122-32000 Parallax Inc, 122-32000 Datasheet - Page 161

• Manufacturer Part Number: 122-32000
• Description: MANUAL PROPELLER
• Manufacturer: Parallax Inc

Specifications of 122-32000

• Accessory Type: Manual
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

ABORT
Exit from
((PUB ┆ PRI))
Returns: Either the current
Explanation
ABORT
execution.
ABORT
stack repeatedly until either the call stack is empty or it reaches a caller with an Abort Trap,
(
ABORT
elevated status to the immediate caller or one its previous callers.
application may be involved in a complicated chain of events where any one of those events
could lead to a different branch of the chain or a final action decision. It may be easier to
write that application using small, specialized methods that are called in a nested fashion,
each meant to deal with a specific sub-event in the chain. When one of the simple methods
determines a course of action, it can issue an abort that completely collapses the nested call
chain and prevents all the intermediate methods from continuing.
When
built-in
returns that Value instead.
About the Call Stack
When methods are called simply by referring to them from other methods, there must be
some mechanism in place to store where to return to once the called method is completed.
This mechanism is a called a “stack” but we’ll use the term “call stack” here. It is simply
RAM memory used to store return addresses, return values, parameters and intermediate
results. As more and more methods are called, the call stack logically gets longer. As more
\
ABORT 〈
), and delivers a value in the process.
•
causes a return from a
is useful for cases where a method needs to terminate and indicate an abnormal or
ABORT
is one of two commands (
Value
the
RESULT
PUB
PUB
Value
appears without the optional Value, it returns the current value of the
/
is an optional expression whose value is to be returned, with abort status, from
PRI
variable. If the Value field was entered, however, the
or
〉
method using abort status with optional return Value.
PRI
method.
RESULT
PUB
ABORT
or
value, or Value if provided.
PRI
and
method with abort status; meaning it pops the call
4: Spin Language Reference –
RETURN
) that terminate a
Propeller Manual v1.0 · Page 161
PUB
PUB
For example, an
or
or
PRI
PRI
aborts and
method’s
PUB
/
PRI
’s