Programming languages should have a tree traversal primitive

a year ago

Programming languages lack a tree traversal primitive, similar to for/foreach loops for linear traversal.
Proposal for a 'for_tree' control flow construct in C++-ish syntax to simplify tree-like traversal.
'for_tree' would compile down to recursive function calls, offering a cleaner, less error-prone alternative.
Additional benefits include using 'break', 'continue', and 'return' within the loop body, similar to for loops.
Introduction of 'prune' keyword to prevent traversal into branches of the current node.
Comparison with range-based for loops highlights 'for_tree's ability to operate on non-memory data structures.
Discussion on depth-first vs. breadth-first traversal, favoring depth-first for minimal memory usage.
Example provided for generating strings of length ≤8 using 'for_tree', showcasing its versatility.
Potential footgun: traversing one level deeper than necessary, with manual solutions proposed.
Proof-of-concept C++ implementation using templates and macros, acknowledging limitations.

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