91 lines
2.9 KiB
Python
91 lines
2.9 KiB
Python
# Copyright (c) 2014-2024, Chris Pressey, Cat's Eye Technologies.
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# This file is distributed under a 2-clause BSD license. See LICENSES/ dir.
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# SPDX-License-Identifier: LicenseRef-BSD-2-Clause-X-SixtyPical
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# encoding: UTF-8
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import re
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class SixtyPicalSyntaxError(ValueError):
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def __init__(self, filename, line_number, message):
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super(SixtyPicalSyntaxError, self).__init__(filename, line_number, message)
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def __str__(self):
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return "{}, line {}: {}".format(self.args[0], self.args[1], self.args[2])
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class Scanner(object):
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def __init__(self, text, filename):
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self.text = text
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self.filename = filename
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self.token = None
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self.type = None
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self.pos = 0
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self.line_number = 1
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self.scan()
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def scan_pattern(self, pattern, type, token_group=1):
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pattern = r'(' + pattern + r')'
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regexp = re.compile(pattern, flags=re.DOTALL)
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match = regexp.match(self.text, pos=self.pos)
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if not match:
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return False
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else:
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self.type = type
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self.token = match.group(token_group)
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self.pos += len(match.group(0))
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self.line_number += self.token.count('\n')
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return True
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def scan(self):
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self.scan_pattern(r'[ \t\n\r]*', 'whitespace')
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while self.scan_pattern(r'\/\/.*?[\n\r]', 'comment'):
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self.scan_pattern(r'[ \t\n\r]*', 'whitespace')
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if self.pos >= len(self.text):
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self.token = None
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self.type = 'EOF'
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return
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if self.scan_pattern(r'\,|\@|\+|\:|\<|\>|\{|\}|\[|\]|\^', 'operator'):
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return
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if self.scan_pattern(r'\d+', 'integer literal'):
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return
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if self.scan_pattern(r'\$([0-9a-fA-F]+)', 'integer literal', token_group=2):
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# ecch
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self.token = str(eval('0x' + self.token))
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return
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if self.scan_pattern(r'\"(.*?)\"', 'string literal', token_group=2):
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return
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if self.scan_pattern(r'\w+', 'identifier'):
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return
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if self.scan_pattern(r'.', 'unknown character'):
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return
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else:
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raise AssertionError("this should never happen, self.text=({}), self.pos=({})".format(self.text, self.pos))
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def expect(self, token):
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if self.token == token:
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self.scan()
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else:
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self.syntax_error("Expected '{}', but found '{}'".format(token, self.token))
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def on(self, *tokens):
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return self.token in tokens
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def on_type(self, type):
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return self.type == type
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def check_type(self, type):
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if not self.type == type:
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self.syntax_error("Expected {}, but found '{}'".format(self.type, self.token))
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def consume(self, token):
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if self.token == token:
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self.scan()
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return True
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else:
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return False
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def syntax_error(self, msg):
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raise SixtyPicalSyntaxError(self.filename, self.line_number, msg)
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