clarify relation of tasks and plans

This commit is contained in:
Valentin Gagarin 2022-05-12 12:30:28 +02:00
parent 2a8532fb61
commit 689b32a543

View file

@ -13,21 +13,21 @@ Nix consists of hierarchical [layers](https://en.m.wikipedia.org/wiki/Multitier_
| evaluates | manages
V |
[ configuration language ] |
| V
+-------------------------------|---------------------------------+
| store | |
| | evaluates to |
| | |
| referenced by V builds |
| [ build input ] --> [ build task ] --> [ build result ] |
| |
+-------------------------------|---------------------V-----------+
| store | evaluates to |
| .............................V............................... |
| : build plan : |
| : referenced by builds : |
| : [ build input ] --> [ build task ] --> [ build result ] : |
| :...........................................................: |
+-----------------------------------------------------------------+
```
At the top is the *command line interface*, translating from invocations of Nix executables to interactions with the underlying layers.
Below that is the *Nix language*, a [purely functional](https://en.m.wikipedia.org/wiki/Purely_functional_programming) configuration language.
It is used to compose expressions which ultimately evaluate to self-contained *build tasks*, used to derive *build results* from referenced *build inputs*.
It is used to compose expressions which ultimately evaluate to self-contained *build plans*, made up *build tasks* used to derive *build results* from referenced *build inputs*.
::: {.note}
The Nix language itself does not have a notion of *packages* or *configurations*.
@ -40,4 +40,3 @@ The command line and Nix language are what users interact with most.
Underlying everything is the *Nix store*, a mechanism to keep track of build tasks, data, and references between them.
It can also execute *build instructions*, captured in the build tasks, to produce new data.
A series of build tasks is a *build plan*.