7.6 KiB
Relish: Rusty Expressive LIsp SHell
- Purpose statement
- Goals
- Contact
- How to use
- Guide to codebase
- Current Status / TODO list
- Rudimentary Control Flow
- Help function
- Eval function
- Input function
- Env function
- Load (load a script) function
- Main shell calls Load function on arg and exits
- Custom error struct with pretty printing
- Custom ast pretty print
- Shell module
- list operations
- boolean operations
- string operations
- arithmetic operations
- file operations
- Network library
Note: this document is best read within a dedicated ORG mode interpreter
Purpose statement
The purpose of Relish is to create a highly expressive POSIX shell using a lisp interpreter.
Goals
- Iterate on the ideas and designs that were tested with SHS
- Act as both a high level scripting language and as a system shell
- To be as portable as possible
- To provide code and framework that can be embedded in other applications needing a user facing interpreter
- To be well tested code
- No unsafe code without extreme consideration and rigorous containment
Contact
- Matrix chat: #vomitorium:matrix.sunnypup.io
How to use
Syntax
Basic data types
TODO
S-Expressions
TODO
calling a function
TODO
Control flow
TODO
Defining variables and functions
TODO
Undefining variables and functions
TODO
Builtin functions
TODO
Configuration
By default Relish will read from ~/.relishrc for configuration, but the default shell will also accept a filename from the RELISH_CFG_FILE environment variable. See file:snippets/basic_minimal_configuration.rls for an example of a basic minimal configuration file.
The configuration file
The configuration file is a script containing arbitrary Relish code. On start, any shell which leverages the configuration code in the config module (file:src/config.rs) will create a clean seperate context, including default configuration values, within which the standard library will be initialized. The configuration file is evaluated and run as a standalone script and may include arbitrary executable code. Afterwards, configuration values found in the variable map will be used to configure the standard library function mappings that the shell will use. Errors during configuration are non-terminal. In such a case any defaults which have not been overwritten will remain present.
Important points to note
- When the configuration file is run, it will be run with default configuration values.
- The user/script interpreter will be run with the standard library configured to use the previously defined configuration variables.
- The standard library will then be re-processed and re-added to the symbol table with new configuration.
- Variables and functions defined during configuration will carry over to the user/script interpreter, allowing the user to load any number of custom functions and variables.
Configuration Values
- CFG_RELISH_POSIX (default 0): when on, enables POSIX style job control.
- CFG_RELISH_ENV (default 1): when on, interpreter's variable table and environment variable table are kept in sync.
- CFG_RELISH_PROMPT (default (echo "λ ")): A function definition which is called in order to output the prompt for each loop of the REPL. This function will be reloaded each REPL loop and will be called by the interpreter with no arguments.
Compilation
cargo buildTesting
cargo testRunning (the main shell)
cargo run src/bin/main.rsGuide to codebase
file:tests directory
Start here if you are new. Most of these files have unimplemented tests commented out in them. Contributions that help fill out all of these tests
Eval tests: file:tests/test_eval.rs
These are particularly easy to read and write tests.
Func tests: file:tests/test_func.rs
You can consider these to extend the eval tests to cover the co-recursive nature between eval and func calls.
Lex tests: file:tests/test_lex.rs
These tests verify the handling of syntax.
Lib tests: (tests/test_lib*)
These tests are unique per stdlib module.
file:src directory
This directory contains all of the user facing code in relish. Just a few entries of note:
segment: file:src/segment.rs
This file lays out the spiritual theological ideological theoretical mechanical underpinnings of the entire interpreter.
The entire LISP machine centers around a singlet or pairing of datum.
The Ctr datatype provides an abstraction for which any type of data, including a Seg can be a datum.
The Seg datatype provides a mechanism to hold a single datum or a pair of datum. It is implemented as two Ctr~s: ~car and cdr.
A primitive type system is provided through the Rust Enum datatype. A number of utility functions follow.
lib: file:src/lib.rs
This defines a library that can be included to provide an interpreter interface within any Rust project. It includes the core interpreter mechanisms, full stdlib, and the configuration system. Your project can use or not use any number of these components. They can certainly be used to support language development for other LISP machines, or even other languages.
config: file:src/config.rs
This file contains default configuration values as well as functions which load and run the configuration file script. For more information see the configuraiton section above in this Readme.
stl: file:src/stl.rs
This defines the static_stdlib function and the dynamic_stdlib function.
The static_stdlib function loads all symbols in the standard library which do not need further configuration into the symbol table.
The dyanmic_stdlib function loads all symbols in the standard library which do need configuration into the symbol table.
The dynamic_stdlib function uses variables saved in the symbol table to configure the functions and variables it loads.
For more information see file:src/config.
Any new addition to the stdlib must make its way here to be included in the main shell (and any other shell using the included get_stdlib function).
You may choose to override these functions if you would like to include your own special functions in your own special interpreter, or if you would like to pare down the stdlib to a small minimal subet of what it is.
You can view the code for standard library functions in file:src/stl/.
bin: file:src/bin/
This contains any executable target of this project. Notably the main shell file:src/bin/main.rs.
Current Status / TODO list
Note: this section will not show the status of each item unless you are viewing it with a proper orgmode viewer
TODO Rudimentary Control Flow
DONE if clause
TODO loop clause
TODO while clause
TODO circuit clause
TODO Help function
TODO Eval function
TODO Input function
TODO Env function
TODO Load (load a script) function
Pull/Refactor the logic out of the configure functions. Optionally return a list of new variables and/or functions? Will need a concatenate function for tables