# Development tips and tricks

## How to enter λ, ‼ and ↳

On Unix-like operating systems running either X or Wayland:

	; example of ~/.XCompose
	include "%L"
	<Multi_key> <parenleft> <parenleft> : "λ" U03BB
	<Multi_key> <e> <n> : "↳" U21B3
	<Multi_key> <2> <exclam> : "‼" U203C

## Adding a new VM opcode

 * add the new opcode to `tools/gen.sl` (place it at the end of the `ops`
   vector).
 * bootstrap (`ninja -C build bootstrap`)
 * add the new opcode handling logic to `src/vm_jmptbl.c` and `src/vm_funcs.c`
 * build
 * update the compiler to emit the opcode when needed
 * bootstrap again

Run `./build/sl tools/disenv.sl` before and after, compare the outputs with
`diff` - this will show how the newly built environment looks like in VM
instructions assembly.