| 1 | #!/usr/bin/env python2
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| 2 | """
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| 3 | parse.py
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| 4 | """
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| 5 | from __future__ import print_function
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| 6 |
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| 7 | import os
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| 8 | import sys
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| 9 |
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| 10 | # PYTHONPATH=$REPO_ROOT/vendor
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| 11 | from typing import Tuple, List, Optional, cast
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| 12 |
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| 13 | # PYTHONPATH=$REPO_ROOT/mycpp
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| 14 | from mycpp.mylib import log, tagswitch
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| 15 | from mycpp import mylib
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| 16 | from _devbuild.gen.expr_asdl import (expr, expr_e, expr_t, tok_e, tok_t,
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| 17 | CompoundWord, Measure_v, MeasuredDoc)
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| 18 |
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| 19 | # PYTHONPATH=$REPO_ROOT
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| 20 | from asdl import format as fmt
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| 21 |
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| 22 |
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| 23 | class Lexer(object):
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| 24 | # "type declaration" of members
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| 25 |
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| 26 | def __init__(self, s):
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| 27 | # type: (str) -> None
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| 28 | self.s = s
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| 29 | self.i = 0
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| 30 | self.n = len(s)
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| 31 |
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| 32 | def Read(self):
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| 33 | # type: () -> Tuple[tok_t, str]
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| 34 | if self.i >= self.n:
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| 35 | return tok_e.Eof, '' # sentinel
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| 36 |
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| 37 | tok = self.s[self.i]
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| 38 | self.i += 1
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| 39 |
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| 40 | if tok.isdigit():
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| 41 | return tok_e.Const, tok
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| 42 | if tok.isalpha():
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| 43 | return tok_e.Var, tok
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| 44 | if tok in '+-':
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| 45 | return tok_e.Op1, tok # lower precedence
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| 46 | if tok in '*/':
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| 47 | return tok_e.Op2, tok # higher precedence
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| 48 | if tok in '()':
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| 49 | return tok_e.Paren, tok
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| 50 |
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| 51 | return tok_e.Invalid, tok
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| 52 |
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| 53 | def _MethodCallingOtherMethod(self):
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| 54 | # type: () -> None
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| 55 | # Make sure we don't get a member var called Read!
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| 56 | # This is easy because we're only checking assignment statements.
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| 57 | self.Read()
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| 58 |
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| 59 |
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| 60 | class ParseError(Exception):
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| 61 |
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| 62 | def __init__(self, msg):
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| 63 | # type: (str) -> None
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| 64 | self.msg = msg
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| 65 |
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| 66 |
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| 67 | class Parser(object):
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| 68 | """
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| 69 | Grammar from http://compilers.iecc.com/crenshaw/tutor6.txt, adapted to ANTLR
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| 70 | syntax.
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| 71 |
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| 72 | Expr = Term ('+' Term)*
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| 73 | Term = Factor ('*' Factor)*
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| 74 | Factor = VAR
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| 75 | | CONST
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| 76 | | '(' Expr ')'
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| 77 | """
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| 78 |
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| 79 | def __init__(self, lexer):
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| 80 | # type: (Lexer) -> None
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| 81 | self.lexer = lexer
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| 82 | self.tok_type = tok_e.Eof # type: tok_t
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| 83 | self.tok_val = ''
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| 84 |
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| 85 | def Next(self):
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| 86 | # type: () -> None
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| 87 | self.tok_type, self.tok_val = self.lexer.Read()
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| 88 | #log('-- %r %r', self.tok_type, self.tok_val)
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| 89 |
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| 90 | def Eat(self, tok_val):
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| 91 | # type: (str) -> None
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| 92 | if self.tok_val != tok_val:
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| 93 | #raise ParseError('Expected %r, got %r' % (tok_val, self.tok_val))
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| 94 | raise ParseError('Expected ' + tok_val)
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| 95 | self.Next()
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| 96 |
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| 97 | def ParseFactor(self):
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| 98 | # type: () -> expr_t
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| 99 |
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| 100 | #log('ParseFactor')
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| 101 | if self.tok_type == tok_e.Var:
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| 102 | n1 = expr.Var(self.tok_val)
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| 103 | self.Next()
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| 104 | return n1
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| 105 |
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| 106 | if self.tok_type == tok_e.Const:
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| 107 | n2 = expr.Const(int(self.tok_val))
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| 108 | self.Next()
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| 109 | return n2
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| 110 |
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| 111 | if self.tok_type == tok_e.Paren:
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| 112 | self.Eat('(')
