CRYSTAL-EVAL(1) Crystal Compiler Command Line Reference Guide CRYSTAL-EVAL(1)

crystal-eval - Evaluate a crystal program

crystal eval [options] [source]

Evaluate code from arguments or, if no arguments are passed, from the standard input. Useful for experiments.

-d, --debug

Generate the output with symbolic debug symbols. These are read when debugging the built program with tools like lldb, gdb, valgrind etc. and provide mappings to the original source code for those tools.

--no-debug

Generate the output without any symbolic debug symbols.

-D FLAG, --define FLAG

Define a compile-time flag. This is useful to conditionally define types, methods, or commands based on flags available at compile time. The default flags are from the target triple given with --target-triple or the hosts default, if none is given.

--error-trace

Show full error trace.

-O LEVEL

Optimization mode: 0 (default), 1, 2, 3. See OPTIMIZATIONS for details.

--release

Compile in release mode. Equivalent to -O3 --single-module

-s, --stats

Print statistics about the different compiler stages for the current build. Output time and used memory for each compiler process.

-p, --progress

Print statistics about the progress for the current build.

-t, --time

Print statistics about the execution time.

--no-color

Disable colored output.
2026-07-23 crystal 1.21.0