SBash

Description

Strict Bash Shell, compiler and interpreter. Designed to be used as a Linux interactive shell with minimal dependencies, and compile bash script to standalone static binaries. Will only support a subset of bash syntax.

TODO

• eval in repl mode
• builtins in repl mode
• source external file
• implement alias
• chain commands with pipes
• assign command output to variable
• use a single model for commands/builtins/functions output
• implement redirections
• implement if/for block
• finish autocompletion
• copy from the terminal output of previous command
• step by step execution with depth control, display command and wait
• option to automatically redirect output of commands to a file

Features

• not a posix shell
• fast compilation
• statically compiled with no dependencies
• support a unique bash syntax for variable/function declaration
• cannot override a function, first definition
• local variables (starting with a lowercase) are not propagated outside the function
• function arguments with no default value are considered mandatory
• error when calling a function without enough mandatory args
• error when trying to access undefined variables
• always assume a { after a $ and that the brackets/parenthesis are correctly closed
• 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 (yet?) for multi-lines strings
• variables must always be quoted
• builtins implemented as simple rust functions (+maybe macro to simplify?)
• no external config or controllable hidden variables
• functions cannot create new global variables
• function arguments must be assigned to local variables at the beginning of the func
• execution starts from main function

Limitations

• can fail on some edge cases
• no support for nested quotes
• no redirections yet
• support only ${alphaornum}, no $@ or $* or any other form
• max 9 args passed to user defined functions
• no if/while/for yet
• no math yet, will probably be implemented as builtins if needed

Objectives

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

Build

bash cargo build --target x86_64-unknown-linux-musl --release

Other

fix some warnings

bash cargo fix --allow-dirty