🐞Expander

[saladuit]

This should be taken care of https://stackoverflow.com/questions/5163144/what-are-the-special-dollar-sign-shell-variables/5163260#5163260

• [x] $1, $2, $3, ... are the positional parameters.
• [x] "$@" is an array-like construct of all positional parameters, {$1, $2, $3 ...}.
• [x] "$*" is the IFS expansion of all positional parameters, $1 $2 $3 ....
• [x] $# is the number of positional parameters.
• [x] $- current options set for the shell.
• [x] $$ pid of the current shell (not subshell).
• [x] $_ most recent parameter (or the abs path of the command to start the current shell immediately after startup).
• [x] $IFS is the (input) field separator.
• [x] $? is the most recent foreground pipeline exit status.
• [x] $! is the PID of the most recent background command.
• [x] $0 is the name of the shell or shell script.

[saladuit]

except $? everything should be invalid input when exporting as key.

[saladuit]

Lexical analyzer should handle all invalid input including unclosed quotes, so that shouldn't be handled by expander

[saladuit]

 1:32:50 ~/repos/minishell
> echo $SHELL$SHELL
/bin/zsh/bin/zsh
 1:33:00 ~/repos/minishell
> echo $SHELL$SHELL$$$$
/bin/zsh/bin/zsh37793779
 1:33:12 ~/repos/minishell
> echo $SHELL$SHELL'$$'$$
/bin/zsh/bin/zsh$$3779
 1:33:24 ~/repos/minishell
> echo "$SHELL$SHELL'$$'$$"
/bin/zsh/bin/zsh'3779'3779
 1:33:36 ~/repos/minishell

[saladuit]

closed by #48