Initial commit

gtkblueprinttool/errors.py

@@ -0,0 +1,103 @@
+# errors.py
+#
+# Copyright 2021 James Westman <james@jwestman.net>
+#
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation; either version 3 of the
+# License, or (at your option) any later version.
+#
+# This file is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# SPDX-License-Identifier: LGPL-3.0-or-later
+
+
+import sys, traceback
+
+
+class _colors:
+    RED = '\033[91m'
+    YELLOW = '\033[33m'
+    FAINT = '\033[2m'
+    BOLD = '\033[1m'
+    CLEAR = '\033[0m'
+
+class PrintableError(Exception):
+    """ Parent class for errors that can be pretty-printed for the user, e.g.
+    compilation warnings and errors. """
+
+    def pretty_print(self, filename, code):
+        raise NotImplementedError()
+
+
+class CompileError(PrintableError):
+    category = "error"
+
+    def __init__(self, message, start, end=None):
+        super().__init__(message)
+
+        self.message = message
+        self.start = start
+        self.end = end
+
+    def pretty_print(self, filename, code):
+        sp = code[:self.start+1].splitlines(keepends=True)
+        line_num = len(sp)
+        col_num = len(sp[-1])
+        line = code.splitlines(True)[line_num-1]
+
+        print(f"""{_colors.RED}{_colors.BOLD}{self.category}: {self.message}{_colors.CLEAR}
+at {filename} line {line_num} column {col_num}:
+{_colors.FAINT}{line_num :>4} |{_colors.CLEAR} {line}     {_colors.FAINT}|{" "*(col_num)}^{_colors.CLEAR}
+""")
+
+
+class TokenizeError(CompileError):
+    def __init__(self, start):
+        super().__init__("Could not determine what kind of syntax is meant here", start)
+
+
+class ParseError(CompileError):
+    pass
+
+
+class MultipleErrors(PrintableError):
+    """ If multiple errors occur during compilation, they can be collected into
+    a list and re-thrown using the MultipleErrors exception. It will
+    pretty-print all of the errors and a count of how many errors there are. """
+
+    def __init__(self, errors: [CompileError]):
+        super().__init__()
+        self.errors = errors
+
+    def pretty_print(self, filename, code) -> str:
+        for error in self.errors:
+            error.pretty_print(filename, code)
+        if len(self.errors) != 1:
+            print(f"{len(self.errors)} errors")
+
+
+class CompilerBugError(Exception):
+    """ Emitted on assertion errors """
+
+
+def assert_true(truth: bool, message:str=None):
+    if not truth:
+        raise CompilerBugError(message)
+
+
+def report_compile_error():
+    """ Report an error and ask people to report it. """
+
+    print(traceback.format_exc())
+    print(f"Arguments: {sys.argv}\n")
+    print(f"""{_colors.BOLD}{_colors.RED}***** COMPILER BUG *****
+The gtk-blueprint-tool program has crashed. Please report the above stacktrace
+to the maintainers, along with the input file(s) if possible.{_colors.CLEAR}""")
+