/* Integration Test: Functional Programming */
/* Combines: first-class functions, higher-order functions, composition */

..out "=== Integration Test: Functional Programming ===";

/* Basic functions */
double_func : x -> x * 2;
square_func : x -> x * x;
add1 : x -> x + 1;
identity_func : x -> x;
isEven : x -> x % 2 = 0;

/* Function composition */
composed1 : compose @double_func @square_func 3;
composed2 : compose @square_func @double_func 2;
composed3 : compose @add1 @double_func 5;

..assert composed1 = 18;
..assert composed2 = 16;
..assert composed3 = 11;

/* Function piping */
piped1 : pipe @double_func @square_func 3;
piped2 : pipe @square_func @double_func 2;
piped3 : pipe @add1 @double_func 5;

..assert piped1 = 36;
..assert piped2 = 8;
..assert piped3 = 12;

/* Function application */
applied1 : apply @double_func 7;
applied2 : apply @square_func 4;
applied3 : apply @add1 10;

..assert applied1 = 14;
..assert applied2 = 16;
..assert applied3 = 11;

/* Function selection with case expressions */
getOperation : type -> 
  when type is
    "double" then @double_func
    "square" then @square_func
    "add1"   then @add1
    _        then @identity_func;

/* Test function selection */
op1 : getOperation "double";
op2 : getOperation "square";
op3 : getOperation "add1";
op4 : getOperation "unknown";

result1 : op1 5;
result2 : op2 4;
result3 : op3 7;
result4 : op4 3;

..assert result1 = 10;
..assert result2 = 16;
..assert result3 = 8;
..assert result4 = 3;

/* Complex functional composition */
complex : compose @double_func (compose @square_func @add1) 3;
..assert complex = 32;

..out "Functional programming integration test completed";