macro PIF : (condition action else-action)
PIF, PWHEN and PUNLESS are the SubL procedural variants of if, when and unless from Common Lisp. For each, the condition argument must be a functional construct. Also, PIF takes exactly three arguments, making the action and else-actions identical in form.
FIF, FWHEN and FUNLESS are the SubL functional variants of if, when and unless from Common Lisp.
PCOND and PCASE are the SubL procedural equivalents of cond and case from Common Lisp.