Add interrupt handler (#102)

Add an interrupt handler and SIGUSR1 handler. (On MS Windows, SIGURS1 doesn't exist)

This includes interrupt completion for prompt_toolkit and GNU Readline.

Also, the `Abort[]` response: $Aborted, is now showing.

Author: rocky

mathicsscript/__main__.py

@@ -24,13 +24,12 @@
 from pygments import highlight
 
 from mathicsscript.asymptote import asymptote_version
+from mathicsscript.interrupt import setup_signal_handler
 from mathicsscript.settings import definitions
 from mathicsscript.termshell import ShellEscapeException, mma_lexer
 from mathicsscript.termshell_gnu import TerminalShellGNUReadline
-from mathicsscript.termshell_prompt import (
-    TerminalShellCommon,
-    TerminalShellPromptToolKit,
-)
+from mathicsscript.termshell import TerminalShellCommon
+from mathicsscript.termshell_prompt import TerminalShellPromptToolKit
 from mathicsscript.version import __version__
 
 try:
@@ -123,7 +122,7 @@ def load_settings(shell):
                     continue
                 evaluation.evaluate(query)
         except KeyboardInterrupt:
-            print("\nKeyboardInterrupt")
+            shell.errmsg("\nKeyboardInterrupt")
     return True
 
 
@@ -145,16 +144,17 @@ def interactive_eval_loop(
     shell: TerminalShellCommon,
     unicode,
     prompt,
-    matplotlib: bool,
-    asymptote: bool,
     strict_wl_output: bool,
 ):
+    setup_signal_handler()
+
     def identity(x: Any) -> Any:
         return x
 
     def fmt_fun(query: Any) -> Any:
         return highlight(str(query), mma_lexer, shell.terminal_formatter)
 
+    shell.fmt_fn = fmt_fun
     while True:
         try:
             if have_readline and shell.using_readline:
@@ -173,6 +173,11 @@ def fmt_fun(query: Any) -> Any:
                     fmt = fmt_fun
 
             evaluation = Evaluation(shell.definitions, output=TerminalOutput(shell))
+
+            # Store shell into the evaluation so that an interrupt handler
+            # has access to this
+            evaluation.shell = shell
+
             query, source_code = evaluation.parse_feeder_returning_code(shell)
             if mathics_core.PRE_EVALUATION_HOOK is not None:
                 mathics_core.PRE_EVALUATION_HOOK(query, evaluation)
@@ -214,7 +219,7 @@ def fmt_fun(query: Any) -> Any:
                 try:
                     print(open(source_code[2:], "r").read())
                 except Exception:
-                    print(str(sys.exc_info()[1]))
+                    shell.errmsg(str(sys.exc_info()[1]))
             else:
                 subprocess.run(source_code[1:], shell=True)
 
@@ -224,13 +229,13 @@ def fmt_fun(query: Any) -> Any:
                 # shell.definitions.increment_line(1)
 
         except KeyboardInterrupt:
-            print("\nKeyboardInterrupt")
+            shell.errmsg("\nKeyboardInterrupt")
         except EOFError:
             if prompt:
-                print("\n\nGoodbye!\n")
+                shell.errmsg("\n\nGoodbye!\n")
             break
         except SystemExit:
-            print("\n\nGoodbye!\n")
+            shell.errmsg("\n\nGoodbye!\n")
             # raise to pass the error code on, e.g. Quit[1]
             raise
         finally:
@@ -526,9 +531,7 @@ def main(
     )
 
     definitions.set_line_no(0)
-    interactive_eval_loop(
-        shell, charset, prompt, asymptote, matplotlib, strict_wl_output
-    )
+    interactive_eval_loop(shell, charset, prompt, strict_wl_output)
     return exit_rc
 
 

mathicsscript/completion.py

@@ -23,7 +23,12 @@
 from mathics.core.symbols import strip_context
 from mathics_scanner import named_characters
 from mathics_pygments.lexer import Regex
-from prompt_toolkit.completion import CompleteEvent, Completion, WordCompleter
+from prompt_toolkit.completion import (
+    CompleteEvent,
+    Completer,
+    Completion,
+    WordCompleter,
+)
 from prompt_toolkit.document import Document
 
 SYMBOLS = rf"[`]?({Regex.IDENTIFIER}|{Regex.NAMED_CHARACTER})(`({Regex.IDENTIFIER}|{Regex.NAMED_CHARACTER}))+[`]?"
@@ -54,6 +59,28 @@ def get_datadir():
     return osp.realpath(datadir)
 
 
+class InterruptCompleter(Completer):
+    """
+    Completer for the simple command set: 'continue', 'abort', 'exit', 'show'.
+    """
+
+    COMMANDS = [
+        "abort",
+        "continue",
+        "exit",
+        "inspect",
+        "show",
+    ]
+
+    def get_completions(
+        self, document: Document, complete_event
+    ) -> Iterable[Completion]:
+        word = document.get_word_before_cursor()
+        for cmd in self.COMMANDS:
+            if cmd.startswith(word):
+                yield Completion(cmd, -len(word))
+
+
 class MathicsCompleter(WordCompleter):
     def __init__(self, definitions):
         self.definitions = definitions

mathicsscript/format.py

@@ -11,6 +11,7 @@
 from mathics.core.atoms import String
 from mathics.core.symbols import Symbol
 from mathics.core.systemsymbols import (
+    SymbolAborted,
     SymbolExport,
     SymbolExportString,
     SymbolFullForm,
@@ -21,6 +22,7 @@
     SymbolOutputForm,
     SymbolPlot,
     SymbolStandardForm,
+    SymbolStringForm,
     SymbolTeXForm,
 )
 from mathics.session import get_settings_value
@@ -61,7 +63,7 @@
 
 def format_output(obj, expr, format=None):
     """
-    Handle unformatted output using the *specific* capabilities of mathics-django.
+    Handle unformatted output using the *specific* capabilities of mathicsscript
 
     evaluation.py format_output() from which this was derived is similar but
     it can't make use of a front-ends specific capabilities.
@@ -161,7 +163,15 @@ def eval_boxes(result, fn: Callable, obj, **options):
         write_asy_and_view(asy_str)
         return expr_type
 
+    if expr is SymbolAborted:
+        obj.out = ["$Aborted"]
+        obj.last_eval = SymbolAborted
+        return "$Aborted"
     if format == "text":
+        if expr_head is SymbolStringForm:
+            return expr.elements[0].value
+        elif isinstance(expr, String):
+            return expr.value
         result = expr.format(obj, SymbolOutputForm)
     elif format == "xml":
         result = Expression(SymbolStandardForm, expr).format(obj, SymbolMathMLForm)