, see
+
+http://pkg-build.racket-lang.org/doc/tools/drracket_module-language-tools.html#%28elem._drracket~3atoolbar-buttons%29
+
+|#
+
+(define (make-command-char-button command-char)
+  (let ([label (format "Insert command char ~a" command-char)]
+        [bitmap (make-object bitmap% html-png-path 'png/mask)]
+        [callback (λ (drr-frame)
+                    (define editor (send drr-frame get-definitions-text))
+                    (send editor begin-edit-sequence)
+                    (send editor insert command-char)
+                    (send editor end-edit-sequence))]
+        [number 99])
+    (list label bitmap callback number)))
+
+(define (make-drracket-buttons command-char)
+  (let ([command-char-button (make-command-char-button command-char)])
+    (list command-char-button)))

reader-base.rkt

@@ -1,6 +1,6 @@
 #lang racket/base
 (require racket/syntax syntax/strip-context racket/class)
-(require (only-in scribble/reader make-at-reader) pollen/file pollen/world pollen/project racket/list)
+(require (only-in scribble/reader make-at-reader) pollen/world pollen/project racket/list)
 (provide define+provide-reader-in-mode (all-from-out pollen/world))
 
 
@@ -64,20 +64,28 @@
     (define custom-read-syntax (make-custom-read-syntax reader-mode))
     (define custom-read (make-custom-read custom-read-syntax))
     (define (get-info in mod line col pos)
-      (λ (key default)
-        (case key
-          [(color-lexer)
-           (define my-make-scribble-inside-lexer
-             (dynamic-require 'syntax-color/scribble-lexer 'make-scribble-inside-lexer (λ () #f)))
-           (cond [my-make-scribble-inside-lexer
-                  (define definitions-frame (object-name in))
-                  (define maybe-source-path (with-handlers ([exn:fail? (λ(exn) #f)])
-                                              (send definitions-frame get-filename))) ; will be #f if unsaved file
-                  (define my-command-char (if maybe-source-path
-                                              (parameterize ([current-directory (dirname maybe-source-path)])
-                                                (world:current-command-char))
-                                              world:command-char))
-                  (my-make-scribble-inside-lexer #:command-char my-command-char)]
-                 [else default])]
-          [else default])))
+      ;; DrRacket caches source file information per session,
+      ;; so we can do the same to avoid multiple searches for the command char.
+      (let ([command-char-cache (make-hash)])
+        (λ (key default)
+          (case key
+            [(color-lexer drracket:toolbar-buttons) ; only do source-path searching if we have one of these keys
+             (define maybe-source-path (with-handlers ([exn:fail? (λ(exn) #f)])
+                                         ;; Robert Findler does not endorse `get-filename` here,
+                                         ;; because it's sneaky and may not always work.
+                                         ;; OTOH Scribble relies on it, so IMO it's highly unlikely to change.
+                                         (let ([maybe-definitions-frame (object-name in)])
+                                           (send maybe-definitions-frame get-filename)))) ; will be #f if unsaved file
+             (define my-command-char (hash-ref! command-char-cache maybe-source-path (λ _ (world:current-command-char maybe-source-path))))
+             (case key
+               [(color-lexer)
+                (define my-make-scribble-inside-lexer
+                  (dynamic-require 'syntax-color/scribble-lexer 'make-scribble-inside-lexer (λ () #f)))
+                (cond [my-make-scribble-inside-lexer
+                       (my-make-scribble-inside-lexer #:command-char my-command-char)]
+                      [else default])]
+               [(drracket:toolbar-buttons)
+                (define my-make-drracket-buttons (dynamic-require 'pollen/drracket-buttons 'make-drracket-buttons))
+                (my-make-drracket-buttons my-command-char)])]
+            [else default]))))
     (provide (rename-out [custom-read read] [custom-read-syntax read-syntax]) get-info)))

scribblings/command.scrbl

@@ -37,6 +37,10 @@ But don't knock the lozenge till you try it.
 
 @subsection{Lozenge helpers}
 
+@subsubsection{DrRacket}
+
+When you use DrRacket, you'll see a button in the toolbar that says @onscreen{Insert command char}. This will insert the lozenge (or whatever command character you've defined for your project).
+
 
 @subsubsection{AHK script}