06d3b28987
This reverts commit d9a7d03da8.
Reason for this is that it actually doesn't migitate the issue on nix
stable for another reason: builtins.tryEval doesn't prevent the error
generated by builtins.functionArgs from halting evaluation:
> builtins.tryEval (builtins.functionArgs builtins.functionArgs)
error: 'functionArgs' requires a function, at (string):1:19
Thus it seems that there is no workaround to make
lib.generators.toPretty work with nix stable and primops since there is
no way to distinguish between primops and lambdas in nix.
310 lines
11 KiB
Nix
310 lines
11 KiB
Nix
/* Functions that generate widespread file
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* formats from nix data structures.
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*
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* They all follow a similar interface:
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* generator { config-attrs } data
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*
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* `config-attrs` are “holes” in the generators
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* with sensible default implementations that
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* can be overwritten. The default implementations
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* are mostly generators themselves, called with
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* their respective default values; they can be reused.
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*
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* Tests can be found in ./tests.nix
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* Documentation in the manual, #sec-generators
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*/
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{ lib }:
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with (lib).trivial;
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let
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libStr = lib.strings;
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libAttr = lib.attrsets;
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inherit (lib) isFunction;
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in
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rec {
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## -- HELPER FUNCTIONS & DEFAULTS --
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/* Convert a value to a sensible default string representation.
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* The builtin `toString` function has some strange defaults,
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* suitable for bash scripts but not much else.
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*/
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mkValueStringDefault = {}: v: with builtins;
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let err = t: v: abort
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("generators.mkValueStringDefault: " +
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"${t} not supported: ${toPretty {} v}");
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in if isInt v then toString v
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# we default to not quoting strings
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else if isString v then v
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# isString returns "1", which is not a good default
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else if true == v then "true"
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# here it returns to "", which is even less of a good default
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else if false == v then "false"
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else if null == v then "null"
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# if you have lists you probably want to replace this
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else if isList v then err "lists" v
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# same as for lists, might want to replace
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else if isAttrs v then err "attrsets" v
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# functions can’t be printed of course
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else if isFunction v then err "functions" v
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# Floats currently can't be converted to precise strings,
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# condition warning on nix version once this isn't a problem anymore
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# See https://github.com/NixOS/nix/pull/3480
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else if isFloat v then libStr.floatToString v
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else err "this value is" (toString v);
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/* Generate a line of key k and value v, separated by
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* character sep. If sep appears in k, it is escaped.
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* Helper for synaxes with different separators.
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*
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* mkValueString specifies how values should be formatted.
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*
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* mkKeyValueDefault {} ":" "f:oo" "bar"
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* > "f\:oo:bar"
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*/
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mkKeyValueDefault = {
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mkValueString ? mkValueStringDefault {}
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}: sep: k: v:
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"${libStr.escape [sep] k}${sep}${mkValueString v}";
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## -- FILE FORMAT GENERATORS --
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/* Generate a key-value-style config file from an attrset.
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*
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* mkKeyValue is the same as in toINI.
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*/
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toKeyValue = {
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mkKeyValue ? mkKeyValueDefault {} "=",
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listsAsDuplicateKeys ? false
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}:
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let mkLine = k: v: mkKeyValue k v + "\n";
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mkLines = if listsAsDuplicateKeys
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then k: v: map (mkLine k) (if lib.isList v then v else [v])
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else k: v: [ (mkLine k v) ];
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in attrs: libStr.concatStrings (lib.concatLists (libAttr.mapAttrsToList mkLines attrs));
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/* Generate an INI-style config file from an
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* attrset of sections to an attrset of key-value pairs.
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*
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* generators.toINI {} {
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* foo = { hi = "${pkgs.hello}"; ciao = "bar"; };
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* baz = { "also, integers" = 42; };
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* }
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*
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*> [baz]
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*> also, integers=42
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*>
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*> [foo]
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*> ciao=bar
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*> hi=/nix/store/y93qql1p5ggfnaqjjqhxcw0vqw95rlz0-hello-2.10
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*
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* The mk* configuration attributes can generically change
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* the way sections and key-value strings are generated.
