perf: replace list length-checks with pattern matching#128
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mhanberg merged 1 commit intoelixir-tools:mainfrom Apr 23, 2026
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katafrakt
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Apr 15, 2026
| arity = length(args) | ||
| case args do | ||
| [_, _ | _] -> | ||
| arity = length(args) |
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We still need arity here to pass to Macro.operator? and Macro.special_form?, but we calculate it only if we know it's more than one.
mkaput
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Less obvious (for me) than #128, but also seems like a quick perf win. Perhaps surprisingly, using tail recursion is generally faster than Keyword.has_key? by about 10%. In this case though the most important thing is that we iterate over the list only once, instead of 2-3 times. The benchmark shows 7-8% improvement on parsing files.
This replaces few length check on hot paths with patternmatching. According to benchmarks I ran it gives 3-8% or performance gains on parsing a realistic files.
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This replaces few length check on hot paths with patternmatching. According to benchmarks I ran it gives 3-8% or performance gains on parsing a realistic files.