# Seek for a detailed description on scopes and modules

**URL:** <https://discourse.julialang.org/t/seek-for-a-detailed-description-on-scopes-and-modules/16442>\
**Category:** New to Julia\
**Created:** [October 17, 2018, 1:42pm UTC](https://discourse.julialang.org/t/seek-for-a-detailed-description-on-scopes-and-modules/16442 "2018-10-17T13:42:52Z")\
**Posts on this page:** 1\
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**Author:** ![StefanKarpinski](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stefankarpinski/32/24_2.png) [@StefanKarpinski](https://discourse.julialang.org/u/StefanKarpinski)\
**Post date:** [October 17, 2018, 3:05pm UTC](https://discourse.julialang.org/t/seek-for-a-detailed-description-on-scopes-and-modules/16442/7 "2018-10-17T15:05:52Z")

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Yes, that is not assignment, it is mutation of the `Dict` object, which is very different:

> [@Explicit denotation of variability and immutability](https://discourse.julialang.org/t/explicit-denotation-of-variability-and-immutability/8686/51):
>
> There are the following assignment-like syntaxes:
> 
> - `x = ...` is assignment. The name `x` is bound to the value that the `...` evaluates to. Local bindings never leak out of their scope. It doesn’t matter what `x` was bound to before this happens, that _value_ is not affected in any way. No object is mutated by this and no other binding besides `x` is changed.
> 
> - `x.f = ...` is equivalent to `setproperty!(x, :f, ...)` which, by default mutates the object `x` by changing its field `f` to the value of the expression `...` . If `x` is visible in another scope or by another bindings, this change will be seen everywhere. No bindings are changed by this.
> 
> - `x[i] = ...` is equivalent to `setindex!(x, ..., i)` which, for arrays mutates the array `x` by changing its `i` th slot to refer to the value of the expression `...` . If `x` is visible in another scope or by another bindings, this change will be seen everywhere. No bindings are changed by this.

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