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| 113 | n3 = self.ParseExpr()
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| 114 | self.Eat(')')
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| 115 | return n3
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| 116 |
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| 117 | #raise ParseError('Unexpected token %s %s' % (self.tok_type, self.tok_val))
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| 118 | raise ParseError('Unexpected token ' + self.tok_val)
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| 119 |
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| 120 | def ParseTerm(self):
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| 121 | # type: () -> expr_t
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| 122 |
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| 123 | #log('ParseTerm')
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| 124 | node = self.ParseFactor()
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| 125 |
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| 126 | # TODO: Iterate and create nodes
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| 127 | while self.tok_type == tok_e.Op2:
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| 128 | op = self.tok_val
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| 129 | self.Next()
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| 130 | n2 = self.ParseFactor()
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| 131 | node = expr.Binary(op, node, n2)
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| 132 | return node
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| 133 |
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| 134 | def ParseExpr(self):
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| 135 | # type: () -> expr_t
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| 136 |
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| 137 | #log('ParseExpr')
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| 138 | node = self.ParseTerm()
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| 139 |
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| 140 | while self.tok_type == tok_e.Op1:
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| 141 | op = self.tok_val
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| 142 | self.Next()
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| 143 | n2 = self.ParseTerm()
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| 144 | node = expr.Binary(op, node, n2)
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| 145 | return node
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| 146 |
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| 147 | def Parse(self):
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| 148 | # type: () -> expr_t
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| 149 | self.Next()
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| 150 | return self.ParseExpr()
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| 151 |
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| 152 |
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| 153 | def TestParse():
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| 154 | # type: () -> None
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| 155 |
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| 156 | lex = Lexer('abc')
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| 157 | while True:
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| 158 | tok_type, tok_val = lex.Read()
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| 159 | if tok_type == tok_e.Eof:
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| 160 | break
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| 161 | #print('%s %s' % (tok_type, tok_val))
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| 162 | log('tok_val %s', tok_val)
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| 163 |
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| 164 | CASES = [
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| 165 | '1+2',
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| 166 | '1+2*3',
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| 167 | '1*2+3',
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| 168 | '(1+2)*3',
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| 169 | 'a+b+c+d',
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| 170 | 'a*b*3*4',
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| 171 | '1',
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| 172 | 'a',
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| 173 |
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| 174 | # expect errors here:
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| 175 | '(',
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| 176 | ')',
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| 177 | '(a+b',
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| 178 | ' ',
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| 179 | ' $$ ',
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| 180 | ]
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| 181 | for expr_ in CASES:
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| 182 | lex = Lexer(expr_)
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| 183 | p = Parser(lex)
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| 184 | log('')
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| 185 | log('--')
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| 186 | log('%s =>', expr_)
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| 187 |
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| 188 | node = None # type: Optional[expr_t]
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| 189 | try:
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| 190 | node = p.Parse()
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| 191 | except ParseError as e:
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| 192 | log('Parse error: %s', e.msg)
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| 193 | continue
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| 194 |
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| 195 | #log('%s', tree)
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| 196 |
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| 197 | htree = node.PrettyTree(False)
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| 198 | f = mylib.Stdout()
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| 199 |
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| 200 | fmt.HNodePrettyPrint(htree, f)
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| 201 |
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| 202 | UP_node = node
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| 203 | with tagswitch(UP_node) as case:
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| 204 | if case(expr_e.Const):
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| 205 | node = cast(expr.Const, UP_node)
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| 206 | log('Const %d', node.i)
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| 207 |
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| 208 | elif case(expr_e.Var):
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| 209 | node = cast(expr.Var, UP_node)
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| 210 | log('Var %s', node.name)
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| 211 |
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| 212 | else:
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| 213 | log('Other')
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| 214 |
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| 215 |
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| 216 | def TestCreateNull():
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| 217 | # type: () -> None
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| 218 |
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| 219 | c = expr.Const.CreateNull(alloc_lists=True)
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| 220 | log('c.i %d', c.i)
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| 221 |
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| 222 | v = expr.Var.CreateNull(alloc_lists=True)
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| 223 | log('v.name %r', v.name)
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| 224 |
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| 225 | b = expr.Binary.CreateNull(alloc_lists=True)
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| 226 | log('b.op %r', b.op)
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| 227 | b.op = '+'
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| 228 |
