1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
|
/* 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.nix
* Documentation in the manual, #sec-generators
*/
{ lib }:
with (lib).trivial;
let
libStr = lib.strings;
libAttr = lib.attrsets;
inherit (lib) isFunction;
in
rec {
## -- HELPER FUNCTIONS & DEFAULTS --
/* 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.
*/
mkValueStringDefault = {}: v: with builtins;
let err = t: v: abort
("generators.mkValueStringDefault: " +
"${t} not supported: ${toPretty {} v}");
in if isInt v then toString v
# we default to not quoting strings
else if isString v then v
# isString returns "1", which is not a good default
else if true == v then "true"
# here it returns to "", which is even less of a good default
else if false == v then "false"
else if null == v then "null"
# if you have lists you probably want to replace this
else if isList v then err "lists" v
# same as for lists, might want to replace
else if isAttrs v then err "attrsets" v
# functions can’t be printed of course
else if isFunction v then err "functions" v
# let’s not talk about floats. There is no sensible `toString` for them.
else if isFloat v then err "floats" v
else err "this value is" (toString v);
/* Generate a line of key k and value v, separated by
* character sep. If sep appears in k, it is escaped.
* Helper for synaxes with different separators.
*
* mkValueString specifies how values should be formatted.
*
* mkKeyValueDefault {} ":" "f:oo" "bar"
* > "f\:oo:bar"
*/
mkKeyValueDefault = {
mkValueString ? mkValueStringDefault {}
}: sep: k: v:
"${libStr.escape [sep] k}${sep}${mkValueString v}";
## -- FILE FORMAT GENERATORS --
/* Generate a key-value-style config file from an attrset.
*
* mkKeyValue is the same as in toINI.
*/
toKeyValue = {
mkKeyValue ? mkKeyValueDefault {} "="
}: attrs:
let mkLine = k: v: mkKeyValue k v + "\n";
in libStr.concatStrings (libAttr.mapAttrsToList mkLine attrs);
/* Generate an INI-style config file from an
* attrset of sections to an attrset of key-value pairs.
*
* generators.toINI {} {
* foo = { hi = "${pkgs.hello}"; ciao = "bar"; };
* baz = { "also, integers" = 42; };
* }
*
*> [baz]
*> also, integers=42
*>
*> [foo]
*> ciao=bar
*> hi=/nix/store/y93qql1p5ggfnaqjjqhxcw0vqw95rlz0-hello-2.10
*
* The mk* configuration attributes can generically change
* the way sections and key-value strings are generated.
*
* For more examples see the test cases in ./tests.nix.
*/
toINI = {
# apply transformations (e.g. escapes) to section names
mkSectionName ? (name: libStr.escape [ "[" "]" ] name),
# format a setting line from key and value
mkKeyValue ? mkKeyValueDefault {} "="
}: attrsOfAttrs:
let
# map function to string for each key val
mapAttrsToStringsSep = sep: mapFn: attrs:
libStr.concatStringsSep sep
(libAttr.mapAttrsToList mapFn attrs);
mkSection = sectName: sectValues: ''
[${mkSectionName sectName}]
'' + toKeyValue { inherit mkKeyValue; } sectValues;
in
# map input to ini sections
mapAttrsToStringsSep "\n" mkSection attrsOfAttrs;
/* Generates JSON from an arbitrary (non-function) value.
* For more information see the documentation of the builtin.
*/
toJSON = {}: builtins.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 = {}@args: toJSON args;
/* Pretty print a value, akin to `builtins.trace`.
* Should probably be a builtin as well.
*/
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
}@args: v: with builtins;
let isPath = v: typeOf v == "path";
in if isInt v then toString v
else if isFloat v then "~${toString v}"
else if isString v then ''"${libStr.escape [''"''] v}"''
else if true == v then "true"
else if false == v then "false"
else if null == v then "null"
else if isPath v then toString v
else if isList v then "[ "
+ libStr.concatMapStringsSep " " (toPretty args) v
+ " ]"
else if isAttrs v then
# apply pretty values if allowed
if attrNames v == [ "__pretty" "val" ] && allowPrettyValues
then v.__pretty v.val
# TODO: there is probably a better representation?
else if v ? type && v.type == "derivation" then
"<δ:${v.name}>"
# "<δ:${concatStringsSep "," (builtins.attrNames v)}>"
else "{ "
+ libStr.concatStringsSep " " (libAttr.mapAttrsToList
(name: value:
"${toPretty args name} = ${toPretty args value};") v)
+ " }"
else if isFunction v then
let fna = lib.functionArgs v;
showFnas = concatStringsSep "," (libAttr.mapAttrsToList
(name: hasDefVal: if hasDefVal then "(${name})" else name)
fna);
in if fna == {} then "<λ>"
else "<λ:{${showFnas}}>"
else abort "generators.toPretty: should never happen (v = ${v})";
# PLIST handling
toPlist = {}: v: let
isFloat = builtins.isFloat or (x: false);
expr = ind: x: with builtins;
if x == null then "" else
if isBool x then bool ind x else
if isInt x then int ind x else
if isString x then str ind x else
if isList x then list ind x else
if isAttrs x then attrs ind x else
if isFloat x then float ind x else
abort "generators.toPlist: should never happen (v = ${v})";
literal = ind: x: ind + x;
bool = ind: x: literal ind (if x then "<true/>" else "<false/>");
int = ind: x: literal ind "<integer>${toString x}</integer>";
str = ind: x: literal ind "<string>${x}</string>";
key = ind: x: literal ind "<key>${x}</key>";
float = ind: x: literal ind "<real>${toString x}</real>";
indent = ind: expr "\t${ind}";
item = ind: libStr.concatMapStringsSep "\n" (indent ind);
list = ind: x: libStr.concatStringsSep "\n" [
(literal ind "<array>")
(item ind x)
(literal ind "</array>")
];
attrs = ind: x: libStr.concatStringsSep "\n" [
(literal ind "<dict>")
(attr ind x)
(literal ind "</dict>")
];
attr = let attrFilter = name: value: name != "_module" && value != null;
in ind: x: libStr.concatStringsSep "\n" (lib.flatten (lib.mapAttrsToList
(name: value: lib.optional (attrFilter name value) [
(key "\t${ind}" name)
(expr "\t${ind}" value)
]) x));
in ''<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
${expr "" v}
</plist>'';
}
|
