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Merge pull request #312407 from hsjobeki/doc/lib-generators

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doc: init lib.generators reference documentation
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Silvan Mosberger 2024-06-26 22:09:05 +02:00 committed by GitHub
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1
doc/default.nix
View file

@ -23,6 +23,7 @@ let
{ name = "fileset"; description = "file set functions"; }
{ name = "sources"; description = "source filtering functions"; }
{ name = "cli"; description = "command-line serialization functions"; }
{ name = "generators"; description = "functions that create file formats from nix data structures"; }
{ name = "gvariant"; description = "GVariant formatted string serialization functions"; }
{ name = "customisation"; description = "Functions to customise (derivation-related) functions, derivatons, or attribute sets"; }
{ name = "meta"; description = "functions for derivation metadata"; }

2
doc/functions/generators.section.md
View file

@ -54,4 +54,4 @@ merge:"diff3"
Nix store paths can be converted to strings by enclosing a derivation attribute like so: `"${drv}"`.
:::
Detailed documentation for each generator can be found in `lib/generators.nix`.
Detailed documentation for each generator can be found [here](#sec-functions-library-generators)

520
lib/generators.nix
View file

@ -1,17 +1,22 @@
/* Functions that generate widespread file
* formats from nix data structures.
*
* They all follow a similar interface:
* generator { config-attrs } data
*
* `config-attrs` are “holes” in the generators
* with sensible default implementations that
* can be overwritten. The default implementations
* are mostly generators themselves, called with
* their respective default values; they can be reused.
*
* Tests can be found in ./tests/misc.nix
* Documentation in the manual, #sec-generators
/**
Functions that generate widespread file
formats from nix data structures.
They all follow a similar interface:
```nix
generator { config-attrs } data
```
`config-attrs` are “holes” in the generators
with sensible default implementations that
can be overwritten. The default implementations
are mostly generators themselves, called with
their respective default values; they can be reused.
Tests can be found in ./tests/misc.nix
Further Documentation can be found [here](#sec-generators).
*/
{ lib }:
@ -68,10 +73,19 @@ let
;
## -- HELPER FUNCTIONS & DEFAULTS --
in rec {
/**
Convert a value to a sensible default string representation.
The builtin `toString` function has some strange defaults,
suitable for bash scripts but not much else.
/* Convert a value to a sensible default string representation.
* The builtin `toString` function has some strange defaults,
* suitable for bash scripts but not much else.
# Inputs
Options
: Empty set, there may be configuration options in the future
`v`
: 2\. Function argument
*/
mkValueStringDefault = {}: v:
let err = t: v: abort
@ -100,14 +114,35 @@ let
else err "this value is" (toString v);
/* Generate a line of key k and value v, separated by
* character sep. If sep appears in k, it is escaped.
* Helper for synaxes with different separators.
*
* mkValueString specifies how values should be formatted.
*
* mkKeyValueDefault {} ":" "f:oo" "bar"
* > "f\:oo:bar"
/**
Generate a line of key k and value v, separated by
character sep. If sep appears in k, it is escaped.
Helper for synaxes with different separators.
mkValueString specifies how values should be formatted.
```nix
mkKeyValueDefault {} ":" "f:oo" "bar"
> "f\:oo:bar"
```
# Inputs
Structured function argument
: mkValueString (optional, default: `mkValueStringDefault {}`)
: Function to convert values to strings
`sep`
: 2\. Function argument
`k`
: 3\. Function argument
`v`
: 4\. Function argument
*/
mkKeyValueDefault = {
mkValueString ? mkValueStringDefault {}
@ -118,9 +153,22 @@ let
## -- FILE FORMAT GENERATORS --
/* Generate a key-value-style config file from an attrset.
*
* mkKeyValue is the same as in toINI.
/**
Generate a key-value-style config file from an attrset.
# Inputs
Structured function argument
: mkKeyValue (optional, default: `mkKeyValueDefault {} "="`)
: format a setting line from key and value
: listsAsDuplicateKeys (optional, default: `false`)
: allow lists as values for duplicate keys
: indent (optional, default: `""`)
: Initial indentation level
*/
toKeyValue = {
mkKeyValue ? mkKeyValueDefault {} "=",
@ -134,32 +182,51 @@ let
in attrs: concatStrings (concatLists (mapAttrsToList mkLines attrs));
/* Generate an INI-style config file from an
* attrset of sections to an attrset of key-value pairs.