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| 229 | # Must assign these
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| 230 | b.left = c
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| 231 | b.right = v
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| 232 |
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| 233 | htree = b.PrettyTree(False)
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| 234 | f = mylib.Stdout()
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| 235 | fmt.HNodePrettyPrint(htree, f)
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| 236 |
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| 237 |
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| 238 | def TestSubtype():
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| 239 | # type: () -> None
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| 240 |
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| 241 | # TODO:
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| 242 | c = CompoundWord.New()
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| 243 | #c = CompoundWord.Take([])
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| 244 | c.append('foo')
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| 245 | c.append('bar')
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| 246 |
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| 247 | log('len(c) = %d', len(c))
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| 248 |
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| 249 | # It behaves like a container
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| 250 | s1 = c[1]
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| 251 | log('s1 = %r', s1)
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| 252 |
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| 253 | c[1] = 'zz'
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| 254 | log('c[1] = %r', c[1])
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| 255 |
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| 256 | # Iterate over it like a List
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| 257 | for s in c:
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| 258 | log("s = %r", s)
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| 259 |
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| 260 | strs = ['a', 'b', 'c', 'd'] # type: List[str]
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| 261 |
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| 262 | # TODO: does this need to work? Or do we use casting?
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| 263 | #c2 = CompoundWord(strs)
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| 264 |
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| 265 | c3 = cast(CompoundWord, strs)
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| 266 | log('len(c3) = %d', len(c3))
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| 267 |
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| 268 | # Hm this opposite cast crashes in mycpp - should probably work
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| 269 | #strs2 = cast(List[str], c)
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| 270 | #log('len(strs2) = %d', len(strs2))
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| 271 |
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| 272 | # AList constructor
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| 273 |
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| 274 | c4 = CompoundWord.Take(strs)
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| 275 | log('len(c4) = %d', len(c4))
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| 276 |
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| 277 | # The length is zero after taking!
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| 278 | log('len(strs) = %d', len(strs))
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| 279 |
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| 280 | if c[0] is None:
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| 281 | log('NULL BUG')
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| 282 | else:
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| 283 | log('not null')
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| 284 |
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| 285 | log('c4[0] = %s', c4[0])
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| 286 |
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| 287 | # this is back to zero, can technically be reused
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| 288 | strs.append('e')
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| 289 | log('len(strs) = %d', len(strs))
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| 290 |
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| 291 | for s in c4:
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| 292 | print("s = %r" % s)
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| 293 |
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| 294 |
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| 295 | def TestLeafValue():
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| 296 | # type: () -> None
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| 297 |
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| 298 | f = mylib.Stdout()
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| 299 |
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| 300 | n = 10
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| 301 | for i in xrange(n):
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| 302 | m = Measure_v(i, i + 1)
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| 303 | d = MeasuredDoc('s%d' % i, m)
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| 304 |
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| 305 | tree = d.PrettyTree(False)
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| 306 | fmt.HNodePrettyPrint(tree, f)
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| 307 |
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| 308 |
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| 309 | def run_tests():
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| 310 | # type: () -> None
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| 311 |
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| 312 | TestParse()
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| 313 | TestCreateNull()
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| 314 |
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| 315 | TestSubtype()
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| 316 |
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| 317 | TestLeafValue()
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| 318 |
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| 319 |
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| 320 | def run_benchmarks():
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| 321 | # type: () -> None
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| 322 | n = 100000
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| 323 |
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| 324 | result = 0
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| 325 | i = 0
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| 326 | while i < n:
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| 327 | lex = Lexer('a*b*3*4')
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| 328 | p = Parser(lex)
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| 329 | tree = p.Parse()
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| 330 |
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| 331 | i += 1
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| 332 |
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| 333 | mylib.MaybeCollect() # manual GC point
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| 334 |
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| 335 | log('result = %d', result)
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| 336 | log('iterations = %d', n)
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| 337 |
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| 338 |
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| 339 | if __name__ == '__main__':
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| 340 | if os.getenv('BENCHMARK'):
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| 341 | log('Benchmarking...')
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| 342 | run_benchmarks()
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| 343 | else:
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| 344 | run_tests()
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