Added the blogger scraper.

README.md

@@ -21,29 +21,29 @@ To use this library in your project, add the following leiningen dependency:
 
 To use it in your namespace, require:
 
-    [html-to-md/transformer :refer [transform process]]
+    [html-to-md.core :refer [html-to-md]]
-    [html-to-md/html-to-md :refer [markdown-dispatcher]]
+
+For default usage, that's all you need. To play more sophisticated tricks,
+consider:
+
+    [html-to-md.transformer :refer [transform process]]
+    [html-to-md.html-to-md :refer [markdown-dispatcher]]
 
 The intended usage is as follows:
 
 ```clojure
-(require '[html-to-md.transformer :refer [transform]])
+(require '[html-to-md.core :refer [html-to-md]])
-(require '[html-to-md.html-to-md :refer [markdown-dispatcher]])
 
-(transform URL markdown-dispatcher)
+(html-to-md url output-file)
 ```
 
-Where URL is any URL that references an HTML, SGML, XHTML or XML document.
+This will read (X)HTML from `url` and write Markdown to `output-file`. If
-However, my fancy multi-method doesn't work yet and may well be the wrong
+`output-file` is not supplied, it will return the markdown as a string:
-approach, so for now use
 
 ```clojure
+(require '[html-to-md.core :refer [html-to-md]])
 
-(require '[html-to-md.transformer :refer [process]])
+(def md (html-to-md url))
-(require '[html-to-md.html-to-md :refer [markdown-dispatcher]])
-(require '[net.cgrand.enlive-html :as html])
-
-(process (html/html-resource URL) markdown-dispatcher)
 ```
 
 ## Extending the transformer
@@ -66,3 +66,4 @@ Copyright © 2019 Simon Brooke <simon@journeyman.cc>
 
 Distributed under the Eclipse Public License either version 1.0 or (at
 your option) any later version.
+

doc/intro.md

@@ -1,3 +1,116 @@
 # Introduction to html-to-md
 
 TODO: write [great documentation](http://jacobian.org/writing/what-to-write/)
+
+## Introduction
+
+The itch I'm trying to scratch at present is to transform
+[Blogger.com](http://www.blogger.com)'s dreadful tag-soup markup into markdown;
+but my architecture for doing this is to build a completely general [HT|SG|X]ML
+transformation framework and then specialise it.
+
+**WARNING:** this is presently alpha-quality code, although it does have fair
+unit test coverage.
+
+## Usage
+
+To use this library in your project, add the following leiningen dependency:
+
+    [org.clojars.simon_brooke/html-to-md "0.1.0"]
+
+To use it in your namespace, require:
+
+    [html-to-md.core :refer [html-to-md]]
+
+For default usage, that's all you need. To play more sophisticated tricks,
+consider:
+
+    [html-to-md.transformer :refer [transform process]]
+    [html-to-md.html-to-md :refer [markdown-dispatcher]]
+
+The intended usage is as follows:
+
+```clojure
+(require '[html-to-md.core :refer [html-to-md]])
+
+(html-to-md url output-file)
+```
+
+This will read (X)HTML from `url` and write Markdown to `output-file`. If
+`output-file` is not supplied, it will return the markdown as a string:
+
+```clojure
+(require '[html-to-md.core :refer [html-to-md]])
+
+(def md (html-to-md url))
+```
+
+## Extending the transformer
+
+In principle, the transformer can transform any [HT|SG|X]ML markup into any
+other, or into any textual form. To extend it to do something other than
+markdown, supply a **dispatcher**. A dispatcher is essentially a function of one
+argument, a [HT|SG|X]ML tag represented as a Clojure keyword, which returns
+a **processor,** which should be a function of two arguments, an element assumed
+to have that tag, and a dispatcher. The processor should return the value that
+you want elements of that tag transformed into.
+
+Thus the `html-to-md.html-to-md` namespace comprises a number of *processor*
+functions, such as this one:
+
+```clojure
+(defn markdown-a
+    "Process the anchor element `e` into markdown, using dispatcher `d`."
+    [e d]
+    (str
+        "["
+        (s/trim (apply str (process (:content e) d)))
+        "]("
+        (-> e :attrs :href)
+        ")"))
+```
+
+and a *dispatcher* map:
+
+```clojure
+(def markdown-dispatcher
+    "A despatcher for transforming (X)HTML into Markdown."
+    {:a markdown-a
+     :b markdown-strong
+     :br markdown-br
+     :code markdown-code
+     :body markdown-default
+     :div markdown-div
+     :em markdown-em
+     :h1 markdown-h1
+     :h2 markdown-h2
+     :h3 markdown-h3
+     :h4 markdown-h4
+     :h5 markdown-h5
+     :h6 markdown-h6
+     :html markdown-html
+     :i markdown-em
+     :img markdown-img
+     :ol markdown-ol
+     :p markdown-div
+     :pre markdown-pre
+     :samp markdown-code
+     :script markdown-omit
+     :span markdown-default
+     :strong markdown-strong
+     :style markdown-omit
+     :ul markdown-ul
+     })
+```
+
+Obviously it is convenient to write dispatchers as maps, but it isn't required
+that you do so: anything which, given a keyword, will return a processor, will
+work.
+
+## License
+
+Copyright © 2019 Simon Brooke <simon@journeyman.cc>
+
+Distributed under the Eclipse Public License either version 1.0 or (at
+your option) any later version.
+

src/html_to_md/core.clj

@@ -1,6 +1,11 @@
-(ns html-to-md.core)
+(ns html-to-md.core
+    (:require [html-to-md.transformer :refer [transform process]]
+              [html-to-md.html-to-md :refer [markdown-dispatcher]]))
 
-(defn foo
+(defn html-to-md
-  "I don't do a whole lot."
+    "Transform the HTML document referenced by `url` into Markdown, and write
-  [x]
+    it to `output`, if supplied."
-  (println x "Hello, World!"))
+    ([url]
+     (apply str (transform url markdown-dispatcher)))
+    ([url output]
+     (spit output (html-to-md url))))

src/html_to_md/html_to_md.clj

@@ -165,6 +165,7 @@
 
 
 (def markdown-dispatcher
+    "A despatcher for transforming (X)HTML into Markdown."
     {:a markdown-a
      :b markdown-strong
      :br markdown-br

src/html_to_md/transformer.clj

@@ -29,7 +29,7 @@
 
         (string? element) element
         (or (seq? element) (vector? element))
-        (doall (map #(process % dispatcher) element))))
+        (remove nil? (map #(process % dispatcher) element))))
 
 (defn- transformer-dispatch
     [a _]
@@ -45,7 +45,7 @@
     (process obj dispatcher))
 
 (defmethod transform java.net.URI [uri dispatcher]
-    (process (html/html-resource uri) dispatcher))
+    (remove nil? (process (html/html-resource uri) dispatcher)))
 
 (defmethod transform java.net.URL [url dispatcher]
     (transform (.toURI url) dispatcher))