Master programming syntax, solve interactive challenges & run live code in Syntaxis Explore Arena →
Syntaxis
menu_book Course Curriculum (Crystal) expand_more
Basics
variables type inference constants symbols strings string interpolation tuples named tuples ranges nilable types
Control Flow
if unless case while until each times loop do break next begin rescue ensure
Methods
method definitions default arguments named arguments splat arguments double splat blocks yield block forwarding overloads macros vs methods
Types
classes structs modules enums abstract classes inheritance include extend properties class variables
Collections
Array Hash Set Deque Iterator Enumerable map select compact_map group_by sort_by
Generics and Macros
generic classes generic methods typeof is_a? narrowing case type narrowing macro macro for loops annotations compile-time run verbatim macro
Concurrency
spawn Fiber Channel buffered channel select sleep Mutex WaitGroup pattern HTTP server concurrency fiber exception handling
I/O and Ecosystem
File.read File.write IO.copy JSON serialization YAML parsing HTTP client HTTP server command execution spec tests shards dependencies
Crystal / Generics and Macros

macro for loops

Learn macro for loops in Crystal with a construct-specific explanation, unique example, engineering boundary, and mastery check.

10 min read • Intermediate

macro for loops is a focused Crystal topic inside Generics and Macros. This lesson explains the construct itself, the state or value it operates on, and the observable result it produces.

Read the example as a small executable experiment. Identify the exact syntax that belongs to macro for loops, then change one input and predict the result before running it.

Topic-specific example

crystal-06-07-macro-for-loops.cr
crystal Try It Live 
{% for name in %w(id name status) %}
  getter {{name.id}}
{% end %}
Edge case / engineering note

macro for loops has rules that are easy to miss when the example is copied mechanically. Check the feature-specific boundary shown by this construct: scope, mutability, evaluation order, type constraints, lifetime, error behavior, compile-time restrictions, or resource cleanup where applicable.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

macro for loops Mastery Check →
← PREVIOUS
macro
NEXT →
annotations