Notes on software and the ideas behind it

Find the meaning
behind the code.

I’m Fred Yang. I write about software—how it works, why it behaves the way it does, and the ideas that make code easier to reason about.

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Working notes / 2026

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Architecture, reactivity, and the hidden relationships that shape frontend systems.

F#

f# essential - part 5 - mutable, ref

As mentioned in previous post, the "let" syntax define a identifier binding, which is immutable. So it is not variable in the sense of traditional programming. But we can not programming in pure functional...
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F#

f# essential part 4 - closure

f# support closure. Here is the definition of closure In computer science, a closure (also lexical closure, function closure or function value) is a function together with a referencing environment for the nonlocal names...
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F#

f# essential - part 3 matching shortcut

F# provide a shortcut to define a function which purely use input parameter for matching purpose. For example the following are equal. let printInt = function 1 -> printfn "1" | 2 -> printfn...
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F#

f# essential - part 2 - pipleline operator

Before I discuss pipeline operator, let's talk about operator. F# allow us to define operator as function. The following are infix operators $ % & * + - . / < = > @...
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F#

f# essential - part 1 binding

I was very puzzled with some concept when learning F#. Here is some. Even I explain it here, you may be still confused, but it is ok, as you read on. let t1 =...
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