elna/TODO

# Compiler

- Whitespaces are checked twice, in the source class and by lexing.
- Catch exceptions thrown by the argument parser and print them normally.
- Parser should be able to collect errors.
- Provide position information on parse tree nodes.
- Move constants to the symbol table, so we can check at parse time for duplicates.
- Don't pass raw pointers to the visitor methods.
- While loop.
- Comparision operators.
- Procedures.
- Calculate additional stack space needed for subexpressions in the allocator
  visitor and not in the backend.
- Support immediates greater than 12 bits.
- It seems instructions are correctly encoded only if the compiler is running
  on a little endian architecture.
- Print filename in the error message.
- Merge declaration and definition nodes.

# Shell
- Persist the history.
- Replace hard coded ANSI codes with constants or functions.

## Completion

- Configure fzf to show only the current directory files
- Support multiple selections for insertion in fzf.
- Don't hardcode fzf binary path.
- Send the word under the cursor to fzf as initial input.
- Home directory expansion.
- Show files in the PATH if starting at the beginning of the prompt

## Appearance

- Add a bar with additional information under the prompt (edit_bar), like the hostname.
- Show current time in the prompt.