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Common Lisp / Bindings & Control

block return-from

Learn block return-from in Common Lisp through a focused explanation, a dedicated construct-specific example, an engineering boundary, and a mastery check.

10 min read • Beginner

block return-from is an atomic Common Lisp topic inside Bindings & Control. This lesson focuses on how the block return-from construct is written, what it changes, and when it is the right tool.

Trace the example line by line. Identify the exact syntax for block return-from, the input state before it runs, and the resulting value, control flow, database state, hardware behavior, or runtime effect afterward. Neighboring lessons use different constructs rather than renamed copies of this one.

Topic-specific example

common-lisp-02-10-block-return-from.lisp
common-lisp Try It Live 
(block search (dolist (x '(2 7 9)) (when (> x 5) (return-from search x))) nil)
Edge case / engineering note

For block return-from, test the boundary that belongs to this exact feature rather than a generic failure case. Check invalid or empty input, NULL/unknown state, numeric limits, transaction or exception behavior, synthesis/runtime constraints, ownership/permission rules, or backtracking/control-flow effects where they apply.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

block return-from Mastery Check →
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