Add include support, with variables and the whole shebang

Fixes #462

4 files changed, 54 insertions, 34 deletions

diff --git a/lib/parse/code_include.js b/lib/parse/code_include.js
deleted file mode 100644
index 977dc3d..0000000
--- a/lib/parse/code_include.js
+++ /dev/null
@@ -1,20 +0,0 @@
-var fs = require('graceful-fs');
-var path = require('path');
-
-module.exports = function(code, folder) {
-    folder = folder || '';
-
-    return code.replace(/{{([\s\S]+?)}}/g, function(match, filename) {
-        // Normalize filename
-        var fname = path.join(folder, filename.trim());
-
-        // Try including snippet from FS
-        try {
-            // Trim trailing newlines/space of imported snippets
-            return fs.readFileSync(fname, 'utf8').trimRight();
-        } catch(err) {}
-
-        // If fails leave content as is
-        return match;
-    });
-};
diff --git a/lib/parse/include.js b/lib/parse/include.js
new file mode 100644
index 0000000..5fba2be
--- /dev/null
+++ b/lib/parse/include.js
@@ -0,0 +1,48 @@
+var _ = require('lodash');
+var fs = require('graceful-fs');
+var path = require('path');
+
+
+// Include helper
+function importInclude(name, paths) {
+    return paths
+    .map(function(folder) {
+        // Try including snippet from FS
+        try {
+            var fname = path.join(folder, name);
+            // Trim trailing newlines/space of imported snippets
+            return fs.readFileSync(fname, 'utf8').trimRight();
+        } catch(err) {}
+    })
+    .filter(Boolean)[0];
+}
+
+function includer(ctx, folders) {
+    return function(key) {
+        key = key.trim();
+        return ctx[key] || importInclude(key, folders);
+    };
+}
+
+module.exports = function(markdown, folder, ctx) {
+    // List of folders to search for includes
+    var folders = [];
+
+    // Handle folder arg (string or array)
+    if(_.isString(folder)) {
+        folders = [folder];
+    } else if(_.isArray(folder)) {
+        folders = folder;
+    }
+
+    // variable context
+    ctx = ctx || {};
+
+    // Memoized include function (to cache lookups)
+    var _include = _.memoize(includer(ctx, folders));
+
+    return markdown.replace(/{{([\s\S]+?)}}/g, function(match, key) {
+        // If fails leave content as is
+        return _include(key) || match;
+    });
+};
diff --git a/lib/parse/page.js b/lib/parse/page.js
index ae71666..846d339 100644
--- a/lib/parse/page.js
+++ b/lib/parse/page.js
@@ -5,7 +5,7 @@ var hljs = require('highlight.js');
 var lex = require('./lex');
 var renderer = require('./renderer');
 
-var codeInclude = require('./code_include');
+var include = require('./include');
 var lnormalize = require('../utils/lang').normalize;
 
 
@@ -51,7 +51,7 @@ function parsePage(src, options) {
     options = options || {};
 
     // Lex if not already lexed
-    return (_.isArray(src) ? src : lex(src))
+    return (_.isArray(src) ? src : lex(include(src, options.dir, options.variables)))
     .map(function(section) {
         // Transform given type
         if(section.type === 'exercise') {
@@ -74,20 +74,15 @@ function parsePage(src, options) {
             // Main language
             var lang = validLangs ? langs[0] : null;
 
-            // codeInclude shortcut
-            var ci = function(code) {
-                return codeInclude(code, options.dir);
-            };
-
             return {
                 id: section.id,
                 type: section.type,
                 content: render(nonCodeNodes, options),
                 lang: lang,
                 code: {
-                    base: ci(codeNodes[0].text),
-                    solution: ci(codeNodes[1].text),
-                    validation: ci(codeNodes[2].text),
+                    base: codeNodes[0].text,
+                    solution: codeNodes[1].text,
+                    validation: codeNodes[2].text,
                     // Context is optional
                     context: codeNodes[3] ? codeNodes[3].text : null,
                 }
diff --git a/lib/parse/renderer.js b/lib/parse/renderer.js
index faa416c..61b3d9b 100644
--- a/lib/parse/renderer.js
+++ b/lib/parse/renderer.js
@@ -1,8 +1,6 @@
 var url = require('url');
 var inherits = require('util').inherits;
 var links = require('../utils').links;
-var codeInclude = require('./code_include');
-
 
 var path = require('path');
 
@@ -130,8 +128,7 @@ GitBookRenderer.prototype.listitem = function(text) {
 GitBookRenderer.prototype.code = function(code, lang, escaped) {
     return GitBookRenderer.super_.prototype.code.call(
         this,
-        // Import code snippets
-        codeInclude(code, this._extra_options.dir),
+        code,
         lang,
         escaped
     );