refactor template functions

scribblings/template.scrbl

@@ -1,6 +1,6 @@
 #lang scribble/manual
 
-@(require scribble/eval pollen/cache pollen/world (for-label racket (except-in pollen #%module-begin) pollen/template pollen/render xml pollen/pagetree))
+@(require scribble/eval pollen/cache pollen/world (for-label racket (except-in pollen #%module-begin) pollen/template pollen/render xml pollen/pagetree sugar/coerce/value))
 
 @(define my-eval (make-base-eval))
 @(my-eval `(require pollen pollen/template xml))
@@ -11,6 +11,8 @@
 
 Convenience functions for templates. These are automatically imported into the @racket[eval] environment when rendering with a template (see @racket[render]).
 
+This module also provides everything from @racket[sugar/coerce/value].
+
 @defproc[
 (->html
 [xexpr xexpr?])
@@ -34,52 +36,52 @@ Be careful not to pass existing HTML strings into this function, because the @co
 @deftogether[(
 
 @defproc[
-(from
-[query symbolish?]
-[pagenode pagenodeish?])
+(select
+[key symbolish?]
+[value-source (or/c hash? txexpr? pagenode? pathish?)])
 (or/c #f txexpr-element?)]
 
 @defproc[
-(from*
-[query symbolish?]
-[pagenode pagenodeish?])
+(select*
+[key symbolish?]
+[value-source (or/c hash? txexpr? pagenode? pathish?)])
 (or/c #f (listof txexpr-element?))]
 
 )]
-Find matches for @racket[_query] in @racket[_pagenode], first by looking in its @code{metas} (using @racket[from-metas]) and then by looking in its @code{doc} (using @racket[from-doc]). With @racket[from], you get the first result; with @racket[from*], you get them all. In both cases, you get @racket[#f] if there are no matches.
+Find matches for @racket[_key] in @racket[_value-source], first by looking in its @code{metas} (using @racket[select-from-metas]) and then by looking in its @code{doc} (using @racket[select-from-doc]). With @racket[select], you get the first result; with @racket[select*], you get them all. In both cases, you get @racket[#f] if there are no matches.
 
 
 
 
 @defproc[
-(from-metas
-[query symbolish?]
-[meta-source (or/c pagenodeish? hash?)])
+(select-from-metas
+[key symbolish?]
+[meta-source (or/c hash? pagenodeish? pathish?)])
 (or/c #f txexpr-element?)]
-Look up the value of @racket[_query] in @racket[_meta-source]. The @racket[_meta-source] argument can be either a set of metas (i.e., a @racket[hash]) or a @racket[pagenode?], from which metas are pulled. If no value exists for @racket[_query], you get @racket[#f].
+Look up the value of @racket[_key] in @racket[_meta-source]. The @racket[_meta-source] argument can be either a set of metas (i.e., a @racket[hash]) or a @racket[pagenode?], from which metas are pulled. If no value exists for @racket[_key], you get @racket[#f].
 
 @examples[#:eval my-eval
 (define my-metas (hash 'template "sub.xml.pt" 'target "print"))
-(from-metas 'template  my-metas)
-('target . from-metas . my-metas)
-(from-metas 'nonexistent-key my-metas)
+(select-from-metas 'template  my-metas)
+('target . select-from-metas . my-metas)
+(select-from-metas 'nonexistent-key my-metas)
 ]
 
 
 
 @defproc[
-(from-doc
-[query symbolish?]
-[doc-source (or/c pagenodeish? txexpr?)])
+(select-from-doc
+[key symbolish?]
+[doc-source (or/c txexpr? pagenodeish? pathish?)])
 (or/c #f txexpr-element?)]
-Look up the value of @racket[_query] in @racket[_doc-source]. The @racket[_doc-source] argument can be either be a @code{doc} (i.e., a @racket[txexpr]) or a @racket[pagenode?], from which doc is pulled. If no value exists for @racket[_query], you get @racket[#f].
+Look up the value of @racket[_key] in @racket[_doc-source]. The @racket[_doc-source] argument can be either be a @code{doc} (i.e., a @racket[txexpr]) or a @racket[pagenode?], from which doc is pulled. If no value exists for @racket[_key], you get @racket[#f].
 
 @examples[#:eval my-eval
 (define my-doc '(body (question "Gelato?") 
 (answer "Nocciola") (answer "Pistachio")))
-(from-doc 'question  my-doc)
-('answer . from-doc . my-doc)
-(from-doc 'nonexistent-key my-doc)
+(select-from-doc 'question  my-doc)
+('answer . select-from-doc . my-doc)
+(select-from-doc 'nonexistent-key my-doc)
 ]
 
 

template.rkt

@@ -10,60 +10,66 @@
 
 (define/contract+provide (metas->here metas)
   (hash? . -> . pagenode?)
-  (path->pagenode ('here-path . from-metas . metas)))
+  (path->pagenode (select-from-metas 'here-path metas)))
 
