Implementing built-ins (non-POSIX extensions)

[magicant]

This issue tracks the implementation of non-portable extensions for built-in utilities.
Portable features are tracked in #7.

In the list below, built-ins are grouped by their dependent environments.
However, most built-ins additionally depend on the standard output and error file descriptors and variables.

Execution control

• .
  • Non-portable options
    • -A, --no-alias
    • -L, --autoload
    • --help
• break
  • Non-portable options
    • -i, --iteration
    • --help
• continue
  • Non-portable options
    • -i, --iteration
    • --help
• eval
  • Non-portable options
    • -i, --iteration
    • --help
• exec
  • Non-portable options
    • -a ..., --as=...
    • -c, --clear
    • --cloexec
    • -f, --force
    • --help
• exit
  • Semantics
    • Allow exit status of 256+
  • Non-portable options
    • -f, --force
    • --help
• newgrp
• return
  • Semantics
    • Allow exit status of 256+
    • Only return from functions and dot scripts in POSIXly-correct mode (Reject returning from trap, exiting the shell, etc.)
  • Non-portable options
    • -n, --no-return
    • --help

Printing

• echo
  • Implement echo built-in
• help
  • Implement help built-in
• printf
  • Implement printf built-in

Working directory

• cd
  • Semantics
    • Allow - operand used together with -L or -P option
    • $YASH_AFTER_CD
  • Non-portable options
    • Long options
    • --default-directory=...
    • --help
• dirs
  • Show directory stack
• popd
  • Update directory stack
• pushd
  • Update directory stack
• pwd
  • Non-portable options
    • Long options
    • --help

File creation mask

• umask
  • Non-portable options
    • Long options
    • --help

Limits

• ulimit
  • Semantics
    • Support limits other than file size (-f)
  • Non-portable options
    • Long options
    • --help

Spent times

• times
  • Non-portable options
    • --help

Signals

• kill
  • Semantics
    • (Dis)allow signal names prefixed with SIG
    • (Dis)allow non-zero numbers as an argument to -s option
    • (Dis)allow signal names as operands for -l option
    • (Dis)allow multiple operands with -l option
  • Non-portable options
    • -n
    • -v
    • Include descriptions with -v
    • --help
• suspend
  • Implement suspend built-in
• trap
  • Semantics
    • Allow non-uppercase signal names
    • Allow signal names prefixed with SIG
  • Non-portable options
    • -p, --print
    • --help

Jobs

• bg
  • Semantics
    • Allow job IDs without the % prefix
    • Send SIGCONT even if the target job is already running
  • Non-portable options
    • --help
• disown
  • Implement disown built-in
• fg
  • Semantics
    • Allow job IDs without the % prefix
    • Allow more than one job ID operand per invocation
    • Print the job number on resuming a job
    • Consider saving/restoring the terminal state before/after resuming the job
  • Non-portable options
    • --help
• jobs
  • Semantics
    • Allow job IDs without the % prefix
  • Non-portable options
    • Long options
    • -n, --new
    • -r, --running-only
    • -s, --stopped-only
    • -t, --terminated-only
    • (Idea: option to print the locations jobs were started at)
    • --help
• wait
  • Semantics
    • Print job status after waiting (if interactive and monitoring)
  • Non-portable options
    • --help

Variables and functions

• array
  • Implement array built-in
• export
  • Disable non-portable syntax in POSIX mode / Allow non-portable extensions in non-POSIX mode
  • Non-portable options
    • --help
    • Legacy options (-r and -X)
• getopts
  • Semantics
    • Allow parsing non-alphanumeric options
  • Non-portable options
    • --help
• local
  • Redirect local to typeset
• read
  • Non-portable options
    • Long options
    • -A, --array
    • -e, --line-editing
    • -P, --ps1
    • -p ..., --prompt=...
    • --help
• readonly
  • Disable non-portable syntax in POSIX mode / Allow non-portable extensions in non-POSIX mode
  • Non-portable options
    • --help
    • Legacy options (-x and -X)
• shift
  • Semantics
    • Allow negative operands
  • Non-portable options
    • -A ..., --array=...
    • --help
• typeset
  • typeset built-in #316
• unset
  • Semantics
    • Allow unset used without any operands
  • Non-portable options
    • Long options
    • -l, --local
    • --help

Aliases

• alias
  • Semantics
    • Allow/reject non-portable alias names
  • Non-portable options
    • -g, --global
    • -p, --prefix
    • -v, --verbose (show locations where aliases were defined)
    • --help
• unalias
  • Non-portable options
    • Long options
    • --help

Command path cache

• hash
  • Non-portable options
    • Long options
    • -a, --all
    • -d, --directory
    • --help

Built-ins

• builtin, disable (TBD)
  • Execute a built-in (ignoring the same-named functions)
  • Disable built-ins
  • Re-enable built-ins

Command history

• fc
  • Non-portable options
    • Long options
    • -q, --quiet
    • -v, --verbose
    • --help
• history
  • Implement history built-in

Line-editing

• bindkey
  • Implement bindkey built-in
• complete
  • Implement complete built-in

Miscellaneous

• [, test
  • -G
  • -k
  • -N
  • -O
  • -nt, -ot
  • -ef
  • ==
  • Locale-based string comparison (===, !==, <, <=, >, >=)
  • =~
  • Version number comparison (-veq, -vne, -vgt, -vge, -vlt, -vle)
  • -o (unary)
• command, type
  • Semantics
    • Allow -v and -V used together
    • Allow more than one command name operand for -v and -V
    • Disable invalid option combination (e.g. type -f)
  • Non-portable options
    • Long options
    • -a, --alias
    • -b, --builtin-command
    • -e, --external-command
    • -f, --function
    • -k, --keyword
    • --help
• set
  • Disable non-portable options in POSIXly-correct mode
  • Disable long options in POSIXly-correct mode
  • Disable non-portable use of the no prefix
  • Disable non-portable normalization & case folding of option names
  • --help