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Tracking Issue: List of Builtins to Implement

If you have an idea for a builtin which is not on this list, discuss it below.

Conditional Builtins

  • true: Simply returns a SUCCESS status
  • false: Simply returns a FAILED status
  • not <command>: Reverses the exit status value of the given command. (@drosseau)
  • contains $key @values: Returns 0 exit status if the key is contained within the values.
  • starts-with $key @values
  • ends-with $key @values
  • matches $key $regex: A regex-based evaluator
  • isatty [FD]: Returns 0 exit status if the supplied FD is a tty
  • and <command>: Execute the command only if the shell's previous status is 0
    • true; and echo true
  • or <command>: The reverse of and.
    • false; or echo false
  • exists -b BINARY: Returns 0 exit status if the binary is in PATH
  • exists -f PATH: Returns 0 exit status if the path is a file
  • exists -d PATH: Returns 0 exit status if the path is a directory
  • exists -s STRING: Returns 0 exit status if the string var is not empty
  • exists -a ARRAY: Returns 0 exit status if the array var is not empty
  • exists STRING: Returns 0 exit status if the string is not empty
  • is $var $value: Returns 0 exit status if both arguments are the same
  • is not $var $value: The opposite of the above
  • bool $value: If the value is "1" or "true", return 0 exit status
  • < (Polish Notation)
  • <= (Polish Notation)
  • > (Polish Notation)
  • >= (Polish Notation)
  • = (Polish Notation)

Job Control

  • jobs: Lists available background jobs
  • bg: Sends SIGCONT to a given background job
  • fg: Does the same as bg, but also brings it to the foreground via tcsetpgrp
  • wait: waits until background jobs have finished
  • exit: waits until background jobs have finished, and exits
  • suspend: suspends the shell via a SIGTSTOP

Misc

  • ion-docs: Opens the locally-installed Ion documentation in a web browser
  • which: Prints the kind and/or path of the given command

Math & Crypto

  • calc: built-in calculator that will eventually be arbitrary precision
  • random: generate random numbers

I/O

  • echo: Prints the evaluated expression to standard output
  • read: Stores the next line of input to standard input into a specified variable
  • printf: Implement the same as other shells
  • printr: Rusty variant maybe?
  • cat: Perhaps copy cat from coreutils into Ion.

Command Execution

  • eval: Evaluates and executes the evaluated expression
  • time: Prints timing statistics once it's job has finished
  • exec: Replace the shell process with the specified command

Possible Builtins From POSIX Shells

  • command -v: often used to determine if a binary exists in a PATH
Edited by matu3ba