*
* generators.toINI {} {
* foo = { hi = "${pkgs.hello}"; ciao = "bar"; };
* baz = { "also, integers" = 42; };
* }
*
*> [baz]
*> also, integers=42
*>
*> [foo]
*> ciao=bar
*> hi=/nix/store/y93qql1p5ggfnaqjjqhxcw0vqw95rlz0-hello-2.10
*
* The mk* configuration attributes can generically change
* the way sections and key-value strings are generated.
*
* For more examples see the test cases in ./tests/misc.nix.
/**
Generate an INI-style config file from an
attrset of sections to an attrset of key-value pairs.
# Inputs
Structured function argument
: mkSectionName (optional, default: `(name: escape [ "[" "]" ] name)`)
: apply transformations (e.g. escapes) to section names
: mkKeyValue (optional, default: `{} "="`)
: format a setting line from key and value
: listsAsDuplicateKeys (optional, default: `false`)
: allow lists as values for duplicate keys
# Examples
:::{.example}
## `lib.generators.toINI` usage example
```nix
generators.toINI {} {
foo = { hi = "${pkgs.hello}"; ciao = "bar"; };
baz = { "also, integers" = 42; };
}
> [baz]
> also, integers=42
>
> [foo]
> ciao=bar
> hi=/nix/store/y93qql1p5ggfnaqjjqhxcw0vqw95rlz0-hello-2.10
```
The mk* configuration attributes can generically change
the way sections and key-value strings are generated.
For more examples see the test cases in ./tests/misc.nix.
:::
*/
toINI = {
# apply transformations (e.g. escapes) to section names
mkSectionName ? (name: escape [ "[" "]" ] name),
# format a setting line from key and value
mkKeyValue ? mkKeyValueDefault {} "=",
# allow lists as values for duplicate keys
listsAsDuplicateKeys ? false
}: attrsOfAttrs:
let
@ -174,43 +241,70 @@ let
# map input to ini sections
mapAttrsToStringsSep "\n" mkSection attrsOfAttrs;
/* Generate an INI-style config file from an attrset
* specifying the global section (no header), and an
* attrset of sections to an attrset of key-value pairs.
*
* generators.toINIWithGlobalSection {} {
* globalSection = {
* someGlobalKey = "hi";
* };
* sections = {
* foo = { hi = "${pkgs.hello}"; ciao = "bar"; };
* baz = { "also, integers" = 42; };
* }
*
*> someGlobalKey=hi
*>
*> [baz]
*> also, integers=42
*>
*> [foo]
*> ciao=bar
*> hi=/nix/store/y93qql1p5ggfnaqjjqhxcw0vqw95rlz0-hello-2.10
*
* The mk* configuration attributes can generically change
* the way sections and key-value strings are generated.
*
* For more examples see the test cases in ./tests/misc.nix.
*
* If you don’t need a global section, you can also use
* `generators.toINI` directly, which only takes
* the part in `sections`.
/**
Generate an INI-style config file from an attrset
specifying the global section (no header), and an
attrset of sections to an attrset of key-value pairs.
# Inputs
1\. Structured function argument
: mkSectionName (optional, default: `(name: escape [ "[" "]" ] name)`)
: apply transformations (e.g. escapes) to section names
: mkKeyValue (optional, default: `{} "="`)
: format a setting line from key and value
: listsAsDuplicateKeys (optional, default: `false`)
: allow lists as values for duplicate keys
2\. Structured function argument
: globalSection (required)
: global section key-value pairs
: sections (optional, default: `{}`)
: attrset of sections to key-value pairs
# Examples
:::{.example}
## `lib.generators.toINIWithGlobalSection` usage example
```nix
generators.toINIWithGlobalSection {} {
globalSection = {
someGlobalKey = "hi";
};
sections = {
foo = { hi = "${pkgs.hello}"; ciao = "bar"; };
baz = { "also, integers" = 42; };
}
> someGlobalKey=hi
>
> [baz]
> also, integers=42
>
> [foo]
> ciao=bar
> hi=/nix/store/y93qql1p5ggfnaqjjqhxcw0vqw95rlz0-hello-2.10
```
The mk* configuration attributes can generically change
the way sections and key-value strings are generated.
For more examples see the test cases in ./tests/misc.nix.
