The Sys module provides system-level operations and environment management functionalities, including environment variable management, variable definition checks, expression quoting, error handling, and system information retrieval. All functions support pipeline operations and provide a unified error handling mechanism.
Function Overview#
| Function Category | Main Functions | Purpose |
|---|---|---|
| Environment Management | env, set, unset | Get and manage root environment variables |
| Variable Checks | vars, has, defined | Check variable definition status |
| Expression Operations | quote | Quote an expression |
| Error Handling | error, ecodes_rt, ecodes_lm | Error generation and error code queries |
| System Information | info | Retrieve operating system information |
| Output Control | print_tty, discard | TTY output and data discard |
Environment Management Functions#
These functions are used to manage system environment variables:
env - Get the root environment as a mapping
- Parameters: None
- Returns:
Map- All variables in the root environment
set <var> <val> - Define a variable in the root environment
- Parameters:
var(required):String- Variable name,val(required):Any- Variable value - Returns:
None
unset <var> - Remove a variable from the root environment
- Parameters:
var(required):String- Name of the variable to remove - Returns:
None
Variable Check Functions#
These functions are used to check the definition status of variables:
vars - Get the defined variables in the current environment
- Parameters: None
- Returns:
Map- Mapping of variables in the current environment
has <var> - Check if a variable is defined in the current environment
- Parameters:
var(required):String- Name of the variable to check - Returns:
Boolean- Whether the variable exists
defined <var> - Check if a variable is defined in the current environment tree
- Parameters:
var(required):String- Name of the variable to check - Returns:
Boolean- Whether the variable is defined in the environment tree
Expression Operation Functions#
quote <expr> - Quote an expression
- Parameters:
expr(required):Expression- Expression to quote - Returns:
Quote- Quoted expression
Error Handling Functions#
These functions are used for error handling and debugging:
error <msg> - Return a runtime error
- Parameters:
msg(required):String- Error message - Returns: Throws
LmError::CustomError
ecodes_rt - Display runtime error codes
- Parameters: None
- Returns:
Expression- List of runtime error codes
ecodes_lm - Display LmError error codes
- Parameters: None
- Returns:
Expression- List of LmError error codes
System Information Functions#
info - Get operating system information
- Parameters: None
- Returns:
String- Operating system information string
Output Control Functions#
print_tty <arg> - Print control sequences to TTY
- Parameters:
arg(required):String- Content to print - Returns:
None
discard <arg> - Send data to /dev/null
- Parameters:
arg(required):Any- Data to discard - Returns:
None
Notes#
The Sys module is one of the core components of the Lumesh built-in module system, registered as "Sys" in the module registry. The functions in this module are primarily used for system-level operations, complementing other application-level modules such as String and Parse.
The set and unset functions in the module are also available as global built-in functions and can be used directly without the module prefix.