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*
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* For more examples see the test cases in ./tests.nix.
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*/
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toINI = {
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# apply transformations (e.g. escapes) to section names
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mkSectionName ? (name: libStr.escape [ "[" "]" ] name),
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# format a setting line from key and value
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mkKeyValue ? mkKeyValueDefault {} "=",
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# allow lists as values for duplicate keys
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listsAsDuplicateKeys ? false
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}: attrsOfAttrs:
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let
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# map function to string for each key val
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mapAttrsToStringsSep = sep: mapFn: attrs:
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libStr.concatStringsSep sep
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(libAttr.mapAttrsToList mapFn attrs);
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mkSection = sectName: sectValues: ''
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[${mkSectionName sectName}]
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'' + toKeyValue { inherit mkKeyValue listsAsDuplicateKeys; } sectValues;
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in
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# map input to ini sections
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mapAttrsToStringsSep "\n" mkSection attrsOfAttrs;
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/* Generate a git-config file from an attrset.
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*
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* It has two major differences from the regular INI format:
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*
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* 1. values are indented with tabs
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* 2. sections can have sub-sections
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*
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* generators.toGitINI {
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* url."ssh://git@github.com/".insteadOf = "https://github.com";
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* user.name = "edolstra";
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* }
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*
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*> [url "ssh://git@github.com/"]
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*> insteadOf = https://github.com/
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*>
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*> [user]
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*> name = edolstra
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*/
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toGitINI = attrs:
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with builtins;
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let
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mkSectionName = name:
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let
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containsQuote = libStr.hasInfix ''"'' name;
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sections = libStr.splitString "." name;
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section = head sections;
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subsections = tail sections;
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subsection = concatStringsSep "." subsections;
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in if containsQuote || subsections == [ ] then
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name
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else
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''${section} "${subsection}"'';
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# generation for multiple ini values
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mkKeyValue = k: v:
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let mkKeyValue = mkKeyValueDefault { } " = " k;
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in concatStringsSep "\n" (map (kv: "\t" + mkKeyValue kv) (lib.toList v));
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# converts { a.b.c = 5; } to { "a.b".c = 5; } for toINI
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gitFlattenAttrs = let
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recurse = path: value:
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if isAttrs value then
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lib.mapAttrsToList (name: value: recurse ([ name ] ++ path) value) value
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else if length path > 1 then {
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${concatStringsSep "." (lib.reverseList (tail path))}.${head path} = value;
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} else {
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${head path} = value;
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};
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in attrs: lib.foldl lib.recursiveUpdate { } (lib.flatten (recurse [ ] attrs));
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toINI_ = toINI { inherit mkKeyValue mkSectionName; };
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in
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toINI_ (gitFlattenAttrs attrs);
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/* Generates JSON from an arbitrary (non-function) value.
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* For more information see the documentation of the builtin.
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*/
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toJSON = {}: builtins.toJSON;
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/* YAML has been a strict superset of JSON since 1.2, so we
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* use toJSON. Before it only had a few differences referring
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* to implicit typing rules, so it should work with older
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* parsers as well.
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*/
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toYAML = {}@args: toJSON args;
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/* Pretty print a value, akin to `builtins.trace`.
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* Should probably be a builtin as well.
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*/
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toPretty = {
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/* If this option is true, attrsets like { __pretty = fn; val = …; }
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will use fn to convert val to a pretty printed representation.
