Explain λ icon from astro build

[tordans]

I am getting this output from astro build

I am trying to understand what the λ icon means.

Places I searched

• There is nothing in the output in the console
• Searching the docs does not return a result

  

• Searching the code only explains what it is not, it is not something of type page, redirect or fallback
  https://github.com/search?q=org%3Awithastro%20%CE%BB&type=code

I am getting it for my feed.xml.ts and some custom api/campaigns.json.ts so it might be an indicator for JSON or XML output?

One thing that makes me look at this is, that with NextJS, there are Icons and they reference the fact that a route is dynamic vs. static. Which would be something I need to know with Astro, because I need my page to be fully static…

[delucis]

Ah, good question. Yeah that icon is supposed to mean “endpoint” AFAIK. So it just indicates that the file was generated with an endpoint instead of a .astro (or .md/.mdx) file that outputs HTML.

I need my page to be fully static

All those paths you see listed under “generating static routes” are static. Dynamic/on-demand rendered routes do not log anything in that part of the build.

[tordans]

Thanks for clarifying.

TBH, I wonder if this info is actually worth having, given that the generated file is also visible in the output as "*.html" or ".json".

I am thinking about where to document this best and the best in place documentation would likely be below the "generating static routes" section. https://docs.astro.build/en/reference/cli-reference/#astro-build might also be a place but that already requires some research steps for users…

[Fryuni]

Just sharing a bit of curiosity since I was browsing through the open discussions, that symbol is the greek letter "lambda". There is a bit of history as to why it is used here.

There is a particular branch of mathematics that deals with formalizing the concept of formal systems that are logically consistent, there are multiple of those in mathematics. One of them is called Lambda Calculus that can model any computation with just repeated application of symbolic manipulation of expressions. Maths in general looooves symbols, they can be assigned very precise meanings that ignore language barriers.

In Lambda Calculus, an expression is denoted as $\lambda x . x x$, using the letter lambda to declare the start of a function definition. That is why in some programming languages an anonymous function uses the lambda symbol or the name, like Python (lambda x: x * x).

So here we use the lambda symbol to represent an endpoint in the sense that it is a function and not a template componen.

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Another bit of curiosity from that bit of curiosity. The example from above ($\lambda x . x x$) is the M combinator, from the study of combinatory logic that is part of lambda calculus. The super famous startup accelerator "Y Combinator" is named after one such combinator, this one:

$$\lambda f . (\lambda x . f (x x)) (\lambda x . f (x x))$$

It is the combinator that allows for recursive functions in lambda calculus.