Initial draft of first class functions

content/lambdas.md

@@ -1,5 +0,0 @@
----
-title: First Class Functions
----
-
-# First Class Functions

content/procvars.md

@@ -0,0 +1,29 @@
+---
+title: First Class Functions
+---
+
+# First Class Functions
+
+Nimrod supports closures as well as passing functions. Two different syntaxes available for closures, proc syntax, which is identical to regular procedure syntax, and "do notation", which 
+
+``` nimrod
+import sequtils
+
+let powersOfTwo = @[1, 2, 4, 8, 16, 32, 64, 128, 256]
+
+echo powersOfTwo.filter do (x: int) -> bool : x > 32
+echo powersOfTwo.filter(proc (x: int): bool = x > 32)
+```
+``` console
+$ nimrod c -r filterclosure.nim
+@[64, 128, 256]
+@[64, 128, 256]
+```
+
+Existing procedures can also be passed as functions, but only if they are annotated with the `{.procvar.}` pragma.
+
+``` nimrod
+proc greaterThan32(x: int): bool {.procvar.} = x > 32
+
+echo powersOfTwo.filter(greaterThan32)
+```