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(This means fn is type Val -> String.) */
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allowPrettyValues ? false,
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/* If this option is true, the output is indented with newlines for attribute sets and lists */
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multiline ? true
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}@args: let
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go = indent: v: with builtins;
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let isPath = v: typeOf v == "path";
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introSpace = if multiline then "\n${indent} " else " ";
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outroSpace = if multiline then "\n${indent}" else " ";
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in if isInt v then toString v
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else if isFloat v then "~${toString v}"
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else if isString v then
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let
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# Separate a string into its lines
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newlineSplits = filter (v: ! isList v) (builtins.split "\n" v);
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# For a '' string terminated by a \n, which happens when the closing '' is on a new line
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multilineResult = "''" + introSpace + concatStringsSep introSpace (lib.init newlineSplits) + outroSpace + "''";
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# For a '' string not terminated by a \n, which happens when the closing '' is not on a new line
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multilineResult' = "''" + introSpace + concatStringsSep introSpace newlineSplits + "''";
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# For single lines, replace all newlines with their escaped representation
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singlelineResult = "\"" + libStr.escape [ "\"" ] (concatStringsSep "\\n" newlineSplits) + "\"";
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in if multiline && length newlineSplits > 1 then
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if lib.last newlineSplits == "" then multilineResult else multilineResult'
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else singlelineResult
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else if true == v then "true"
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else if false == v then "false"
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else if null == v then "null"
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else if isPath v then toString v
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else if isList v then
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if v == [] then "[ ]"
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else "[" + introSpace
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+ libStr.concatMapStringsSep introSpace (go (indent + " ")) v
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+ outroSpace + "]"
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else if isFunction v then
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let fna = lib.functionArgs v;
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showFnas = concatStringsSep ", " (libAttr.mapAttrsToList
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(name: hasDefVal: if hasDefVal then name + "?" else name)
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fna);
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in if fna == {} then "<function>"
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else "<function, args: {${showFnas}}>"
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else if isAttrs v then
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# apply pretty values if allowed
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if attrNames v == [ "__pretty" "val" ] && allowPrettyValues
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then v.__pretty v.val
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else if v == {} then "{ }"
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else if v ? type && v.type == "derivation" then
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"<derivation ${v.drvPath}>"
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else "{" + introSpace
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+ libStr.concatStringsSep introSpace (libAttr.mapAttrsToList
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(name: value:
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"${libStr.escapeNixIdentifier name} = ${go (indent + " ") value};") v)
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+ outroSpace + "}"
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else abort "generators.toPretty: should never happen (v = ${v})";
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in go "";
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# PLIST handling
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toPlist = {}: v: let
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isFloat = builtins.isFloat or (x: false);
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expr = ind: x: with builtins;
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if x == null then "" else
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if isBool x then bool ind x else
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if isInt x then int ind x else
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if isString x then str ind x else
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if isList x then list ind x else
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if isAttrs x then attrs ind x else
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if isFloat x then float ind x else
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abort "generators.toPlist: should never happen (v = ${v})";
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literal = ind: x: ind + x;
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bool = ind: x: literal ind (if x then "<true/>" else "<false/>");
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int = ind: x: literal ind "<integer>${toString x}</integer>";
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str = ind: x: literal ind "<string>${x}</string>";
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key = ind: x: literal ind "<key>${x}</key>";
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float = ind: x: literal ind "<real>${toString x}</real>";
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indent = ind: expr "\t${ind}";
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item = ind: libStr.concatMapStringsSep "\n" (indent ind);
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list = ind: x: libStr.concatStringsSep "\n" [
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(literal ind "<array>")
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(item ind x)
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(literal ind "</array>")
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];
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attrs = ind: x: libStr.concatStringsSep "\n" [
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(literal ind "<dict>")
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(attr ind x)
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(literal ind "</dict>")
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];
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attr = let attrFilter = name: value: name != "_module" && value != null;
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in ind: x: libStr.concatStringsSep "\n" (lib.flatten (lib.mapAttrsToList
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(name: value: lib.optional (attrFilter name value) [
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(key "\t${ind}" name)
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(expr "\t${ind}" value)
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]) x));
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in ''<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
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<plist version="1.0">
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${expr "" v}
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</plist>'';
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}
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