introduce build tasks

while it appears a bit much for the overview, this way we set the stage
for going directly into data types when describing the store, instead of
first having to say what build tasks are and how they relate to build
plans.
This commit is contained in:
Valentin Gagarin 2022-05-26 02:52:10 +02:00
parent 7c3bca1372
commit d5eea66615

View file

@ -43,5 +43,37 @@ In practice this amounts to a set of files in a file system.
Underlying these is the [Nix store](./store/store.md), a mechanism to keep track of build plans, data, and references between them.
It can also execute build plans to produce new data.
A build plan is a series of *build tasks*.
Each build task has a special build input which is used as *build instructions*.
The result of a build task can be input to another build task.
```
+-----------------------------------------------------------------------------------------+
| store |
| ................................................. |
| : build plan : |
| : : |
| [ build input ]-----instructions-, : |
| : | : |
| : v : |
| [ build input ]----------->[ build task ]--instructions-, : |
| : | : |
| : | : |
| : v : |
| : [ build task ]----->[ build result ] |
| [ build input ]-----instructions-, ^ : |
| : | | : |
| : v | : |
| [ build input ]----------->[ build task ]---------------' : |
| : ^ : |
| : | : |
| [ build input ]------------------' : |
| : : |
| : : |
| :...............................................: |
| |
+-----------------------------------------------------------------------------------------+
```
[layer-architecture]: https://en.m.wikipedia.org/wiki/Multitier_architecture#Layers
[purely-functional-programming]: https://en.m.wikipedia.org/wiki/Purely_functional_programming