Synopsis
affogato eval [-h] [--json] [--raw] [--show-trace] [--strict] [-A=ATTR] [--system=SYS] [--arg=NAME EXPR]… [--argstr=NAME VALUE]… [-I=PATH]… (-E=EXPR | FILE)
Description
Evaluate an expression and print the result, like nix-instantiate --eval.
Options
- -A, --attr=ATTR
-
Select an attribute path in the result.
- --arg=NAME EXPR
-
Call a function result with NAME bound to EXPR.
- --argstr=NAME VALUE
-
Call a function result with NAME bound to the string VALUE.
- -E, --expr=EXPR
-
Evaluate EXPR.
- -h, --help
-
Show this help and exit.
- -I, --include=PATH
-
Add an entry to the search path of lookups such as <nixpkgs>, as nixpkgs=/path/to/nixpkgs; the entries of NIX_PATH come after.
- --json
-
Print the result as JSON.
- --raw
-
Print a string result without quotes or escapes.
- --show-trace
-
Print the Nix call stack when the evaluation fails.
- --strict
-
Force the result deeply before printing it.
- --system=SYS
-
Set builtins.currentSystem.
Arguments
- FILE
-
Evaluate FILE, or the default.nix of a directory.
Exit status
- 0
-
The evaluation succeeded.
- 1
-
The evaluation failed.
- 2
-
The command line is invalid.
Engine options
Any other --name or --name=value option goes to the GraalVM polyglot engine, as name=true or name=value. This includes the language’s own --nix.* options and the Truffle tools, such as --inspect for the Chrome DevTools debugger and --cpusampler to profile the evaluation.
Runtime compilation is off by default: on nixpkgs it made evaluations 4 to 10% slower for 1.5 times the CPU and memory. --engine.Compilation=true turns it back on.