The Codeless Code: Case 176 Many Happy Returns
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A novice monk said to master Kaimu, “I have heard that it
is preferable to have only one return statement in a
function. Do you agree?”
Kaimu asked, “Where is your bowl?”
The monk apologized and left to fetch his bowl.
When the monk returned, he showed his bowl to the master and
said, “I have heard that it is preferable to have only one
return statement in a function. Do you agree?”
Kaimu asked, “Why is there no rice in your bowl?”
The monk apologized and left to fetch some rice.
When the monk returned, he showed his bowl full of steaming
white rice to the master and said, “I have heard that it is
preferable to have only one return statement in a function.
Do you agree?”
Kaimu took the monk’s bowl and placed it on his desk.
“You speak of a most venerable design principle, known as
Single-Entry Single-Exit,” said the master. He then told the
monk of the glorious days of coding long past, when memory
was low, hardware was slow, and resources had to be managed
with care. “For C did you no favors,” said Kaimu, “and
Assembly did half as many as that. So if your function
borrowed a thing, then your function had to put it back. And
how was this most easily done? By putting all the cleanup
code in one place, at the function’s bottom... a tradition
that continues to this day.”
Kaimu then spoke of the birth of objects, of destructors and
finalizers. He spoke of garbage collection too; of reference
counting and mark-and-sweep, and compilers that could tell
when an object went out of scope. He spoke of buffers that
grew as needed and vanished when not, of files that closed
themselves, of connection pools and thread pools and
try-with-resources, and of how wondrous and magical was the
modern bestiary of languages, where monks could devote their
energies to more interesting problems instead of fussing
about with malloc and free and goto fail.
“Yes,” said the weary monk at last. “But do you agree with
the design principle of Single-Entry Single-Exit, or do you
not?”
Kaimu looked down and said, “Why is the rice in your bowl
white, and not brown?”
