diff options
Diffstat (limited to 'nixpkgs/lib/strings.nix')
| -rw-r--r-- | nixpkgs/lib/strings.nix | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/nixpkgs/lib/strings.nix b/nixpkgs/lib/strings.nix index 74e3eaa0722..0baa942355c 100644 --- a/nixpkgs/lib/strings.nix +++ b/nixpkgs/lib/strings.nix @@ -612,6 +612,22 @@ rec { */ fixedWidthNumber = width: n: fixedWidthString width "0" (toString n); + /* Convert a float to a string, but emit a warning when precision is lost + during the conversion + + Example: + floatToString 0.000001 + => "0.000001" + floatToString 0.0000001 + => trace: warning: Imprecise conversion from float to string 0.000000 + "0.000000" + */ + floatToString = float: let + result = toString float; + precise = float == builtins.fromJSON result; + in if precise then result + else lib.warn "Imprecise conversion from float to string ${result}" result; + /* Check whether a value can be coerced to a string */ isCoercibleToString = x: builtins.elem (builtins.typeOf x) [ "path" "string" "null" "int" "float" "bool" ] || |