Partial work on procs

content/procs.md

@@ -1,7 +1,7 @@
 ---
-title: Procedures
+title: Procs
 ---
-# Procedures
+# Procs
 
 Procedures in Nimrod are declared using `proc` and require that their parameter and return types be annotated. After the types and parameters, an `=` is used to denote the start of the function body.
 
@@ -12,3 +12,57 @@ proc fibonacci(n: int): int =
   else:
     result = fibonacci(n - 1) + fibonacci(n - 2)
 ```
+
+## Exporting symbols
+
+<!-- XXX Move into module topic -->
+Encapsulation is also supported, not by conventions such as perpending the name with underscores but by annotating a procedure with `*`, which exports it and makes it available for use by modules.
+
+``` nimrod
+# module1:
+proc foo*(): int = 2
+proc bar(): int = 3
+
+# module2:
+echo foo()  # Valid
+echo bar()  # will not compile
+```
+
+## Side effect analyses
+
+Nimrod provides support for functional programming and so includes the `{.noSideEffect.}` pragma, which statically ensures there are no side effects.
+
+``` nimrod
+proc sum(x, y: int): int {. noSideEffect .} =
+  x + y
+
+proc minus(x, y: int): int {. noSideEffect .} =
+  echo x  # error: 'minus' can have side effects
+  x - y
+```
+
+## Operators
+
+To create an operator, the symbols that are to be used must be encased inside `` ` ``s to signify they are operators.
+
+``` nimrod
+proc `$`(a: array[2, array[2, int]]): string =
+  result = ""
+  for y in a:
+    for vx in v:
+      result.add($vx & ", ")
+    result.add("\n")
+
+echo [[1, 2],  # See Varargs for how 
+      [3, 4]]  # echo works
+
+proc `^&*^@%`(a, b: string): string =
+  ## An confusingly named useless proc
+  result = a[0] & b[high(str)]
+
+assert("foo" ^&*^@% "bar" == "fr")
+``` 
+
+
+- operators
+- generics