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_notes/Signals.md

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+---
+title: Signals
+tags: se
+---
+
+<status>Status: 🌿 </status>
+
+Signals, as <a class="external-link" href="https://sandimetz.com">Sandi Metz</a> calls them (not sure if she came up with the name or just passed along) is obvious in hindsight but brilliant programming tool.
+
+Here examples will describe best what they are, so:
+
+1. Prime/large numbers - pick arbitrary prime/large number, so it signals insignificance of a number. For example, in tests, you can write 5000 where any other number is not bigger than 10; this is a **signal** for others to not search for a meaning behind a number. Personally, I prefer `0` or large numbers instead of primes, as they are more clear on intent.
+2. Strings. Same as with numbers, but there's more flexibility. For example, if I need to pass a user ETH wallet address, but it's irrelevant for testing I will go with `"0xfakeaddress"` - so it's clear that it's there just as it's needed and there's no special meaning. If it was a legit address it could make someone believe it's important.
+
+Signals can also imply meaning. While I'm yet to find this usecase, Sandi shown this example
+
+In Ruby code blocks can be in `{ }` or `do end`
+
+1. code in `do end` has side effects
+2. code in `{ }` has no side effects
+
+*(note that it's not any official standard and it's not enforced by anyone or any tool)*
+
+This is example of syntax based signal that gives clear understanding of a code (outside tests) to show what's happening even before reading the code in the code block.

_notes/codex vitae.md

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 ---
 title: Codex Vitae
+tag: personal
 ---
 
 <status>Status: 🌱 </status>

_notes/excuse hydra.md

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 ---
 title: Excuse Hydra
+tag: opinions
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 <status>Status: 🌱 </status>

_notes/software engineering.md

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 During my years working with code I stumbled upon stories to share and some thoughts to explore. All of those will be put here
 
 [[SOLID for FP]]
+[[Signals]]

_notes/solid for fp.md

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 ---
 title: SOLID for FP
+tags: se, fp
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 <status>Status: 🌱 </status>