start gang helper

pollen/private/gang-helper.rkt

@@ -0,0 +1,55 @@
+#lang racket/base
+(require (for-syntax racket/base
+                     syntax/strip-context
+                     "project.rkt"
+                     "../setup.rkt")
+         racket/stxparam
+         racket/splicing
+         "external/include-template.rkt"
+         "../cache.rkt"
+         "../pagetree.rkt"
+         "../core.rkt"
+         "../setup.rkt"
+         "../template.rkt"
+         "../top.rkt")
+
+(provide (rename-out [mb #%module-begin])
+         (except-out (all-from-out racket/base) #%module-begin))
+
+(define-syntax-parameter doc (λ (stx) (error 'doc-not-parameterized)))
+(define-syntax-parameter metas (λ (stx) (error 'metas-not-parameterized)))
+(define-syntax-parameter result (λ (stx) (error 'result-not-parameterized)))
+
+(define-syntax (mb stx)
+  (syntax-case stx ()
+    ;; markup / markdown branch
+    [(_ #:sources SOURCE-PATH-STRING ...
+        #:template TEMPLATE-PATH-STRING
+        #:result-id RESULT-ID)
+     (let ([source-path (syntax->datum (car (syntax->list #'(SOURCE-PATH-STRING ...))))])
+       (with-syntax ([DIRECTORY-REQUIRE-FILES
+                      (replace-context #'here (require-directory-require-files source-path))]
+                     [DOC-ID pollen-main-export]
+                     [METAS-ID pollen-meta-export]
+                     [COMMAND-CHAR (setup:command-char source-path)]
+                     [(SUBRESULT ...) (generate-temporaries #'(SOURCE-PATH-STRING ...))])
+         #'(#%module-begin 
+            DIRECTORY-REQUIRE-FILES
+            (splicing-syntax-parameterize
+                ([doc (make-rename-transformer #'DOC-ID)]
+                 [metas (make-rename-transformer #'METAS-ID)]
+                 [result (make-rename-transformer #'RESULT-ID)])
+              (define SUBRESULT
+                (parameterize ([current-pagetree (make-project-pagetree (current-project-root))]
+                               [current-metas (cached-metas SOURCE-PATH-STRING)])
+                  (define doc (cached-doc SOURCE-PATH-STRING))
+                  (define metas (current-metas))
+                  (define here (path->pagenode
+                                (or (select-from-metas pollen-here-path-key metas) 'unknown)))
+                  (if (bytes? doc) ; if main export is binary, just pass it through
+                      doc
+                      ;; allows `require` in a template
+                      (splicing-let-syntax ([require (make-rename-transformer #'local-require)])
+                        (include-template #:command-char COMMAND-CHAR (file TEMPLATE-PATH-STRING)))))) ...
+              (define result (list SUBRESULT ...))
+              (provide result)))))]))