Skip to main content

terminal_style

What it is​

Utilities for a Rich-powered SPARQL terminal UI:

  • Pretty-print SPARQL queries, results, errors, and system messages
  • Read user input with simple multiline support and in-memory history
  • Persist command/query history to ~/.sparql_terminal_history
  • Set the terminal window title to “SPARQL Terminal”

Public API​

Functions:

  • set_terminal_title(): Set terminal title to "SPARQL Terminal" (Windows via title, Unix-like via escape sequence).
  • print_query_result(result): Render a SPARQL result (expects an iterable with .vars) as a Rich table.
  • print_query_error(error): Render an exception/error message inside a red Rich panel.
  • print_system_message(text): Render a yellow “System” panel with the provided text.
  • print_query(query): Render a SPARQL query with syntax highlighting inside a panel.
  • clear_screen(): Clear the terminal using Rich (console.clear()).
  • print_welcome_message(): Set title and print an introductory panel with usage instructions.
  • print_divider(): Print a dim horizontal divider sized to the console width.
  • preinput(): Save current readline buffer into current_input and return it.
  • get_user_input(): Prompt for user input:
    • Recognizes special commands: exit, help, clear (returns lowercase)
    • Supports multiline queries; terminates on a line ending with ; or on an empty line after content
    • Stores unique commands/queries in an in-memory history list
    • Returns "exit" on EOFError or KeyboardInterrupt
  • save_history(): Write command_history to ~/.sparql_terminal_history (best-effort; errors ignored).
  • load_history(): Load history from ~/.sparql_terminal_history into command_history (best-effort; errors ignored).

Module-level behavior:

  • Registers save_history() via atexit.register(save_history).
  • Calls load_history() at import time.

Configuration/Dependencies​

Dependencies:

  • rich (Console, Panel, Syntax, Text, Table, ROUNDED)
  • Standard library: os, platform, readline, atexit

Files:

  • History file: ~/.sparql_terminal_history

State:

  • Uses module globals:
    • command_history (list)
    • history_index (int; defined but not used in current logic)
    • current_input (str)

Usage​

Minimal example (interactive):

from naas_abi.apps.sparql_terminal.terminal_style import (
    print_welcome_message,
    get_user_input,
    print_query,
)

print_welcome_message()

while True:
    user_text = get_user_input()
    if user_text == "exit":
        break
    if user_text in ("help", "clear"):
        # caller handles these commands as desired
        print(f"Command: {user_text}")
        continue

    print_query(user_text)  # display what was entered

Printing results (expects an object similar to RDFLib SPARQLResult with .vars and row iteration):

from naas_abi.apps.sparql_terminal.terminal_style import print_query_result

# result = graph.query("SELECT ...")  # from RDFLib (not shown)
# print_query_result(result)

Caveats​

  • Importing the module loads history immediately and registers an atexit handler that writes history on process exit.
  • get_user_input() uses console.input() and does not implement custom key handling; history navigation depends on the underlying readline behavior.
  • Multiline termination rules:
    • A line ending with ; ends input (the final ; is stripped from the returned query).
    • An empty line ends input only after at least one line has been entered.