:::
If you don’t need a global section, you can also use
`generators.toINI` directly, which only takes
the part in `sections`.
*/
toINIWithGlobalSection = {
# apply transformations (e.g. escapes) to section names
mkSectionName ? (name: escape [ "[" "]" ] name),
# format a setting line from key and value
mkKeyValue ? mkKeyValueDefault {} "=",
# allow lists as values for duplicate keys
listsAsDuplicateKeys ? false
}: { globalSection, sections ? {} }:
( if globalSection == {}
@ -219,23 +313,42 @@ let
+ "\n")
+ (toINI { inherit mkSectionName mkKeyValue listsAsDuplicateKeys; } sections);
/* Generate a git-config file from an attrset.
*
* It has two major differences from the regular INI format:
*
* 1. values are indented with tabs
* 2. sections can have sub-sections
*
* generators.toGitINI {
* url."ssh://git@github.com/".insteadOf = "https://github.com";
* user.name = "edolstra";
* }
*
*> [url "ssh://git@github.com/"]
*> insteadOf = "https://github.com"
*>
*> [user]
*> name = "edolstra"
/**
Generate a git-config file from an attrset.
It has two major differences from the regular INI format:
1. values are indented with tabs
2. sections can have sub-sections
Further: https://git-scm.com/docs/git-config#EXAMPLES
# Examples
:::{.example}
## `lib.generators.toGitINI` usage example
```nix
generators.toGitINI {
url."ssh://git@github.com/".insteadOf = "https://github.com";
user.name = "edolstra";
}
> [url "ssh://git@github.com/"]
> insteadOf = "https://github.com"
>
> [user]
> name = "edolstra"
```
:::
# Inputs
`attrs`
: Key-value pairs to be converted to a git-config file.
See: https://git-scm.com/docs/git-config#_variables for possible values.
*/
toGitINI = attrs:
let
@ -280,20 +393,40 @@ let
in
toINI_ (gitFlattenAttrs attrs);
# mkKeyValueDefault wrapper that handles dconf INI quirks.
# The main differences of the format is that it requires strings to be quoted.
/**
mkKeyValueDefault wrapper that handles dconf INI quirks.
The main differences of the format is that it requires strings to be quoted.
*/
mkDconfKeyValue = mkKeyValueDefault { mkValueString = v: toString (gvariant.mkValue v); } "=";
# Generates INI in dconf keyfile style. See https://help.gnome.org/admin/system-admin-guide/stable/dconf-keyfiles.html.en
# for details.
/**
Generates INI in dconf keyfile style. See https://help.gnome.org/admin/system-admin-guide/stable/dconf-keyfiles.html.en
for details.
*/
toDconfINI = toINI { mkKeyValue = mkDconfKeyValue; };
/**
Recurses through a `Value` limited to a certain depth. (`depthLimit`)
If the depth is exceeded, an error is thrown, unless `throwOnDepthLimit` is set to `false`.
# Inputs
Structured function argument
: depthLimit (required)
: If this option is not null, the given value will stop evaluating at a certain depth
: throwOnDepthLimit (optional, default: `true`)
: If this option is true, an error will be thrown, if a certain given depth is exceeded
Value
: The value to be evaluated recursively
*/
withRecursion =
{
/* If this option is not null, the given value will stop evaluating at a certain depth */
depthLimit
/* If this option is true, an error will be thrown, if a certain given depth is exceeded */
, throwOnDepthLimit ? true
depthLimit,
throwOnDepthLimit ? true
}:
assert isInt depthLimit;
let
@ -323,20 +456,33 @@ let
in
mapAny 0;
/* Pretty print a value, akin to `builtins.trace`.
* Should probably be a builtin as well.
* The pretty-printed string should be suitable for rendering default values
* in the NixOS manual. In particular, it should be as close to a valid Nix expression
* as possible.
/**
Pretty print a value, akin to `builtins.trace`.
Should probably be a builtin as well.
The pretty-printed string should be suitable for rendering default values
in the NixOS manual. In particular, it should be as close to a valid Nix expression
as possible.
# Inputs
Structured function argument
: allowPrettyValues
: If this option is true, attrsets like { __pretty = fn; val = …; }
will use fn to convert val to a pretty printed representation.
(This means fn is type Val -> String.)
: multiline
: If this option is true, the output is indented with newlines for attribute sets and lists
: indent
: Initial indentation level
Value
: The value to be pretty printed
*/
toPretty = {
/* If this option is true, attrsets like { __pretty = fn; val = …; }
will use fn to convert val to a pretty printed representation.
