add `current-metas` parameter (addresses #166)

pollen/core.rkt

@@ -15,6 +15,7 @@
 
 (define+provide define-meta identity) ;; stub so it will be picked up for docs
 
+(define+provide current-metas (make-parameter #f))
 
 (define+provide/contract (select* key value-source [caller 'select*])
   ((coerce/symbol? (or/c is-meta-value? is-doc-value? pagenode? pathish?)) (symbol?) . ->* . (or/c #f txexpr-elements?))

pollen/private/main-base.rkt

@@ -1,6 +1,6 @@
 #lang racket/base
 (require (for-syntax racket/base racket/syntax "../setup.rkt" "split-metas.rkt")
-         "to-string.rkt" "../pagetree.rkt" "splice.rkt" "../setup.rkt")
+         "to-string.rkt" "../pagetree.rkt" "splice.rkt" "../setup.rkt" "../core.rkt")
 (provide (except-out (all-from-out racket/base) #%module-begin)
          (rename-out [dialect-module-begin #%module-begin]))
 
@@ -64,8 +64,11 @@
             (module inner pollen/private/doclang-raw
               DOC-RAW ; positional arg for doclang-raw that sets name of export
               (require pollen/top pollen/core pollen/setup (submod ".." META-MOD-ID))
+              (and (current-metas METAS-ID) "\n") ; because newlines get stripped, voids don't
               (provide (all-defined-out) METAS-ID)
               . EXPRS-WITHOUT-METAS)            
+
+            (define prev-metas (current-metas))
             (require 'inner)
 
             (define DOC-ID
@@ -76,4 +79,5 @@
                      [doc-elements-spliced (splice doc-elements (setup:splicing-tag))])
                 (proc doc-elements-spliced)))
 
+            (current-metas prev-metas)
             (provide DOC-ID (except-out (all-from-out 'inner) DOC-RAW)))))]))

pollen/private/ts.rktd

@@ -1 +1 @@
-1516502120
+1516572991