 
-(define/contract (get-doc pagenode-or-path)
-  ((or/c pagenode? pathish?) . -> . (or/c txexpr? string?))
-  (define source-path (->source-path (cond
-                                       [(pagenode? pagenode-or-path) (pagenode->path pagenode-or-path)]
-                                       [else pagenode-or-path])))
-  (if source-path
-      (cached-require source-path world:main-pollen-export)
-      (error (format "get-doc: no source found for '~a' in directory ~a" pagenode-or-path (current-directory)))))
+(define (pagenode->path pagenode)
+  (build-path (world:current-project-root) (symbol->string pagenode)))
 
 
-(define/contract (get-metas pagenode-or-path)
-  ((or/c pagenode? pathish?) . -> . hash?)
-  (define source-path (->source-path (cond
-                                       [(pagenode? pagenode-or-path) (pagenode->path pagenode-or-path)]
-                                       [else pagenode-or-path])))
-  (if source-path
-      (cached-require source-path world:meta-pollen-export)
-      (error (format "get-metas: no source found for '~a' in directory ~a" pagenode-or-path (current-directory)))))
+(define+provide/contract (select key value-source)
+  (coerce/symbol? (or/c hash? txexpr? pagenode? pathish?) . -> . (or/c #f txexpr-element?))
+  (define metas-result (and (not (txexpr? value-source)) (select-from-metas key value-source)))
+  (or metas-result
+      (let ([doc-result (select-from-doc key value-source)])
+        (and doc-result (car doc-result)))))
 
 
-(define (pagenode->path pagenode)
-  (build-path (world:current-project-root) (symbol->string pagenode)))
+(define+provide/contract (select* key value-source)
+  (coerce/symbol? (or/c hash? txexpr?) . -> . (or/c #f (listof txexpr-element?)))
+  (define metas-result (and (not (txexpr? value-source)) (select-from-metas key value-source)))
+  (define doc-result (select-from-doc key value-source))
+  (define result (append (or (and metas-result (list metas-result)) null) (or doc-result null)))
+  (and (not (null? result)) result))
+
 
+(define+provide/contract (select-from-metas key metas-source)
+  (coerce/symbol? (or/c hash? pagenode? pathish?) . -> . (or/c #f txexpr-element?))
+  (define metas (cond
+                  [(hash? metas-source) metas-source]
+                  [else (get-metas metas-source)]))
+  (and (hash-has-key? metas key) (hash-ref metas key)))
 
-(define+provide/contract (from query pagenode)
-  (coerce/symbol? coerce/symbol? . -> . (or/c #f txexpr-element?))
-  (define result (from* query pagenode))
-  (if (null? result) #f (car result)))
 
+(define+provide/contract (select-from-doc key doc-source)
+  (coerce/symbol? (or/c txexpr? pagenode? pathish?) . -> . (or/c #f (listof txexpr-element?)))
+  (define doc (cond
+                [(txexpr? doc-source) doc-source]
+                [else (get-doc doc-source)]))
+  (define result (se-path*/list (list key) doc))
+  (and (not (null? result)) result))
 
-(define+provide/contract (from* query pagenode)
-  (coerce/symbol? coerce/symbol? . -> . (or/c #f (listof txexpr-element?)))
-  (define meta-result (from-metas query pagenode))
-  (define doc-result (from-doc query pagenode))
-  (define combined-result (append (if meta-result (list meta-result) null) 
-          (or doc-result null)))
-  (if (null? combined-result) #f combined-result))
 
+(define (get-metas pagenode-or-path)
+;  ((or/c pagenode? pathish?) . -> . hash?)
+  (define source-path (->source-path (cond
+                                       [(pagenode? pagenode-or-path) (pagenode->path pagenode-or-path)]
+                                       [else pagenode-or-path])))
+  (if source-path
+      (cached-require source-path world:meta-pollen-export)
+      (error (format "get-metas: no source found for '~a' in directory ~a" pagenode-or-path (current-directory)))))
 
-(define/contract+provide (from-metas query meta-source)
-  (coerce/symbol? (or/c pagenode? hash?) . -> . (or/c #f txexpr-element?))
-  (let ([metas (or (and (pagenode? meta-source) (get-metas meta-source)) meta-source)])
-    (with-handlers ([exn:fail? (λ(e) #f)])
-      (hash-ref metas query))))
+
+(define (get-doc pagenode-or-path)
+;  ((or/c pagenode? pathish?) . -> . (or/c txexpr? string?))
+  (define source-path (->source-path (cond
+                                       [(pagenode? pagenode-or-path) (pagenode->path pagenode-or-path)]
+                                       [else pagenode-or-path])))
+  (if source-path
+      (cached-require source-path world:main-pollen-export)
+      (error (format "get-doc: no source found for '~a' in directory ~a" pagenode-or-path (current-directory)))))
 
 
-(define/contract+provide (from-doc query doc-source) 
-  (coerce/symbol? (or/c pagenode? txexpr?) . -> . (or/c #f txexpr-elements?))
-  (let ([doc (or (and (pagenode? doc-source) (get-doc doc-source)) doc-source)])
-    (with-handlers ([exn:fail? (λ(e) #f)])
-      (se-path*/list (list query) doc))))
 
 
 (define+provide/contract (->html x)