Irsh

Description

Bash like interpreter and maybe compiler? Designed to be used as an interactive shell with minimal dependencies, will not support all bash syntax.

Features

• support a unique bash syntax for variable/function declaration
• always assume a { after a $ and that the brackets/parenthesis are correctly closed
• ignore corner cases due to unclosed blocks/quote and crash for an easier (and faster?) implem
• functions/program arguments with no default value are considered mandatory
• one level of sub-command only
• sub-commands can only be used at the beginning of double quoted string
• sub-commands are limited to variables/words and redirection symbols
• no support for nested quotes
• no support (yet?) for multi-lines strings
• value must be quoted when declaring a variable

Limitations

• can fail on some edge cases
• only &> redirection will be implemented
• support only ${alphanum}, no $@ or $* or any other form
• infinite loop if non closed sub-command
• infinite loop if $() without the ""

Objectives

• parse bash variables with scoping and defaults
• parse bash functions via function keyword
• support invocation of external commands
• implement a subset of basic bash functionalities
• support stdout/err redirections