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nixpkgs/pkgs/build-support/coq/extra-lib.nix
2021-01-09 11:56:17 +01:00

146 lines
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Nix

{ lib }:
with builtins; with lib; recursiveUpdate lib (rec {
versions =
let
truncate = n: v: concatStringsSep "." (take n (splitVersion v));
opTruncate = op: v0: v: let n = length (splitVersion v0); in
op (truncate n v) (truncate n v0);
in rec {
/* Get string of the first n parts of a version string.
Example:
- truncate 2 "1.2.3-stuff"
=> "1.2"
- truncate 4 "1.2.3-stuff"
=> "1.2.3.stuff"
*/
inherit truncate;
/* Get string of the first three parts (major, minor and patch)
of a version string.
Example:
majorMinorPatch "1.2.3-stuff"
=> "1.2.3"
*/
majorMinorPatch = truncate 3;
/* Version comparison predicates,
- isGe v0 v <-> v is greater or equal than v0 [*]
- isLe v0 v <-> v is lesser or equal than v0 [*]
- isGt v0 v <-> v is strictly greater than v0 [*]
- isLt v0 v <-> v is strictly lesser than v0 [*]
- isEq v0 v <-> v is equal to v0 [*]
- range low high v <-> v is between low and high [**]
[*] truncating v to the same number of digits as v0
[**] truncating v to low for the lower bound and high for the upper bound
Examples:
- isGe "8.10" "8.10.1"
=> true
- isLe "8.10" "8.10.1"
=> true
- isGt "8.10" "8.10.1"
=> false
- isGt "8.10.0" "8.10.1"
=> true
- isEq "8.10" "8.10.1"
=> true
- range "8.10" "8.11" "8.11.1"
=> true
- range "8.10" "8.11+" "8.11.0"
=> false
- range "8.10" "8.11+" "8.11+beta1"
=> false
*/
isGe = opTruncate versionAtLeast;
isGt = opTruncate (flip versionOlder);
isLe = opTruncate (flip versionAtLeast);
isLt = opTruncate versionOlder;
isEq = opTruncate pred.equal;
range = low: high: pred.inter (versions.isGe low) (versions.isLe high);
};
/* Returns a list of list, splitting it using a predicate.
This is analoguous to builtins.split sep list,
with a predicate as a separator and a list instead of a string.
Type: splitList :: (a -> bool) -> [a] -> [[a]]
Example:
splitList (x: x == "x") [ "y" "x" "z" "t" ]
=> [ [ "y" ] "x" [ "z" "t" ] ]
*/
splitList = pred: l: # put in file lists
let loop = (vv: v: l: if l == [] then vv ++ [v]
else let hd = head l; tl = tail l; in
if pred hd then loop (vv ++ [ v hd ]) [] tl else loop vv (v ++ [hd]) tl);
in loop [] [] l;
pred = {
/* Predicate intersection, union, and complement */
inter = p: q: x: p x && q x;
union = p: q: x: p x || q x;
compl = p: x: ! p x;
true = p: true;
false = p: false;
/* predicate "being equal to y" */
equal = y: x: x == y;
};
/* Emulate a "switch - case" construct,
instead of relying on `if then else if ...` */
/* Usage:
```nix
switch-if [
if-clause-1
..
if-clause-k
] default-out
```
where a if-clause has the form `{ cond = b; out = r; }`
the first branch such as `b` is true */
switch-if = c: d: (findFirst (getAttr "cond") {} c).out or d;
/* Usage:
```nix
switch x [
simple-clause-1
..
simple-clause-k
] default-out
```
where a simple-clause has the form `{ case = p; out = r; }`
the first branch such as `p x` is true
or
```nix
switch [ x1 .. xn ] [
complex-clause-1
..
complex-clause-k
] default-out
```
where a complex-clause is either a simple-clause
or has the form { cases = [ p1 .. pn ]; out = r; }
in which case the first branch such as all `pi x` are true
if the variables p are not functions,
they are converted to a equal p
if out is missing the default-out is taken */
switch = var: clauses: default: with pred; let
compare = f: if isFunction f then f else equal f;
combine = cl: var:
if cl?case then compare cl.case var
else all (equal true) (zipListsWith compare cl.cases var); in
switch-if (map (cl: { cond = combine cl var; inherit (cl) out; }) clauses) default;
})