add dry-run switch to render and setup

pollen/private/command.rkt

@@ -76,18 +76,20 @@ version                print the version" (current-server-port) (make-publish-di
 (define (handle-setup)
   (message "preheating cache ...")
   (define setup-parallel? (make-parameter #false))
+  (define dry-run? (make-parameter #false))
   (define parsed-args
     (command-line #:program "raco pollen setup"
                   #:argv (vector-drop (current-command-line-arguments) 1) ; snip the 'setup' from the front
                   #:once-any
                   [("-p" "--parallel") "Setup in parallel using all cores" (setup-parallel? #true)]
                   [("-j" "--jobs") job-count "Setup in parallel using <job-count> jobs" (setup-parallel? (or (string->number job-count) (raise-argument-error 'handle-setup "exact positive integer" job-count)))]
+                  [("-d" "--dry-run") "Print paths that would be compiled" (dry-run? #true)]
                   #:args other-args
                   other-args))
   (define starting-dir (match parsed-args
                          [(list dir) dir]
                          [_  (current-directory)]))
-  ((dynamic-require 'pollen/private/preheat-cache 'preheat-cache) starting-dir (setup-parallel?)))
+  ((dynamic-require 'pollen/private/preheat-cache 'preheat-cache) starting-dir (setup-parallel?) (dry-run?)))
 
 (define (handle-render)
   (define render-batch (dynamic-require 'pollen/render 'render-batch))
@@ -96,6 +98,7 @@ version                print the version" (current-server-port) (make-publish-di
   (define render-target-wanted (make-parameter (current-poly-target)))
   (define render-with-subdirs? (make-parameter #f))
   (define render-parallel? (make-parameter #f))
+  (define dry-run? (make-parameter #f))
   (define parsed-args
     (command-line #:program "raco pollen render"
                   #:argv (vector-drop (current-command-line-arguments) 1) ; snip the 'render' from the front
@@ -105,11 +108,18 @@ version                print the version" (current-server-port) (make-publish-di
                   [("-r" "--recursive") "Render subdirectories recursively"
                                         (render-with-subdirs? 'recursive)]
                   [("-s" "--subdir") "Render subdirectories nonrecursively" (render-with-subdirs? 'include)]
+                  [("-d" "--dry-run") "Print paths that would be rendered" (dry-run? #true)]
                   #:once-any
                   [("-p" "--parallel") "Render in parallel using all cores" (render-parallel? #true)]
                   [("-j" "--jobs") job-count "Render in parallel using <job-count> jobs" (render-parallel? (or (string->number job-count) (raise-argument-error 'handle-render "exact positive integer" job-count)))]
                   #:args other-args
                   other-args))
+
+  (define (handle-batch-render paths)
+    (if (dry-run?)
+        (for-each message paths)
+        (apply render-batch paths #:parallel (render-parallel?))))
+  
   (parameterize ([current-poly-target (render-target-wanted)]) ;; applies to both cases
     (let loop ([args parsed-args])
       (match args
@@ -137,14 +147,14 @@ version                print the version" (current-server-port) (make-publish-di
                         [_
                          (message (format "rendering preproc & pagetree files in directory ~a" dir))
                          (append preprocs static-pagetrees)])))
-               (apply render-batch paths-to-render #:parallel (render-parallel?))
+               (handle-batch-render paths-to-render)
                (when (render-with-subdirs?)
                  (for ([path (in-list dirlist)]
                        #:when (directory-exists? path))
                       (render-one-dir (->complete-path path)))))))]
         [path-args ;; path mode
          (message (format "rendering ~a" (string-join (map ->string path-args) " ")))
-         (apply render-batch (map very-nice-path path-args) #:parallel (render-parallel?))]))))
+         (handle-batch-render (map very-nice-path path-args))]))))
 
 (define (handle-start)
   (define launch-wanted #f)

pollen/private/preheat-cache.rkt

@@ -16,7 +16,7 @@
   (and (file-exists? cache-db-file)
        (hash-has-key? (file->value cache-db-file) (paths->key path))))
 
-(define (preheat-cache starting-dir [wants-parallel-setup #false])
+(define (preheat-cache starting-dir [wants-parallel-setup? #false] [wants-dry-run? #false])
   (unless (and (path-string? starting-dir) (directory-exists? starting-dir))
     (raise-argument-error 'preheat-cache "directory" starting-dir))
   
@@ -33,17 +33,17 @@
               (path->complete-path path)))
 
   (cond
-    [(null? uncached-paths)
-     (message "all cached files are up to date")]
-    [wants-parallel-setup
+    [wants-dry-run? (for-each message uncached-paths)]
+    [(null? uncached-paths) (message "all cached files are up to date")]
+    [wants-parallel-setup?
      
      (define job-count
        (min
         (length uncached-paths)
-        (match wants-parallel-setup
+        (match wants-parallel-setup?
           [#true (processor-count)]
           [(? exact-positive-integer? count) count]
-          [_ (raise-argument-error 'preheat-cache "exact positive integer" wants-parallel-setup)])))    
+          [_ (raise-argument-error 'preheat-cache "exact positive integer" wants-parallel-setup?)])))    
 
      (define worker-evts
        (for/list ([wpidx (in-range job-count)])

pollen/private/ts.rktd

@@ -1 +1 @@
-1573164977
+1573239737

pollen/scribblings/raco.scrbl

@@ -49,7 +49,7 @@ Displays a list of available commands.
 
 Start the project server from the current directory using the default port, which is the value of the parameter @racket[current-server-port] (by default, port @id[default-project-server-port]).
 
-This command can be invoked with two optional arguments, and one optional switch.
+This command can be invoked with two optional arguments, and several optional switches.
 
 @racket[raco pollen start _path] will start the project server from @racket[_path] rather than the current directory (making @racket[_path] its root directory).
 
@@ -115,6 +115,8 @@ As a rule of thumb, parallel rendering works best if you do @exec{raco setup} fi
 > raco pollen render -p 
 }
 
+The optional @exec{--dry-run} or @exec{-d} switch prints the paths that would be rendered by this command without actually doing so.
+
 
 @italic{Warning}: In all cases, the newly rendered output file will overwrite any previous output file.
 
@@ -167,6 +169,8 @@ The alternative @exec{--jobs <count>} or @exec{-j <count>} switch does the same
 > raco pollen setup -j 4
 }
 
+The optional @exec{--dry-run} or @exec{-d} switch prints the paths that would be compiled by this command without actually doing so.
+
 
 @section{@exec{raco pollen reset}}