Initial data commit

Task/Higher-order-functions/Jq/higher-order-functions-1.jq

@@ -0,0 +1,8 @@
+def foo( filter ):
+  ("world" | filter) as $str
+  | "hello \($str)" ;
+
+# blue is defined here as a filter that adds blue to its input:
+def blue: "blue \(.)";
+
+foo( blue ) # prints "hello blue world"

Task/Higher-order-functions/Jq/higher-order-functions-2.jq

@@ -0,0 +1,3 @@
+def g(f; x; y): [x,y] | f;
+
+g(add; 2; 3) # => 5

Task/Higher-order-functions/Jq/higher-order-functions-3.jq

@@ -0,0 +1,4 @@
+def is_even:
+  if floor == . then (. % 2) == 0
+  else error("is_even expects its input to be an integer")
+  end;

Task/Higher-order-functions/Jq/higher-order-functions-4.jq

@@ -0,0 +1,26 @@
+# Are all integers between 1 and 5 even?
+# For this example, we will use all/2 even
+# though it requires a release of jq after jq 1.4;
+# we do so to highlight the fact that all/2
+# terminates the generator once the condition is satisfied:
+all( range(1;6); is_even )
+false
+
+# Display the even integers in the given range:
+range(1;6) | select(is_even)
+2
+4
+
+# Evaluate is_even for each integer in an array
+[range(1;6)] | map(is_even)
+[false, true, false, true, false]
+
+# Note that in jq, there is actually no need to call
+# a higher-order function in cases like this.
+# For example one can simply write:
+range(1;6) | is_even
+false
+true
+false
+true
+false