blob: 381c8ddff748de9035b74b86bc9ee0b88859f9fd (
plain) (
blame)
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
|
{ depot, lib, ... }:
let
inherit (depot.users.sterni.nix.char)
chr
ord
;
inherit (depot.users.sterni.nix)
int
flow
;
take = n: s:
builtins.substring 0 n s;
drop = n: s:
builtins.substring n int.maxBound s;
charAt = i: s:
let
r = builtins.substring i 1 s;
in
if r == "" then null else r;
charIndex = char: s:
let
len = builtins.stringLength s;
go = i:
flow.cond [
[ (i >= len) null ]
[ (charAt i s == char) i ]
[ true (go (i + 1)) ]
];
in
go 0;
toChars = lib.stringToCharacters;
fromChars = lib.concatStrings;
toBytes = str:
builtins.map ord (toChars str);
fromBytes = is: lib.concatMapStrings chr is;
pad = { left ? 0, right ? 0, char ? " " }: s:
let
leftS = fromChars (builtins.genList (_: char) left);
rightS = fromChars (builtins.genList (_: char) right);
in
"${leftS}${s}${rightS}";
fit = { char ? " ", width, side ? "left" }: s:
let
diff = width - builtins.stringLength s;
in
if diff <= 0
then s
else pad { inherit char; "${side}" = diff; } s;
# pattern matching for strings only
match = val: matcher: matcher."${val}";
/* Bare-bones printf implementation. Supported format specifiers:
* `%%` escapes `%`
* `%s` is substituted by a string
As expected, the first argument is a format string and the values
for its format specifiers need to provided as the next arguments
in order.
Type: string -> (printfVal : either string (a -> printfVal))
*/
printf = formatString:
let
specifierWithArg = token: builtins.elem token [
"%s"
];
isSpecifier = lib.hasPrefix "%";
tokens = lib.flatten (builtins.split "(%.)" formatString);
argsNeeded = builtins.length (builtins.filter specifierWithArg tokens);
format = args: (builtins.foldl'
({ out ? "", argIndex ? 0 }: token: {
argIndex = argIndex + (if specifierWithArg token then 1 else 0);
out =
if token == "%s" then out + builtins.elemAt args argIndex
else if token == "%%" then out + "%"
else if isSpecifier token then throw "Unsupported format specifier ${token}"
else out + token;
})
{ }
tokens).out;
accumulateArgs = argCount: args:
if argCount > 0
then arg: accumulateArgs (argCount - 1) (args ++ [ arg ])
else format args;
in
accumulateArgs argsNeeded [ ];
in
{
inherit
take
drop
charAt
charIndex
toBytes
fromBytes
toChars
fromChars
pad
fit
match
printf
;
}
|
