603 lines
19 KiB
Nix
603 lines
19 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/misc.nix
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* Documentation in the manual, #sec-generators
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*/
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{ lib }:
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let
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inherit (lib)
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addErrorContext
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assertMsg
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attrNames
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concatLists
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concatMapStringsSep
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concatStrings
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concatStringsSep
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const
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elem
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escape
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filter
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flatten
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foldl
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functionArgs # Note: not the builtin; considers `__functor` in attrsets.
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gvariant
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hasInfix
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head
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id
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init
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isAttrs
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isBool
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isDerivation
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isFloat
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isFunction # Note: not the builtin; considers `__functor` in attrsets.
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isInt
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isList
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isPath
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isString
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last
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length
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mapAttrs
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mapAttrsToList
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optionals
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recursiveUpdate
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replaceStrings
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reverseList
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splitString
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tail
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toList
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;
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inherit (lib.strings)
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escapeNixIdentifier
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floatToString
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match
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split
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toJSON
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typeOf
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;
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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:
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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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# convert derivations to store paths
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else if isDerivation 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 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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"${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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indent ? ""
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}:
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let mkLine = k: v: indent + mkKeyValue k v + "\n";
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mkLines = if listsAsDuplicateKeys
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then k: v: map (mkLine k) (if isList v then v else [v])
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else k: v: [ (mkLine k v) ];
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in attrs: concatStrings (concatLists (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/misc.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: 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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concatStringsSep sep
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(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 an INI-style config file from an attrset
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* specifying the global section (no header), and an
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* attrset of sections to an attrset of key-value pairs.
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*
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* generators.toINIWithGlobalSection {} {
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* globalSection = {
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* someGlobalKey = "hi";
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* };
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* sections = {
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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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*> someGlobalKey=hi
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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/misc.nix.
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*
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* If you don’t need a global section, you can also use
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* `generators.toINI` directly, which only takes
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* the part in `sections`.
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*/
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toINIWithGlobalSection = {
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# apply transformations (e.g. escapes) to section names
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mkSectionName ? (name: 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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}: { globalSection, sections ? {} }:
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( if globalSection == {}
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then ""
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else (toKeyValue { inherit mkKeyValue listsAsDuplicateKeys; } globalSection)
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+ "\n")
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+ (toINI { inherit mkSectionName mkKeyValue listsAsDuplicateKeys; } sections);
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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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let
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mkSectionName = name:
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let
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containsQuote = hasInfix ''"'' name;
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sections = 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} "${subsection}"'';
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mkValueString = v:
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let
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escapedV = ''
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"${
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replaceStrings [ "\n" " " ''"'' "\\" ] [ "\\n" "\\t" ''\"'' "\\\\" ] v
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}"'';
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in mkValueStringDefault { } (if isString v then escapedV else v);
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# generation for multiple ini values
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mkKeyValue = k: v:
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let mkKeyValue = mkKeyValueDefault { inherit mkValueString; } " = " k;
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in concatStringsSep "\n" (map (kv: "\t" + mkKeyValue kv) (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 && !isDerivation value then
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mapAttrsToList (name: value: recurse ([ name ] ++ path) value) value
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else if length path > 1 then {
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${concatStringsSep "." (reverseList (tail path))}.${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: foldl recursiveUpdate { } (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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# mkKeyValueDefault wrapper that handles dconf INI quirks.
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# The main differences of the format is that it requires strings to be quoted.
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mkDconfKeyValue = mkKeyValueDefault { mkValueString = v: toString (gvariant.mkValue v); } "=";
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# Generates INI in dconf keyfile style. See https://help.gnome.org/admin/system-admin-guide/stable/dconf-keyfiles.html.en
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# for details.
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toDconfINI = toINI { mkKeyValue = mkDconfKeyValue; };
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withRecursion =
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{
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/* If this option is not null, the given value will stop evaluating at a certain depth */
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depthLimit
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/* If this option is true, an error will be thrown, if a certain given depth is exceeded */
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, throwOnDepthLimit ? true
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}:
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assert isInt depthLimit;
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let
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specialAttrs = [
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"__functor"
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"__functionArgs"
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"__toString"
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"__pretty"
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];
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stepIntoAttr = evalNext: name:
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if elem name specialAttrs
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then id
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else evalNext;
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transform = depth:
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if depthLimit != null && depth > depthLimit then
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if throwOnDepthLimit
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then throw "Exceeded maximum eval-depth limit of ${toString depthLimit} while trying to evaluate with `generators.withRecursion'!"
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else const "<unevaluated>"
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else id;
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mapAny = depth: v:
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let
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evalNext = x: mapAny (depth + 1) (transform (depth + 1) x);
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in
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if isAttrs v then mapAttrs (stepIntoAttr evalNext) v
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else if isList v then map evalNext v
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else transform (depth + 1) v;
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in
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mapAny 0;
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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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* The pretty-printed string should be suitable for rendering default values
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* in the NixOS manual. In particular, it should be as close to a valid Nix expression
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* as possible.
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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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/* Initial indentation level */
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indent ? ""
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}:
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let
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go = indent: v:
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let 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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# toString loses precision on floats, so we use toJSON instead. This isn't perfect
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# as the resulting string may not parse back as a float (e.g. 42, 1e-06), but for
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# pretty-printing purposes this is acceptable.
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else if isFloat v then builtins.toJSON v
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else if isString v then
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let
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lines = filter (v: ! isList v) (split "\n" v);
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escapeSingleline = escape [ "\\" "\"" "\${" ];
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escapeMultiline = replaceStrings [ "\${" "''" ] [ "''\${" "'''" ];
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singlelineResult = "\"" + concatStringsSep "\\n" (map escapeSingleline lines) + "\"";
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multilineResult = let
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escapedLines = map escapeMultiline lines;
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# The last line gets a special treatment: if it's empty, '' is on its own line at the "outer"
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# indentation level. Otherwise, '' is appended to the last line.
