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1 import collections, re
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152
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2
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3 from ppci import CompilerError, SourceLocation, Token
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4
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5 """
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6 Lexical analyzer part. Splits the input character stream into tokens.
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7 """
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8
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9 keywords = ['and', 'or', 'not', 'true', 'false', \
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10 'else', 'if', 'while', 'return', \
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11 'function', 'var', 'type', 'const', \
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12 'struct', 'cast', \
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13 'import', 'package' ]
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14
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15 def tokenize(s):
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16 """
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17 Tokenizer, generates an iterator that
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18 returns tokens!
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19
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20 This GREAT example was taken from python re doc page!
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21 """
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22 tok_spec = [
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23 ('REAL', r'\d+\.\d+'),
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24 ('HEXNUMBER', r'0x[\da-fA-F]+'),
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25 ('NUMBER', r'\d+'),
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26 ('ID', r'[A-Za-z][A-Za-z\d_]*'),
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27 ('NEWLINE', r'\n'),
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28 ('SKIP', r'[ \t]'),
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29 ('COMMENTS', r'//.*'),
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30 ('LONGCOMMENTBEGIN', r'\/\*'),
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31 ('LONGCOMMENTEND', r'\*\/'),
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32 ('LEESTEKEN', r'==|->|<<|>>|[\.,=:;\-+*\[\]/\(\)]|>=|<=|<>|>|<|{|}|&|\^|\|'),
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33 ('STRING', r"'.*?'")
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34 ]
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35 tok_re = '|'.join('(?P<%s>%s)' % pair for pair in tok_spec)
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36 gettok = re.compile(tok_re).match
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37 line = 1
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38 pos = line_start = 0
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39 mo = gettok(s)
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40 incomment = False
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41 while mo is not None:
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42 typ = mo.lastgroup
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43 val = mo.group(typ)
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44 if typ == 'NEWLINE':
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45 line_start = pos
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46 line += 1
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47 elif typ == 'COMMENTS':
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48 pass
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49 elif typ == 'LONGCOMMENTBEGIN':
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50 incomment = True
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51 elif typ == 'LONGCOMMENTEND':
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52 incomment = False
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53 elif typ == 'SKIP':
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54 pass
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55 elif incomment:
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56 pass # Wait until we are not in a comment section
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57 else:
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58 if typ == 'ID':
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59 if val in keywords:
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60 typ = val
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61 elif typ == 'LEESTEKEN':
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62 typ = val
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63 elif typ == 'NUMBER':
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64 val = int(val)
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65 elif typ == 'HEXNUMBER':
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66 val = int(val[2:], 16)
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67 typ = 'NUMBER'
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68 elif typ == 'REAL':
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69 val = float(val)
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70 elif typ == 'STRING':
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71 val = val[1:-1]
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72 loc = SourceLocation(line, mo.start()-line_start, mo.end() - mo.start())
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73 yield Token(typ, val, loc)
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74 pos = mo.end()
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75 mo = gettok(s, pos)
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76 if pos != len(s):
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205
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77 col = pos - line_start
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78 loc = SourceLocation(line, col, 1)
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79 raise CompilerError('Unexpected character "{0}"'.format(s[pos]), loc)
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80 loc = SourceLocation(line, 0, 0)
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81 yield Token('END', '', loc)
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82
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