(This means fn is type Val -> String.) */
allowPrettyValues ? false,
/* If this option is true, the output is indented with newlines for attribute sets and lists */
multiline ? true,
/* Initial indentation level */
indent ? ""
}:
let
@ -397,7 +543,17 @@ let
else abort "generators.toPretty: should never happen (v = ${v})";
in go indent;
# PLIST handling
/**
Translate a simple Nix expression to [Plist notation](https://en.wikipedia.org/wiki/Property_list).
# Inputs
Options
: Empty set, there may be configuration options in the future
Value
: The value to be converted to Plist
*/
toPlist = {}: v: let
expr = ind: x:
if x == null then "" else
@ -447,9 +603,21 @@ let
${expr "" v}
</plist>'';
/* Translate a simple Nix expression to Dhall notation.
* Note that integers are translated to Integer and never
* the Natural type.
/**
Translate a simple Nix expression to Dhall notation.
Note that integers are translated to Integer and never
the Natural type.
# Inputs
Options
: Empty set, there may be configuration options in the future
Value
: The value to be converted to Dhall
*/
toDhall = { }@args: v:
let concatItems = concatStringsSep ", ";
@ -471,19 +639,47 @@ ${expr "" v}
else
toJSON v;
/*
/**
Translate a simple Nix expression to Lua representation with occasional
Lua-inlines that can be constructed by mkLuaInline function.
Configuration:
* multiline - by default is true which results in indented block-like view.
* indent - initial indent.
* asBindings - by default generate single value, but with this use attrset to set global vars.
Attention:
Regardless of multiline parameter there is no trailing newline.
Example:
# Inputs
Structured function argument
: multiline (optional, default: `true`)
: If this option is true, the output is indented with newlines for attribute sets and lists
: indent (optional, default: `""`)
: Initial indentation level
: asBindings (optional, default: `false`)
: Interpret as variable bindings
Value
: The value to be converted to Lua
# Type
```
toLua :: AttrSet -> Any -> String
```
# Examples
:::{.example}
## `lib.generators.toLua` usage example
```nix
generators.toLua {}
{
cmd = [ "typescript-language-server" "--stdio" ];
@ -501,16 +697,13 @@ ${expr "" v}
}
}
}
```
Type:
toLua :: AttrSet -> Any -> String
:::
*/
toLua = {
/* If this option is true, the output is indented with newlines for attribute sets and lists */
multiline ? true,
/* Initial indentation level */
indent ? "",
/* Interpret as variable bindings */
asBindings ? false,
}@args: v:
let
@ -559,44 +752,55 @@ ${expr "" v}
else
abort "generators.toLua: type ${typeOf v} is unsupported";
/*
/**
Mark string as Lua expression to be inlined when processed by toLua.
Type:
# Inputs
`expr`
: 1\. Function argument
# Type
```
mkLuaInline :: String -> AttrSet
```
*/
mkLuaInline = expr: { _type = "lua-inline"; inherit expr; };
} // {
/**
Generates JSON from an arbitrary (non-function) value.
For more information see the documentation of the builtin.
in
# Inputs
# Everything in this attrset is the public interface of the file.
{
inherit
mkDconfKeyValue
mkKeyValueDefault
mkLuaInline
mkValueStringDefault
toDconfINI
toDhall
toGitINI
toINI
toINIWithGlobalSection
toKeyValue
toLua
toPlist
toPretty
withRecursion
;
Options
/* Generates JSON from an arbitrary (non-function) value.
* For more information see the documentation of the builtin.
: Empty set, there may be configuration options in the future
Value
: The value to be converted to JSON
*/
toJSON = {}: toJSON;
toJSON = {}: lib.strings.toJSON;
/* YAML has been a strict superset of JSON since 1.2, so we
* use toJSON. Before it only had a few differences referring
* to implicit typing rules, so it should work with older
* parsers as well.
/**
YAML has been a strict superset of JSON since 1.2, so we
use toJSON. Before it only had a few differences referring
to implicit typing rules, so it should work with older
parsers as well.
# Inputs
Options
: Empty set, there may be configuration options in the future
Value
: The value to be converted to YAML
*/
toYAML = {}: toJSON;
toYAML = {}: lib.strings.toJSON;
}