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lastLine = last escapedLines;
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in "''" + introSpace + concatStringsSep introSpace (init escapedLines)
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+ (if lastLine == "" then outroSpace else introSpace + lastLine) + "''";
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in
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if multiline && length lines > 1 then multilineResult 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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+ 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 = functionArgs v;
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showFnas = concatStringsSep ", " (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 allowPrettyValues && v ? __pretty && v ? val
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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 ${v.name or "???"}>"
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else "{" + introSpace
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+ concatStringsSep introSpace (mapAttrsToList
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(name: value:
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"${escapeNixIdentifier name} = ${
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addErrorContext "while evaluating an attribute `${name}`"
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(go (indent + " ") value)
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};") 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 indent;
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# PLIST handling
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toPlist = {}: v: let
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expr = ind: x:
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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 isPath x then str ind (toString 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: concatMapStringsSep "\n" (indent ind);
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list = ind: x: 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: 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: concatStringsSep "\n" (flatten (mapAttrsToList
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(name: value: optionals (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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/* Translate a simple Nix expression to Dhall notation.
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* Note that integers are translated to Integer and never
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* the Natural type.
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*/
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toDhall = { }@args: v:
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let concatItems = concatStringsSep ", ";
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in if isAttrs v then
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"{ ${
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concatItems (mapAttrsToList
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(key: value: "${key} = ${toDhall args value}") v)
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} }"
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else if isList v then
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"[ ${concatItems (map (toDhall args) v)} ]"
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else if isInt v then
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"${if v < 0 then "" else "+"}${toString v}"
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else if isBool v then
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(if v then "True" else "False")
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else if isFunction v then
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abort "generators.toDhall: cannot convert a function to Dhall"
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else if v == null then
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abort "generators.toDhall: cannot convert a null to Dhall"
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else
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toJSON v;
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/*
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Translate a simple Nix expression to Lua representation with occasional
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Lua-inlines that can be constructed by mkLuaInline function.
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Configuration:
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* multiline - by default is true which results in indented block-like view.
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* indent - initial indent.
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* asBindings - by default generate single value, but with this use attrset to set global vars.
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Attention:
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Regardless of multiline parameter there is no trailing newline.
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Example:
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generators.toLua {}
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{
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cmd = [ "typescript-language-server" "--stdio" ];
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settings.workspace.library = mkLuaInline ''vim.api.nvim_get_runtime_file("", true)'';
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}
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->
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{
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["cmd"] = {
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"typescript-language-server",
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"--stdio"
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},
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["settings"] = {
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["workspace"] = {
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["library"] = (vim.api.nvim_get_runtime_file("", true))
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}
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}
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}
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|
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Type:
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toLua :: AttrSet -> Any -> String
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*/
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toLua = {
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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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/* Initial indentation level */
|
||
indent ? "",
|
||
/* Interpret as variable bindings */
|
||
asBindings ? false,
|
||
}@args: v:
|
||
let
|
||
innerIndent = "${indent} ";
|
||
introSpace = if multiline then "\n${innerIndent}" else " ";
|
||
outroSpace = if multiline then "\n${indent}" else " ";
|
||
innerArgs = args // {
|
||
indent = if asBindings then indent else innerIndent;
|
||
asBindings = false;
|
||
};
|
||
concatItems = concatStringsSep ",${introSpace}";
|
||
isLuaInline = { _type ? null, ... }: _type == "lua-inline";
|
||
|
||
generatedBindings =
|
||
assert assertMsg (badVarNames == []) "Bad Lua var names: ${toPretty {} badVarNames}";
|
||
concatStrings (
|
||
mapAttrsToList (key: value: "${indent}${key} = ${toLua innerArgs value}\n") v
|
||
);
|
||
|
||
# https://en.wikibooks.org/wiki/Lua_Programming/variable#Variable_names
|
||
matchVarName = match "[[:alpha:]_][[:alnum:]_]*(\\.[[:alpha:]_][[:alnum:]_]*)*";
|
||
badVarNames = filter (name: matchVarName name == null) (attrNames v);
|
||
in
|
||
if asBindings then
|
||
generatedBindings
|
||
else if v == null then
|
||
"nil"
|
||
else if isInt v || isFloat v || isString v || isBool v then
|
||
toJSON v
|
||
else if isList v then
|
||
(if v == [ ] then "{}" else
|
||
"{${introSpace}${concatItems (map (value: "${toLua innerArgs value}") v)}${outroSpace}}")
|
||
else if isAttrs v then
|
||
(
|
||
if isLuaInline v then
|
||
"(${v.expr})"
|
||
else if v == { } then
|
||
"{}"
|
||
else if isDerivation v then
|
||
''"${toString v}"''
|
||
else
|
||
"{${introSpace}${concatItems (
|
||
mapAttrsToList (key: value: "[${toJSON key}] = ${toLua innerArgs value}") v
|
||
)}${outroSpace}}"
|
||
)
|
||
else
|
||
abort "generators.toLua: type ${typeOf v} is unsupported";
|
||
|
||
/*
|
||
Mark string as Lua expression to be inlined when processed by toLua.
|
||
|
||
Type:
|
||
mkLuaInline :: String -> AttrSet
|
||
*/
|
||
mkLuaInline = expr: { _type = "lua-inline"; inherit expr; };
|
||
|
||
in
|
||
|
||
# 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
|
||
;
|
||
|
||
/* Generates JSON from an arbitrary (non-function) value.
|
||
* For more information see the documentation of the builtin.
|
||
*/
|
||
toJSON = {}: 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.
|
||
*/
|
||
toYAML = {}: toJSON;
|
||
}
|