lib/generators: introduce a sane default for mkValueString

So far, `mkValueString` defaulted to `toString`,
which is a bad match for most configuration file formats,
especially because how booleans are formatted.
This also improves error messages for unsupported types.

Add a test to codify the formatting.
This commit is contained in:
Profpatsch 2018-03-26 17:31:05 +02:00
parent a7e45fdd8e
commit fa71407f36
2 changed files with 51 additions and 1 deletions

View file

@ -28,6 +28,30 @@ 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: ${toPretty {} v}");
in if isInt v then toString v
# we default to not quoting strings
else if isString v then v
# isString returns "1", which is not a good default
else if true == v then "true"
# here it returns to "", which is even less of a good default
else if false == v then "false"
else if null == v then "null"
# if you have lists you probably want to replace this
else if isList v then err "lists" v
# same as for lists, might want to replace
else if isAttrs v then err "attrsets" v
else if isFunction v then err "functions" v
else err "this value is" (toString v);
/* Generate a line of key k and value v, separated by
* character sep. If sep appears in k, it is escaped.
* Helper for synaxes with different separators.
@ -38,7 +62,7 @@ rec {
* > "f\:oo:bar"
*/
mkKeyValueDefault = {
mkValueString ? toString
mkValueString ? mkValueStringDefault {}
}: sep: k: v:
"${libStr.escape [sep] k}${sep}${mkValueString v}";

View file

@ -207,6 +207,29 @@ runTests {
expected = ''f\:oo:bar'';
};
testMkValueString = {
expr = let
vals = {
int = 42;
string = ''fo"o'';
bool = true;
bool2 = false;
null = null;
# float = 42.23; # floats are strange
};
in mapAttrs
(const (generators.mkValueStringDefault {}))
vals;
expected = {
int = "42";
string = ''fo"o'';
bool = "true";
bool2 = "false";
null = "null";
# float = "42.23" true false [ "bar" ] ]'';
};
};
testToKeyValue = {
expr = generators.toKeyValue {} {
key = "value";
@ -249,6 +272,8 @@ runTests {
"section 1" = {
attribute1 = 5;
x = "Me-se JarJar Binx";
# booleans are converted verbatim by default
boolean = false;
};
"foo[]" = {
"he\\h=he" = "this is okay";
@ -260,6 +285,7 @@ runTests {
[section 1]
attribute1=5
boolean=false
x=Me-se JarJar Binx
'';
};