Table of Contents

• 1. exit
  • 1.1. Syntax
  • 1.2. Stack Effects
  • 1.3. Description
  • 1.4. PostScript Level
  • 1.5. Examples
  • 1.6. Common Use Cases
    • 1.6.1. Search with Early Exit
    • 1.6.2. Conditional Loop Termination
    • 1.6.3. Breaking from Nested Loops
  • 1.7. Common Pitfalls
  • 1.8. Error Conditions
  • 1.9. Implementation Notes
  • 1.10. See Also

1. exit

Terminates the innermost enclosing loop.

1.1. Syntax

– exit → –

1.2. Stack Effects

Table 1. Before/After

Level	Object
(none)	Exits innermost loop context

1.3. Description

exit terminates execution of the innermost, dynamically enclosing looping context, regardless of lexical relationship.

Valid looping contexts created by:

• for

• repeat

• loop

• forall

• pathforall, kshow, cshow, filenameforall, resourceforall

exit pops the execution stack to the level of the loop operator, then resumes execution at the next object after that operator.

1.4. PostScript Level

Level 1 and later

1.5. Examples

Exit from for loop

0 1 10 {
  dup 5 eq { exit } if
  =
} for
% Prints: 0 1 2 3 4 (stops at 5)

Exit from repeat

10 {
  randomCondition { exit } if
  doWork
} repeat

Exit from loop

{
  getData
  dup endMarker eq { pop exit } if
  process
} loop

Exit from forall

[1 2 3 4 5] {
  dup 3 eq { exit } if
  10 mul
} forall
% Stack: 10 20 (stopped at 3)

1.6. Common Use Cases

1.6.1. Search with Early Exit

/findInArray {  % array value => index or -1
  false 0
  3 -1 roll {
    3 index eq {
      exch pop true exch exit
    } if
    1 add
  } forall
  exch { } { pop -1 } ifelse
} def

1.6.2. Conditional Loop Termination

{
  processItem
  shouldStop { exit } if
} loop

1.6.3. Breaking from Nested Loops

/found false def
1 1 10 {
  /i exch def
  1 1 10 {
    /j exch def
    i j testCondition {
      /found true def
      exit  % Exits inner loop only
    } if
  } for
  found { exit } if  % Exit outer loop
} for

1.7. Common Pitfalls

Must Be in Loop - exit only works within a looping context.

{ exit } if  % Error: invalidexit (not in loop)

Exits Innermost Loop Only - In nested loops, only exits the immediately enclosing loop.

1 1 10 {
  1 1 10 {
    exit  % Only exits inner loop
  } for
} for

Cannot Exit run or stopped - Attempting to exit these contexts causes [invalidexit].

{ { exit } loop } stopped  % Error: invalidexit

Use Flag for Outer Loop Exit - Set a flag variable to exit multiple levels.

1.8. Error Conditions

Error	Condition
[invalidexit]	No enclosing loop context, or attempted to exit run/stopped

1.9. Implementation Notes

• Unwinds execution stack to loop level

• Very fast operation

• Does not affect operand or dictionary stacks

• Only affects execution flow

1.10. See Also

• for - Numeric loop

• repeat - Fixed repetition

• loop - Indefinite loop

• stop - Exit stopped context

• forall - Collection iteration