Improved metadata processing

1 files changed, 23 insertions, 0 deletions

diff --git a/scripts/lib/common.lua b/scripts/lib/common.lua
index 5ed3e31..ee7c6aa 100644
--- a/scripts/lib/common.lua
+++ b/scripts/lib/common.lua
@@ -39,6 +39,20 @@ function pandoc.List:flatMap(fn)
     return result
 end
 
+function pandoc.List:filterMap(fn)
+    local mapped = self:map(fn)
+    local result = pandoc.List()
+
+    for i = 1, #mapped do
+        local val = mapped[i]
+        if val then
+            result:insert(val)
+        end
+    end
+
+    return result
+end
+
 function pandoc.List:take(n)
     if n >= #self then return self end
 
@@ -59,6 +73,15 @@ function pandoc.List:skip(n)
     return result
 end
 
+function pandoc.List:shuffle()
+    for i = #self, 2, -1 do
+        local j = math.random(i)
+        self[i], self[j] = self[j], self[i]
+    end
+
+    return self
+end
+
 return {
     dump = dump
 }