Lisp evangelists that miss the point about syntax(confusionist.tumblr.com)

  #include "node.h"
  #include "type_I.h"

  static struct node *reduce(struct node *parent)
      {
      return parent->RIGHT;
      }

  static struct type type = { reduce, clear_pair };

  struct node *make_I(void)
      {
      return make_pair(&type,0,0);
      }

  #include "node.h"
  #include "type_app.h"
  #include "type_Y.h"

  static struct node *reduce(struct node *parent)
      {
      return make_app(parent->RIGHT,parent);
      }

  static struct type type = { reduce, clear_pair };

  struct node *make_Y(void)
      {
      return make_pair(&type,0,0);
      }

  #include "node.h"
  #include "type_app.h"
  #include "type_S.h"

  static struct node *reduce(struct node *parent)
      {
      if (0 == parent->LEFT->LEFT || 0 == parent->LEFT->LEFT->LEFT)
          {
          parent->type = parent->LEFT->type;
          return parent;
          }

      struct node *x = parent->LEFT->LEFT->RIGHT;
      struct node *y = parent->LEFT->RIGHT;
      struct node *z = parent->RIGHT;

      struct node *fun = make_app(x,z);
      struct node *arg = make_app(y,z);

      hold(fun);
      hold(arg);

      parent->type->clear(parent);
      parent->LEFT = fun;
      parent->RIGHT = arg;

      return fun->type->reduce(parent);
      }

  static struct type type = { reduce, clear_pair };

  struct node *make_S(void)
      {
      return make_pair(&type,0,0);
      }

  #include "node.h"
  #include "type_app.h"

  static struct node *reduce(struct node *parent)
      {
      struct node *curr = parent->LEFT;

      while (curr->type == parent->type)
          {
          struct node *self = curr->LEFT;
          struct node *next = self->type->reduce(curr);

          if (next != curr)
              {
              hold(next);
              drop(curr);
              curr = next;
              }
          }

      parent->LEFT = curr;

      return curr->type->reduce(parent);
      }

  static struct type type = { reduce, clear_pair };

  struct node *make_app(struct node *f, struct node *x)
      {
      return make_pair(&type, f, x);
      }