System Variables #

Quest provides system-level information through the sys module, which is automatically available in all scripts without needing to import it.

Overview #

The sys module gives you access to:

• Command-line arguments (sys.argc and sys.argv)
• Runtime information (sys.version, sys.platform, sys.executable)
• Available modules (sys.builtin_module_names)

For complete documentation, see the sys Module page.

Quick Example #

# script.q - Display system information
puts("Quest version:", sys.version)
puts("Platform:", sys.platform)
puts("Script name:", sys.argv[0])
puts("Arguments:", sys.argc - 1)

$ quest script.q arg1 arg2
Quest version: 0.1.0
Platform: darwin
Script name: script.q
Arguments: 2

Command-Line Arguments #

The most commonly used system variables are for handling command-line arguments:

# greet.q
if sys.argc < 2
    puts("Usage:", sys.argv[0], "<name>")
else
    let name = sys.argv[1]
    puts("Hello,", name .. "!")
end

$ quest greet.q Alice
Hello, Alice!

Key Differences from Other Languages #

Compared to Python #

Python:

import sys
print(sys.argv[0])      # Script name
print(len(sys.argv))    # Argument count

Quest:

# No import needed - sys is automatic
puts(sys.argv[0])       # Script name
puts(sys.argc)          # Argument count (dedicated variable)

Compared to Bash #

Bash:

echo $0        # Script name
echo $#        # Argument count
echo $1 $2     # Individual arguments

Quest:

puts(sys.argv[0])      # Script name
puts(sys.argc)         # Argument count
puts(sys.argv[1], sys.argv[2])  # Individual arguments

Important Notes #

• Automatic availability: The sys module is injected into script scope automatically
• Script-only: System variables are only available when running scripts, not in the REPL
• Read-only: All sys properties are read-only and cannot be modified
• String arguments: All command-line arguments in sys.argv are strings

Complete Documentation #

For detailed information about all sys module features, including:

• All available properties
• Platform-specific behavior
• Practical examples and patterns
• Best practices for argument parsing

See the complete sys Module Documentation.